not great

* adding memory-file mapping to Windows.

* making memory-file mapping optional under windows, as it is fragile

* removing non-ascii

* saving.

* bumping up

* take 2

.github/workflows/vs17-ci.yml

@@ -13,18 +13,20 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - {gen: Visual Studio 17 2022, arch: Win32, shared: ON, build_type: Release}
+          - {gen: Visual Studio 17 2022, arch: Win32, shared: ON, build_type: Release, memory_map: OFF}
-          - {gen: Visual Studio 17 2022, arch: Win32, shared: OFF, build_type: Release}
+          - {gen: Visual Studio 17 2022, arch: Win32, shared: OFF, build_type: Release, memory_map: OFF}
-          - {gen: Visual Studio 17 2022, arch: x64, shared: ON, build_type: Release}
+          - {gen: Visual Studio 17 2022, arch: x64, shared: ON, build_type: Release, memory_map: OFF}
-          - {gen: Visual Studio 17 2022, arch: x64, shared: OFF, build_type: Debug}
+          - {gen: Visual Studio 17 2022, arch: x64, shared: OFF, build_type: Debug, memory_map: OFF}
-          - {gen: Visual Studio 17 2022, arch: x64, shared: OFF, build_type: Release}
+          - {gen: Visual Studio 17 2022, arch: x64, shared: OFF, build_type: Release, memory_map: OFF}
-          - {gen: Visual Studio 17 2022, arch: x64, shared: OFF, build_type: RelWithDebInfo}
+          - {gen: Visual Studio 17 2022, arch: x64, shared: OFF, build_type: RelWithDebInfo, memory_map: OFF}
+          # Exercise the opt-in Windows memory-file mapping path at least once in CI.
+          - {gen: Visual Studio 17 2022, arch: x64, shared: OFF, build_type: Release, memory_map: ON}
     steps:
     - name: checkout
       uses: actions/checkout@v4
     - name: Configure
       run: |
-        cmake -G "${{matrix.gen}}" -A ${{matrix.arch}} -DSIMDJSON_DEVELOPER_MODE=ON -DSIMDJSON_COMPETITION=OFF -DBUILD_SHARED_LIBS=${{matrix.shared}} -B build
+        cmake -G "${{matrix.gen}}" -A ${{matrix.arch}} -DSIMDJSON_DEVELOPER_MODE=ON -DSIMDJSON_COMPETITION=OFF -DBUILD_SHARED_LIBS=${{matrix.shared}} -DSIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS=${{matrix.memory_map}} -B build
     - name: Build Debug
       run: cmake --build build --config ${{matrix.build_type}} --verbose
     - name: Run tests

CMakeLists.txt

@@ -75,6 +75,41 @@ if(SIMDJSON_DEVELOPMENT_CHECKS)
   )
 endif()
 
+# padded_memory_map is always available on POSIX. On Windows it is disabled
+# by default because it depends on the `CreateFileMapping2` / `MapViewOfFile3`
+# APIs, which require Windows 10 version 1803 or later and are exported via
+# onecore.lib rather than the default kernel32.lib. Turn this option ON to
+# opt into the feature on Windows; simdjson will then set the appropriate
+# Windows version macros and link onecore, so everything that links
+# simdjson picks up both the compile-time declarations and the import
+# library automatically. The option is a no-op on POSIX (where the feature
+# is unconditionally enabled).
+option(SIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS
+  "Enable simdjson::padded_memory_map on Windows (requires Windows 10 \
+version 1803 or later). Always enabled on POSIX." OFF)
+if(SIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS)
+  simdjson_add_props(
+      target_compile_definitions PUBLIC
+      SIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS=1
+  )
+  if(WIN32)
+    # Raise the Windows version floor so that <windows.h> declares the
+    # modern memory-mapping APIs, and link the import library that
+    # actually exports them. _WIN32_WINNT / WINVER / NTDDI_VERSION together
+    # tell <sdkddkver.h> which APIs to light up.
+    simdjson_add_props(
+        target_compile_definitions PUBLIC
+        _WIN32_WINNT=0x0A00
+        WINVER=0x0A00
+        NTDDI_VERSION=0x0A000006 # NTDDI_WIN10_RS5, Windows 10 version 1809
+    )
+    simdjson_add_props(
+        target_link_libraries PUBLIC
+        onecore
+    )
+  endif()
+endif()
+
 if(is_top_project)
   option(SIMDJSON_INSTALL "Enable target install" ON)
   option(SIMDJSON_DEVELOPER_MODE "Enable targets for developing simdjson" OFF)

benchmark/CMakeLists.txt

@@ -1,9 +1,10 @@
 add_subdirectory(dom)
 
 
-include_directories( . linux )
+include_directories( . )
 link_libraries(simdjson-windows-headers test-data)
 link_libraries(simdjson)
+link_libraries(counters)
 if(SIMDJSON_STATIC_REFLECTION)
   add_compile_definitions(SIMDJSON_STATIC_REFLECTION=1)
 endif(SIMDJSON_STATIC_REFLECTION)
@@ -15,6 +16,7 @@ if (TARGET benchmark::benchmark)
   link_libraries(benchmark::benchmark)
   add_executable(bench_parse_call bench_parse_call.cpp)
   add_executable(bench_dom_api bench_dom_api.cpp)
+  add_executable(bench_stream_formats bench_stream_formats.cpp)
   if(SIMDJSON_EXCEPTIONS)
     add_executable(bench_ondemand bench_ondemand.cpp)
     if(TARGET yyjson)

benchmark/bench_ondemand.cpp

@@ -40,6 +40,7 @@ SIMDJSON_POP_DISABLE_WARNINGS
 #include "json2msgpack/boostjson.h"
 
 #include "partial_tweets/simdjson_ondemand.h"
+#include "partial_tweets/simdjson_ondemand_key_selector.h"
 #include "partial_tweets/simdjson_dom.h"
 #include "partial_tweets/yyjson.h"
 #if SIMDJSON_COMPETITION_ONDEMAND_SAJSON

benchmark/bench_stream_formats.cpp

@@ -0,0 +1,216 @@
+#include <benchmark/benchmark.h>
+#include <string>
+#include "simdjson.h"
+
+using namespace simdjson;
+
+namespace {
+
+enum class stream_case {
+  ndjson_small,
+  ndjson_large,
+  rfc7464_small,
+  rfc7464_large,
+  comma_delimited_small,
+  comma_delimited_large
+};
+
+constexpr size_t TARGET_BYTES = 128 * 1000 * 1000;
+constexpr size_t SMALL_PAYLOAD = 16;
+constexpr size_t LARGE_PAYLOAD = 4096;
+constexpr size_t BATCH_SIZE = 1 << 20;
+
+struct stream_dataset {
+  padded_string json;
+  size_t count{};
+};
+
+std::string make_document(size_t id, size_t payload_size) {
+  return std::string{"{\"id\":"} + std::to_string(id) +
+    ",\"name\":\"aaaaaaaa\",\"payload\":\"" +
+    std::string(payload_size, 'x') + "\",\"flag\":true}";
+}
+
+stream_dataset build_dataset(stream_case which) {
+  const bool small = which == stream_case::ndjson_small ||
+                     which == stream_case::rfc7464_small ||
+                     which == stream_case::comma_delimited_small;
+  const bool rfc = which == stream_case::rfc7464_small ||
+                   which == stream_case::rfc7464_large;
+  const bool comma = which == stream_case::comma_delimited_small ||
+                     which == stream_case::comma_delimited_large;
+  const size_t payload_size = small ? SMALL_PAYLOAD : LARGE_PAYLOAD;
+  const size_t count = TARGET_BYTES / (payload_size + 48);
+  std::string out;
+  out.reserve(count * (payload_size + 64));
+  for (size_t i = 0; i < count; i++) {
+    if (rfc) {
+      out += char(0x1E);
+    }
+    if (comma && i > 0) {
+      out += ',';
+    }
+    out += make_document(i, payload_size);
+    if (!comma) {
+      out += '\n';
+    }
+  }
+  return {padded_string(out), count};
+}
+
+const stream_dataset &get_dataset(stream_case which) {
+  static const stream_dataset ndjson_small =
+    build_dataset(stream_case::ndjson_small);
+  static const stream_dataset ndjson_large =
+    build_dataset(stream_case::ndjson_large);
+  static const stream_dataset rfc_small =
+    build_dataset(stream_case::rfc7464_small);
+  static const stream_dataset rfc_large =
+    build_dataset(stream_case::rfc7464_large);
+  static const stream_dataset comma_small =
+    build_dataset(stream_case::comma_delimited_small);
+  static const stream_dataset comma_large =
+    build_dataset(stream_case::comma_delimited_large);
+  switch (which) {
+    case stream_case::ndjson_small:
+      return ndjson_small;
+    case stream_case::ndjson_large:
+      return ndjson_large;
+    case stream_case::rfc7464_small:
+      return rfc_small;
+    case stream_case::rfc7464_large:
+      return rfc_large;
+    case stream_case::comma_delimited_small:
+      return comma_small;
+    case stream_case::comma_delimited_large:
+      return comma_large;
+  }
+  return ndjson_small;
+}
+
+void set_counters(benchmark::State &state, const stream_dataset &dataset) {
+  state.SetBytesProcessed(int64_t(state.iterations()) * int64_t(dataset.json.size()));
+  state.SetItemsProcessed(int64_t(state.iterations()) * int64_t(dataset.count));
+}
+
+template <stream_case which, bool threaded = true>
+static void bench_ondemand(benchmark::State &state) {
+  const auto &dataset = get_dataset(which);
+  ondemand::parser parser;
+  parser.threaded = threaded;
+  stream_format format = stream_format::whitespace_delimited;
+  if constexpr (which == stream_case::rfc7464_small ||
+                which == stream_case::rfc7464_large) {
+    format = stream_format::json_sequence;
+  } else if constexpr (which == stream_case::comma_delimited_small ||
+                       which == stream_case::comma_delimited_large) {
+    format = stream_format::comma_delimited;
+  }
+  for (const auto _ : state) {
+    ondemand::document_stream docs;
+    auto error = parser.iterate_many(dataset.json, BATCH_SIZE, format).get(docs);
+    if (error) {
+      state.SkipWithError(error_message(error));
+      return;
+    }
+    uint64_t sum = 0;
+    for (auto doc : docs) {
+      ondemand::object obj;
+      if ((error = doc.get_object().get(obj))) {
+        state.SkipWithError(error_message(error));
+        return;
+      }
+      uint64_t id;
+      if ((error = obj["id"].get_uint64().get(id))) {
+        state.SkipWithError(error_message(error));
+        return;
+      }
+      sum += id;
+    }
+    benchmark::DoNotOptimize(sum);
+  }
+  set_counters(state, dataset);
+}
+
+template <stream_case which>
+static void bench_dom(benchmark::State &state) {
+  const auto &dataset = get_dataset(which);
+  dom::parser parser;
+  parser.threaded = true;
+  stream_format format = stream_format::whitespace_delimited;
+  if constexpr (which == stream_case::rfc7464_small ||
+                which == stream_case::rfc7464_large) {
+    format = stream_format::json_sequence;
+  } else if constexpr (which == stream_case::comma_delimited_small ||
+                       which == stream_case::comma_delimited_large) {
+    format = stream_format::comma_delimited;
+  }
+  for (const auto _ : state) {
+    dom::document_stream docs;
+    auto error = parser.parse_many(dataset.json, BATCH_SIZE, format).get(docs);
+    if (error) {
+      state.SkipWithError(error_message(error));
+      return;
+    }
+    uint64_t sum = 0;
+    for (auto doc : docs) {
+      uint64_t id;
+      if ((error = doc["id"].get(id))) {
+        state.SkipWithError(error_message(error));
+        return;
+      }
+      sum += id;
+    }
+    benchmark::DoNotOptimize(sum);
+  }
+  set_counters(state, dataset);
+}
+
+} // namespace
+
+BENCHMARK(bench_ondemand<stream_case::ndjson_small>)
+    ->UseRealTime()
+    ->DisplayAggregatesOnly(true);
+BENCHMARK(bench_ondemand<stream_case::ndjson_large>)
+    ->UseRealTime()
+    ->DisplayAggregatesOnly(true);
+BENCHMARK(bench_ondemand<stream_case::rfc7464_small>)
+    ->UseRealTime()
+    ->DisplayAggregatesOnly(true);
+BENCHMARK(bench_ondemand<stream_case::rfc7464_large>)
+    ->UseRealTime()
+    ->DisplayAggregatesOnly(true);
+BENCHMARK(bench_ondemand<stream_case::comma_delimited_small>)
+    ->UseRealTime()
+    ->DisplayAggregatesOnly(true);
+BENCHMARK(bench_ondemand<stream_case::comma_delimited_large>)
+    ->UseRealTime()
+    ->DisplayAggregatesOnly(true);
+// Non-threaded comma_delimited for comparison
+BENCHMARK(bench_ondemand<stream_case::comma_delimited_small, false>)
+    ->UseRealTime()
+    ->DisplayAggregatesOnly(true);
+BENCHMARK(bench_ondemand<stream_case::comma_delimited_large, false>)
+    ->UseRealTime()
+    ->DisplayAggregatesOnly(true);
+
+BENCHMARK(bench_dom<stream_case::ndjson_small>)
+    ->UseRealTime()
+    ->DisplayAggregatesOnly(true);
+BENCHMARK(bench_dom<stream_case::ndjson_large>)
+    ->UseRealTime()
+    ->DisplayAggregatesOnly(true);
+BENCHMARK(bench_dom<stream_case::rfc7464_small>)
+    ->UseRealTime()
+    ->DisplayAggregatesOnly(true);
+BENCHMARK(bench_dom<stream_case::rfc7464_large>)
+    ->UseRealTime()
+    ->DisplayAggregatesOnly(true);
+BENCHMARK(bench_dom<stream_case::comma_delimited_small>)
+    ->UseRealTime()
+    ->DisplayAggregatesOnly(true);
+BENCHMARK(bench_dom<stream_case::comma_delimited_large>)
+    ->UseRealTime()
+    ->DisplayAggregatesOnly(true);
+
+BENCHMARK_MAIN();

benchmark/benchfeatures.cpp

@@ -1,4 +1,5 @@
-#include "event_counter.h"
+#include <counters/event_counter.h>
+using namespace counters;
 
 #include <cassert>
 #include <cctype>
@@ -25,7 +26,6 @@
 #include <string>
 #include <vector>
 
-#include "linux-perf-events.h"
 #ifdef __linux__
 #include <libgen.h>
 #endif
@@ -204,12 +204,8 @@ struct feature_benchmarker {
   }
   // Rate of 1-7-structural misses per 8-structural flip
   double struct1_7_miss_rate(BenchmarkStage stage) const {
-#if SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS
-    return 1;
-#else
     if (!has_events()) { return 1; }
     return struct7_miss[stage].best.branch_misses() - struct7[stage].best.branch_misses() / double(struct7_miss.stats->blocks_with_1_structural_flipped);
-#endif
   }
   // Extra cost of an 8-15 structural block over a 1-7 structural block
   double struct8_15_cost(BenchmarkStage stage) const {
@@ -221,12 +217,8 @@ struct feature_benchmarker {
   }
   // Rate of 8-15-structural misses per 8-structural flip
   double struct8_15_miss_rate(BenchmarkStage stage) const {
-#if SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS
-    return 1;
-#else
     if (!has_events()) { return 1; }
     return double(struct15_miss[stage].best.branch_misses() - struct15[stage].best.branch_misses()) / double(struct15_miss.stats->blocks_with_8_structurals_flipped);
-#endif
   }
 
   // Extra cost of a 16+-structural block over an 8-15 structural block (actual varies based on # of structurals!)
@@ -239,12 +231,8 @@ struct feature_benchmarker {
   }
   // Rate of 16-structural misses per 16-structural flip
   double struct16_miss_rate(BenchmarkStage stage) const {
-#if SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS
-    return 1;
-#else
     if (!has_events()) { return 1; }
     return double(struct23_miss[stage].best.branch_misses() - struct23[stage].best.branch_misses()) / double(struct23_miss.stats->blocks_with_16_structurals_flipped);
-#endif
   }
 
 
@@ -258,12 +246,8 @@ struct feature_benchmarker {
   }
   // Rate of UTF-8 misses per UTF-8 flip
   double utf8_miss_rate(BenchmarkStage stage) const {
-#if SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS
-    return 1;
-#else
     if (!has_events()) { return 1; }
     return double(utf8_miss[stage].best.branch_misses() - utf8[stage].best.branch_misses()) / double(utf8_miss.stats->blocks_with_utf8_flipped);
-#endif
   }
   // Extra cost of having escapes in a block
   double escape_cost(BenchmarkStage stage) const {
@@ -275,12 +259,8 @@ struct feature_benchmarker {
   }
   // Rate of escape misses per escape flip
   double escape_miss_rate(BenchmarkStage stage) const {
-#if SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS
-    return 1;
-#else
     if (!has_events()) { return 1; }
     return double(escape_miss[stage].best.branch_misses() - escape[stage].best.branch_misses()) / double(escape_miss.stats->blocks_with_escapes_flipped);
-#endif
   }
 
 
@@ -378,22 +358,6 @@ struct feature_benchmarker {
   }
 };
 
-#if SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS
-void print_file_effectiveness(BenchmarkStage stage, const char* filename, const benchmarker& results, const feature_benchmarker& features) {
-  double actual = results[stage].best.elapsed_ns() / double(results.stats->blocks);
-  double calc = features.calc_expected(stage, results);
-  double calc_misses = features.calc_expected_misses(stage, results);
-  double calc_miss_cost = features.calc_expected_miss_cost(stage, results);
-  printf("        | %-8s ", benchmark_stage_name(stage));
-  printf("| %-15s ",   filename);
-  printf("|    %8.3g ", features.calc_expected_feature_cost(stage, results));
-  printf("|    %8.3g ", calc_miss_cost);
-  printf("| %8.3g ",  calc);
-  printf("| %8.3g ",  actual);
-  printf("| %+8.3g ", actual - calc);
-  printf("| %13llu ", (long long unsigned)(calc_misses));
-}
-#else
 void print_file_effectiveness(BenchmarkStage stage, const char* filename, const benchmarker& results, const feature_benchmarker& features) {
   double actual = results[stage].best.elapsed_ns() / double(results.stats->blocks);
   double calc = features.calc_expected(stage, results);
@@ -417,7 +381,6 @@ void print_file_effectiveness(BenchmarkStage stage, const char* filename, const
   }
   printf("|\n");
 }
-#endif
 
 int main(int argc, char *argv[]) {
   // Read options

benchmark/benchmark.h

@@ -1,7 +1,8 @@
 #ifndef _BENCHMARK_H_
 #define _BENCHMARK_H_
 
-#include "event_counter.h"
+#include <counters/event_counter.h>
+using namespace counters;
 
 /*
  * Prints the best number of operations per cycle where

benchmark/benchmarker.h

@@ -1,7 +1,8 @@
 #ifndef __BENCHMARKER_H
 #define __BENCHMARKER_H
 
-#include "event_counter.h"
+#include <counters/event_counter.h>
+using namespace counters;
 #include "simdjson.h"
 
 #include <cassert>
@@ -28,11 +29,9 @@
 #include <string>
 #include <vector>
 
-#include "linux-perf-events.h"
 #ifdef __linux__
 #include <libgen.h>
 #endif
-#include "simdjson.h"
 
 #include <functional>
 
@@ -423,18 +422,12 @@ struct benchmarker {
         stage.instructions() / static_cast<double>(stats->structurals),
         stage.instructions() / static_cast<double>(stage.cycles())
       );
-#if !SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS
+      printf("%s%-13s: %7.0f branch misses (%6.2f%%)\n",
-      // NOTE: removed cycles/miss because it is a somewhat misleading stat
-      printf("%s%-13s: %7.0f branch misses (%6.2f%%) - %.0f cache misses (%6.2f%%) - %.2f cache references\n",
         prefix,
         "Misses",
         stage.branch_misses(),
-        percent(stage.branch_misses(), all_stages_without_allocation.branch_misses()),
+        percent(stage.branch_misses(), all_stages_without_allocation.branch_misses())
-        stage.cache_misses(),
-        percent(stage.cache_misses(), all_stages_without_allocation.cache_misses()),
-        stage.cache_references()
       );
-#endif
     }
   }
 

benchmark/car_builder/benchmark_car_builder.cpp

@@ -1,4 +1,5 @@
-#include "event_counter.h"
+#include <counters/event_counter.h>
+using namespace counters;
 #include <random>
 #include <vector>
 

benchmark/dom/CMakeLists.txt

@@ -1,11 +1,12 @@
-include_directories( .. ../linux )
+include_directories( .. )
 link_libraries(simdjson-windows-headers test-data)
 link_libraries(simdjson)
+link_libraries(counters)
 
 add_executable(perfdiff perfdiff.cpp)
 add_executable(parse parse.cpp)
 add_executable(parse_stream parse_stream.cpp)
-add_executable(statisticalmodel statisticalmodel.cpp)
+
 
 add_executable(parse_noutf8validation parse.cpp)
 target_compile_definitions(parse_noutf8validation PRIVATE SIMDJSON_SKIPUTF8VALIDATION)

benchmark/dom/parse.cpp

@@ -1,4 +1,5 @@
-#include "event_counter.h"
+#include <counters/event_counter.h>
+using namespace counters;
 
 #include <cassert>
 #include <cctype>
@@ -24,7 +25,6 @@
 #include <string>
 #include <vector>
 
-#include "linux-perf-events.h"
 #ifdef __linux__
 #include <libgen.h>
 #endif

benchmark/dom/statisticalmodel.cpp

@@ -1,207 +0,0 @@
-#include <iostream>
-#include <unistd.h>
-#include "simdjson.h"
-#ifdef __linux__
-#include "linux-perf-events.h"
-#endif
-
-size_t count_nonasciibytes(const uint8_t *input, size_t length) {
-  size_t count = 0;
-  for (size_t i = 0; i < length; i++) {
-    count += input[i] >> 7;
-  }
-  return count;
-}
-
-size_t count_backslash(const uint8_t *input, size_t length) {
-  size_t count = 0;
-  for (size_t i = 0; i < length; i++) {
-    count += (input[i] == '\\') ? 1 : 0;
-  }
-  return count;
-}
-
-struct stat_s {
-  size_t integer_count;
-  size_t float_count;
-  size_t string_count;
-  size_t backslash_count;
-  size_t non_ascii_byte_count;
-  size_t object_count;
-  size_t array_count;
-  size_t null_count;
-  size_t true_count;
-  size_t false_count;
-  size_t byte_count;
-  size_t structural_indexes_count;
-  bool valid;
-};
-
-using stat_t = struct stat_s;
-
-
-
-simdjson_inline void simdjson_process_atom(stat_t &s,
-                                         simdjson::dom::element element) {
-  if (element.is<int64_t>()) {
-    s.integer_count++;
-  } else if(element.is<std::string_view>()) {
-    s.string_count++;
-  } else if(element.is<double>()) {
-    s.float_count++;
-  } else if (element.is<bool>()) {
-    bool v;
-    simdjson::error_code error;
-    if ((error = element.get(v))) { std::cerr << error << std::endl; abort(); }
-    if (v) {
-      s.true_count++;
-    } else {
-      s.false_count++;
-    }
-  } else if (element.is_null()) {
-    s.null_count++;
-  }
-}
-
-void simdjson_recurse(stat_t &s, simdjson::dom::element element) {
-  simdjson::error_code error;
-  if (element.is<simdjson::dom::array>()) {
-    s.array_count++;
-    simdjson::dom::array array;
-    if ((error = element.get(array))) { std::cerr << error << std::endl; abort(); }
-    for (auto child : array) {
-      if (child.is<simdjson::dom::array>() || child.is<simdjson::dom::object>()) {
-        simdjson_recurse(s, child);
-      } else {
-        simdjson_process_atom(s, child);
-      }
-    }
-  } else if (element.is<simdjson::dom::object>()) {
-    s.object_count++;
-    simdjson::dom::object object;
-    if ((error = element.get(object))) { std::cerr << error << std::endl; abort(); }
-    for (auto field : object) {
-      s.string_count++; // for key
-      if (field.value.is<simdjson::dom::array>() || field.value.is<simdjson::dom::object>()) {
-        simdjson_recurse(s, field.value);
-      } else {
-        simdjson_process_atom(s, field.value);
-      }
-    }
-  } else {
-    simdjson_process_atom(s, element);
-  }
-}
-
-stat_t simdjson_compute_stats(const simdjson::padded_string &p) {
-  stat_t answer{};
-  simdjson::dom::parser parser;
-  simdjson::dom::element doc;
-  auto error = parser.parse(p).get(doc);
-  if (error) {
-    answer.valid = false;
-    return answer;
-  }
-  answer.valid = true;
-  answer.backslash_count =
-      count_backslash(reinterpret_cast<const uint8_t *>(p.data()), p.size());
-  answer.non_ascii_byte_count = count_nonasciibytes(
-      reinterpret_cast<const uint8_t *>(p.data()), p.size());
-  answer.byte_count = p.size();
-  answer.structural_indexes_count = parser.implementation->n_structural_indexes;
-  simdjson_recurse(answer, doc);
-  return answer;
-}
-
-int main(int argc, char *argv[]) {
-#ifndef _MSC_VER
-  int c;
-  while ((c = getopt(argc, argv, "")) != -1) {
-    switch (c) {
-
-    default:
-      abort();
-    }
-  }
-#else
-  int optind = 1;
-#endif
-  if (optind >= argc) {
-    std::cerr << "Reads json, prints stats. " << std::endl;
-    std::cerr << "Usage: " << argv[0] << " <jsonfile>" << std::endl;
-
-    exit(1);
-  }
-  const char *filename = argv[optind];
-  if (optind + 1 < argc) {
-    std::cerr << "warning: ignoring everything after " << argv[optind + 1]
-              << std::endl;
-  }
-  simdjson::padded_string p;
-  auto error = simdjson::padded_string::load(filename).get(p);
-  if (error) {
-    std::cerr << "Could not load the file " << filename << std::endl;
-    return EXIT_FAILURE;
-  }
-  stat_t s = simdjson_compute_stats(p);
-  if (!s.valid) {
-    std::cerr << "not a valid JSON" << std::endl;
-    return EXIT_FAILURE;
-  }
-
-  printf("# integer_count float_count string_count backslash_count "
-         "non_ascii_byte_count object_count array_count null_count true_count "
-         "false_count byte_count structural_indexes_count ");
-#ifdef __linux__
-  printf("  stage1_cycle_count stage1_instruction_count  stage2_cycle_count "
-         " stage2_instruction_count  stage3_cycle_count "
-         "stage3_instruction_count  ");
-#else
-  printf("(you are not under linux, so perf counters are disaabled)");
-#endif
-  printf("\n");
-  printf("%zu %zu %zu %zu %zu %zu %zu %zu %zu %zu %zu %zu ", s.integer_count,
-         s.float_count, s.string_count, s.backslash_count,
-         s.non_ascii_byte_count, s.object_count, s.array_count, s.null_count,
-         s.true_count, s.false_count, s.byte_count, s.structural_indexes_count);
-#ifdef __linux__
-  simdjson::dom::parser parser;
-  simdjson::error_code alloc_error = parser.allocate(p.size());
-  if (alloc_error) {
-    std::cerr << alloc_error << std::endl;
-    return EXIT_FAILURE;
-  }
-  const uint32_t iterations = p.size() < 1 * 1000 * 1000 ? 1000 : 50;
-  std::vector<int> evts;
-  evts.push_back(PERF_COUNT_HW_CPU_CYCLES);
-  evts.push_back(PERF_COUNT_HW_INSTRUCTIONS);
-  LinuxEvents<PERF_TYPE_HARDWARE> unified(evts);
-  unsigned long cy1 = 0, cy2 = 0;
-  unsigned long cl1 = 0, cl2 = 0;
-  std::vector<unsigned long long> results;
-  results.resize(evts.size());
-  for (uint32_t i = 0; i < iterations; i++) {
-    unified.start();
-    // The default template is simdjson::architecture::NATIVE.
-    bool isok = (parser.implementation->stage1((const uint8_t *)p.data(), p.size(), simdjson::stage1_mode::regular) == simdjson::SUCCESS);
-    unified.end(results);
-
-    cy1 += results[0];
-    cl1 += results[1];
-
-    unified.start();
-    isok = isok && (parser.implementation->stage2(parser.doc) == simdjson::SUCCESS);
-    unified.end(results);
-
-    cy2 += results[0];
-    cl2 += results[1];
-    if (!isok) {
-      std::cerr << "failure?" << std::endl;
-    }
-  }
-  printf("%f %f %f %f ", static_cast<double>(cy1) / static_cast<double>(iterations), static_cast<double>(cl1) / static_cast<double>(iterations),
-         static_cast<double>(cy2) / static_cast<double>(iterations), static_cast<double>(cl2) / static_cast<double>(iterations));
-#endif // __linux__
-  printf("\n");
-  return EXIT_SUCCESS;
-}

benchmark/event_counter.h

@@ -1,201 +0,0 @@
-#ifndef __EVENT_COUNTER_H
-#define __EVENT_COUNTER_H
-
-#ifndef SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS
-#ifdef __aarch64__
-// on ARM, we use just cycles and instructions
-#define SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS 1
-#else
-// elsewhere, we try to use four counters.
-#define SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS 0
-#endif
-#endif
-#include <cassert>
-#include <cctype>
-#ifndef _MSC_VER
-#include <dirent.h>
-#endif
-#include <unistd.h>
-#include <cinttypes>
-
-#include <cstdio>
-#include <cstdlib>
-#include <cstring>
-
-#include <algorithm>
-#include <chrono>
-#include <cstring>
-#include <fstream>
-#include <iomanip>
-#include <iostream>
-#include <map>
-#include <set>
-#include <sstream>
-#include <string>
-#include <vector>
-
-#ifdef __linux__
-#include "linux-perf-events.h"
-#include <libgen.h>
-#endif
-
-#if __APPLE__ &&  __aarch64__
-#include "apple/apple_arm_events.h"
-#endif
-
-#include "simdjson.h"
-
-using std::string;
-using std::vector;
-using std::chrono::steady_clock;
-using std::chrono::time_point;
-using std::chrono::duration;
-
-struct event_count {
-  duration<double> elapsed;
-  vector<unsigned long long> event_counts;
-  event_count() : elapsed(0), event_counts{0,0,0,0,0} {}
-  event_count(const duration<double> _elapsed, const vector<unsigned long long> _event_counts) : elapsed(_elapsed), event_counts(_event_counts) {}
-  event_count(const event_count& other): elapsed(other.elapsed), event_counts(other.event_counts) { }
-
-  // The types of counters (so we can read the getter more easily)
-  #if SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS
-  enum event_counter_types {
-    CPU_CYCLES,
-    INSTRUCTIONS
-  };
-  #else
-  enum event_counter_types {
-    CPU_CYCLES,
-    INSTRUCTIONS,
-    BRANCH_MISSES,
-    CACHE_REFERENCES,
-    CACHE_MISSES
-  };
-  #endif
-  double elapsed_sec() const { return duration<double>(elapsed).count(); }
-  double elapsed_ns() const { return duration<double, std::nano>(elapsed).count(); }
-  double cycles() const { return static_cast<double>(event_counts[CPU_CYCLES]); }
-  double instructions() const { return static_cast<double>(event_counts[INSTRUCTIONS]); }
-#if !SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS
-  double branch_misses() const { return static_cast<double>(event_counts[BRANCH_MISSES]); }
-  double cache_references() const { return static_cast<double>(event_counts[CACHE_REFERENCES]); }
-  double cache_misses() const { return static_cast<double>(event_counts[CACHE_MISSES]); }
-#endif
-  event_count& operator=(const event_count& other) {
-    this->elapsed = other.elapsed;
-    this->event_counts = other.event_counts;
-    return *this;
-  }
-  event_count operator+(const event_count& other) const {
-    return event_count(elapsed+other.elapsed, {
-      event_counts[0]+other.event_counts[0],
-      event_counts[1]+other.event_counts[1],
-      event_counts[2]+other.event_counts[2],
-      event_counts[3]+other.event_counts[3],
-      event_counts[4]+other.event_counts[4],
-    });
-  }
-
-  void operator+=(const event_count& other) {
-    *this = *this + other;
-  }
-};
-
-struct event_aggregate {
-  int iterations = 0;
-  event_count total{};
-  event_count best{};
-  event_count worst{};
-
-  event_aggregate() {}
-
-  void operator<<(const event_count& other) {
-    if (iterations == 0 || other.elapsed < best.elapsed) {
-      best = other;
-    }
-    if (iterations == 0 || other.elapsed > worst.elapsed) {
-      worst = other;
-    }
-    iterations++;
-    total += other;
-  }
-
-  double elapsed_sec() const { return total.elapsed_sec() / iterations; }
-  double total_elapsed_ns() const { return total.elapsed_ns(); }
-  double elapsed_ns() const { return total.elapsed_ns() / iterations; }
-  double cycles() const { return total.cycles() / iterations; }
-  double instructions() const { return total.instructions() / iterations; }
-#if !SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS
-  double branch_misses() const { return total.branch_misses() / iterations; }
-  double cache_references() const { return total.cache_references() / iterations; }
-  double cache_misses() const { return total.cache_misses() / iterations; }
-#endif
-};
-
-struct event_collector {
-  event_count count{};
-  time_point<steady_clock> start_clock{};
-
-#if defined(__linux__)
-  LinuxEvents<PERF_TYPE_HARDWARE> linux_events;
-  event_collector() : linux_events(vector<int>{
-  #if SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS
-    PERF_COUNT_HW_CPU_CYCLES,
-    PERF_COUNT_HW_INSTRUCTIONS,
-  #else
-    PERF_COUNT_HW_CPU_CYCLES,
-    PERF_COUNT_HW_INSTRUCTIONS,
-    PERF_COUNT_HW_BRANCH_MISSES,
-    PERF_COUNT_HW_CACHE_REFERENCES,
-    PERF_COUNT_HW_CACHE_MISSES
-  #endif
-  }) {}
-  bool has_events() {
-    return linux_events.is_working();
-  }
-#elif __APPLE__ &&  __aarch64__
-  AppleEvents apple_events;
-  performance_counters diff;
-  event_collector() : diff(0) {
-    apple_events.setup_performance_counters();
-  }
-  bool has_events() {
-    return apple_events.setup_performance_counters();
-  }
-#else
-  event_collector() {}
-  bool has_events() {
-    return false;
-  }
-#endif
-
-  simdjson_inline void start() {
-#if defined(__linux)
-    linux_events.start();
-#elif __APPLE__ &&  __aarch64__
-    if(has_events()) { diff = apple_events.get_counters(); }
-#endif
-    start_clock = steady_clock::now();
-  }
-  simdjson_inline event_count& end() {
-    time_point<steady_clock> end_clock = steady_clock::now();
-#if defined(__linux)
-    linux_events.end(count.event_counts);
-#elif __APPLE__ &&  __aarch64__
-    if(has_events()) {
-      performance_counters end = apple_events.get_counters();
-      diff = end - diff;
-    }
-    count.event_counts[0] = diff.cycles;
-    count.event_counts[1] = diff.instructions;
-    count.event_counts[2] = diff.missed_branches;
-    count.event_counts[3] = 0;
-    count.event_counts[4] = 0;
-#endif
-    count.elapsed = end_clock - start_clock;
-    return count;
-  }
-};
-
-#endif

benchmark/from/benchmark_helpers.h

@@ -1,7 +1,8 @@
 #ifndef BENCHMARK_HELPERS_H
 #define BENCHMARK_HELPERS_H
 
-#include "event_counter.h"
+#include <counters/event_counter.h>
+using namespace counters;
 #include <atomic>
 
 event_collector collector;

benchmark/json_benchmark/run_json_benchmark.h

@@ -1,7 +1,8 @@
 #pragma once
 
 #include "simdjson.h"
-#include "event_counter.h"
+#include <counters/event_counter.h>
+using namespace counters;
 #include <iostream>
 
 namespace json_benchmark {
@@ -58,11 +59,7 @@ template<typename B, typename R> static void run_json_benchmark(benchmark::State
   if (collector.has_events()) {
     state.counters["instructions"] = events.instructions();
     state.counters["cycles"]       = events.cycles();
-#if !SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS
     state.counters["branch_miss"]  = events.branch_misses();
-    state.counters["cache_miss"]   = events.cache_misses();
-    state.counters["cache_ref"]    = events.cache_references();
-#endif
     state.counters["instructions_per_byte"]  = events.instructions() / double(bench.bytes_per_iteration());
     state.counters["instructions_per_cycle"] = events.instructions() / events.cycles();
     state.counters["cycles_per_byte"]        = events.cycles()       / double(bench.bytes_per_iteration());
@@ -70,11 +67,7 @@ template<typename B, typename R> static void run_json_benchmark(benchmark::State
 
     state.counters["best_instructions"] = events.best.instructions();
     state.counters["best_cycles"]       = events.best.cycles();
-#if !SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS
     state.counters["best_branch_miss"]  = events.best.branch_misses();
-    state.counters["best_cache_miss"]   = events.best.cache_misses();
-    state.counters["best_cache_ref"]    = events.best.cache_references();
-#endif
 
     state.counters["best_instructions_per_byte"]  = events.best.instructions() / double(bench.bytes_per_iteration());
     state.counters["best_instructions_per_cycle"] = events.best.instructions() / events.best.cycles();
@@ -95,11 +88,7 @@ template<typename B, typename R> static void run_json_benchmark(benchmark::State
   if (collector.has_events()) {
     label << " instructions=" << setw(12) << uint64_t(events.best.instructions())     << setw(0);
     label << " cycles="       << setw(12) << uint64_t(events.best.cycles())           << setw(0);
-#if !SIMDJSON_SIMPLE_PERFORMANCE_COUNTERS
     label << " branch_miss="  << setw(8)  << uint64_t(events.best.branch_misses())    << setw(0);
-    label << " cache_miss="   << setw(8)  << uint64_t(events.best.cache_misses())     << setw(0);
-    label << " cache_ref="    << setw(10) << uint64_t(events.best.cache_references()) << setw(0);
-#endif
   }
 
   label << " items=" << setw(10) << bench.items_per_iteration() << setw(0);

benchmark/large_amazon_cellphones/large_amazon_cellphones.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "json_benchmark/string_runner.h"
+#include <fstream>
 #include <map>
 #include <string>
 

benchmark/linux/linux-perf-events.h

@@ -1,105 +0,0 @@
-#pragma once
-#ifdef __linux__
-
-#include <asm/unistd.h>       // for __NR_perf_event_open
-#include <linux/perf_event.h> // for perf event constants
-#include <sys/ioctl.h>        // for ioctl
-#include <unistd.h>           // for syscall
-
-#include <cerrno>  // for errno
-#include <cstring> // for memset
-#include <stdexcept>
-
-#include <iostream>
-#include <vector>
-
-template <int TYPE = PERF_TYPE_HARDWARE> class LinuxEvents {
-  int fd;
-  bool working;
-  perf_event_attr attribs{};
-  size_t num_events{};
-  std::vector<uint64_t> temp_result_vec{};
-  std::vector<uint64_t> ids{};
-
-public:
-  explicit LinuxEvents(std::vector<int> config_vec) : fd(0), working(true) {
-    memset(&attribs, 0, sizeof(attribs));
-    attribs.type = TYPE;
-    attribs.size = sizeof(attribs);
-    attribs.disabled = 1;
-    attribs.exclude_kernel = 1;
-    attribs.exclude_hv = 1;
-
-    attribs.sample_period = 0;
-    attribs.read_format = PERF_FORMAT_GROUP | PERF_FORMAT_ID;
-    const int pid = 0;  // the current process
-    const int cpu = -1; // all CPUs
-    const unsigned long flags = 0;
-
-    int group = -1; // no group
-    num_events = config_vec.size();
-    ids.resize(config_vec.size());
-    uint32_t i = 0;
-    for (auto config : config_vec) {
-      attribs.config = config;
-      int _fd = static_cast<int>(syscall(__NR_perf_event_open, &attribs, pid, cpu, group, flags));
-      if (_fd == -1) {
-        report_error("perf_event_open");
-      }
-      ioctl(_fd, PERF_EVENT_IOC_ID, &ids[i++]);
-      if (group == -1) {
-        group = _fd;
-        fd = _fd;
-      }
-    }
-
-    temp_result_vec.resize(num_events * 2 + 1);
-  }
-
-  ~LinuxEvents() { if (fd != -1) { close(fd); } }
-
-  inline void start() {
-    if (fd != -1) {
-      if (ioctl(fd, PERF_EVENT_IOC_RESET, PERF_IOC_FLAG_GROUP) == -1) {
-        report_error("ioctl(PERF_EVENT_IOC_RESET)");
-      }
-
-      if (ioctl(fd, PERF_EVENT_IOC_ENABLE, PERF_IOC_FLAG_GROUP) == -1) {
-        report_error("ioctl(PERF_EVENT_IOC_ENABLE)");
-      }
-    }
-  }
-
-  inline void end(std::vector<unsigned long long> &results) {
-    if (fd != -1) {
-      if (ioctl(fd, PERF_EVENT_IOC_DISABLE, PERF_IOC_FLAG_GROUP) == -1) {
-        report_error("ioctl(PERF_EVENT_IOC_DISABLE)");
-      }
-
-      if (read(fd, temp_result_vec.data(), temp_result_vec.size() * 8) == -1) {
-        report_error("read");
-      }
-    }
-    // our actual results are in slots 1,3,5, ... of this structure
-    for (uint32_t i = 1; i < temp_result_vec.size(); i += 2) {
-      results[i / 2] = temp_result_vec[i];
-    }
-    for (uint32_t i = 2; i < temp_result_vec.size(); i += 2) {
-      if(ids[i/2-1] != temp_result_vec[i]) {
-        report_error("event mismatch");
-      }
-    }
-
-
-  }
-
-  bool is_working() {
-    return working;
-  }
-
-private:
-  void report_error(const std::string &) {
-    working = false;
-  }
-};
-#endif

benchmark/static_reflect/benchmark_utils/benchmark_helper.h

@@ -1,6 +1,7 @@
 #ifndef BENCHMARK_HELPER_HPP
 #define BENCHMARK_HELPER_HPP
-#include "event_counter.h"
+#include <counters/event_counter.h>
+using namespace counters;
 #include <atomic>
 
 inline event_collector &get_collector() {

dependencies/CMakeLists.txt

@@ -20,6 +20,14 @@ if(SIMDJSON_GOOGLE_BENCHMARKS)
   )
 endif()
 
+CPMAddPackage(
+        NAME counters
+        URL https://github.com/lemire/counters/archive/refs/tags/v3.1.0.zip
+        OPTIONS
+        "COUNTERS_BUILD_TESTS OFF"
+        "COUNTERS_INSTALL OFF"
+)
+
 CPMAddPackage(
         NAME simdjson-data
         URL https://github.com/simdjson/simdjson-data/archive/351949906abde446f0314bf79606fb5d884f5be7.zip

doc/basics.md

@@ -269,10 +269,35 @@ ondemand::document doc = parser.iterate(simdjson::pad(json));
 We recommend against creating many `std::string` or many `std::padded_string` instances in your application to store your JSON data.
 Consider reusing the same buffers and limiting memory allocations.
 
-**Memory-file mapping (non-Windows).** You can use memory-file mapping to create a `simdjson::padded_string_view`
+**Memory-file mapping.** You can use `simdjson::padded_memory_map` to create a
-from a file on disk:
+`simdjson::padded_string_view` from a file on disk. On POSIX systems (Linux,
+macOS, BSD, ...) it uses `mmap` for true zero-copy access and is always
+available. On Windows it is an **opt-in** feature because it relies on the
+`CreateFileMapping2` / `MapViewOfFile3` APIs (Windows 10, version 1803 or
+later) which are exported from `onecore.lib` rather than the default
+`kernel32.lib`. To enable it, you must satisfy **all** of the following:
+
+1. Building simdjson with `-DSIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS=ON`, or
+   defining `SIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS=1` and raising
+   `NTDDI_VERSION` to at least `NTDDI_WIN10_RS4` (Windows 10, version 1803)
+   and linking `onecore.lib` manually if you are consuming simdjson as a
+   pre-built library.
+2. `#include <windows.h>` before including simdjson, in every translation
+   unit that uses `padded_memory_map`.
+
+The Windows implementation then uses `CreateFileMapping2` / `MapViewOfFile3`
+for true zero-copy access whenever possible, with a transparent
+buffered-read fallback for files that end too close to a page boundary.
+
+The availability of the class can be tested with the preprocessor macro
+`SIMDJSON_HAS_PADDED_MEMORY_MAP`.
 
 ```cpp
+#ifdef _WIN32
+#include <windows.h> // Must come BEFORE <simdjson.h> on Windows
+#endif
+#include "simdjson.h"
+// ...
 simdjson::padded_memory_map map(myfilename);
 if (!map.is_valid()) { /* handle error */ }
 simdjson::padded_string_view view = map.view();
@@ -305,7 +330,7 @@ Some users may want to browse code along with the compiled assembly:
 | `simdjson::pad(std::string&)`                | Adds padding if needed                                                              | Returns `padded_string_view` pointing to the (possibly resized) string                 | References original string                   | Recommended to silence sanitizers when using `std::string`.                      |
 | `padded_string(data, length)` or `padded_string(std::string)` | Automatic (copies into padded buffer)                                              | Explicit copy into owned padded buffer                                                 | Owned by `padded_string`                     | Safe when you want full ownership and padding guaranteed.                        |
 | `padded_string_view` (manual)                | User guarantees `SIMDJSON_PADDING` extra bytes after the viewed length             | User provides pointer + length + capacity                                              | Non-owning view                              | Low-level; requires careful buffer management.                                   |
-| Memory-mapped file (`padded_memory_map`)     | Automatic via mapping (non-Windows only)                                            | Creates view with sufficient padding                                                   | Non-owning (tied to map lifetime)            | Advanced; efficient for large files on Linux/macOS/etc.                          |
+| Memory-mapped file (`padded_memory_map`)     | Automatic via mapping / padded read                                                 | Creates view with sufficient padding                                                   | Non-owning (tied to map lifetime)            | Always available on POSIX (zero-copy `mmap`). On Windows, opt-in via `-DSIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS=ON` (requires Windows 10 1803+ and links `onecore.lib`) and `#include <windows.h>` before simdjson; uses `CreateFileMapping2` + `MapViewOfFile3`. |
 
 
 Documents are iterators
@@ -1415,6 +1440,8 @@ With this code, deserializing an `std::list<Car>` instance would capture only th
 that are not made by Toyota.
 
 
+**Performance tip**: You will get better performance if you order the attributes (make, model)
+in the order they appear in the JSON document.
 
 
 ### 3. Using static reflection (C++26)
@@ -1491,6 +1518,10 @@ void f() {
 }
 ```
 
+
+**Performance tip**: You will get better performance if you order the attributes (make, model)
+in the order they appear in the JSON document.
+
 #### Special cases
 
 However, there are instances where the construction cannot

doc/dom.md

@@ -127,11 +127,31 @@ codepage, and they may call SetFileApisToOEM accordingly.
 
 
 **Advanced feature:**
-On non-Windows systems, you can use memory-file mapping to create a `simdjson::padded_string_view`
+You can use `simdjson::padded_memory_map` to create a `simdjson::padded_string_view`
-from a file on disk.
+from a file on disk without copying the file contents into your own buffer.
+On POSIX systems (Linux, macOS, BSD, ...) it uses `mmap` for true zero-copy
+access. On Windows it is available as an **opt-in** feature and requires:
+
+1. Building simdjson with `-DSIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS=ON`, or
+   defining `SIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS=1` and raising
+   `NTDDI_VERSION` to at least `NTDDI_WIN10_RS4` (Windows 10, version 1803)
+   and linking `onecore.lib` manually if you are consuming simdjson as a
+   pre-built library.
+2. `#include <windows.h>` before `#include "simdjson.h"` in every
+   translation unit where you want to use `padded_memory_map`.
+
+When enabled on Windows, the implementation uses `CreateFileMapping2` and
+`MapViewOfFile3` for true zero-copy mapping whenever the file does not end
+within `SIMDJSON_PADDING` bytes of a page boundary; otherwise it falls back
+to reading the file into a padded heap buffer. If those requirements are
+not met, the class is not declared and the code below will fail to compile.
 
 ```cpp
-// if the macro _WIN32 is defined, this will not work since we do not support Windows
+#ifdef _WIN32
+#include <windows.h> // Must come BEFORE <simdjson.h> on Windows
+#endif
+#include "simdjson.h"
+// ...
 simdjson::padded_memory_map map(TWITTER_JSON);
 if (!map.is_valid()) { /* handle error */ }
 simdjson::padded_string_view view = map.view(); // view is usable while padded_memory_map is in scope
@@ -770,6 +790,9 @@ void basics_treewalk_1() {
 }
 ```
 
+Notice that we do not include `dom::element_type::BIGINT` in this example
+as `dom::element_type::BIGINT` type is only generated if the parser was
+set to support big integers (`parser.number_as_string(true)`).
 
 
 Reusing the parser for maximum efficiency

doc/iterate_many.md

@@ -22,10 +22,12 @@ Contents
   - [Threads](#threads)
 - [Support](#support)
 - [API](#api)
+- [Streaming directly from a memory-mapped file](#streaming-directly-from-a-memory-mapped-file)
 - [Use cases](#use-cases)
 - [Tracking your position](#tracking-your-position)
 - [Incomplete streams](#incomplete-streams)
 - [C++20 features](#c20-features)
+- [C++26 features (static reflection)](#c26-features-static-reflection)
 
 Motivation
 -----------
@@ -132,7 +134,7 @@ E.g., `[1,2]{"32":1}` is recognized as two documents.
 Some official formats **(non-exhaustive list)**:
 - [Newline-Delimited JSON (NDJSON)](https://github.com/ndjson/ndjson-spec/)
 - [JSON lines (JSONL)](http://jsonlines.org/)
-- [Record separator-delimited JSON (RFC 7464)](https://tools.ietf.org/html/rfc7464) <- Not supported by simdjson!
+- [Record separator-delimited JSON (RFC 7464)](https://tools.ietf.org/html/rfc7464)
 - [More on Wikipedia...](https://en.wikipedia.org/wiki/JSON_streaming)
 
 API
@@ -155,13 +157,79 @@ for (auto doc : docs) {
 See [basics.md](basics.md#newline-delimited-json-ndjson-and-json-lines) for an overview of the API.
 
 
-**Advanced feature:**
+Streaming directly from a memory-mapped file
-On non-Windows systems, you can use memory-file mapping to create a `simdjson::padded_string_view`
+--------------------------------------------
-from a file on disk.
+
+When your input is a large NDJSON / JSON-lines file on disk, the most efficient
+way to feed `iterate_many` is to use `simdjson::padded_memory_map`. It returns
+a `padded_string_view` with the right amount of trailing padding, so you can
+hand it straight to `iterate_many` without ever copying the file contents into
+your own buffer.
+
+`padded_memory_map` is available on POSIX systems (Linux, macOS, BSD, ...) by
+default. On Windows it is an **opt-in** feature with the following
+requirements:
+
+1. Build simdjson with `-DSIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS=ON`, or — if
+   you consume simdjson as a pre-built library — define
+   `SIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS=1`, raise `NTDDI_VERSION` to at
+   least `NTDDI_WIN10_RS4` (`0x0A000005`, Windows 10 version 1803), and
+   add `onecore.lib` to your link line yourself. The Windows
+   implementation uses the modern memory APIs `CreateFileMapping2` /
+   `MapViewOfFile3`, which are available starting with that version of
+   Windows and are exported by `onecore.lib`.
+2. `#include <windows.h>` before `#include "simdjson.h"` in every
+   translation unit where you want to use `padded_memory_map`. simdjson
+   deliberately does not pull in `<windows.h>` itself, so the class is
+   only declared when the Win32 types are already visible.
+
+If either requirement is not met on Windows, the `padded_memory_map` class is
+not declared at all and any code that references it fails to compile with an
+"unknown identifier" error. The availability of the class can be tested with
+the macro `SIMDJSON_HAS_PADDED_MEMORY_MAP`.
+
+On POSIX, `padded_memory_map` uses `mmap` to map the file directly into
+memory with zero copies. On Windows (when enabled), it uses
+`CreateFileMapping2` + `MapViewOfFile3` for true zero-copy mapping
+whenever the file does not end within `SIMDJSON_PADDING` bytes of a page
+boundary; for those rare cases, it transparently falls back to reading
+the file into a heap-allocated padded buffer so that the returned view
+always has `SIMDJSON_PADDING` accessible zero bytes after the file content.
+
+```cpp
+#ifdef _WIN32
+#include <windows.h> // Must come BEFORE <simdjson.h> on Windows
+#endif
+#include "simdjson.h"
+
+// ...
+
+simdjson::padded_memory_map map("huge_stream.ndjson");
+if (!map.is_valid()) { /* file missing, unreadable, too large, ... */ return; }
+
+simdjson::ondemand::parser parser;
+simdjson::ondemand::document_stream stream;
+auto error = parser.iterate_many(map.view()).get(stream);
+if (error) { std::cerr << error << std::endl; return; }
+
+for (auto doc : stream) {
+  // process each JSON document in the stream
+  std::cout << doc << std::endl;
+}
+```
+
+Important lifetime rule: the `padded_string_view` returned by `map.view()` is
+only valid while the `padded_memory_map` instance is alive, so keep `map`
+alive for as long as you are iterating the stream.
+
+The file must not be modified while the memory map is in use. If you need a
+fully independent copy of the data, use `simdjson::padded_string::load(...)`
+instead.
+
+If you prefer single-document parsing on a memory-mapped file, the same
+pattern applies to `parser.iterate(...)`:
 
 ```cpp
-// If the macro _WIN32 is defined, this will not work since we do not support memory-file mapping
-// under Windows at this time.
 simdjson::padded_memory_map map(myfilename);
 if (!map.is_valid()) { /* handle error */ }
 simdjson::padded_string_view view = map.view(); // view is usable while padded_memory_map is in scope
@@ -278,39 +346,131 @@ Importantly, you should only call `truncated_bytes()` after iterating through al
 Comma-separated documents
 -----------
 
-We also support comma-separated documents, but with some performance limitations. The `iterate_many` function  takes in an option to allow parsing of comma separated documents (which defaults on false). In this mode, the entire buffer is processed in one batch. Therefore, the total size of the document should not exceed the maximal capacity of the parser (4 GB). This mode also effectively disallow multithreading. It is therefore mostly suitable for not "very large" inputs. In this mode, the batch_size parameter
+To parse comma-separated documents like `{"a":1},{"b":2},{"c":3}`, use the `stream_format::comma_delimited` parameter:
-is effectively ignored, as it is set to at least the document size.
-
-Example:
 
 ```cpp
-    auto json = R"( 1, 2, 3, 4, "a", "b", "c", {"hello": "world"} , [1, 2, 3])"_padded;
+auto json = R"({"a":1},{"b":2},{"c":3})"_padded;
-    ondemand::parser parser;
+ondemand::parser parser;
-    ondemand::document_stream doc_stream;
+ondemand::document_stream stream;
-    // We pass '32' as the batch size, but it is a bogus parameter because, since
+auto error = parser.iterate_many(json, ondemand::DEFAULT_BATCH_SIZE,
-    // we pass 'true' to the allow_comma parameter, the batch size will be set to at least
+                                 simdjson::stream_format::comma_delimited).get(stream);
-    // the document size.
+if (error) { std::cerr << error << std::endl; return; }
-    auto error = parser.iterate_many(json, 32, true).get(doc_stream);
+for (auto doc : stream) {
-    if (error) { std::cerr << error << std::endl; return; }
+    std::cout << doc << std::endl;
-    for (auto doc : doc_stream) {
+}
-        std::cout << doc.type() << std::endl;
+// Prints: {"a":1}
-    }
+//         {"b":2}
- ```
+//         {"c":3}
-
- This will print:
-
 ```
-number
+
-number
+Whitespace around the commas is allowed:
-number
+```cpp
-number
+auto json = R"({"a":1} , {"b":2} , {"c":3})"_padded;  // Also works
-string
-string
-string
-object
-array
 ```
 
+Nested commas inside objects and arrays are preserved:
+```cpp
+auto json = R"({"arr":[1,2,3]},{"obj":{"x":1,"y":2}})"_padded;
+// Correctly parses as 2 documents, not 6
+```
+
+Mixed document types are supported:
+```cpp
+auto json = R"(1, 2, 3, 4, "a", "b", "c", {"hello": "world"}, [1, 2, 3])"_padded;
+ondemand::parser parser;
+ondemand::document_stream doc_stream;
+auto error = parser.iterate_many(json, ondemand::DEFAULT_BATCH_SIZE,
+                                 simdjson::stream_format::comma_delimited).get(doc_stream);
+if (error) { std::cerr << error << std::endl; return; }
+for (auto doc : doc_stream) {
+    std::cout << doc.type() << std::endl;
+}
+// Prints: number number number number string string string object array
+```
+
+Extra top-level separators are tolerated for compatibility with the legacy
+`allow_comma_separated` behavior. For example, leading commas, trailing commas,
+and repeated commas are treated as empty separators rather than documents.
+
+### Legacy `allow_comma_separated` parameter (deprecated)
+
+The `allow_comma_separated` boolean parameter is deprecated. When set to `true`, it now internally maps to `stream_format::comma_delimited`.
+
+The old single-batch limitation no longer applies - comma-delimited parsing now supports multi-batch processing and threading for optimal performance on large files.
+
+JSON Text Sequences (RFC 7464)
+------------------------------
+
+[RFC 7464](https://tools.ietf.org/html/rfc7464) defines a format for streaming JSON values using ASCII Record Separator (RS, 0x1E) as a delimiter. Each JSON text is preceded by RS and optionally followed by ASCII Line Feed (LF, 0x0A).
+
+Example input:
+```
+<RS>{"name":"doc1"}<LF>
+<RS>{"name":"doc2"}<LF>
+<RS>{"name":"doc3"}<LF>
+```
+
+To parse JSON text sequences, use the `stream_format::json_sequence` parameter:
+
+```cpp
+// Build input with RS (0x1E) and LF (0x0A) delimiters
+std::string input_str;
+input_str += '\x1e'; input_str += "{\"a\":1}"; input_str += '\x0a';
+input_str += '\x1e'; input_str += "{\"b\":2}"; input_str += '\x0a';
+input_str += '\x1e'; input_str += "{\"c\":3}"; input_str += '\x0a';
+simdjson::padded_string input(input_str);
+
+ondemand::parser parser;
+ondemand::document_stream stream;
+auto error = parser.iterate_many(input, ondemand::DEFAULT_BATCH_SIZE,
+                                 simdjson::stream_format::json_sequence).get(stream);
+if (error) { std::cerr << error << std::endl; return; }
+for (auto doc : stream) {
+    std::cout << doc << std::endl;
+}
+```
+
+The `stream_format` enum has the following values:
+- `stream_format::whitespace_delimited` (default): Standard NDJSON/JSON Lines format
+- `stream_format::json_sequence`: RFC 7464 format with RS delimiters
+- `stream_format::comma_delimited`: Comma-separated JSON documents
+- `stream_format::comma_delimited_array`: A single JSON array whose elements are iterated as comma-delimited documents (see below)
+
+The trailing LF after each JSON text is optional but recommended by the RFC for robustness.
+
+JSON Array As A Document Stream
+-------------------------------
+
+Sometimes an input is a single, well-formed JSON array — `[{"a":1},{"b":2},{"c":3}]` — but you want to iterate its elements one at a time without materializing the whole array. Use `stream_format::comma_delimited_array`:
+
+```cpp
+auto json = R"([{"a":1},{"b":2},{"c":3}])"_padded;
+ondemand::parser parser;
+ondemand::document_stream stream;
+auto error = parser.iterate_many(json, ondemand::DEFAULT_BATCH_SIZE,
+                                 simdjson::stream_format::comma_delimited_array).get(stream);
+if (error) { std::cerr << error << std::endl; return; }
+for (auto doc : stream) {
+    std::cout << doc << std::endl;
+}
+// Prints: {"a":1}
+//         {"b":2}
+//         {"c":3}
+```
+
+The parser strips the outer `[` and `]` plus any surrounding JSON whitespace (space, tab, LF, CR) and then behaves exactly like `stream_format::comma_delimited` over the remaining bytes. All comma-delimited features are inherited: multi-batch processing, threading, mixed scalar types, and nested commas preserved inside inner objects and arrays.
+
+```cpp
+// All of these work:
+auto a = R"([1, "x", true, null, {"k":"v"}, [1,2]])"_padded;  // mixed scalars
+auto b = R"(  [ 1, 2, 3 ] )"_padded;                          // whitespace
+auto c = R"([])"_padded;                                      // empty array → 0 docs
+```
+
+If the input is not a well-formed outer array (missing `[`, missing `]`, or empty / all-whitespace), `iterate_many` returns `TAPE_ERROR`. Content **inside** the array is not validated up front — individual document parse errors surface when you iterate, just like `comma_delimited`.
+
+Positions reported via `current_index()` are relative to the **stripped** buffer (the bytes between `[` and `]`), not the original input, for consistency with the existing BOM-stripping behavior.
+
 
 C++20 features
 --------------------
@@ -418,3 +578,161 @@ Otherwise you may use this longer version for explicit handling of errors:
     cars.push_back(c);
   }
 ```
+
+**Performance tip**: You will get better performance if you order the attributes (make, model)
+in the order they appear in the JSON document.
+
+C++26 features (static reflection)
+-----------------------------------
+
+If you have a C++26 compatible compiler with [P2996](https://wg21.link/P2996)
+static reflection support, you can compile the simdjson library with the
+`SIMDJSON_STATIC_REFLECTION` macro set to `1`. When this is the case, simdjson
+can deserialize a stream of JSON documents directly into your own structures
+**without** writing any `tag_invoke` function. The library inspects the
+non-static public members of your type at compile time and produces the
+parsing code automatically.
+
+```cpp
+#define SIMDJSON_STATIC_REFLECTION 1
+#include "simdjson.h"
+```
+
+Consider the same `Car` structure used in the C++20 example, but **without**
+any `tag_invoke` glue:
+
+```cpp
+struct Car {
+  std::string make;
+  std::string model;
+  int year;
+  std::vector<double> tire_pressure;
+};
+```
+
+With C++26 static reflection enabled, you can iterate a stream of cars and
+push them into a `std::vector<Car>` directly:
+
+```cpp
+auto json = R"( { "make": "Toyota", "model": "Camry",  "year": 2018,
+                  "tire_pressure": [ 40.1, 39.9 ] }
+                { "make": "Kia",    "model": "Soul",   "year": 2012,
+                  "tire_pressure": [ 30.1, 31.0 ] }
+                { "make": "Toyota", "model": "Tercel", "year": 1999,
+                  "tire_pressure": [ 29.8, 30.0 ] } )"_padded;
+ondemand::parser parser;
+ondemand::document_stream stream;
+auto error = parser.iterate_many(json).get(stream);
+if (error) { /* handle error */ }
+std::vector<Car> cars;
+for (auto doc : stream) {
+  Car c;
+  if ((error = doc.get<Car>().get(c))) { /* handle error */ }
+  cars.push_back(c);
+}
+```
+
+This works for every `stream_format` value supported by `iterate_many`. The
+following examples each parse the same three cars, but laid out using a
+different streaming convention.
+
+### Whitespace-delimited (default, NDJSON / JSON Lines)
+
+```cpp
+auto json = R"( { "make": "Toyota", "model": "Camry",  "year": 2018,
+                  "tire_pressure": [ 40.1, 39.9 ] }
+                { "make": "Kia",    "model": "Soul",   "year": 2012,
+                  "tire_pressure": [ 30.1, 31.0 ] }
+                { "make": "Toyota", "model": "Tercel", "year": 1999,
+                  "tire_pressure": [ 29.8, 30.0 ] } )"_padded;
+ondemand::parser parser;
+ondemand::document_stream stream;
+auto error = parser.iterate_many(json, ondemand::DEFAULT_BATCH_SIZE,
+                                 simdjson::stream_format::whitespace_delimited).get(stream);
+if (error) { /* handle error */ }
+std::vector<Car> cars;
+for (auto doc : stream) {
+  cars.push_back((Car)doc); // throws on error
+}
+```
+
+### Comma-delimited documents
+
+```cpp
+auto json = R"( { "make": "Toyota", "model": "Camry",  "year": 2018,
+                  "tire_pressure": [ 40.1, 39.9 ] },
+                { "make": "Kia",    "model": "Soul",   "year": 2012,
+                  "tire_pressure": [ 30.1, 31.0 ] },
+                { "make": "Toyota", "model": "Tercel", "year": 1999,
+                  "tire_pressure": [ 29.8, 30.0 ] } )"_padded;
+ondemand::parser parser;
+ondemand::document_stream stream;
+auto error = parser.iterate_many(json, ondemand::DEFAULT_BATCH_SIZE,
+                                 simdjson::stream_format::comma_delimited).get(stream);
+if (error) { /* handle error */ }
+std::vector<Car> cars;
+for (auto doc : stream) {
+  Car c;
+  if ((error = doc.get<Car>().get(c))) { /* handle error */ }
+  cars.push_back(c);
+}
+```
+
+### A single JSON array as a stream of documents
+
+When the input is a single JSON array, you can stream its elements one at a
+time without materializing the entire array as a `std::vector` upfront:
+
+```cpp
+auto json = R"( [ { "make": "Toyota", "model": "Camry",  "year": 2018,
+                    "tire_pressure": [ 40.1, 39.9 ] },
+                  { "make": "Kia",    "model": "Soul",   "year": 2012,
+                    "tire_pressure": [ 30.1, 31.0 ] },
+                  { "make": "Toyota", "model": "Tercel", "year": 1999,
+                    "tire_pressure": [ 29.8, 30.0 ] } ] )"_padded;
+ondemand::parser parser;
+ondemand::document_stream stream;
+auto error = parser.iterate_many(json, ondemand::DEFAULT_BATCH_SIZE,
+                                 simdjson::stream_format::comma_delimited_array).get(stream);
+if (error) { /* handle error */ }
+std::vector<Car> cars;
+for (auto doc : stream) {
+  Car c;
+  if ((error = doc.get<Car>().get(c))) { /* handle error */ }
+  cars.push_back(c);
+}
+```
+
+### JSON Text Sequences (RFC 7464)
+
+```cpp
+// Build input with RS (0x1E) and LF (0x0A) delimiters
+std::string input_str;
+auto append = [&](std::string_view doc) {
+  input_str += '\x1e'; input_str += doc; input_str += '\x0a';
+};
+append(R"({ "make": "Toyota", "model": "Camry",  "year": 2018, "tire_pressure": [ 40.1, 39.9 ] })");
+append(R"({ "make": "Kia",    "model": "Soul",   "year": 2012, "tire_pressure": [ 30.1, 31.0 ] })");
+append(R"({ "make": "Toyota", "model": "Tercel", "year": 1999, "tire_pressure": [ 29.8, 30.0 ] })");
+simdjson::padded_string input(input_str);
+
+ondemand::parser parser;
+ondemand::document_stream stream;
+auto error = parser.iterate_many(input, ondemand::DEFAULT_BATCH_SIZE,
+                                 simdjson::stream_format::json_sequence).get(stream);
+if (error) { /* handle error */ }
+std::vector<Car> cars;
+for (auto doc : stream) {
+  Car c;
+  if ((error = doc.get<Car>().get(c))) { /* handle error */ }
+  cars.push_back(c);
+}
+```
+
+In every case, the user-defined type (`Car` here) does not need a hand-written
+`tag_invoke` overload: the library generates the deserialization code from the
+type's public data members at compile time.
+
+
+**Performance tip**: You will get better performance if you order the attributes (make, model)
+in the order they appear in the JSON document.

doc/parse_many.md

@@ -18,6 +18,7 @@ Contents
 - [How it works](#how-it-works)
 - [Support](#support)
 - [API](#api)
+- [Streaming directly from a memory-mapped file](#streaming-directly-from-a-memory-mapped-file)
 - [Use cases](#use-cases)
 - [Tracking your position](#tracking-your-position)
 - [Incomplete streams](#incomplete-streams)
@@ -132,7 +133,7 @@ Whitespace Characters:
 Some official formats **(non-exhaustive list)**:
 - [Newline-Delimited JSON (NDJSON)](https://github.com/ndjson/ndjson-spec)
 - [JSON lines (JSONL)](http://jsonlines.org/)
-- [Record separator-delimited JSON (RFC 7464)](https://tools.ietf.org/html/rfc7464) <- Not supported by simdjson!
+- [Record separator-delimited JSON (RFC 7464)](https://tools.ietf.org/html/rfc7464)
 - [More on Wikipedia...](https://en.wikipedia.org/wiki/JSON_streaming)
 
 API
@@ -218,17 +219,83 @@ got full document at 29
 
 
 
-**Advanced feature:**
+Streaming directly from a memory-mapped file
-On non-Windows systems, you can use memory-file mapping to create a `simdjson::padded_string_view`
+--------------------------------------------
-from a file on disk.
+
+When your input is a large NDJSON / JSON-lines file on disk, the most
+efficient way to feed `parse_many` is to use `simdjson::padded_memory_map`.
+It returns a `padded_string_view` with the right amount of trailing padding,
+so you can pass it directly to `parse_many` without copying the file content
+into your own buffer first.
+
+`padded_memory_map` is available on POSIX systems (Linux, macOS, BSD, ...) by
+default. On Windows it is an **opt-in** feature with the following
+requirements:
+
+1. Build simdjson with `-DSIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS=ON`, or — if
+   you consume simdjson as a pre-built library — define
+   `SIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS=1`, raise `NTDDI_VERSION` to at
+   least `NTDDI_WIN10_RS4` (`0x0A000005`, Windows 10 version 1803), and
+   add `onecore.lib` to your link line yourself. The Windows
+   implementation uses the modern memory APIs `CreateFileMapping2` /
+   `MapViewOfFile3`, which are available starting with that version of
+   Windows and are exported by `onecore.lib`.
+2. `#include <windows.h>` before `#include "simdjson.h"` in every
+   translation unit where you want to use `padded_memory_map`. simdjson
+   deliberately does not pull in `<windows.h>` itself, so the class is
+   only declared when the Win32 types are already visible.
+
+If either requirement is not met on Windows, the `padded_memory_map` class is
+not declared at all and any code that references it fails to compile with an
+"unknown identifier" error. The availability of the class can be tested with
+the macro `SIMDJSON_HAS_PADDED_MEMORY_MAP`.
+
+On POSIX, `padded_memory_map` uses `mmap` to map the file directly into
+memory with zero copies. On Windows (when enabled), it uses
+`CreateFileMapping2` + `MapViewOfFile3` for true zero-copy mapping
+whenever the file does not end within `SIMDJSON_PADDING` bytes of a page
+boundary; for those rare cases, it transparently falls back to reading
+the file into a heap-allocated padded buffer so that the returned view
+always has `SIMDJSON_PADDING` accessible zero bytes after the file content.
+
+```cpp
+#ifdef _WIN32
+#include <windows.h> // Must come BEFORE <simdjson.h> on Windows
+#endif
+#include "simdjson.h"
+
+// ...
+
+simdjson::padded_memory_map map("huge_stream.ndjson");
+if (!map.is_valid()) { /* file missing, unreadable, too large, ... */ return; }
+
+simdjson::dom::parser parser;
+simdjson::dom::document_stream stream;
+auto error = parser.parse_many(map.view()).get(stream);
+if (error) { std::cerr << error << std::endl; return; }
+
+for (auto doc : stream) {
+  // process each JSON document in the stream
+  std::cout << doc << std::endl;
+}
+```
+
+Important lifetime rule: the `padded_string_view` returned by `map.view()` is
+only valid while the `padded_memory_map` instance is alive, so keep `map`
+alive for as long as you are iterating the stream.
+
+The file must not be modified while the memory map is in use. If you need a
+fully independent copy of the data, use `simdjson::padded_string::load(...)`
+instead.
+
+If you prefer single-document parsing on a memory-mapped file, the same
+pattern applies to `parser.parse(...)`:
 
 ```cpp
-// If the macro _WIN32 is defined, this will not work since we do not support memory-file mapping
-// under Windows at this time.
 simdjson::padded_memory_map map(myfilename);
 if (!map.is_valid()) { /* handle error */ }
 simdjson::padded_string_view view = map.view(); // view is usable while padded_memory_map is in scope
-ondemand::document doc = parser.iterate(view); // parse the JSON
+simdjson::dom::element doc = parser.parse(view); // parse the JSON
 ```
 
 Incomplete streams
@@ -253,3 +320,115 @@ Consider the following example where a truncated document (`{"key":"intentionall
 
 
 Importantly, you should only call `truncated_bytes()` after iterating through all of the documents since the stream cannot tell whether there are truncated documents at the very end when it may not have accessed that part of the data yet.
+
+JSON Text Sequences (RFC 7464)
+------------------------------
+
+[RFC 7464](https://tools.ietf.org/html/rfc7464) defines a format for streaming JSON values using ASCII Record Separator (RS, 0x1E) as a delimiter. Each JSON text is preceded by RS and optionally followed by ASCII Line Feed (LF, 0x0A).
+
+Example input:
+```
+<RS>{"name":"doc1"}<LF>
+<RS>{"name":"doc2"}<LF>
+<RS>{"name":"doc3"}<LF>
+```
+
+To parse JSON text sequences, use the `stream_format::json_sequence` parameter:
+
+```cpp
+// Build input with RS (0x1E) and LF (0x0A) delimiters
+std::string input_str;
+input_str += '\x1e'; input_str += "{\"a\":1}"; input_str += '\x0a';
+input_str += '\x1e'; input_str += "{\"b\":2}"; input_str += '\x0a';
+input_str += '\x1e'; input_str += "{\"c\":3}"; input_str += '\x0a';
+simdjson::padded_string input(input_str);
+
+simdjson::dom::parser parser;
+simdjson::dom::document_stream stream;
+auto error = parser.parse_many(input, simdjson::dom::DEFAULT_BATCH_SIZE,
+                               simdjson::stream_format::json_sequence).get(stream);
+if (error) { std::cerr << error << std::endl; return; }
+for (auto doc : stream) {
+    std::cout << doc << std::endl;
+}
+```
+
+The `stream_format` enum has the following values:
+- `stream_format::whitespace_delimited` (default): Standard NDJSON/JSON Lines format
+- `stream_format::json_sequence`: RFC 7464 format with RS delimiters
+- `stream_format::comma_delimited`: Comma-separated JSON documents
+- `stream_format::comma_delimited_array`: A single JSON array whose elements are iterated as comma-delimited documents (see below)
+
+The trailing LF after each JSON text is optional but recommended by the RFC for robustness.
+
+Comma-Separated Documents
+-------------------------
+
+Some systems produce JSON documents separated by commas, like `{"a":1},{"b":2},{"c":3}`. This is common when extracting elements from a JSON array or when APIs return comma-separated results.
+
+To parse comma-separated documents, use the `stream_format::comma_delimited` parameter:
+
+```cpp
+auto json = R"({"a":1},{"b":2},{"c":3})"_padded;
+simdjson::dom::parser parser;
+simdjson::dom::document_stream stream;
+auto error = parser.parse_many(json, simdjson::dom::DEFAULT_BATCH_SIZE,
+                               simdjson::stream_format::comma_delimited).get(stream);
+if (error) { std::cerr << error << std::endl; return; }
+for (auto doc : stream) {
+    std::cout << doc << std::endl;
+}
+// Prints: {"a":1}
+//         {"b":2}
+//         {"c":3}
+```
+
+Whitespace around the commas is allowed:
+```cpp
+auto json = R"({"a":1} , {"b":2} , {"c":3})"_padded;  // Also works
+```
+
+Nested commas inside objects and arrays are preserved:
+```cpp
+auto json = R"({"arr":[1,2,3]},{"obj":{"x":1,"y":2}})"_padded;
+// Correctly parses as 2 documents, not 6
+```
+
+Extra top-level separators are tolerated for compatibility with the legacy
+On-Demand comma-separated mode. Leading commas, trailing commas, and repeated
+commas are treated as empty separators rather than documents.
+
+Unlike the legacy `allow_comma_separated` parameter, `stream_format::comma_delimited` supports multi-batch processing and threading for optimal performance on large files.
+
+JSON Array As A Document Stream
+-------------------------------
+
+Sometimes an input is a single, well-formed JSON array — `[{"a":1},{"b":2},{"c":3}]` — but you want to iterate its elements one at a time without materializing the whole array. Use `stream_format::comma_delimited_array`:
+
+```cpp
+auto json = R"([{"a":1},{"b":2},{"c":3}])"_padded;
+simdjson::dom::parser parser;
+simdjson::dom::document_stream stream;
+auto error = parser.parse_many(json, simdjson::dom::DEFAULT_BATCH_SIZE,
+                               simdjson::stream_format::comma_delimited_array).get(stream);
+if (error) { std::cerr << error << std::endl; return; }
+for (auto doc : stream) {
+    std::cout << doc << std::endl;
+}
+// Prints: {"a":1}
+//         {"b":2}
+//         {"c":3}
+```
+
+The parser strips the outer `[` and `]` plus any surrounding JSON whitespace (space, tab, LF, CR) and then behaves exactly like `stream_format::comma_delimited` over the remaining bytes. All comma-delimited features are inherited: multi-batch processing, threading, mixed scalar types, and nested commas preserved inside inner objects and arrays.
+
+```cpp
+// All of these work:
+auto a = R"([1, "x", true, null, {"k":"v"}, [1,2]])"_padded;  // mixed scalars
+auto b = R"(  [ 1, 2, 3 ] )"_padded;                          // whitespace
+auto c = R"([])"_padded;                                      // empty array → 0 docs
+```
+
+If the input is not a well-formed outer array (missing `[`, missing `]`, or empty / all-whitespace), `parse_many` returns `TAPE_ERROR`. Content **inside** the array is not validated up front — individual document parse errors surface when you iterate, just like `comma_delimited`.
+
+Positions reported via `current_index()` are relative to the **stripped** buffer (the bytes between `[` and `]`), not the original input, for consistency with the existing BOM-stripping behavior.

doc/performance.md

@@ -208,7 +208,7 @@ You can still make sure of this capability in your code if you are an expert
 programmer and you are willing to silence sanitizer warnings.
 
 If you are building simdjson with C++17 or better, you can use `simdjson::padded_input`.
-The `padded_input` struct automatically manages padding for you. It can be constructed from a `std::string_view` or a C-style string with length. If the input already has sufficient padding (up to the end of the memory page), it creates a view without copying. Otherwise, it copies the data into a `padded_string` with proper padding.
+The `padded_input` struct automatically manages padding for you. It can be constructed from a `std::string_view`, a C-style string with length, or a `std::string`. For `std::string`, it takes into account the reserved capacity when determining if sufficient padding exists. If the input already has sufficient padding (up to the end of the memory page), it creates a view without copying. Otherwise, it copies the data into a `padded_string` with proper padding.
 
 Example usage:
 
@@ -216,6 +216,12 @@ Example usage:
 std::string_view json = get_json_data();
 simdjson::padded_input input(json);  // Automatically pads if needed
 auto result = parser.parse(input);
+
+// Also works with std::string, considering capacity
+std::string json_str = get_json_string();
+json_str.reserve(json_str.size() + 100);  // Reserve extra space
+simdjson::padded_input input2(json_str);  // May avoid copying if capacity is sufficient
+auto result2 = parser.parse(input2);
 ```
 
 This simplifies padding management compared to manually checking and allocating.

include/simdjson/base.h

@@ -21,6 +21,10 @@ SIMDJSON_PUSH_DISABLE_UNUSED_WARNINGS
 
 /** The maximum document size supported by simdjson. */
 constexpr size_t SIMDJSON_MAXSIZE_BYTES = 0xFFFFFFFF;
+/** The maximum depth of nested objects and arrays supported by simdjson.
+ A depth of SIMDJSON_MAXSIZE_BYTES/2 is not reasonable and would be
+ adversarial, but it serves as an upper bound for validation purposes. */
+constexpr size_t SIMDJSON_MAX_DEPTH = SIMDJSON_MAXSIZE_BYTES/2;
 
 /**
  * The amount of padding needed in a buffer to parse JSON.
@@ -46,6 +50,21 @@ struct padded_string;
 class padded_string_view;
 enum class stage1_mode;
 
+/**
+ * Stream format for parse_many/iterate_many.
+ */
+enum class stream_format {
+  whitespace_delimited, ///< Whitespace-delimited JSON documents (default, includes NDJSON/JSONL)
+  json_sequence,        ///< RFC 7464 JSON text sequences (RS-delimited)
+  comma_delimited,      ///< Comma-separated JSON documents (e.g., `{...},{...},{...}`)
+  comma_delimited_array ///< A single JSON array whose elements are iterated as
+                        ///< comma-separated documents (e.g., `[{...},{...},{...}]`).
+                        ///< The parser strips the outer `[` / `]` plus any
+                        ///< surrounding JSON whitespace (space, tab, LF, CR)
+                        ///< and then behaves like `comma_delimited` over the
+                        ///< remaining bytes.
+};
+
 namespace internal {
 
 template<typename T>

include/simdjson/concepts.h

@@ -59,6 +59,15 @@ concept appendable_containers =
     details::supports_add<T> || details::supports_append<T> ||
     details::supports_insert<T>) && !string_view_keyed_map<T>;
 
+/// Check if T is a key_selector type for efficient JSON field lookup.
+/// T must expose a compile-time N (number of keys) and static match_raw that
+/// returns [0, N) on hit or N on miss.
+template <typename T>
+concept key_selector_type = requires {
+    { T::size() } -> std::same_as<std::size_t>;
+    { T::N } -> std::convertible_to<std::size_t>;
+};
+
 /// Insert into the container however possible
 template <appendable_containers T, typename... Args>
 constexpr decltype(auto) emplace_one(T &vec, Args &&...args) {

include/simdjson/dom/document-inl.h

@@ -33,6 +33,9 @@ inline error_code document::allocate(size_t capacity) noexcept {
     allocated_capacity = 0;
     return SUCCESS;
   }
+  if (capacity > SIMDJSON_MAXSIZE_BYTES) {
+    return CAPACITY;
+  }
 
   // a pathological input like "[[[[..." would generate capacity tape elements, so
   // need a capacity of at least capacity + 1, but it is also possible to do

include/simdjson/dom/document_stream-inl.h

@@ -89,12 +89,14 @@ simdjson_inline document_stream::document_stream(
   dom::parser &_parser,
   const uint8_t *_buf,
   size_t _len,
-  size_t _batch_size
+  size_t _batch_size,
+  stream_format _format
 ) noexcept
   : parser{&_parser},
     buf{_buf},
     len{_len},
     batch_size{_batch_size <= MINIMAL_BATCH_SIZE ? MINIMAL_BATCH_SIZE : _batch_size},
+    format{_format},
     error{SUCCESS}
 #ifdef SIMDJSON_THREADS_ENABLED
     , use_thread(_parser.threaded) // we need to make a copy because _parser.threaded can change
@@ -112,6 +114,7 @@ simdjson_inline document_stream::document_stream() noexcept
     buf{nullptr},
     len{0},
     batch_size{0},
+    format{stream_format::whitespace_delimited},
     error{UNINITIALIZED}
 #ifdef SIMDJSON_THREADS_ENABLED
     , use_thread(false)
@@ -224,7 +227,14 @@ simdjson_inline std::string_view document_stream::iterator::source() const noexc
   } else {
     size_t next_doc_index = stream->batch_start + stream->parser->implementation->structural_indexes[stream->parser->implementation->next_structural_index];
     size_t svlen = next_doc_index - current_index();
-    while(svlen > 1 && (std::isspace(start[svlen-1]) || start[svlen-1] == '\0')) {
+    // Trim trailing whitespace, NUL, and RS (0x1E). In RFC 7464 json_sequence
+    // mode the scanner classifies RS as a scalar character, so an RS-prefixed
+    // scalar document (number/true/false/null/string) has no closing structural
+    // index and the slice runs all the way up to the next document's RS. RS
+    // cannot legally appear in a JSON value at the source level (control
+    // characters in strings must be escaped as \u001E), so stripping it is
+    // safe in every stream_format.
+    while(svlen > 1 && (std::isspace(start[svlen-1]) || start[svlen-1] == '\0' || static_cast<uint8_t>(start[svlen-1]) == 0x1E)) {
       svlen--;
     }
     return std::string_view(start, svlen);
@@ -274,10 +284,35 @@ inline size_t document_stream::next_batch_start() const noexcept {
 
 inline error_code document_stream::run_stage1(dom::parser &p, size_t _batch_start) noexcept {
   size_t remaining = len - _batch_start;
+  stage1_mode mode;
   if (remaining <= batch_size) {
-    return p.implementation->stage1(&buf[_batch_start], remaining, stage1_mode::streaming_final);
+    // Final batch
+    switch (format) {
+      case stream_format::json_sequence:
+        mode = stage1_mode::json_sequence_final;
+        break;
+      case stream_format::comma_delimited:
+        mode = stage1_mode::comma_delimited_final;
+        break;
+      default:
+        mode = stage1_mode::streaming_final;
+        break;
+    }
+    return p.implementation->stage1(&buf[_batch_start], remaining, mode);
   } else {
-    return p.implementation->stage1(&buf[_batch_start], batch_size, stage1_mode::streaming_partial);
+    // Partial batch
+    switch (format) {
+      case stream_format::json_sequence:
+        mode = stage1_mode::json_sequence_partial;
+        break;
+      case stream_format::comma_delimited:
+        mode = stage1_mode::comma_delimited_partial;
+        break;
+      default:
+        mode = stage1_mode::streaming_partial;
+        break;
+    }
+    return p.implementation->stage1(&buf[_batch_start], batch_size, mode);
   }
 }
 

include/simdjson/dom/document_stream.h

@@ -206,12 +206,14 @@ private:
    * @param buf is the raw byte buffer we need to process
    * @param len is the length of the raw byte buffer in bytes
    * @param batch_size is the size of the windows (must be strictly greater or equal to the largest JSON document)
+   * @param format is the stream format
    */
   simdjson_inline document_stream(
     dom::parser &parser,
     const uint8_t *buf,
     size_t len,
-    size_t batch_size
+    size_t batch_size,
+    stream_format format = stream_format::whitespace_delimited
   ) noexcept;
 
   /**
@@ -261,6 +263,8 @@ private:
   const uint8_t *buf;
   size_t len;
   size_t batch_size;
+  /** The stream format. */
+  stream_format format;
   /** The error (or lack thereof) from the current document. */
   error_code error;
   size_t batch_start{0};

include/simdjson/dom/element.h

@@ -22,6 +22,8 @@ enum class element_type {
   STRING = '"',    ///< std::string_view
   BOOL = 't',      ///< bool
   NULL_VALUE = 'n', ///< null
+  /// The BIGINT type is for integers that do not fit in 64 bits. It is only present
+  // if you set parser.number_as_string(true).
   BIGINT = 'Z'     ///< std::string_view: big integer stored as raw digit string
 };
 

include/simdjson/dom/parser-inl.h

@@ -170,12 +170,7 @@ simdjson_inline simdjson_result<element> parser::parse(const padded_string_view
 }
 
 inline simdjson_result<document_stream> parser::parse_many(const uint8_t *buf, size_t len, size_t batch_size) noexcept {
-  if(batch_size < MINIMAL_BATCH_SIZE) { batch_size = MINIMAL_BATCH_SIZE; }
+  return parse_many(buf, len, batch_size, stream_format::whitespace_delimited);
-  if((len >= 3) && (std::memcmp(buf, "\xEF\xBB\xBF", 3) == 0)) {
-    buf += 3;
-    len -= 3;
-  }
-  return document_stream(*this, buf, len, batch_size);
 }
 inline simdjson_result<document_stream> parser::parse_many(const char *buf, size_t len, size_t batch_size) noexcept {
   return parse_many(reinterpret_cast<const uint8_t *>(buf), len, batch_size);
@@ -186,6 +181,48 @@ inline simdjson_result<document_stream> parser::parse_many(const std::string &s,
 inline simdjson_result<document_stream> parser::parse_many(const padded_string &s, size_t batch_size) noexcept {
   return parse_many(s.data(), s.length(), batch_size);
 }
+inline simdjson_result<document_stream> parser::parse_many(const padded_string_view &v, size_t batch_size) noexcept {
+  return parse_many(v.data(), v.length(), batch_size);
+}
+
+inline simdjson_result<document_stream> parser::parse_many(const uint8_t *buf, size_t len, size_t batch_size, stream_format format) noexcept {
+  if(batch_size < MINIMAL_BATCH_SIZE) { batch_size = MINIMAL_BATCH_SIZE; }
+  if((len >= 3) && (std::memcmp(buf, "\xEF\xBB\xBF", 3) == 0)) {
+    buf += 3;
+    len -= 3;
+  }
+  if (format == stream_format::comma_delimited_array) {
+    // Strip leading JSON whitespace.
+    while (len > 0 && (buf[0] == ' ' || buf[0] == '\t' || buf[0] == '\n' || buf[0] == '\r')) {
+      buf++; len--;
+    }
+    // Expect the opening '['.
+    if (len == 0 || buf[0] != '[') { return TAPE_ERROR; }
+    buf++; len--;
+    // Strip trailing JSON whitespace.
+    while (len > 0 && (buf[len-1] == ' ' || buf[len-1] == '\t' || buf[len-1] == '\n' || buf[len-1] == '\r')) {
+      len--;
+    }
+    // Expect the closing ']'.
+    if (len == 0 || buf[len-1] != ']') { return TAPE_ERROR; }
+    len--;
+    // Fall through to comma_delimited over the array contents.
+    format = stream_format::comma_delimited;
+  }
+  return document_stream(*this, buf, len, batch_size, format);
+}
+inline simdjson_result<document_stream> parser::parse_many(const char *buf, size_t len, size_t batch_size, stream_format format) noexcept {
+  return parse_many(reinterpret_cast<const uint8_t *>(buf), len, batch_size, format);
+}
+inline simdjson_result<document_stream> parser::parse_many(const std::string &s, size_t batch_size, stream_format format) noexcept {
+  return parse_many(s.data(), s.length(), batch_size, format);
+}
+inline simdjson_result<document_stream> parser::parse_many(const padded_string &s, size_t batch_size, stream_format format) noexcept {
+  return parse_many(s.data(), s.length(), batch_size, format);
+}
+inline simdjson_result<document_stream> parser::parse_many(const padded_string_view &v, size_t batch_size, stream_format format) noexcept {
+  return parse_many(v.data(), v.length(), batch_size, format);
+}
 
 simdjson_inline size_t parser::capacity() const noexcept {
   return implementation ? implementation->capacity() : 0;

include/simdjson/dom/parser.h

@@ -490,10 +490,39 @@ public:
   /** @overload parse_many(const uint8_t *buf, size_t len, size_t batch_size) */
   inline simdjson_result<document_stream> parse_many(const padded_string &s, size_t batch_size = dom::DEFAULT_BATCH_SIZE) noexcept;
   inline simdjson_result<document_stream> parse_many(const padded_string &&s, size_t batch_size) = delete;// unsafe
+  /** @overload parse_many(const uint8_t *buf, size_t len, size_t batch_size)
+   *
+   * Because padded_string_view guarantees SIMDJSON_PADDING trailing bytes, this
+   * overload is safe to use with buffers that the caller owns elsewhere (for
+   * example, a padded_memory_map), with no extra copy. Without this overload,
+   * passing a padded_string_view would silently bind to the padded_string
+   * overload via an implicit conversion, allocating and copying the input, and
+   * — because that temporary is destroyed at the end of the full-expression —
+   * leaving the returned document_stream pointing at freed memory. */
+  inline simdjson_result<document_stream> parse_many(const padded_string_view &v, size_t batch_size = dom::DEFAULT_BATCH_SIZE) noexcept;
 
   /** @private We do not want to allow implicit conversion from C string to std::string. */
   simdjson_result<document_stream> parse_many(const char *buf, size_t batch_size = dom::DEFAULT_BATCH_SIZE) noexcept = delete;
 
+  /**
+   * Parse a stream of JSON documents with explicit format specification.
+   *
+   * @param buf The concatenated JSON documents.
+   * @param len The length of the buffer.
+   * @param batch_size The batch size to use.
+   * @param format The stream format.
+   * @return A stream of documents, or an error.
+   */
+  inline simdjson_result<document_stream> parse_many(const uint8_t *buf, size_t len, size_t batch_size, stream_format format) noexcept;
+  /** @overload parse_many(const uint8_t *buf, size_t len, size_t batch_size, stream_format format) */
+  inline simdjson_result<document_stream> parse_many(const char *buf, size_t len, size_t batch_size, stream_format format) noexcept;
+  /** @overload parse_many(const uint8_t *buf, size_t len, size_t batch_size, stream_format format) */
+  inline simdjson_result<document_stream> parse_many(const std::string &s, size_t batch_size, stream_format format) noexcept;
+  /** @overload parse_many(const uint8_t *buf, size_t len, size_t batch_size, stream_format format) */
+  inline simdjson_result<document_stream> parse_many(const padded_string &s, size_t batch_size, stream_format format) noexcept;
+  /** @overload parse_many(const uint8_t *buf, size_t len, size_t batch_size, stream_format format) */
+  inline simdjson_result<document_stream> parse_many(const padded_string_view &v, size_t batch_size, stream_format format) noexcept;
+
   /**
    * Ensure this parser has enough memory to process JSON documents up to `capacity` bytes in length
    * and `max_depth` depth.

include/simdjson/generic/dom_parser_implementation.h

@@ -74,6 +74,7 @@ inline simdjson_warn_unused error_code dom_parser_implementation::set_capacity(s
 }
 
 inline simdjson_warn_unused error_code dom_parser_implementation::set_max_depth(size_t max_depth) noexcept {
+  if(max_depth > SIMDJSON_MAX_DEPTH) { return CAPACITY; }
   // Stage 2 stacks
   open_containers.reset(new (std::nothrow) open_container[max_depth]);
   is_array.reset(new (std::nothrow) bool[max_depth]);

include/simdjson/generic/ondemand/amalgamated.h

@@ -20,6 +20,7 @@
 #include "simdjson/generic/ondemand/document.h"
 #include "simdjson/generic/ondemand/document_stream.h"
 #include "simdjson/generic/ondemand/field.h"
+#include "simdjson/generic/ondemand/key_selector.h"
 #include "simdjson/generic/ondemand/object.h"
 #include "simdjson/generic/ondemand/object_iterator.h"
 #include "simdjson/generic/ondemand/serialization.h"
@@ -39,6 +40,7 @@
 #include "simdjson/generic/ondemand/logger-inl.h"
 #include "simdjson/generic/ondemand/object-inl.h"
 #include "simdjson/generic/ondemand/object_iterator-inl.h"
+#include "simdjson/generic/ondemand/key_selector_iterator.h"
 #include "simdjson/generic/ondemand/parser-inl.h"
 #include "simdjson/generic/ondemand/raw_json_string-inl.h"
 #include "simdjson/generic/ondemand/token_iterator-inl.h"

include/simdjson/generic/ondemand/base.h

@@ -39,6 +39,10 @@ class raw_json_string;
 class token_iterator;
 class value;
 class value_iterator;
+#if SIMDJSON_SUPPORTS_CONCEPTS
+template <typename Selector> class selector_iterator;
+template <typename Selector> class selector_range;
+#endif
 
 } // namespace ondemand
 } // namespace SIMDJSON_IMPLEMENTATION

include/simdjson/generic/ondemand/document_stream-inl.h

@@ -95,13 +95,15 @@ simdjson_inline document_stream::document_stream(
   const uint8_t *_buf,
   size_t _len,
   size_t _batch_size,
-  bool _allow_comma_separated
+  bool _allow_comma_separated,
+  stream_format _format
 ) noexcept
   : parser{&_parser},
     buf{_buf},
     len{_len},
     batch_size{_batch_size <= MINIMAL_BATCH_SIZE ? MINIMAL_BATCH_SIZE : _batch_size},
     allow_comma_separated{_allow_comma_separated},
+    format{_format},
     error{SUCCESS}
     #ifdef SIMDJSON_THREADS_ENABLED
     , use_thread(_parser.threaded) // we need to make a copy because _parser.threaded can change
@@ -120,6 +122,7 @@ simdjson_inline document_stream::document_stream() noexcept
     len{0},
     batch_size{0},
     allow_comma_separated{false},
+    format{stream_format::whitespace_delimited},
     error{UNINITIALIZED}
     #ifdef SIMDJSON_THREADS_ENABLED
     , use_thread(false)
@@ -219,7 +222,10 @@ inline void document_stream::start() noexcept {
     error = run_stage1(*parser, batch_start);
   }
   if (error) { return; }
-  doc_index = batch_start;
+  // For json_sequence mode, structural_indexes[0] points to the actual JSON value
+  // after the RS delimiter and any following whitespace. For regular mode, it is
+  // the offset from batch_start to the first document in the batch.
+  doc_index = batch_start + parser->implementation->structural_indexes[0];
   doc = document(json_iterator(&buf[batch_start], parser));
   doc.iter._streaming = true;
 
@@ -300,7 +306,7 @@ inline void document_stream::next() noexcept {
        */
 
       if (error) { continue; } // If the error was EMPTY, we may want to load another batch.
-      doc_index = batch_start;
+      doc_index = batch_start + parser->implementation->structural_indexes[0];
     }
   }
 }
@@ -329,10 +335,35 @@ inline error_code document_stream::run_stage1(ondemand::parser &p, size_t _batch
   // This code only updates the structural index in the parser, it does not update any json_iterator
   // instance.
   size_t remaining = len - _batch_start;
+  stage1_mode mode;
   if (remaining <= batch_size) {
-    return p.implementation->stage1(&buf[_batch_start], remaining, stage1_mode::streaming_final);
+    // Final batch
+    switch (format) {
+      case stream_format::json_sequence:
+        mode = stage1_mode::json_sequence_final;
+        break;
+      case stream_format::comma_delimited:
+        mode = stage1_mode::comma_delimited_final;
+        break;
+      default:
+        mode = stage1_mode::streaming_final;
+        break;
+    }
+    return p.implementation->stage1(&buf[_batch_start], remaining, mode);
   } else {
-    return p.implementation->stage1(&buf[_batch_start], batch_size, stage1_mode::streaming_partial);
+    // Partial batch
+    switch (format) {
+      case stream_format::json_sequence:
+        mode = stage1_mode::json_sequence_partial;
+        break;
+      case stream_format::comma_delimited:
+        mode = stage1_mode::comma_delimited_partial;
+        break;
+      default:
+        mode = stage1_mode::streaming_partial;
+        break;
+    }
+    return p.implementation->stage1(&buf[_batch_start], batch_size, mode);
   }
 }
 
@@ -353,14 +384,21 @@ simdjson_inline std::string_view document_stream::iterator::source() const noexc
         depth--;
         break;
       default:    // Scalar value document
-        // TODO: We could remove trailing whitespaces
         // This returns a string spanning from start of value to the beginning of the next document (excluded)
         {
           auto next_index = stream->parser->implementation->structural_indexes[++cur_struct_index];
           // normally the length would be next_index - current_index() - 1, except for the last document
           size_t svlen = next_index - current_index();
           const char *start = reinterpret_cast<const char*>(stream->buf) + current_index();
-          while(svlen > 1 && (std::isspace(start[svlen-1]) || start[svlen-1] == '\0')) {
+          // Trim trailing whitespace, NUL, and RS (0x1E). In RFC 7464
+          // json_sequence mode the scanner classifies RS as a scalar
+          // character, so an RS-prefixed scalar document (number / true /
+          // false / null / string) has no closing structural index and the
+          // slice runs all the way up to the next document's RS. RS cannot
+          // legally appear in a JSON value at the source level (control
+          // characters in strings must be escaped as \u001E), so stripping
+          // it is safe in every stream_format.
+          while(svlen > 1 && (std::isspace(start[svlen-1]) || start[svlen-1] == '\0' || static_cast<uint8_t>(start[svlen-1]) == 0x1E)) {
             svlen--;
           }
           return std::string_view(start, svlen);
@@ -441,4 +479,4 @@ simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::document_stre
 
 }
 
-#endif // SIMDJSON_GENERIC_ONDEMAND_DOCUMENT_STREAM_INL_H
+#endif // SIMDJSON_GENERIC_ONDEMAND_DOCUMENT_STREAM_INL_H

include/simdjson/generic/ondemand/document_stream.h

@@ -229,13 +229,16 @@ private:
    * @param buf is the raw byte buffer we need to process
    * @param len is the length of the raw byte buffer in bytes
    * @param batch_size is the size of the windows (must be strictly greater or equal to the largest JSON document)
+   * @param allow_comma_separated whether to allow comma-separated documents
+   * @param format the stream format
    */
   simdjson_inline document_stream(
     ondemand::parser &parser,
     const uint8_t *buf,
     size_t len,
     size_t batch_size,
-    bool allow_comma_separated
+    bool allow_comma_separated,
+    stream_format format = stream_format::whitespace_delimited
   ) noexcept;
 
   /**
@@ -284,6 +287,7 @@ private:
   size_t len;
   size_t batch_size;
   bool allow_comma_separated;
+  stream_format format;
   /**
    * We are going to use just one document instance. The document owns
    * the json_iterator. It implies that we only ever pass a reference

include/simdjson/generic/ondemand/key_selector.h

@@ -0,0 +1,435 @@
+#ifndef SIMDJSON_GENERIC_ONDEMAND_KEY_SELECTOR_H
+#define SIMDJSON_GENERIC_ONDEMAND_KEY_SELECTOR_H
+
+#ifndef SIMDJSON_CONDITIONAL_INCLUDE
+#include "simdjson/base.h"
+#include "simdjson/common_defs.h"
+#include "simdjson/constevalutil.h"
+#include "simdjson/generic/ondemand/raw_json_string.h"
+#endif
+
+#include <array>
+#include <string_view>
+#include <cstddef>
+#include <cstdint>
+#include <cstring>
+
+#if defined(__aarch64__) || defined(__ARM_NEON)
+  #include <arm_neon.h>
+  #define SIMDJSON_KEY_SELECTOR_HAS_NEON 1
+#else
+  #define SIMDJSON_KEY_SELECTOR_HAS_NEON 0
+#endif
+#if defined(__SSE2__)
+  #include <emmintrin.h>
+  #define SIMDJSON_KEY_SELECTOR_HAS_SSE2 1
+#else
+  #define SIMDJSON_KEY_SELECTOR_HAS_SSE2 0
+#endif
+
+#if SIMDJSON_SUPPORTS_CONCEPTS
+
+namespace simdjson {
+namespace SIMDJSON_IMPLEMENTATION {
+namespace ondemand {
+
+namespace key_selector_detail {
+
+inline constexpr std::size_t MAX_POSITIONS   = 4;
+inline constexpr std::size_t MAX_TABLE_SIZE  = 256;
+inline constexpr std::uint8_t POS_LAST_CHAR  = 0xFF;
+inline constexpr std::uint8_t SENTINEL_KEY   = 0xFF;
+
+// All PHF tables live inside this structural type; a single instance becomes a
+// static constexpr member of key_selector<Keys...>, so every field below is a
+// compile-time constant at every call site.
+template <std::size_t N, std::size_t TableSize, std::size_t MaxKeyLen>
+struct phf_data {
+    std::array<std::array<std::uint8_t, 256>, MAX_POSITIONS> asso_values{};
+    std::array<std::uint8_t, MAX_POSITIONS>                  positions{};
+    std::uint8_t                                             num_positions{};
+    std::array<std::uint8_t, TableSize>                      slot_to_key{};
+    // slot_key_bytes[s] holds the key stored at slot s, zero-padded to MaxKeyLenPadded.
+    std::array<std::array<char, ((MaxKeyLen + 31) / 32) * 32>, TableSize> slot_key_bytes{};
+    std::array<std::uint8_t, TableSize>                      slot_key_len{};
+};
+
+constexpr std::size_t next_pow2(std::size_t n) noexcept {
+    std::size_t p = 1;
+    while (p < n) p <<= 1;
+    return p;
+}
+
+// Returns the chosen TableSize (power of two >= N, up to MAX_TABLE_SIZE).
+template <std::size_t N>
+constexpr std::size_t pick_table_size() noexcept {
+    std::size_t t = next_pow2(N);
+    if (t < 2) t = 2;
+    return t;
+}
+
+template <std::size_t N>
+constexpr std::size_t char_at(std::string_view key, std::uint8_t pos) noexcept {
+    if (pos == POS_LAST_CHAR) {
+        return key.empty() ? 256 : static_cast<unsigned char>(key.back());
+    }
+    return (pos < key.size()) ? static_cast<unsigned char>(key[pos]) : 256;
+}
+
+// Try one gperf-style PHF configuration. Returns true if a perfect assignment was found.
+template <std::size_t N, std::size_t TableSize>
+constexpr bool try_phf(
+    const std::array<std::string_view, N>& keys,
+    std::array<std::array<std::uint8_t, 256>, MAX_POSITIONS>& asso,
+    std::array<std::uint8_t, MAX_POSITIONS>& positions,
+    std::uint8_t& num_positions,
+    std::array<std::uint8_t, TableSize>& slot_to_key) noexcept
+{
+    // Helper: reset mapping.
+    auto reset = [&]() {
+        for (std::size_t i = 0; i < TableSize; ++i) slot_to_key[i] = SENTINEL_KEY;
+    };
+
+    // Attempt 1: length-only.
+    reset();
+    {
+        bool ok = true;
+        for (std::size_t i = 0; i < N && ok; ++i) {
+            std::size_t slot = keys[i].size() % TableSize;
+            if (slot_to_key[slot] != SENTINEL_KEY) { ok = false; break; }
+            slot_to_key[slot] = static_cast<std::uint8_t>(i);
+        }
+        if (ok) { num_positions = 0; return true; }
+    }
+
+    // Attempt 2: single position (0), vary offset.
+    for (std::size_t offset = 0; offset < TableSize; ++offset) {
+        reset();
+        for (std::size_t c = 0; c < 256; ++c)
+            asso[0][c] = static_cast<std::uint8_t>((c + offset) % TableSize);
+        positions[0] = 0;
+        num_positions = 1;
+        bool ok = true;
+        for (std::size_t i = 0; i < N && ok; ++i) {
+            std::size_t h = keys[i].size();
+            std::size_t ch = char_at<N>(keys[i], 0);
+            if (ch < 256) h += asso[0][ch];
+            std::size_t slot = h % TableSize;
+            if (slot_to_key[slot] != SENTINEL_KEY) { ok = false; break; }
+            slot_to_key[slot] = static_cast<std::uint8_t>(i);
+        }
+        if (ok) return true;
+    }
+
+    // Attempt 3: positions {0, last_char}.
+    for (std::size_t o1 = 0; o1 < TableSize; ++o1) {
+        for (std::size_t o2 = 0; o2 < TableSize; ++o2) {
+            reset();
+            for (std::size_t c = 0; c < 256; ++c) {
+                asso[0][c] = static_cast<std::uint8_t>((c + o1) % TableSize);
+                asso[1][c] = static_cast<std::uint8_t>((c + o2) % TableSize);
+            }
+            positions[0] = 0;
+            positions[1] = POS_LAST_CHAR;
+            num_positions = 2;
+            bool ok = true;
+            for (std::size_t i = 0; i < N && ok; ++i) {
+                std::size_t h = keys[i].size();
+                std::size_t c1 = char_at<N>(keys[i], 0);
+                if (c1 < 256) h += asso[0][c1];
+                std::size_t c2 = char_at<N>(keys[i], POS_LAST_CHAR);
+                if (c2 < 256) h += asso[1][c2];
+                std::size_t slot = h % TableSize;
+                if (slot_to_key[slot] != SENTINEL_KEY) { ok = false; break; }
+                slot_to_key[slot] = static_cast<std::uint8_t>(i);
+            }
+            if (ok) return true;
+        }
+    }
+    return false;
+}
+
+template <std::size_t N, std::size_t TableSize, std::size_t MaxKeyLen>
+consteval phf_data<N, TableSize, MaxKeyLen>
+compute_phf(const std::array<std::string_view, N>& keys) {
+    // Validate.
+    for (std::size_t i = 0; i < N; ++i) {
+        if (keys[i].empty())        throw "empty keys are not allowed in key_selector";
+        if (keys[i].size() > MaxKeyLen) throw "key length exceeds MaxKeyLen";
+        for (char c : keys[i]) {
+            if (c == '\\')          throw "backslash not allowed in key_selector keys";
+            if (c == '"')           throw "quote not allowed in key_selector keys";
+            if (c == '\0')          throw "null byte not allowed in key_selector keys";
+        }
+        for (std::size_t j = i + 1; j < N; ++j)
+            if (keys[i] == keys[j]) throw "duplicate keys in key_selector";
+    }
+
+    phf_data<N, TableSize, MaxKeyLen> out{};
+    for (std::size_t s = 0; s < TableSize; ++s) out.slot_to_key[s] = SENTINEL_KEY;
+
+    if (!try_phf<N, TableSize>(keys, out.asso_values, out.positions,
+                               out.num_positions, out.slot_to_key))
+        throw "key_selector PHF generation failed";
+
+    // Populate slot key bytes (zero-padded) and lengths.
+    for (std::size_t s = 0; s < TableSize; ++s) {
+        std::uint8_t ki = out.slot_to_key[s];
+        if (ki < N) {
+            auto k = keys[ki];
+            out.slot_key_len[s] = static_cast<std::uint8_t>(k.size());
+            for (std::size_t c = 0; c < k.size(); ++c)
+                out.slot_key_bytes[s][c] = k[c];
+        } else {
+            out.slot_key_len[s] = 0; // sentinel: no length can match
+        }
+    }
+    return out;
+}
+
+// --- SIMD primitives --------------------------------------------------------
+
+// Scan for the terminating '"' starting at p. Returns its byte offset (= key length).
+// Reads at most 16 bytes (if MaxKeyLen <= 15) else up to MaxKeyLen+1 bytes.
+// Caller guarantees SIMDJSON_PADDING bytes past the JSON buffer, so the load is safe.
+template <std::size_t MaxKeyLen>
+simdjson_really_inline std::size_t scan_key_length(const char* p) noexcept {
+#if SIMDJSON_KEY_SELECTOR_HAS_NEON
+    uint8x16_t v0 = vld1q_u8(reinterpret_cast<const uint8_t*>(p));
+    uint8x16_t cmp0 = vceqq_u8(v0, vdupq_n_u8('"'));
+    uint64_t m0 = vget_lane_u64(
+        vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(cmp0), 4)), 0);
+    if constexpr (MaxKeyLen < 16) {
+        // Only the first 16 bytes are relevant.
+        if (simdjson_likely(m0 != 0)) return std::size_t(__builtin_ctzll(m0)) >> 2;
+        return MaxKeyLen + 1;
+    } else {
+        uint8x16_t v1 = vld1q_u8(reinterpret_cast<const uint8_t*>(p) + 16);
+        uint8x16_t cmp1 = vceqq_u8(v1, vdupq_n_u8('"'));
+        uint64_t m1 = vget_lane_u64(
+            vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(cmp1), 4)), 0);
+        // Combine into a single 128-bit-ish mask. If m0 != 0, first-byte lives there.
+        if (simdjson_likely(m0 != 0)) return std::size_t(__builtin_ctzll(m0)) >> 2;
+        if (m1 != 0) return 16 + (std::size_t(__builtin_ctzll(m1)) >> 2);
+        return MaxKeyLen + 1;
+    }
+#elif SIMDJSON_KEY_SELECTOR_HAS_SSE2
+    __m128i v0   = _mm_loadu_si128(reinterpret_cast<const __m128i*>(p));
+    __m128i cmp0 = _mm_cmpeq_epi8(v0, _mm_set1_epi8('"'));
+    unsigned m0  = static_cast<unsigned>(_mm_movemask_epi8(cmp0));
+    if constexpr (MaxKeyLen < 16) {
+        if (simdjson_likely(m0 != 0)) return std::size_t(__builtin_ctz(m0));
+        return MaxKeyLen + 1;
+    } else {
+        __m128i v1   = _mm_loadu_si128(reinterpret_cast<const __m128i*>(p + 16));
+        __m128i cmp1 = _mm_cmpeq_epi8(v1, _mm_set1_epi8('"'));
+        unsigned m1  = static_cast<unsigned>(_mm_movemask_epi8(cmp1));
+        if (simdjson_likely(m0 != 0)) return std::size_t(__builtin_ctz(m0));
+        if (m1 != 0) return 16 + std::size_t(__builtin_ctz(m1));
+        return MaxKeyLen + 1;
+    }
+#else
+    for (std::size_t i = 0; i <= MaxKeyLen; ++i)
+        if (p[i] == '"') return i;
+    return MaxKeyLen + 1;
+#endif
+}
+
+// Byte-equal of p[0..len) against stored[0..len). stored is zero-padded past `len`.
+// Input is read over 16 or 32 bytes (padded JSON buffer guaranteed).
+template <std::size_t MaxKeyLen>
+simdjson_really_inline bool compare_key_bytes(
+    const char* p, const char* stored, std::size_t len) noexcept
+{
+    alignas(16) static constexpr uint8_t idx16[16] =
+        {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
+    if constexpr (MaxKeyLen <= 16) {
+#if SIMDJSON_KEY_SELECTOR_HAS_NEON
+        uint8x16_t vp = vld1q_u8(reinterpret_cast<const uint8_t*>(p));
+        uint8x16_t vs = vld1q_u8(reinterpret_cast<const uint8_t*>(stored));
+        uint8x16_t mask = vcltq_u8(vld1q_u8(idx16), vdupq_n_u8(static_cast<uint8_t>(len)));
+        uint8x16_t diff = veorq_u8(vandq_u8(vp, mask), vs);
+        return vmaxvq_u8(diff) == 0;
+#elif SIMDJSON_KEY_SELECTOR_HAS_SSE2
+        __m128i vp = _mm_loadu_si128(reinterpret_cast<const __m128i*>(p));
+        __m128i vs = _mm_loadu_si128(reinterpret_cast<const __m128i*>(stored));
+        __m128i idx = _mm_load_si128(reinterpret_cast<const __m128i*>(idx16));
+        __m128i mask = _mm_cmplt_epi8(idx, _mm_set1_epi8(static_cast<char>(len)));
+        __m128i eq = _mm_cmpeq_epi8(_mm_and_si128(vp, mask), vs);
+        return _mm_movemask_epi8(eq) == 0xFFFF;
+#else
+        for (std::size_t i = 0; i < len; ++i)
+            if (p[i] != stored[i]) return false;
+        return true;
+#endif
+    } else if constexpr (MaxKeyLen <= 32) {
+        // Two 16-byte lanes. JSON buffer is padded so the second load is safe.
+        alignas(16) static constexpr uint8_t idx32_hi[16] =
+            {16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31};
+#if SIMDJSON_KEY_SELECTOR_HAS_NEON
+        uint8x16_t vp_lo = vld1q_u8(reinterpret_cast<const uint8_t*>(p));
+        uint8x16_t vp_hi = vld1q_u8(reinterpret_cast<const uint8_t*>(p) + 16);
+        uint8x16_t vs_lo = vld1q_u8(reinterpret_cast<const uint8_t*>(stored));
+        uint8x16_t vs_hi = vld1q_u8(reinterpret_cast<const uint8_t*>(stored) + 16);
+        uint8x16_t lenv = vdupq_n_u8(static_cast<uint8_t>(len));
+        uint8x16_t m_lo = vcltq_u8(vld1q_u8(idx16),    lenv);
+        uint8x16_t m_hi = vcltq_u8(vld1q_u8(idx32_hi), lenv);
+        uint8x16_t d_lo = veorq_u8(vandq_u8(vp_lo, m_lo), vs_lo);
+        uint8x16_t d_hi = veorq_u8(vandq_u8(vp_hi, m_hi), vs_hi);
+        return vmaxvq_u8(vorrq_u8(d_lo, d_hi)) == 0;
+#elif SIMDJSON_KEY_SELECTOR_HAS_SSE2
+        __m128i vp_lo = _mm_loadu_si128(reinterpret_cast<const __m128i*>(p));
+        __m128i vp_hi = _mm_loadu_si128(reinterpret_cast<const __m128i*>(p + 16));
+        __m128i vs_lo = _mm_loadu_si128(reinterpret_cast<const __m128i*>(stored));
+        __m128i vs_hi = _mm_loadu_si128(reinterpret_cast<const __m128i*>(stored + 16));
+        __m128i lenv = _mm_set1_epi8(static_cast<char>(len));
+        __m128i m_lo = _mm_cmplt_epi8(_mm_load_si128(reinterpret_cast<const __m128i*>(idx16)),    lenv);
+        __m128i m_hi = _mm_cmplt_epi8(_mm_load_si128(reinterpret_cast<const __m128i*>(idx32_hi)), lenv);
+        __m128i eq_lo = _mm_cmpeq_epi8(_mm_and_si128(vp_lo, m_lo), vs_lo);
+        __m128i eq_hi = _mm_cmpeq_epi8(_mm_and_si128(vp_hi, m_hi), vs_hi);
+        return (_mm_movemask_epi8(eq_lo) & _mm_movemask_epi8(eq_hi)) == 0xFFFF;
+#else
+        for (std::size_t i = 0; i < len; ++i)
+            if (p[i] != stored[i]) return false;
+        return true;
+#endif
+    } else {
+        // MaxKeyLen > 32: byte loop.
+        for (std::size_t i = 0; i < len; ++i)
+            if (p[i] != stored[i]) return false;
+        return true;
+    }
+}
+
+template <std::size_t N>
+constexpr std::size_t compute_max_key_len(const std::array<std::string_view, N>& keys) noexcept {
+    std::size_t m = 0;
+    for (std::size_t i = 0; i < N; ++i) if (keys[i].size() > m) m = keys[i].size();
+    return m;
+}
+
+} // namespace key_selector_detail
+
+/**
+ * Stateless, compile-time key selector.
+ *
+ * Usage:
+ *   using sel_t = decltype(make_key_selector<"id", "text", "user">());
+ *   std::size_t i = sel_t::match_raw(raw_key); // returns sel_t::size() on miss
+ *
+ * All PHF tables are static constexpr — the compiler sees them as compile-time
+ * constants at every call site and fully unrolls compute_hash / compare.
+ */
+template <constevalutil::fixed_string... Keys>
+struct key_selector {
+    static constexpr std::size_t N = sizeof...(Keys);
+    static_assert(N > 0,   "key_selector requires at least one key");
+    static_assert(N <= 100,"key_selector supports at most 100 keys");
+
+    static constexpr std::array<std::string_view, N> keys{ Keys.view()... };
+    static constexpr std::size_t table_size  = key_selector_detail::pick_table_size<N>();
+    static constexpr std::size_t max_key_len = key_selector_detail::compute_max_key_len<N>(keys);
+    static_assert(max_key_len <= SIMDJSON_PADDING,
+                  "key longer than SIMDJSON_PADDING is not supported");
+
+    static constexpr auto phf =
+        key_selector_detail::compute_phf<N, table_size, max_key_len>(keys);
+
+    static constexpr std::size_t size() noexcept { return N; }
+
+    static constexpr std::uint8_t tbl_masks[17][16] = {
+        {0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80},
+        {0,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80},
+        {0,1,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80},
+        {0,1,2,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80},
+        {0,1,2,3,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80},
+        {0,1,2,3,4,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80},
+        {0,1,2,3,4,5,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80},
+        {0,1,2,3,4,5,6,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80},
+        {0,1,2,3,4,5,6,7,0x80,0x80,0x80,0x80,0x80,0x80,0x80,0x80},
+        {0,1,2,3,4,5,6,7,8,0x80,0x80,0x80,0x80,0x80,0x80,0x80},
+        {0,1,2,3,4,5,6,7,8,9,0x80,0x80,0x80,0x80,0x80,0x80},
+        {0,1,2,3,4,5,6,7,8,9,10,0x80,0x80,0x80,0x80,0x80},
+        {0,1,2,3,4,5,6,7,8,9,10,11,0x80,0x80,0x80,0x80},
+        {0,1,2,3,4,5,6,7,8,9,10,11,12,0x80,0x80,0x80},
+        {0,1,2,3,4,5,6,7,8,9,10,11,12,13,0x80,0x80},
+        {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,0x80},
+        {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15},
+    };
+    /**
+     * Look up a JSON key. rjs must point just after an opening quote in a padded
+     * simdjson buffer. Returns the selector index in [0, N) on match, or N on miss.
+     */
+    static simdjson_really_inline std::size_t match_raw(raw_json_string rjs) noexcept {
+        const char* p = rjs.raw();
+        //std::size_t len = key_selector_detail::scan_key_length<max_key_len>(p);
+        uint8x16_t v0 = vld1q_u8(reinterpret_cast<const uint8_t*>(p));
+        uint8x16_t v1 = vld1q_u8(reinterpret_cast<const uint8_t*>(p)+16);
+        uint8x16_t cmp0 = vceqq_u8(v0, vdupq_n_u8('"'));
+        uint8x16_t cmp1 = vceqq_u8(v1, vdupq_n_u8('"'));
+        uint64_t m0 = vget_lane_u64(
+            vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(cmp0), 4)), 0);
+        uint64_t m1 = vget_lane_u64(
+            vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(cmp1), 4)), 0);
+        size_t len = m0 ? std::size_t(__builtin_ctzll(m0)) >> 2 : (m1 ? 16 + (std::size_t(__builtin_ctzll(m1)) >> 2) : max_key_len + 1);
+        if (len == 0 || len > max_key_len) return N;
+        // Compute hash. positions / num_positions / asso_values are compile-time
+        // constants, so this fully unrolls.
+        std::size_t h = len;
+        //printf("len=%zu\n", len);
+        for (std::uint8_t i = 0; i < phf.num_positions; ++i) {
+            std::uint8_t pos = phf.positions[i];
+            std::size_t idx = (pos == key_selector_detail::POS_LAST_CHAR)
+                              ? (len - std::size_t{1})
+                              : static_cast<std::size_t>(pos);
+            std::size_t has = static_cast<std::size_t>(idx < len);
+            std::size_t mask = std::size_t{0} - has;
+            std::size_t safe_idx = idx & mask;
+            unsigned char b = static_cast<unsigned char>(p[safe_idx]);
+            h += static_cast<std::size_t>(phf.asso_values[i][b]) & mask;
+        }
+
+        std::size_t slot = h & (table_size - 1);
+        //printf("len=%zu phf.slot_key_len[slot]=%zu\n", len, phf.slot_key_len[slot]);
+
+        //if(phf.slot_key_len[slot] != len) return N;
+
+        size_t len1 = len <= 16 ? len : 16;
+        uint8x16_t input1 = vqtbl1q_u8(v0, vld1q_u8(tbl_masks[len1]));
+        //std::size_t tail_len = len > 16 ? len - 16 : 0;
+        //uint8x16_t input2 = vqtbl1q_u8(v1, vld1q_u8(tbl_masks[tail_len]));
+
+        std::uint8_t ki = phf.slot_to_key[slot];
+        if (ki >= N) return N;
+        uint8x16_t k0 = vld1q_u8(reinterpret_cast<const uint8_t*>(phf.slot_key_bytes[slot].data()));
+        //uint8x16_t k1 = vld1q_u8(reinterpret_cast<const uint8_t*>(phf.slot_key_bytes[slot].data())+16);
+        uint8x16_t cmpk0 = veorq_u8(input1, k0);
+        //uint8x16_t cmpk1 = veorq_u8(input2, k1);
+        //uint8x16_t cmpk = vorrq_u8(cmpk0, cmpk1);
+
+        uint8x16_t cmpk = cmpk0;
+        if((vmaxvq_u32(cmpk) != 0) | ( (phf.slot_key_len[slot] != len))) return N;
+        return ki;
+    }
+
+    /** Return the key text at selector index i (i in [0, N)). */
+    static constexpr std::string_view key_at(std::size_t i) noexcept {
+        return keys[i];
+    }
+};
+
+/**
+ * Factory for readability, matching make_perfect_set in ConstexprCore.
+ */
+template <constevalutil::fixed_string... Keys>
+consteval auto make_key_selector() noexcept {
+    return key_selector<Keys...>{};
+}
+
+} // namespace ondemand
+} // namespace SIMDJSON_IMPLEMENTATION
+} // namespace simdjson
+
+#endif // SIMDJSON_SUPPORTS_CONCEPTS
+
+#endif // SIMDJSON_GENERIC_ONDEMAND_KEY_SELECTOR_H

include/simdjson/generic/ondemand/key_selector_iterator.h

@@ -0,0 +1,131 @@
+#ifndef SIMDJSON_GENERIC_ONDEMAND_KEY_SELECTOR_ITERATOR_H
+
+#ifndef SIMDJSON_CONDITIONAL_INCLUDE
+#define SIMDJSON_GENERIC_ONDEMAND_KEY_SELECTOR_ITERATOR_H
+#include "simdjson/generic/ondemand/base.h"
+#include "simdjson/generic/ondemand/key_selector.h"
+#include "simdjson/generic/ondemand/object.h"
+#include "simdjson/generic/ondemand/object_iterator.h"
+#include "simdjson/generic/ondemand/field.h"
+#include "simdjson/generic/ondemand/value.h"
+#endif // SIMDJSON_CONDITIONAL_INCLUDE
+
+#include <array>
+#include <cstddef>
+#include <utility>
+
+#if SIMDJSON_SUPPORTS_CONCEPTS
+
+namespace simdjson {
+namespace SIMDJSON_IMPLEMENTATION {
+namespace ondemand {
+
+/**
+ * Forward iterator over selector matches in an object.
+ *
+ * Walks the JSON object once, yielding each (selector_index, value) pair whose
+ * key matches one of the selector's keys, in JSON order. Duplicate matches of
+ * the same key are silently skipped; iteration ends when every selector key
+ * has matched OR the object ends.
+ *
+ *   for (auto [i, val] : obj.select<sel_t>()) {
+ *     switch (i) { case 0: ...; case 1: ...; }
+ *   }
+ */
+template <typename Selector>
+class selector_iterator {
+public:
+    // Yield ondemand::value directly (not simdjson_result<value>); the caller
+    // uses iterator state (error()) to check for errors after iteration.
+    using value_type = std::pair<std::size_t, value>;
+
+    struct end_sentinel {};
+
+    simdjson_inline selector_iterator() noexcept = default;
+
+    simdjson_inline explicit selector_iterator(object obj) noexcept
+      : obj_{std::move(obj)} {
+        auto begin_res = obj_.begin();
+        if (begin_res.error()) { done_ = true; last_error_ = begin_res.error(); return; }
+        it_ = begin_res.value();
+        advance();
+    }
+
+    simdjson_inline value_type operator*() noexcept {
+        return { current_index_, std::move(current_value_) };
+    }
+
+    simdjson_inline selector_iterator& operator++() noexcept { advance(); return *this; }
+
+    simdjson_inline bool operator==(end_sentinel) const noexcept { return done_; }
+    simdjson_inline bool operator!=(end_sentinel) const noexcept { return !done_; }
+
+    /** Error code set if iteration was terminated by an error. */
+    simdjson_inline error_code error() const noexcept { return last_error_; }
+    /** Number of unique selector-key matches produced so far. */
+    simdjson_inline std::size_t matched_count() const noexcept { return matched_; }
+
+private:
+    object obj_{};
+    object_iterator it_{};
+    std::array<bool, Selector::size()> seen_{};
+    std::size_t matched_{0};
+    std::size_t current_index_{Selector::size()};
+    value current_value_{};
+    error_code last_error_{SUCCESS};
+    bool done_{false};
+    bool primed_{false};
+
+    simdjson_inline void advance() noexcept {
+        if (done_) return;
+        if (primed_) { ++it_; primed_ = false; }
+        if (matched_ >= Selector::size()) { done_ = true; return; }
+
+        object_iterator end{};
+        while (it_ != end) {
+            auto f_res = *it_;
+            if (f_res.error()) { last_error_ = f_res.error(); done_ = true; return; }
+            field f = f_res.value_unsafe();
+            std::size_t idx = Selector::match_raw(f.key());
+            if (idx < Selector::size() && !seen_[idx]) {
+                seen_[idx] = true;
+                ++matched_;
+                current_index_ = idx;
+                current_value_ = std::move(f.value());
+                primed_ = true;
+                return;
+            }
+            ++it_;
+        }
+        done_ = true;
+    }
+};
+
+/**
+ * Range adapter returned by object::select<Selector>(). Satisfies the range-for
+ * loop requirements (begin() / end()).
+ */
+template <typename Selector>
+class selector_range {
+public:
+    simdjson_inline explicit selector_range(object obj) noexcept
+      : obj_{std::move(obj)} {}
+
+    simdjson_inline selector_iterator<Selector> begin() noexcept {
+        return selector_iterator<Selector>{std::move(obj_)};
+    }
+    simdjson_inline typename selector_iterator<Selector>::end_sentinel end() const noexcept {
+        return {};
+    }
+
+private:
+    object obj_;
+};
+
+} // namespace ondemand
+} // namespace SIMDJSON_IMPLEMENTATION
+} // namespace simdjson
+
+#endif // SIMDJSON_SUPPORTS_CONCEPTS
+
+#endif // SIMDJSON_GENERIC_ONDEMAND_KEY_SELECTOR_ITERATOR_H

include/simdjson/generic/ondemand/object-inl.h

@@ -63,6 +63,17 @@ simdjson_inline simdjson_result<value> object::find_field(const std::string_view
   return value(iter.child());
 }
 
+#if SIMDJSON_SUPPORTS_CONCEPTS
+template <typename Selector>
+simdjson_inline selector_range<Selector> object::select() & noexcept {
+  return selector_range<Selector>{*this};
+}
+template <typename Selector>
+simdjson_inline selector_range<Selector> object::select() && noexcept {
+  return selector_range<Selector>{std::move(*this)};
+}
+#endif
+
 simdjson_inline simdjson_result<object> object::start(value_iterator &iter) noexcept {
   SIMDJSON_TRY( iter.start_object().error() );
   return object(iter);
@@ -334,6 +345,22 @@ simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> simdjs
   return std::forward<SIMDJSON_IMPLEMENTATION::ondemand::object>(first).find_field(key);
 }
 
+#if SIMDJSON_SUPPORTS_CONCEPTS
+template <typename Selector>
+simdjson_inline SIMDJSON_IMPLEMENTATION::ondemand::selector_range<Selector>
+simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::object>::select() & noexcept {
+  // On error, construct a range over a default (invalid) object; iteration will
+  // yield the stored error at first dereference via the underlying iterator path.
+  return first.template select<Selector>();
+}
+
+template <typename Selector>
+simdjson_inline SIMDJSON_IMPLEMENTATION::ondemand::selector_range<Selector>
+simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::object>::select() && noexcept {
+  return std::forward<SIMDJSON_IMPLEMENTATION::ondemand::object>(first).template select<Selector>();
+}
+#endif
+
 simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::object>::at_pointer(std::string_view json_pointer) noexcept {
   if (error()) { return error(); }
   return first.at_pointer(json_pointer);

include/simdjson/generic/ondemand/object.h

@@ -5,6 +5,7 @@
 #include "simdjson/generic/ondemand/base.h"
 #include "simdjson/generic/implementation_simdjson_result_base.h"
 #include "simdjson/generic/ondemand/value_iterator.h"
+#include "simdjson/generic/ondemand/key_selector.h"
 #include <vector>
 #if SIMDJSON_STATIC_REFLECTION && SIMDJSON_SUPPORTS_CONCEPTS
 #include "simdjson/generic/ondemand/json_string_builder.h"  // for constevalutil::fixed_string
@@ -122,6 +123,27 @@ public:
   /** @overload simdjson_inline simdjson_result<value> find_field_unordered(std::string_view key) & noexcept; */
   simdjson_inline simdjson_result<value> operator[](std::string_view key) && noexcept;
 
+#if SIMDJSON_SUPPORTS_CONCEPTS
+  /**
+   * Iterate over this object, yielding every field whose key is in the compile-time
+   * key_selector Selector. Yields std::pair<std::size_t, simdjson_result<value>>
+   * (selector_index, value) in JSON order. Duplicate keys in the JSON are skipped
+   * (first occurrence wins). Iteration ends when all Selector::size() keys have
+   * matched or the object ends.
+   *
+   * Usage:
+   *   using sel_t = decltype(make_key_selector<"id", "text", "user">());
+   *   for (auto [i, v] : obj.select<sel_t>()) { ... }
+   *
+   * @tparam Selector A stateless key_selector type (see key_selector.h).
+   */
+  template <typename Selector>
+  simdjson_inline selector_range<Selector> select() & noexcept;
+  /** @overload */
+  template <typename Selector>
+  simdjson_inline selector_range<Selector> select() && noexcept;
+#endif
+
   /**
    * Get the value associated with the given JSON pointer. We use the RFC 6901
    * https://tools.ietf.org/html/rfc6901 standard, interpreting the current node
@@ -324,6 +346,12 @@ public:
   simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> find_field(std::string_view key) && noexcept;
   simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> find_field_unordered(std::string_view key) & noexcept;
   simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> find_field_unordered(std::string_view key) && noexcept;
+#if SIMDJSON_SUPPORTS_CONCEPTS
+  template <typename Selector>
+  simdjson_inline SIMDJSON_IMPLEMENTATION::ondemand::selector_range<Selector> select() & noexcept;
+  template <typename Selector>
+  simdjson_inline SIMDJSON_IMPLEMENTATION::ondemand::selector_range<Selector> select() && noexcept;
+#endif
   simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> operator[](std::string_view key) & noexcept;
   simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> operator[](std::string_view key) && noexcept;
   simdjson_inline simdjson_result<SIMDJSON_IMPLEMENTATION::ondemand::value> at_pointer(std::string_view json_pointer) noexcept;

include/simdjson/generic/ondemand/parser-inl.h

@@ -133,6 +133,34 @@ simdjson_warn_unused simdjson_inline simdjson_result<json_iterator> parser::iter
   return json_iterator(reinterpret_cast<const uint8_t *>(json.data()), this);
 }
 
+inline simdjson_result<document_stream> parser::iterate_many(const uint8_t *buf, size_t len, size_t batch_size) noexcept {
+  if(batch_size < MINIMAL_BATCH_SIZE) { batch_size = MINIMAL_BATCH_SIZE; }
+  if((len >= 3) && (std::memcmp(buf, "\xEF\xBB\xBF", 3) == 0)) {
+    buf += 3;
+    len -= 3;
+  }
+  return document_stream(*this, buf, len, batch_size, false, stream_format::whitespace_delimited);
+}
+inline simdjson_result<document_stream> parser::iterate_many(const char *buf, size_t len, size_t batch_size) noexcept {
+  return iterate_many(reinterpret_cast<const uint8_t *>(buf), len, batch_size);
+}
+inline simdjson_result<document_stream> parser::iterate_many(padded_string_view s, size_t batch_size) noexcept {
+  if (!s.has_sufficient_padding()) { return INSUFFICIENT_PADDING; }
+  return iterate_many(s.data(), s.length(), batch_size);
+}
+inline simdjson_result<document_stream> parser::iterate_many(const padded_string &s, size_t batch_size) noexcept {
+  return iterate_many(padded_string_view(s), batch_size);
+}
+inline simdjson_result<document_stream> parser::iterate_many(const std::string &s, size_t batch_size) noexcept {
+  return iterate_many(padded_string_view(s), batch_size);
+}
+inline simdjson_result<document_stream> parser::iterate_many(std::string &s, size_t batch_size) noexcept {
+  return iterate_many(pad(s), batch_size);
+}
+
+#ifndef SIMDJSON_DISABLE_DEPRECATED_API
+SIMDJSON_PUSH_DISABLE_WARNINGS
+SIMDJSON_DISABLE_DEPRECATED_WARNING
 inline simdjson_result<document_stream> parser::iterate_many(const uint8_t *buf, size_t len, size_t batch_size, bool allow_comma_separated) noexcept {
   // Warning: no check is done on the buffer padding. We trust the user.
   if(batch_size < MINIMAL_BATCH_SIZE) { batch_size = MINIMAL_BATCH_SIZE; }
@@ -140,8 +168,11 @@ inline simdjson_result<document_stream> parser::iterate_many(const uint8_t *buf,
     buf += 3;
     len -= 3;
   }
-  if(allow_comma_separated && batch_size < len) { batch_size = len; }
+  // Map allow_comma_separated to stream_format::comma_delimited
-  return document_stream(*this, buf, len, batch_size, allow_comma_separated);
+  if (allow_comma_separated) {
+    return document_stream(*this, buf, len, batch_size, false, stream_format::comma_delimited);
+  }
+  return document_stream(*this, buf, len, batch_size, false, stream_format::whitespace_delimited);
 }
 
 inline simdjson_result<document_stream> parser::iterate_many(const char *buf, size_t len, size_t batch_size, bool allow_comma_separated) noexcept {
@@ -161,6 +192,48 @@ inline simdjson_result<document_stream> parser::iterate_many(const std::string &
 inline simdjson_result<document_stream> parser::iterate_many(std::string &s, size_t batch_size, bool allow_comma_separated) noexcept {
   return iterate_many(pad(s), batch_size, allow_comma_separated);
 }
+SIMDJSON_POP_DISABLE_WARNINGS
+#endif // SIMDJSON_DISABLE_DEPRECATED_API
+
+inline simdjson_result<document_stream> parser::iterate_many(const uint8_t *buf, size_t len, size_t batch_size, stream_format format) noexcept {
+  if(batch_size < MINIMAL_BATCH_SIZE) { batch_size = MINIMAL_BATCH_SIZE; }
+  if((len >= 3) && (std::memcmp(buf, "\xEF\xBB\xBF", 3) == 0)) {
+    buf += 3;
+    len -= 3;
+  }
+  if (format == stream_format::comma_delimited_array) {
+    // Strip leading JSON whitespace.
+    while (len > 0 && (buf[0] == ' ' || buf[0] == '\t' || buf[0] == '\n' || buf[0] == '\r')) {
+      buf++; len--;
+    }
+    // Expect the opening '['.
+    if (len == 0 || buf[0] != '[') { return TAPE_ERROR; }
+    buf++; len--;
+    // Strip trailing JSON whitespace.
+    while (len > 0 && (buf[len-1] == ' ' || buf[len-1] == '\t' || buf[len-1] == '\n' || buf[len-1] == '\r')) {
+      len--;
+    }
+    // Expect the closing ']'.
+    if (len == 0 || buf[len-1] != ']') { return TAPE_ERROR; }
+    len--;
+    // Fall through to comma_delimited over the array contents.
+    format = stream_format::comma_delimited;
+  }
+  return document_stream(*this, buf, len, batch_size, false, format);
+}
+inline simdjson_result<document_stream> parser::iterate_many(const char *buf, size_t len, size_t batch_size, stream_format format) noexcept {
+  return iterate_many(reinterpret_cast<const uint8_t *>(buf), len, batch_size, format);
+}
+inline simdjson_result<document_stream> parser::iterate_many(padded_string_view s, size_t batch_size, stream_format format) noexcept {
+  if (!s.has_sufficient_padding()) { return INSUFFICIENT_PADDING; }
+  return iterate_many(s.data(), s.length(), batch_size, format);
+}
+inline simdjson_result<document_stream> parser::iterate_many(const std::string &s, size_t batch_size, stream_format format) noexcept {
+  return iterate_many(padded_string_view(s), batch_size, format);
+}
+inline simdjson_result<document_stream> parser::iterate_many(const padded_string &s, size_t batch_size, stream_format format) noexcept {
+  return iterate_many(padded_string_view(s), batch_size, format);
+}
 simdjson_pure simdjson_inline size_t parser::capacity() const noexcept {
   return _capacity;
 }

include/simdjson/generic/ondemand/parser.h

@@ -244,32 +244,66 @@ public:
    *                   spot is cache-related: small enough to fit in cache, yet big enough to
    *                   parse as many documents as possible in one tight loop.
    *                   Defaults to 10MB, which has been a reasonable sweet spot in our tests.
-   * @param allow_comma_separated (defaults on false) This allows a mode where the documents are
+   * @param allow_comma_separated @deprecated Use stream_format::comma_delimited instead.
-   *                   separated by commas instead of whitespace. It comes with a performance
+   *                   When true, maps internally to stream_format::comma_delimited.
-   *                   penalty because the entire document is indexed at once (and the document must be
+   *                   Defaults to false.
-   *                   less than 4 GB), and there is no multithreading. In this mode, the batch_size parameter
-   *                   is effectively ignored, as it is set to at least the document size.
    * @return The stream, or an error. An empty input will yield 0 documents rather than an EMPTY error. Errors:
    *         - MEMALLOC if the parser does not have enough capacity and memory allocation fails
    *         - CAPACITY if the parser does not have enough capacity and batch_size > max_capacity.
    *         - other json errors if parsing fails. You should not rely on these errors to always the same for the
    *           same document: they may vary under runtime dispatch (so they may vary depending on your system and hardware).
    */
-  inline simdjson_result<document_stream> iterate_many(const uint8_t *buf, size_t len, size_t batch_size = DEFAULT_BATCH_SIZE, bool allow_comma_separated = false) noexcept;
+  inline simdjson_result<document_stream> iterate_many(const uint8_t *buf, size_t len, size_t batch_size = DEFAULT_BATCH_SIZE) noexcept;
-  /** @overload parse_many(const uint8_t *buf, size_t len, size_t batch_size) */
+  /** @overload iterate_many(const uint8_t *buf, size_t len, size_t batch_size) */
-  inline simdjson_result<document_stream> iterate_many(padded_string_view json, size_t batch_size = DEFAULT_BATCH_SIZE, bool allow_comma_separated = false) noexcept;
+  inline simdjson_result<document_stream> iterate_many(padded_string_view json, size_t batch_size = DEFAULT_BATCH_SIZE) noexcept;
-  /** @overload parse_many(const uint8_t *buf, size_t len, size_t batch_size) */
+  /** @overload iterate_many(const uint8_t *buf, size_t len, size_t batch_size) */
-  inline simdjson_result<document_stream> iterate_many(const char *buf, size_t len, size_t batch_size = DEFAULT_BATCH_SIZE, bool allow_comma_separated = false) noexcept;
+  inline simdjson_result<document_stream> iterate_many(const char *buf, size_t len, size_t batch_size = DEFAULT_BATCH_SIZE) noexcept;
-  /** @overload parse_many(const uint8_t *buf, size_t len, size_t batch_size) */
+  /** @overload iterate_many(const uint8_t *buf, size_t len, size_t batch_size) */
-  inline simdjson_result<document_stream> iterate_many(const std::string &s, size_t batch_size = DEFAULT_BATCH_SIZE, bool allow_comma_separated = false) noexcept;
+  inline simdjson_result<document_stream> iterate_many(const std::string &s, size_t batch_size = DEFAULT_BATCH_SIZE) noexcept;
-  /** @overload parse_many(const uint8_t *buf, size_t len, size_t batch_size)
+  /** @overload iterate_many(const uint8_t *buf, size_t len, size_t batch_size)
     the string might be automatically padded with up to SIMDJSON_PADDING whitespace characters */
-  inline simdjson_result<document_stream> iterate_many(std::string &s, size_t batch_size = DEFAULT_BATCH_SIZE, bool allow_comma_separated = false) noexcept;
+  inline simdjson_result<document_stream> iterate_many(std::string &s, size_t batch_size = DEFAULT_BATCH_SIZE) noexcept;
-  /** @overload parse_many(const uint8_t *buf, size_t len, size_t batch_size) */
+  /** @overload iterate_many(const uint8_t *buf, size_t len, size_t batch_size) */
-  inline simdjson_result<document_stream> iterate_many(const padded_string &s, size_t batch_size = DEFAULT_BATCH_SIZE, bool allow_comma_separated = false) noexcept;
+  inline simdjson_result<document_stream> iterate_many(const padded_string &s, size_t batch_size = DEFAULT_BATCH_SIZE) noexcept;
   /** @private We do not want to allow implicit conversion from C string to std::string. */
   simdjson_result<document_stream> iterate_many(const char *buf, size_t batch_size = DEFAULT_BATCH_SIZE) noexcept = delete;
 
+#ifndef SIMDJSON_DISABLE_DEPRECATED_API
+  /**
+   * @deprecated Use iterate_many with stream_format::comma_delimited instead.
+   */
+  simdjson_deprecated inline simdjson_result<document_stream> iterate_many(const uint8_t *buf, size_t len, size_t batch_size, bool allow_comma_separated) noexcept;
+  /** @overload iterate_many(const uint8_t *buf, size_t len, size_t batch_size, bool allow_comma_separated) */
+  simdjson_deprecated inline simdjson_result<document_stream> iterate_many(padded_string_view json, size_t batch_size, bool allow_comma_separated) noexcept;
+  /** @overload iterate_many(const uint8_t *buf, size_t len, size_t batch_size, bool allow_comma_separated) */
+  simdjson_deprecated inline simdjson_result<document_stream> iterate_many(const char *buf, size_t len, size_t batch_size, bool allow_comma_separated) noexcept;
+  /** @overload iterate_many(const uint8_t *buf, size_t len, size_t batch_size, bool allow_comma_separated) */
+  simdjson_deprecated inline simdjson_result<document_stream> iterate_many(const std::string &s, size_t batch_size, bool allow_comma_separated) noexcept;
+  /** @overload iterate_many(const uint8_t *buf, size_t len, size_t batch_size, bool allow_comma_separated) */
+  simdjson_deprecated inline simdjson_result<document_stream> iterate_many(std::string &s, size_t batch_size, bool allow_comma_separated) noexcept;
+  /** @overload iterate_many(const uint8_t *buf, size_t len, size_t batch_size, bool allow_comma_separated) */
+  simdjson_deprecated inline simdjson_result<document_stream> iterate_many(const padded_string &s, size_t batch_size, bool allow_comma_separated) noexcept;
+#endif // SIMDJSON_DISABLE_DEPRECATED_API
+
+  /**
+   * Parse a stream of JSON documents with explicit format specification.
+   *
+   * @param buf The concatenated JSON documents.
+   * @param len The length of the buffer.
+   * @param batch_size The batch size to use.
+   * @param format The stream format (whitespace_delimited, json_sequence, or comma_delimited).
+   * @return A stream of documents, or an error.
+   */
+  inline simdjson_result<document_stream> iterate_many(const uint8_t *buf, size_t len, size_t batch_size, stream_format format) noexcept;
+  /** @overload iterate_many(const uint8_t *buf, size_t len, size_t batch_size, stream_format format) */
+  inline simdjson_result<document_stream> iterate_many(const char *buf, size_t len, size_t batch_size, stream_format format) noexcept;
+  /** @overload iterate_many(const uint8_t *buf, size_t len, size_t batch_size, stream_format format) */
+  inline simdjson_result<document_stream> iterate_many(padded_string_view s, size_t batch_size, stream_format format) noexcept;
+  /** @overload iterate_many(const uint8_t *buf, size_t len, size_t batch_size, stream_format format) */
+  inline simdjson_result<document_stream> iterate_many(const std::string &s, size_t batch_size, stream_format format) noexcept;
+  /** @overload iterate_many(const uint8_t *buf, size_t len, size_t batch_size, stream_format format) */
+  inline simdjson_result<document_stream> iterate_many(const padded_string &s, size_t batch_size, stream_format format) noexcept;
+
   /** The capacity of this parser (the largest document it can process). */
   simdjson_pure simdjson_inline size_t capacity() const noexcept;
   /** The maximum capacity of this parser (the largest document it is allowed to process). */
@@ -425,4 +459,4 @@ public:
 
 } // namespace simdjson
 
-#endif // SIMDJSON_GENERIC_ONDEMAND_PARSER_H
+#endif // SIMDJSON_GENERIC_ONDEMAND_PARSER_H

include/simdjson/internal/dom_parser_implementation.h

@@ -19,7 +19,12 @@ class document;
 * 3) The stream_final mode allows us to truncate final
 * unterminated strings. It is useful in conjunction with streaming_partial.
 */
-enum class stage1_mode { regular, streaming_partial, streaming_final};
+enum class stage1_mode {
+  regular,
+  streaming_partial, streaming_final,
+  json_sequence_partial, json_sequence_final,
+  comma_delimited_partial, comma_delimited_final
+};
 
 /**
  * Returns true if mode == streaming_partial or mode == streaming_final
@@ -31,7 +36,6 @@ inline bool is_streaming(stage1_mode mode) {
   // return (mode == stage1_mode::streaming_partial || mode == stage1_mode::streaming_final);
 }
 
-
 namespace internal {
 
 

include/simdjson/padded_string-inl.h

@@ -10,13 +10,18 @@
 #include <climits>
 #include <cwchar>
 
-#ifndef _WIN32
+#if SIMDJSON_HAS_UNISTD_H
 #include <fcntl.h>
 #include <stdio.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <unistd.h>
 #endif
+// On Windows, `padded_memory_map` (when it is enabled) depends on types and
+// functions declared in <windows.h>. We deliberately do NOT include that
+// header here: users of simdjson who want `padded_memory_map` on Windows
+// must include <windows.h> themselves *before* including this header. See
+// padded_string.h for the detection logic.
 
 namespace simdjson {
 namespace internal {
@@ -385,7 +390,9 @@ inline bool padded_string_builder::reserve(size_t additional) noexcept {
 }
 
 
-#ifndef _WIN32
+#if SIMDJSON_HAS_PADDED_MEMORY_MAP
+
+#if SIMDJSON_HAS_UNISTD_H
 simdjson_inline padded_memory_map::padded_memory_map(const char *filename) noexcept {
 
     int fd = open(filename, O_RDONLY);
@@ -421,7 +428,132 @@ simdjson_inline padded_memory_map::~padded_memory_map() noexcept {
     munmap(const_cast<char *>(data), size + simdjson::SIMDJSON_PADDING);
   }
 }
+#elif defined(_WIN32)
+// Windows zero-copy implementation using placeholder virtual memory.
+//
+// We use the modern Windows memory APIs (VirtualAlloc2, CreateFileMapping2,
+// MapViewOfFile3 — available since Windows 10 1803) to map the file into a
+// contiguous virtual address range that includes at least SIMDJSON_PADDING
+// zero bytes after the file content, with no data copies.
+//
+// Strategy:
+//   1. If rounding the file size up to the allocation granularity already
+//      exceeds file_size + SIMDJSON_PADDING, the OS page zero-fill provides
+//      the padding and we use a simple MapViewOfFile3 call.
+//   2. Otherwise we reserve a contiguous placeholder region via VirtualAlloc2,
+//      split it at the granularity-aligned file boundary, map the file into
+//      the first part, and commit zero pages for the second part (padding).
+simdjson_inline padded_memory_map::padded_memory_map(const char *filename) noexcept {
+  HANDLE file_handle = ::CreateFileA(
+      filename, GENERIC_READ,
+      FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+      NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
+  if (file_handle == INVALID_HANDLE_VALUE) {
+    return;
+  }
+  LARGE_INTEGER file_size_li;
+  if (!::GetFileSizeEx(file_handle, &file_size_li) || file_size_li.QuadPart < 0) {
+    ::CloseHandle(file_handle);
+    return;
+  }
+#if SIMDJSON_IS_32BITS
+  if (static_cast<unsigned long long>(file_size_li.QuadPart) >
+      static_cast<unsigned long long>(SIZE_MAX - simdjson::SIMDJSON_PADDING)) {
+    ::CloseHandle(file_handle);
+    return;
+  }
+#endif
+  size = static_cast<size_t>(file_size_li.QuadPart);
+  if (size == 0) {
+    ::CloseHandle(file_handle);
+    return;
+  }
 
+  HANDLE section = ::CreateFileMapping2(
+      file_handle, NULL, FILE_MAP_READ, PAGE_READONLY,
+      0, 0, NULL, NULL, 0);
+  ::CloseHandle(file_handle);
+  if (section == NULL) {
+    return;
+  }
+
+  SYSTEM_INFO si;
+  ::GetSystemInfo(&si);
+  const size_t granularity = static_cast<size_t>(si.dwAllocationGranularity);
+  const size_t file_region = (size + granularity - 1) & ~(granularity - 1);
+  const size_t total_needed = size + simdjson::SIMDJSON_PADDING;
+
+  if (file_region >= total_needed) {
+    // The zero-fill in the last page already covers the padding.
+    PVOID view = ::MapViewOfFile3(
+        section, ::GetCurrentProcess(), NULL, 0, 0,
+        0, PAGE_READONLY, NULL, 0);
+    ::CloseHandle(section);
+    if (view != NULL) {
+      data = static_cast<const char *>(view);
+    }
+    return;
+  }
+
+  // We need extra zero pages beyond the file region. Use the placeholder API
+  // to get a contiguous virtual address range spanning both the file mapping
+  // and the zero-filled padding.
+  const size_t padding_region =
+      ((total_needed - file_region) + granularity - 1) & ~(granularity - 1);
+  const size_t reserve_size = file_region + padding_region;
+
+  // Reserve a contiguous placeholder.
+  PVOID placeholder = ::VirtualAlloc2(
+      ::GetCurrentProcess(), NULL, reserve_size,
+      MEM_RESERVE | MEM_RESERVE_PLACEHOLDER, PAGE_NOACCESS, NULL, 0);
+  if (placeholder == NULL) {
+    ::CloseHandle(section);
+    return;
+  }
+
+  // Split into two placeholders at the file_region boundary.
+  if (!::VirtualFree(placeholder, file_region,
+                     MEM_RELEASE | MEM_PRESERVE_PLACEHOLDER)) {
+    ::VirtualFree(placeholder, 0, MEM_RELEASE);
+    ::CloseHandle(section);
+    return;
+  }
+
+  // Map the file into the first placeholder.
+  PVOID file_view = ::MapViewOfFile3(
+      section, ::GetCurrentProcess(), placeholder, 0, file_region,
+      MEM_REPLACE_PLACEHOLDER, PAGE_READONLY, NULL, 0);
+  ::CloseHandle(section);
+  if (file_view == NULL) {
+    ::VirtualFree(placeholder, 0, MEM_RELEASE);
+    ::VirtualFree(static_cast<char *>(placeholder) + file_region,
+                  0, MEM_RELEASE);
+    return;
+  }
+
+  // Commit zero pages in the second placeholder (the padding).
+  void *pad = static_cast<char *>(placeholder) + file_region;
+  PVOID padding_ptr = ::VirtualAlloc2(
+      ::GetCurrentProcess(), pad, padding_region,
+      MEM_REPLACE_PLACEHOLDER | MEM_COMMIT, PAGE_READONLY, NULL, 0);
+  if (padding_ptr == NULL) {
+    ::UnmapViewOfFile(file_view);
+    ::VirtualFree(pad, 0, MEM_RELEASE);
+    return;
+  }
+
+  data = static_cast<const char *>(file_view);
+  padding_view_ = padding_ptr;
+}
+
+simdjson_inline padded_memory_map::~padded_memory_map() noexcept {
+  if (data == nullptr) { return; }
+  ::UnmapViewOfFile(data);
+  if (padding_view_ != nullptr) {
+    ::VirtualFree(padding_view_, 0, MEM_RELEASE);
+  }
+}
+#endif // POSIX or _WIN32
 
 simdjson_inline simdjson::padded_string_view padded_memory_map::view() const noexcept simdjson_lifetime_bound {
   if(!is_valid()) {
@@ -433,7 +565,8 @@ simdjson_inline simdjson::padded_string_view padded_memory_map::view() const noe
 simdjson_inline bool padded_memory_map::is_valid() const noexcept {
   return data != nullptr;
 }
-#endif // _WIN32
+
+#endif // SIMDJSON_HAS_PADDED_MEMORY_MAP
 
 } // namespace simdjson
 

include/simdjson/padded_string.h

@@ -277,11 +277,26 @@ inline std::ostream& operator<<(std::ostream& out, const padded_string& s) { ret
 inline std::ostream& operator<<(std::ostream& out, simdjson_result<padded_string> &s) noexcept(false) { return out << s.value(); }
 #endif
 
-
+#if SIMDJSON_HAS_PADDED_MEMORY_MAP
-#ifndef _WIN32
 /**
  * A class representing a memory-mapped file with padding.
- * It is only available on non-Windows platforms, as Windows has different APIs for memory mapping.
+ *
+ * On POSIX systems (Linux, macOS, BSD, ...), this uses `mmap` to map the file
+ * contents directly into memory, which is efficient for large files (no copy).
+ *
+ * On Windows, this class is disabled by default and must be opted into at
+ * build time by defining `SIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS=1`. When
+ * enabled, `<windows.h>` must also be included before `<simdjson.h>` and
+ * the compilation must target Windows 10, version 1803 or later. The
+ * Windows implementation uses the modern memory APIs (`VirtualAlloc2`,
+ * `CreateFileMapping2`, `MapViewOfFile3`) with the placeholder virtual
+ * memory mechanism to always achieve true zero-copy mapping with
+ * contiguous zero-filled padding.
+ *
+ * Either way, the resulting `padded_string_view` carries at least
+ * `SIMDJSON_PADDING` bytes of accessible zero-filled padding after the file
+ * content, so it can be consumed directly by the simdjson parsers (including
+ * `parse_many` / `iterate_many`).
  */
 class padded_memory_map {
 public:
@@ -289,9 +304,11 @@ public:
    * Create a new padded memory map for the given file.
    * After creating the memory map, you can call view() to get a padded_string_view of the file content.
    * The memory map will be automatically released when the padded_memory_map instance is destroyed.
-   * Note that the file content is not copied, so this is efficient for large files. However,
+   * On POSIX systems, the file content is not copied, so this is efficient for large files.
-   * the file must remain unchanged while the memory map is in use. In case of error (e.g., file not found,
+   * On Windows, the file is mapped into memory via `MapViewOfFile3` (zero-copy).
-   * permission denied, etc.), the memory map will be invalid and view() will return an empty view.
+   * In all cases, the file must remain unchanged while the memory map is in use.
+   * In case of error (e.g., file not found, permission denied, etc.), the memory map will be
+   * invalid and view() will return an empty view.
    * You can check if the memory map is valid by calling is_valid() before using view().
    *
    * @param filename the path to the file to memory-map.
@@ -328,8 +345,14 @@ private:
   padded_memory_map &operator=(const padded_memory_map &) = delete;
   const char *data{nullptr};
   size_t size{0};
+#ifdef _WIN32
+  // When the file ends near an allocation-granularity boundary, we use the
+  // placeholder API to append zero-filled padding pages. This pointer tracks
+  // that region so the destructor can release it with VirtualFree.
+  void *padding_view_{nullptr};
+#endif
 };
-#endif // _WIN32
+#endif // SIMDJSON_HAS_PADDED_MEMORY_MAP
 
 
 

include/simdjson/padded_string_view-inl.h

@@ -7,7 +7,7 @@
 #include <cstring> /* memcmp */
 
 // for page size computation.
-#if defined(__unix__) || defined(__APPLE__) || defined(__linux__)
+#if SIMDJSON_HAS_UNISTD_H
   #include <unistd.h>
   #if defined(__APPLE__)
     #include <sys/sysctl.h>
@@ -113,7 +113,7 @@ inline uint32_t get_page_size() noexcept {
       return static_cast<std::uint32_t>(si.dwPageSize);
     }();
     return cached;
-#elif defined(__unix__) || defined(__APPLE__) || defined(__linux__)
+#elif SIMDJSON_HAS_UNISTD_H
     static const uint32_t cached = []() -> uint32_t {
       long page_size = sysconf(_SC_PAGESIZE);
       if (page_size > 0) {

include/simdjson/portability.h

@@ -285,5 +285,53 @@ using std::size_t;
 #endif
 #endif
 
+#ifndef SIMDJSON_HAS_UNISTD_H
+#if defined(__unix__) || defined(__APPLE__) || defined(__linux__)
+#define SIMDJSON_HAS_UNISTD_H 1
+#else
+#define SIMDJSON_HAS_UNISTD_H 0
+#endif
+#endif
+
+// padded_memory_map availability.
+//
+// On POSIX platforms the class is always available: the implementation uses
+// `mmap` (and a trailing anonymous page for padding) from <sys/mman.h>.
+//
+// On Windows the class is disabled by default and must be explicitly
+// opted into by defining `SIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS=1`. Enabling
+// it requires:
+//   1. `<windows.h>` has been included *before* `<simdjson.h>` (so that
+//      this header can see the Win32 types and the `_WINDOWS_` include
+//      guard),
+//   2. the compilation targets Windows 10, version 1803 or later
+//      (i.e. `NTDDI_VERSION >= NTDDI_WIN10_RS4`, `0x0A000005`). This is
+//      required because the implementation relies on the modern memory
+//      APIs introduced with that version (`CreateFileMapping2` /
+//      `MapViewOfFile3`),
+//   3. the link step pulls in an import library that exports those APIs,
+//      typically `onecore.lib` (or `mincore.lib`).
+//
+// The `SIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS` CMake option arranges (1)-(3)
+// automatically when building simdjson with its own CMake. Consumers using
+// simdjson as a pre-built library are responsible for setting the macro,
+// the Windows version macros, and the link library themselves.
+//
+// If the opt-in conditions are not met on Windows, `padded_memory_map`
+// simply does not exist — any attempt to use it fails at compile time
+// with an "unknown identifier" diagnostic rather than silently degrading.
+//
+// The SIMDJSON_HAS_PADDED_MEMORY_MAP macro reflects whether the class is
+// available in the current translation unit. Users may test this macro to
+// conditionally compile code that depends on padded_memory_map.
+#ifndef SIMDJSON_HAS_PADDED_MEMORY_MAP
+  #if defined(__unix__) || defined(__APPLE__) || defined(__linux__)
+    #define SIMDJSON_HAS_PADDED_MEMORY_MAP 1
+  #elif defined(_WINDOWS_) && defined(SIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS) && SIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS
+    #define SIMDJSON_HAS_PADDED_MEMORY_MAP 1
+  #else
+    #define SIMDJSON_HAS_PADDED_MEMORY_MAP 0
+  #endif
+#endif
 
 #endif // SIMDJSON_PORTABILITY_H

singleheader/amalgamate.py

@@ -268,7 +268,21 @@ class SimdjsonFile:
         print(f"    Adding include: {self} includes {include}")
         if self.is_conditional_include:
             # If I have a dependency file, I can only include something that has a dependency file.
-            assert include.is_conditional_include, f"Error: Amalgamated file '{self}' is trying to include '{include}', but '{include}' is not an amalgamated file. Amalgamated files can only include other amalgamated files to maintain conditional inclusion structure. Check the inclusion rules in the script's 'rules' variable. {rules}"
+            if not include.is_conditional_include:
+                dep = self.dependency_file
+                dep_hint = f" and add it to the dependency file '{dep}'" if dep else ""
+                raise AssertionError(
+                    f"Error: Amalgamated file '{self}' is trying to include '{include}', "
+                    f"but '{include}' is not an amalgamated file.\n\n"
+                    f"FIX: Wrap the #include \"{include}\" in a conditional block:\n\n"
+                    f"    #ifndef SIMDJSON_CONDITIONAL_INCLUDE\n"
+                    f"    #include \"{include}\"\n"
+                    f"    #endif // SIMDJSON_CONDITIONAL_INCLUDE\n\n"
+                    f"This makes the include editor-only (skipped during amalgamation){dep_hint}.\n\n"
+                    f"During amalgamation, '{include}' is already included earlier in the "
+                    f"amalgamated output, so it does not need to be included again.\n\n"
+                    f"{rules}"
+                )
             # TODO make sure we only include amalgamated files that are guaranteed to be included with us (or before us)
             # if include.amalgamator_file:
             #     assert include.amalgamator_file == self, f"{self} cannot include {include}: it should be included from {include.amalgamator_file} instead."
@@ -425,8 +439,10 @@ class Amalgamator:
             self.implementation = "SIMDJSON_BUILTIN_IMPLEMENTATION"
 
         assert not self.editor_only_region, f"Error: Already in an editor-only region when starting to write '{file}'. Ensure proper nesting of conditional blocks."
+        editor_only_start_line = None
+        bare_endif_lines = []
         with open(file.absolute_path, 'r') as fid2:
-            for line in fid2:
+            for line_number, line in enumerate(fid2, 1):
                 line = line.rstrip('\n')
 
                 # Ignore #pragma once, it causes warnings if it ends up in a .cpp file
@@ -439,6 +455,7 @@ class Amalgamator:
                     assert self.in_conditional_include_block, f"Error: File '{file}' uses '#ifndef SIMDJSON_CONDITIONAL_INCLUDE' without a prior '#define SIMDJSON_CONDITIONAL_INCLUDE'. Ensure the define comes first. Stack: {self.include_stack}. {rules}"
                     assert not self.editor_only_region, f"Error: File '{file}' uses '#ifndef SIMDJSON_CONDITIONAL_INCLUDE' twice in a row. Ensure conditional blocks are properly nested and closed. {rules}"
                     self.editor_only_region = True
+                    editor_only_start_line = line_number
 
                 # Handle ignored lines (and ending ignore blocks)
                 end_ignore = endif_conditional_re.search(line)
@@ -453,6 +470,12 @@ class Amalgamator:
                             file.add_editor_only_include(included_file)
                     if end_ignore:
                         self.editor_only_region = False
+                        editor_only_start_line = None
+                    else:
+                        # Track bare #endif lines that might be the intended closer
+                        stripped = line.strip()
+                        if stripped == '#endif' or (stripped.startswith('#endif') and 'SIMDJSON_CONDITIONAL_INCLUDE' not in stripped):
+                            bare_endif_lines.append((line_number, line.strip()))
                     continue
 
                 assert not end_ignore, f"Error: File '{file}' has '#endif // SIMDJSON_CONDITIONAL_INCLUDE' without a matching '#ifndef'. Ensure proper conditional block structure. {rules}"
@@ -501,7 +524,35 @@ class Amalgamator:
 
                 self.write(line)
 
-            assert not self.editor_only_region, f"Error: File '{file}' ended without closing the '#endif // SIMDJSON_CONDITIONAL_INCLUDE'. Ensure all conditional blocks are properly closed. {rules}"
+            if self.editor_only_region:
+                msg = (
+                    f"Error: File '{file}' ended without closing the "
+                    f"'#endif // SIMDJSON_CONDITIONAL_INCLUDE' block "
+                    f"(opened at line {editor_only_start_line}).\n\n"
+                )
+                if bare_endif_lines:
+                    msg += (
+                        f"HINT: Found #endif line(s) inside the block that are missing "
+                        f"the required comment. The amalgamation script looks for exactly:\n\n"
+                        f"    #endif // SIMDJSON_CONDITIONAL_INCLUDE\n\n"
+                        f"but found:\n"
+                    )
+                    for ln, text in bare_endif_lines:
+                        msg += f"    line {ln}: {text}\n"
+                    msg += (
+                        f"\nFIX: Change the #endif to:\n\n"
+                        f"    #endif // SIMDJSON_CONDITIONAL_INCLUDE\n\n"
+                        f"The '// SIMDJSON_CONDITIONAL_INCLUDE' comment is required "
+                        f"for the amalgamation script to recognize it as the closing "
+                        f"of the conditional block.\n"
+                    )
+                else:
+                    msg += (
+                        f"FIX: Add '#endif // SIMDJSON_CONDITIONAL_INCLUDE' to close "
+                        f"the '#ifndef SIMDJSON_CONDITIONAL_INCLUDE' block.\n"
+                    )
+                msg += f"\n{rules}"
+                raise AssertionError(msg)
 
         self.write(f"/* end file {self.file_to_str(file)} */")
 

singleheader/simdjson.h

@@ -4356,10 +4356,55 @@ inline std::ostream& operator<<(std::ostream& out, simdjson_result<padded_string
 #endif
 
 
-#ifndef _WIN32
+// padded_memory_map availability.
+//
+// On POSIX platforms the class is always available: the implementation uses
+// `mmap` (and a trailing anonymous page for padding) from <sys/mman.h>.
+//
+// On Windows the class is only available when all of the following hold:
+//   1. <windows.h> has been included *before* <simdjson.h> (so that this
+//      header can see the Win32 types and the `_WINDOWS_` include guard),
+//   2. the compilation targets Windows 11 or later (NTDDI_VERSION
+//      >= NTDDI_WIN10_CO, 0x0A00000B). This is required because the
+//      implementation relies on the modern memory APIs introduced with
+//      that version (CreateFileMapping2 / MapViewOfFile3).
+//
+// If those conditions are not met on Windows, `padded_memory_map` simply
+// does not exist — any attempt to use it fails at compile time with an
+// "unknown identifier" diagnostic rather than silently degrading.
+//
+// The SIMDJSON_HAS_PADDED_MEMORY_MAP macro reflects whether the class is
+// available in the current translation unit. Users may test this macro to
+// conditionally compile code that depends on padded_memory_map.
+#ifndef SIMDJSON_HAS_PADDED_MEMORY_MAP
+  #if !defined(_WIN32)
+    #define SIMDJSON_HAS_PADDED_MEMORY_MAP 1
+  #elif defined(_WINDOWS_) && defined(NTDDI_VERSION) && (NTDDI_VERSION >= 0x0A00000B /* NTDDI_WIN10_CO — Windows 11 */)
+    #define SIMDJSON_HAS_PADDED_MEMORY_MAP 1
+  #else
+    #define SIMDJSON_HAS_PADDED_MEMORY_MAP 0
+  #endif
+#endif
+
+#if SIMDJSON_HAS_PADDED_MEMORY_MAP
 /**
  * A class representing a memory-mapped file with padding.
- * It is only available on non-Windows platforms, as Windows has different APIs for memory mapping.
+ *
+ * On POSIX systems (Linux, macOS, BSD, ...), this uses `mmap` to map the file
+ * contents directly into memory, which is efficient for large files (no copy).
+ *
+ * On Windows, this class is only available when `<windows.h>` is included
+ * before `<simdjson.h>` and the compilation targets Windows 11 or later
+ * (NTDDI_VERSION >= NTDDI_WIN10_CO). The Windows implementation uses the
+ * modern memory APIs (`CreateFileMapping2` / `MapViewOfFile3`) to map the
+ * file with true zero-copy semantics whenever the last page of the file
+ * provides enough trailing zero-fill for SIMDJSON_PADDING bytes; otherwise
+ * it falls back to a heap-allocated padded buffer populated with `ReadFile`.
+ *
+ * Either way, the resulting `padded_string_view` carries at least
+ * `SIMDJSON_PADDING` bytes of accessible zero-filled padding after the file
+ * content, so it can be consumed directly by the simdjson parsers (including
+ * `parse_many` / `iterate_many`).
  */
 class padded_memory_map {
 public:
@@ -4367,9 +4412,12 @@ public:
    * Create a new padded memory map for the given file.
    * After creating the memory map, you can call view() to get a padded_string_view of the file content.
    * The memory map will be automatically released when the padded_memory_map instance is destroyed.
-   * Note that the file content is not copied, so this is efficient for large files. However,
+   * On POSIX systems, the file content is not copied, so this is efficient for large files.
-   * the file must remain unchanged while the memory map is in use. In case of error (e.g., file not found,
+   * On Windows, the file is mapped into memory via `MapViewOfFile3` whenever possible
-   * permission denied, etc.), the memory map will be invalid and view() will return an empty view.
+   * (zero-copy) and otherwise read into a heap-allocated padded buffer.
+   * In all cases, the file must remain unchanged while the memory map is in use.
+   * In case of error (e.g., file not found, permission denied, etc.), the memory map will be
+   * invalid and view() will return an empty view.
    * You can check if the memory map is valid by calling is_valid() before using view().
    *
    * @param filename the path to the file to memory-map.
@@ -4406,8 +4454,14 @@ private:
   padded_memory_map &operator=(const padded_memory_map &) = delete;
   const char *data{nullptr};
   size_t size{0};
+#ifdef _WIN32
+  // On Windows the underlying storage may either be a memory-mapped view
+  // (released with UnmapViewOfFile) or a heap-allocated padded buffer
+  // (released with delete[]). This flag distinguishes the two cases.
+  bool owns_heap_buffer_{false};
+#endif
 };
-#endif // _WIN32
+#endif // SIMDJSON_HAS_PADDED_MEMORY_MAP
 
 
 
@@ -4700,6 +4754,11 @@ inline padded_string_view pad_with_reserve(std::string& s) noexcept {
 #include <sys/stat.h>
 #include <unistd.h>
 #endif
+// On Windows, `padded_memory_map` (when it is enabled) depends on types and
+// functions declared in <windows.h>. We deliberately do NOT include that
+// header here: users of simdjson who want `padded_memory_map` on Windows
+// must include <windows.h> themselves *before* including this header. See
+// padded_string.h for the detection logic.
 
 namespace simdjson {
 namespace internal {
@@ -5068,6 +5127,8 @@ inline bool padded_string_builder::reserve(size_t additional) noexcept {
 }
 
 
+#if SIMDJSON_HAS_PADDED_MEMORY_MAP
+
 #ifndef _WIN32
 simdjson_inline padded_memory_map::padded_memory_map(const char *filename) noexcept {
 
@@ -5104,7 +5165,141 @@ simdjson_inline padded_memory_map::~padded_memory_map() noexcept {
     munmap(const_cast<char *>(data), size + simdjson::SIMDJSON_PADDING);
   }
 }
+#else // _WIN32
+// Windows 11+ implementation.
+//
+// We use the modern Windows memory APIs (CreateFileMapping2 + MapViewOfFile3,
+// available since Windows 10 1803 and gated on Windows 11 in our build) to
+// map the file directly into the process address space with zero copies.
+//
+// Windows guarantees that after a file view is mapped, any bytes in the
+// trailing partial page beyond the end of the file are zero-filled. As long
+// as the file does not end exactly on (or within SIMDJSON_PADDING bytes of)
+// a page boundary, we therefore get SIMDJSON_PADDING accessible zero bytes
+// for free at the tail of the view. In the rare edge cases where the tail
+// is not large enough (about 1.5% of file sizes if sizes were uniformly
+// distributed), we fall back to reading the file into a heap-allocated
+// padded buffer. That fallback is still correct — it just performs one
+// memory copy instead of a zero-copy mapping.
+simdjson_inline padded_memory_map::padded_memory_map(const char *filename) noexcept {
+  HANDLE file_handle = ::CreateFileA(
+      filename, GENERIC_READ,
+      FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+      NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
+  if (file_handle == INVALID_HANDLE_VALUE) {
+    return; // file not found or cannot be opened
+  }
+  LARGE_INTEGER file_size_li;
+  if (!::GetFileSizeEx(file_handle, &file_size_li) || file_size_li.QuadPart < 0) {
+    ::CloseHandle(file_handle);
+    return; // failed to get file size
+  }
+#if SIMDJSON_IS_32BITS
+  if (static_cast<unsigned long long>(file_size_li.QuadPart) >
+      static_cast<unsigned long long>(SIZE_MAX - simdjson::SIMDJSON_PADDING)) {
+    ::CloseHandle(file_handle);
+    return; // file too large to map on a 32-bit system
+  }
+#endif
+  size = static_cast<size_t>(file_size_li.QuadPart);
 
+  // Fast zero-copy path: only usable when the last partial page of the file
+  // gives us at least SIMDJSON_PADDING bytes of zero-filled slack.
+  if (size > 0) {
+    SYSTEM_INFO sys_info;
+    ::GetSystemInfo(&sys_info);
+    const size_t page_size = static_cast<size_t>(sys_info.dwPageSize);
+    const size_t tail_in_page = size % page_size;
+    const size_t tail_zero_fill = (tail_in_page == 0)
+        ? size_t{0}
+        : (page_size - tail_in_page);
+
+    if (tail_zero_fill >= simdjson::SIMDJSON_PADDING) {
+      // Create the section with the new CreateFileMapping2 API.
+      HANDLE mapping = ::CreateFileMapping2(
+          file_handle, /*SecurityAttributes=*/ NULL,
+          /*DesiredAccess=*/ FILE_MAP_READ,
+          /*PageProtection=*/ PAGE_READONLY,
+          /*AllocationAttributes=*/ 0,
+          /*MaximumSize=*/ 0, // 0 => entire file
+          /*Name=*/ NULL,
+          /*ExtendedParameters=*/ NULL, /*ParameterCount=*/ 0);
+      if (mapping != NULL) {
+        // Map the view with the new MapViewOfFile3 API.
+        PVOID view_ptr = ::MapViewOfFile3(
+            mapping, ::GetCurrentProcess(),
+            /*BaseAddress=*/ NULL,
+            /*Offset=*/ 0,
+            /*ViewSize=*/ size,
+            /*AllocationType=*/ 0,
+            /*PageProtection=*/ PAGE_READONLY,
+            /*ExtendedParameters=*/ NULL, /*ParameterCount=*/ 0);
+        ::CloseHandle(mapping);
+        if (view_ptr != NULL) {
+          ::CloseHandle(file_handle);
+          data = static_cast<const char *>(view_ptr);
+          owns_heap_buffer_ = false;
+          return;
+        }
+      }
+      // Fall through to the buffered-read fallback if the mapping failed.
+    }
+  }
+
+  // Fallback path: the file ends too close to a page boundary (or the
+  // mapping APIs refused) — read the file contents into a heap-allocated
+  // padded buffer. This preserves the class' padding invariant at the cost
+  // of one copy.
+  size_t total_size = size + simdjson::SIMDJSON_PADDING;
+  if (total_size < size) { // overflow guard
+    ::CloseHandle(file_handle);
+    size = 0;
+    return;
+  }
+  char *buffer = new (std::nothrow) char[total_size];
+  if (buffer == nullptr) {
+    ::CloseHandle(file_handle);
+    size = 0;
+    return;
+  }
+  size_t total_read = 0;
+  while (total_read < size) {
+    size_t remaining = size - total_read;
+    const size_t chunk_limit = static_cast<size_t>(0x40000000UL); // 1 GiB per call
+    DWORD to_read = remaining > chunk_limit
+        ? static_cast<DWORD>(chunk_limit)
+        : static_cast<DWORD>(remaining);
+    DWORD bytes_read = 0;
+    if (!::ReadFile(file_handle, buffer + total_read, to_read, &bytes_read, NULL)) {
+      delete[] buffer;
+      ::CloseHandle(file_handle);
+      size = 0;
+      return;
+    }
+    if (bytes_read == 0) {
+      // Unexpected EOF: the file shrank while we were reading it.
+      delete[] buffer;
+      ::CloseHandle(file_handle);
+      size = 0;
+      return;
+    }
+    total_read += bytes_read;
+  }
+  std::memset(buffer + size, 0, simdjson::SIMDJSON_PADDING);
+  data = buffer;
+  owns_heap_buffer_ = true;
+  ::CloseHandle(file_handle);
+}
+
+simdjson_inline padded_memory_map::~padded_memory_map() noexcept {
+  if (data == nullptr) { return; }
+  if (owns_heap_buffer_) {
+    delete[] const_cast<char *>(data);
+  } else {
+    ::UnmapViewOfFile(data);
+  }
+}
+#endif // _WIN32
 
 simdjson_inline simdjson::padded_string_view padded_memory_map::view() const noexcept simdjson_lifetime_bound {
   if(!is_valid()) {
@@ -5116,7 +5311,8 @@ simdjson_inline simdjson::padded_string_view padded_memory_map::view() const noe
 simdjson_inline bool padded_memory_map::is_valid() const noexcept {
   return data != nullptr;
 }
-#endif // _WIN32
+
+#endif // SIMDJSON_HAS_PADDED_MEMORY_MAP
 
 } // namespace simdjson
 

src/fallback.cpp

@@ -226,9 +226,15 @@ simdjson_warn_unused simdjson_inline error_code scan() {
       add_structural();
     // Primitive or invalid character (invalid characters will be checked in stage 2)
     } else {
-      // Anything else, add the structural and go until we find the next one
+      // Anything else, add the structural and go until we find the next one.
+      // We also stop on RS (0x1E) so that RFC 7464 json_sequence inputs
+      // like `\x1e"a"\x1e"b"` produce a separate structural for each RS
+      // rather than being absorbed into a single primitive run. RS is a
+      // control character that is invalid in normal JSON, so breaking
+      // the run here has no effect on well-formed non-json_sequence
+      // inputs.
       add_structural();
-      while (idx+1<len && !char_is_space_or_operator(buf[idx+1])) {
+      while (idx+1<len && !char_is_space_or_operator(buf[idx+1]) && buf[idx+1] != 0x1e) {
         idx++;
       };
     }
@@ -283,6 +289,56 @@ simdjson_warn_unused simdjson_inline error_code scan() {
     // doing.
     parser.structural_indexes[parser.n_structural_indexes] = uint32_t(len);
     if (parser.n_structural_indexes == 0) { return EMPTY; }
+  } else if (partial == stage1_mode::json_sequence_partial) {
+    // RFC 7464: use RS positions for batch boundaries
+    if(unclosed_string) {
+      parser.n_structural_indexes--;
+      if (simdjson_unlikely(parser.n_structural_indexes == 0)) { return CAPACITY; }
+    }
+    uint32_t next_batch_start = uint32_t(len);
+    auto new_structural_indexes = find_next_document_index_json_sequence(parser, len, false, next_batch_start);
+    if (new_structural_indexes == DOCUMENT_TOO_LARGE) {
+      return CAPACITY;
+    }
+    if (new_structural_indexes == 0) {
+      parser.n_structural_indexes = 0;
+      return EMPTY;
+    }
+    parser.n_structural_indexes = new_structural_indexes;
+    parser.structural_indexes[parser.n_structural_indexes] = next_batch_start;
+  } else if (partial == stage1_mode::json_sequence_final) {
+    // RFC 7464: final batch, last document extends to EOF
+    if(unclosed_string) { parser.n_structural_indexes--; }
+    uint32_t next_batch_start = uint32_t(len);
+    parser.n_structural_indexes = find_next_document_index_json_sequence(parser, len, true, next_batch_start);
+    parser.structural_indexes[parser.n_structural_indexes + 1] = parser.structural_indexes[parser.n_structural_indexes];
+    parser.structural_indexes[parser.n_structural_indexes] = uint32_t(len);
+    if (simdjson_unlikely(parser.n_structural_indexes == 0)) { return EMPTY; }
+  } else if (partial == stage1_mode::comma_delimited_partial) {
+    // Comma-delimited: filter root-level commas, use comma positions for batch boundaries
+    if(unclosed_string) {
+      parser.n_structural_indexes--;
+      if (simdjson_unlikely(parser.n_structural_indexes == 0)) { return CAPACITY; }
+    }
+    uint32_t next_batch_start = uint32_t(len);
+    auto new_structural_indexes = filter_comma_delimited(parser, len, false, next_batch_start);
+    if (new_structural_indexes == DOCUMENT_TOO_LARGE) {
+      return CAPACITY;
+    }
+    if (new_structural_indexes == 0) {
+      parser.n_structural_indexes = 0;
+      return EMPTY;
+    }
+    parser.n_structural_indexes = new_structural_indexes;
+    parser.structural_indexes[parser.n_structural_indexes] = next_batch_start;
+  } else if (partial == stage1_mode::comma_delimited_final) {
+    // Comma-delimited: final batch, last document extends to EOF
+    if(unclosed_string) { parser.n_structural_indexes--; }
+    uint32_t next_batch_start = uint32_t(len);
+    parser.n_structural_indexes = filter_comma_delimited(parser, len, true, next_batch_start);
+    parser.structural_indexes[parser.n_structural_indexes + 1] = parser.structural_indexes[parser.n_structural_indexes];
+    parser.structural_indexes[parser.n_structural_indexes] = uint32_t(len);
+    if (simdjson_unlikely(parser.n_structural_indexes == 0)) { return EMPTY; }
   } else if(unclosed_string) { error = UNCLOSED_STRING; }
   return error;
 }

src/generic/stage1/find_next_document_index.h

@@ -97,9 +97,280 @@ simdjson_inline uint32_t find_next_document_index(dom_parser_implementation &par
   return 0;
 }
 
+/**
+ * Sentinel value returned to indicate a document started but didn't fit
+ * (CAPACITY error), as opposed to 0 which means no document content found
+ * (EMPTY).
+ */
+constexpr uint32_t DOCUMENT_TOO_LARGE = UINT32_MAX;
+
+/**
+ * For RFC 7464 JSON text sequences, filter RS from structural indexes and
+ * find batch boundaries.
+ *
+ * In JSON sequence mode, RS (0x1E) marks the start of each JSON text.
+ * RS bytes appear in structural_indexes as they are classified as scalars.
+ * This function:
+ * 1. Scans structural_indexes to find and count RS positions
+ * 2. Filters RS out of structural_indexes in-place
+ * 3. Determines batch boundaries based on RS positions
+ *
+ * @param parser The parser with structural_indexes and buf.
+ * @param len The length of the current batch buffer.
+ * @param is_final True if this is the final batch (no more data coming).
+ * @param next_batch_start Output: offset where the next batch should start.
+ * @return The number of structural indexes to keep (after RS filtering),
+ *         0 if no document content found (EMPTY),
+ *         or DOCUMENT_TOO_LARGE if a document started but didn't fit (CAPACITY).
+ */
+simdjson_inline uint32_t find_next_document_index_json_sequence(
+    dom_parser_implementation &parser,
+    size_t len,
+    bool is_final,
+    uint32_t &next_batch_start) {
+  // Default: next batch starts at end of buffer
+  next_batch_start = uint32_t(len);
+
+  if (parser.n_structural_indexes == 0) { return 0; }
+
+  // Phase 1: Scan structural_indexes to find RS positions and handle them.
+  // RS marks the start of a JSON text. For objects/arrays, the '{' or '[' after RS
+  // is already in structural_indexes (it's an operator). For scalars like numbers,
+  // the digit following RS is NOT in structural_indexes because the scanner sees
+  // RS as a scalar, making the digit a scalar continuation, not a start.
+  // We must: (1) remove RS from structural_indexes, and (2) for scalars, add the
+  // actual value start position.
+  uint32_t write_idx = 0;
+  uint32_t last_rs_pos = 0;
+  uint32_t rs_count = 0;
+
+  for (uint32_t read_idx = 0; read_idx < parser.n_structural_indexes; read_idx++) {
+    const uint32_t pos = parser.structural_indexes[read_idx];
+    if (parser.buf[pos] == 0x1E) {
+      // This is an RS character - find the actual JSON value start.
+      last_rs_pos = pos;
+      rs_count++;
+      // Skip past this RS and any whitespace *and any additional RSes*
+      // to locate the real value. Consecutive RSes are degenerate
+      // "empty records" per RFC 7464; we collapse them here. They do
+      // not always appear as separate entries in structural_indexes
+      // because the scanner groups runs of adjacent non-whitespace
+      // scalar bytes (including RS) into a single scalar start.
+      uint32_t value_start = pos + 1;
+      while (value_start < len) {
+        const uint8_t c = parser.buf[value_start];
+        if (c == ' ' || c == '\t' || c == '\n' || c == '\r') {
+          value_start++;
+        } else if (c == 0x1E) {
+          // Collapsed empty record. Still count it so rs_count reflects
+          // the true number of record markers and last_rs_pos tracks
+          // the final one.
+          last_rs_pos = value_start;
+          rs_count++;
+          value_start++;
+        } else {
+          break;
+        }
+      }
+      // If the scanner emitted additional structurals inside the
+      // whitespace+RS run we just walked over (i.e., isolated RSes
+      // separated by whitespace), skip past them so we do not
+      // double-count or double-emit.
+      while (read_idx + 1 < parser.n_structural_indexes &&
+             parser.structural_indexes[read_idx + 1] < value_start) {
+        read_idx++;
+      }
+      // Check if the value start is an operator (always present in
+      // scanner structural_indexes) or a scalar-like start (which may
+      // be missing from structural_indexes and must be added here).
+      // Note: '"' is NOT always in structural_indexes. The scanner
+      // classifies '"' as a scalar character and emits it as a
+      // structural only when it is a *scalar start* (preceded by
+      // whitespace or an operator). When '"' immediately follows an
+      // RS (which the scanner also classifies as scalar), it is
+      // treated as a scalar continuation and not emitted - so we
+      // must add it here just like any other scalar value.
+      if (value_start < len) {
+        const uint8_t c = parser.buf[value_start];
+        const bool is_operator =
+            (c == '{' || c == '}' || c == '[' || c == ']' ||
+             c == ':' || c == ',');
+        // If the next scanner structural is exactly at value_start,
+        // the scanner already emitted it (it followed whitespace) and
+        // we must not add a duplicate - a subsequent iteration will
+        // copy it into write_idx.
+        const bool already_emitted =
+            (read_idx + 1 < parser.n_structural_indexes &&
+             parser.structural_indexes[read_idx + 1] == value_start);
+        if (!is_operator && !already_emitted) {
+          // Scalar value (number/true/false/null/string) - add its
+          // position since scanner missed it.
+          parser.structural_indexes[write_idx++] = value_start;
+        }
+      }
+    } else {
+      // Not RS, copy to output
+      parser.structural_indexes[write_idx++] = pos;
+    }
+  }
+
+  // Update structural index count
+  parser.n_structural_indexes = write_idx;
+
+  if (parser.n_structural_indexes == 0) { return 0; }
+  if (rs_count == 0) {
+    // No RS found; for final batch, try generic boundary detection
+    return is_final ? find_next_document_index(parser) : 0;
+  }
+
+  // Phase 2: Determine batch boundaries based on RS positions
+
+  if (is_final) {
+    // Final batch: all documents are complete (last one ends at EOF).
+    // In json_sequence mode, RS markers define document boundaries, so all
+    // remaining structurals form complete documents. Return them all directly.
+    // (Calling find_next_document_index() would fail for scalar documents.)
+    return parser.n_structural_indexes;
+  }
+
+  // Partial batch: need to find complete documents only.
+  // A document starting at an RS is complete if there is another RS after it.
+  next_batch_start = last_rs_pos;
+
+  if (rs_count < 2) {
+    // Only one RS, so we have at most one document that may be incomplete.
+    // We cannot confirm it is complete without another RS.
+    // Return DOCUMENT_TOO_LARGE if content was found (write_idx > 0), 0 if only separators.
+    return (parser.n_structural_indexes > 0) ? DOCUMENT_TOO_LARGE : 0;
+  }
+
+  // We have at least 2 RS markers. The last complete document ends before last_rs_pos.
+
+  // Find the structural index cutoff: keep only structurals < last_rs_pos.
+  // Since we already filtered RS, all remaining structurals are valid.
+  // We iterate backward to find the last structural before last_rs_pos.
+  uint32_t keep_count = 0;
+  for (uint32_t i = parser.n_structural_indexes; i > 0; i--) {
+    if (parser.structural_indexes[i - 1] < last_rs_pos) {
+      keep_count = i;
+      break;
+    }
+  }
+
+  // No structurals before the last RS - no complete documents
+  if (keep_count == 0) { return 0; }
+
+  // All documents before the last RS are complete by definition (the next RS
+  // confirms their end). No need to call find_next_document_index() which
+  // would fail for scalar documents like `1` or `"hello"`.
+  return keep_count;
+}
+
+/**
+ * Filter comma-delimited documents by removing root-level commas from
+ * structural indexes.
+ *
+ * For comma-delimited format like `{...},{...},{...}`, we need to remove
+ * the commas that separate documents (depth 0) while preserving commas
+ * inside arrays and objects (depth > 0).
+ *
+ * After filtering, the structural indexes look like whitespace-delimited
+ * documents, so find_next_document_index() works unchanged.
+ *
+ * @param parser The parser with structural_indexes and buf.
+ * @param len The length of the current batch buffer.
+ * @param is_final True if this is the final batch (no more data coming).
+ * @param next_batch_start Output: offset where the next batch should start.
+ * @return The number of structural indexes to keep,
+ *         0 if no document content found (EMPTY),
+ *         or DOCUMENT_TOO_LARGE if a document started but didn't fit (CAPACITY).
+ */
+simdjson_inline uint32_t filter_comma_delimited(
+    dom_parser_implementation &parser,
+    size_t len,
+    bool is_final,
+    uint32_t &next_batch_start) {
+  // Default: next batch starts at end of buffer
+  next_batch_start = uint32_t(len);
+
+  if (parser.n_structural_indexes == 0) { return 0; }
+
+  // Track depth to identify root-level commas (depth 0)
+  int depth = 0;
+  uint32_t write_idx = 0;
+  uint32_t last_root_comma_pos = 0;
+  uint32_t root_comma_count = 0;
+
+  for (uint32_t i = 0; i < parser.n_structural_indexes; i++) {
+    uint32_t idx = parser.structural_indexes[i];
+    uint8_t c = parser.buf[idx];
+
+    switch (c) {
+      case '{': case '[':
+        depth++;
+        parser.structural_indexes[write_idx++] = idx;
+        break;
+      case '}': case ']':
+        depth--;
+        parser.structural_indexes[write_idx++] = idx;
+        break;
+      case ',':
+        if (depth == 0) {
+          // Root-level comma = document boundary, skip it
+          last_root_comma_pos = idx;
+          root_comma_count++;
+          continue;
+        }
+        parser.structural_indexes[write_idx++] = idx;
+        break;
+      default:
+        // Colons, scalars, etc.
+        parser.structural_indexes[write_idx++] = idx;
+        break;
+    }
+  }
+
+  // Update structural index count
+  parser.n_structural_indexes = write_idx;
+
+  if (parser.n_structural_indexes == 0) { return 0; }
+
+  if (is_final) {
+    // Final batch: use standard boundary detection on filtered indexes
+    return find_next_document_index(parser);
+  }
+
+  // Partial batch: need to find complete documents only.
+  // A document ending with a root comma is complete.
+  if (root_comma_count == 0) {
+    // No root commas found; we cannot confirm any document is complete.
+    // The whole batch might be one incomplete document.
+    // Return DOCUMENT_TOO_LARGE if content was found (write_idx > 0), 0 if only commas.
+    return (parser.n_structural_indexes > 0) ? DOCUMENT_TOO_LARGE : 0;
+  }
+
+  // We have at least one root comma. Documents before the last comma are complete.
+  next_batch_start = last_root_comma_pos + 1;
+
+  // Find the structural index cutoff: keep only structurals < last_root_comma_pos
+  uint32_t keep_count = 0;
+  for (uint32_t i = parser.n_structural_indexes; i > 0; i--) {
+    if (parser.structural_indexes[i - 1] < last_root_comma_pos) {
+      keep_count = i;
+      break;
+    }
+  }
+
+  if (keep_count == 0) { return 0; }
+
+  // Use standard boundary detection on the complete portion
+  parser.n_structural_indexes = keep_count;
+  return find_next_document_index(parser);
+}
+
 } // namespace stage1
 } // unnamed namespace
 } // namespace SIMDJSON_IMPLEMENTATION
 } // namespace simdjson
 
-#endif // SIMDJSON_SRC_GENERIC_STAGE1_FIND_NEXT_DOCUMENT_INDEX_H
+#endif // SIMDJSON_SRC_GENERIC_STAGE1_FIND_NEXT_DOCUMENT_INDEX_H

src/generic/stage1/json_structural_indexer.h

@@ -314,7 +314,6 @@ simdjson_inline error_code json_structural_indexer::finish(dom_parser_implementa
         return EMPTY;
       }
     }
-
     parser.n_structural_indexes = new_structural_indexes;
   } else if (partial == stage1_mode::streaming_final) {
     if(have_unclosed_string) { parser.n_structural_indexes--; }
@@ -342,6 +341,56 @@ simdjson_inline error_code json_structural_indexer::finish(dom_parser_implementa
         // the trailing garbage.
         return EMPTY;
     }
+  } else if (partial == stage1_mode::json_sequence_partial) {
+    // RFC 7464: use RS positions for batch boundaries
+    if(have_unclosed_string) {
+      parser.n_structural_indexes--;
+      if (simdjson_unlikely(parser.n_structural_indexes == 0u)) { return CAPACITY; }
+    }
+    uint32_t next_batch_start = uint32_t(len);
+    auto new_structural_indexes = find_next_document_index_json_sequence(parser, len, false, next_batch_start);
+    if (new_structural_indexes == DOCUMENT_TOO_LARGE) {
+      return CAPACITY;
+    }
+    if (new_structural_indexes == 0) {
+      parser.n_structural_indexes = 0;
+      return EMPTY;
+    }
+    parser.n_structural_indexes = new_structural_indexes;
+    parser.structural_indexes[parser.n_structural_indexes] = next_batch_start;
+  } else if (partial == stage1_mode::json_sequence_final) {
+    // RFC 7464: final batch, last document extends to EOF
+    if(have_unclosed_string) { parser.n_structural_indexes--; }
+    uint32_t next_batch_start = uint32_t(len);
+    parser.n_structural_indexes = find_next_document_index_json_sequence(parser, len, true, next_batch_start);
+    parser.structural_indexes[parser.n_structural_indexes + 1] = parser.structural_indexes[parser.n_structural_indexes];
+    parser.structural_indexes[parser.n_structural_indexes] = uint32_t(len);
+    if (simdjson_unlikely(parser.n_structural_indexes == 0u)) { return EMPTY; }
+  } else if (partial == stage1_mode::comma_delimited_partial) {
+    // Comma-delimited: filter root-level commas, use comma positions for batch boundaries
+    if(have_unclosed_string) {
+      parser.n_structural_indexes--;
+      if (simdjson_unlikely(parser.n_structural_indexes == 0u)) { return CAPACITY; }
+    }
+    uint32_t next_batch_start = uint32_t(len);
+    auto new_structural_indexes = filter_comma_delimited(parser, len, false, next_batch_start);
+    if (new_structural_indexes == DOCUMENT_TOO_LARGE) {
+      return CAPACITY;
+    }
+    if (new_structural_indexes == 0) {
+      parser.n_structural_indexes = 0;
+      return EMPTY;
+    }
+    parser.n_structural_indexes = new_structural_indexes;
+    parser.structural_indexes[parser.n_structural_indexes] = next_batch_start;
+  } else if (partial == stage1_mode::comma_delimited_final) {
+    // Comma-delimited: final batch, last document extends to EOF
+    if(have_unclosed_string) { parser.n_structural_indexes--; }
+    uint32_t next_batch_start = uint32_t(len);
+    parser.n_structural_indexes = filter_comma_delimited(parser, len, true, next_batch_start);
+    parser.structural_indexes[parser.n_structural_indexes + 1] = parser.structural_indexes[parser.n_structural_indexes];
+    parser.structural_indexes[parser.n_structural_indexes] = uint32_t(len);
+    if (simdjson_unlikely(parser.n_structural_indexes == 0u)) { return EMPTY; }
   }
   checker.check_eof();
   return checker.errors();

tests/CMakeLists.txt

@@ -4,6 +4,10 @@ include(${PROJECT_SOURCE_DIR}/cmake/add_cpp_test.cmake)
 add_subdirectory(dom)
 add_subdirectory(ondemand)
 
+# compilation_failure_tests is added before the global link_libraries(simdjson) so that
+# multiple_include/myexe does not receive a duplicate simdjson entry alongside the one
+# already propagated by mylib PUBLIC simdjson::simdjson.
+add_subdirectory(compilation_failure_tests)
 
 # All remaining tests link with simdjson proper
 link_libraries(simdjson)
@@ -27,6 +31,5 @@ endif()
 # SIMDJSON_FORCE_IMPLEMENTATION, so we know we're testing what we think we're testing
 add_cpp_test(checkimplementation LABELS other per_implementation)
 
-add_subdirectory(compilation_failure_tests)
 add_subdirectory(builder)
 add_subdirectory(compile_time)

tests/compilation_failure_tests/CMakeLists.txt

@@ -14,6 +14,17 @@ function(add_dual_compile_test TEST_NAME)
 endfunction(add_dual_compile_test)
 
 
+if(NOT BUILD_SHARED_LIBS)
+  # Add multiple_include BEFORE link_libraries(simdjson) so that myexe only receives
+  # simdjson once (through mylib PUBLIC simdjson::simdjson) and not a second time from
+  # a directory-wide link entry.
+  add_subdirectory(multiple_include)
+endif()
+
+# Dual-compile tests build executables that reference simdjson symbols, so they need
+# the library linked in.
+link_libraries(simdjson)
+
 add_dual_compile_test(example_compiletest)
 # These don't compile with exceptions off
 if (SIMDJSON_EXCEPTIONS)
@@ -24,9 +35,4 @@ if (SIMDJSON_EXCEPTIONS)
   add_dual_compile_test(dangling_parser_parse_stdstring)
   add_dual_compile_test(dangling_parser_parse_padstring)
   add_dual_compile_test(unsafe_parse_many)
-endif()
-
-if(NOT BUILD_SHARED_LIBS)
-  # We only check that it builds
-  add_subdirectory(multiple_include)
 endif()

tests/document_stream_fuzz_test_common.h

@@ -0,0 +1,230 @@
+#ifndef SIMDJSON_TESTS_DOCUMENT_STREAM_FUZZ_TEST_COMMON_H
+#define SIMDJSON_TESTS_DOCUMENT_STREAM_FUZZ_TEST_COMMON_H
+
+#include <cstdint>
+#include <random>
+#include <string>
+#include <vector>
+
+#include "simdjson.h"
+
+namespace document_stream_fuzz {
+
+constexpr uint64_t fixed_seed = 0x5eed1234ULL;
+constexpr size_t batch_size = 512;
+constexpr size_t minimum_total_bytes = 4096;
+constexpr size_t minimum_document_count = 128;
+
+struct stream_case {
+  const char *name;
+  simdjson::stream_format format;
+  std::string input;
+  std::vector<std::string> expected_documents;
+};
+
+inline char random_char(std::mt19937_64 &rng) {
+  static constexpr char alphabet[] =
+      "abcdefghijklmnopqrstuvwxyz"
+      "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+      "0123456789 _-/.";
+  std::uniform_int_distribution<size_t> dist(0, sizeof(alphabet) - 2);
+  return alphabet[dist(rng)];
+}
+
+inline std::string make_ascii_text(std::mt19937_64 &rng, size_t min_length, size_t max_length) {
+  std::uniform_int_distribution<size_t> length_dist(min_length, max_length);
+  const size_t length = length_dist(rng);
+  std::string text;
+  text.reserve(length);
+  for (size_t i = 0; i < length; i++) {
+    text.push_back(random_char(rng));
+  }
+  return text;
+}
+
+inline std::string quote_json_string(const std::string &text) {
+  std::string quoted;
+  quoted.reserve(text.size() + 2);
+  quoted.push_back('"');
+  for (char ch : text) {
+    if (ch == '\\' || ch == '"') {
+      quoted.push_back('\\');
+    }
+    quoted.push_back(ch);
+  }
+  quoted.push_back('"');
+  return quoted;
+}
+
+inline std::string make_integer_literal(std::mt19937_64 &rng) {
+  std::uniform_int_distribution<int64_t> dist(-1000000, 1000000);
+  return std::to_string(dist(rng));
+}
+
+inline std::string make_float_literal(std::mt19937_64 &rng) {
+  std::uniform_int_distribution<int64_t> whole_dist(-250000, 250000);
+  std::uniform_int_distribution<int64_t> fraction_dist(1, 9999);
+  return std::to_string(whole_dist(rng)) + "." + std::to_string(fraction_dist(rng));
+}
+
+inline std::string make_scalar(std::mt19937_64 &rng) {
+  std::uniform_int_distribution<int> type_dist(0, 4);
+  switch (type_dist(rng)) {
+    case 0: return quote_json_string(make_ascii_text(rng, 0, 20));
+    case 1: return make_integer_literal(rng);
+    case 2: return make_float_literal(rng);
+    case 3: return (rng() & 1) ? "true" : "false";
+    default: return "null";
+  }
+}
+
+inline std::string make_value(std::mt19937_64 &rng, int depth);
+
+inline std::string make_array(std::mt19937_64 &rng, int depth) {
+  std::uniform_int_distribution<int> count_dist(0, depth == 0 ? 5 : 3);
+  const int count = count_dist(rng);
+  std::string out = "[";
+  for (int i = 0; i < count; i++) {
+    if (i > 0) {
+      out.push_back(',');
+    }
+    out += make_value(rng, depth + 1);
+  }
+  out.push_back(']');
+  return out;
+}
+
+inline std::string make_object(std::mt19937_64 &rng, int depth) {
+  std::uniform_int_distribution<int> count_dist(0, depth == 0 ? 5 : 3);
+  const int count = count_dist(rng);
+  std::string out = "{";
+  for (int i = 0; i < count; i++) {
+    if (i > 0) {
+      out.push_back(',');
+    }
+    std::string key = "k";
+    key += std::to_string(depth);
+    key += '_';
+    key += std::to_string(i);
+    key += '_';
+    key += make_ascii_text(rng, 1, 6);
+    out += quote_json_string(key);
+    out.push_back(':');
+    out += make_value(rng, depth + 1);
+  }
+  out.push_back('}');
+  return out;
+}
+
+inline std::string make_value(std::mt19937_64 &rng, int depth) {
+  if (depth >= 3) {
+    return make_scalar(rng);
+  }
+  std::uniform_int_distribution<int> type_dist(0, 6);
+  switch (type_dist(rng)) {
+    case 0: return quote_json_string(make_ascii_text(rng, 0, 20));
+    case 1: return make_integer_literal(rng);
+    case 2: return make_float_literal(rng);
+    case 3: return (rng() & 1) ? "true" : "false";
+    case 4: return "null";
+    case 5: return make_array(rng, depth);
+    default: return make_object(rng, depth);
+  }
+}
+
+inline std::vector<std::string> make_documents() {
+  std::vector<std::string> docs = {
+    "0",
+    "-17",
+    "3.125",
+    "true",
+    "false",
+    "null",
+    "\"alpha beta\"",
+    "[]",
+    "[1,true,\"x\"]",
+    "{}",
+    "{\"a\":1,\"b\":[2,3],\"c\":{\"d\":false}}"
+  };
+
+  size_t total_bytes = 0;
+  for (const auto &doc : docs) {
+    total_bytes += doc.size();
+  }
+
+  std::mt19937_64 rng(fixed_seed);
+  while (docs.size() < minimum_document_count || total_bytes < minimum_total_bytes) {
+    docs.push_back(make_value(rng, 0));
+    total_bytes += docs.back().size();
+  }
+  return docs;
+}
+
+inline std::vector<std::string> make_wrapped_documents(const std::vector<std::string> &docs) {
+  std::vector<std::string> wrapped;
+  wrapped.reserve(docs.size());
+  for (size_t i = 0; i < docs.size(); i++) {
+    wrapped.push_back("{\"id\":" + std::to_string(i) + ",\"value\":" + docs[i] + "}");
+  }
+  return wrapped;
+}
+
+inline std::string build_whitespace_input(const std::vector<std::string> &docs) {
+  static const char *separators[] = {" ", "\n", "\r\n", "\t", " \n\t", "\r\t "};
+  std::string out = " \n\t";
+  for (size_t i = 0; i < docs.size(); i++) {
+    out += docs[i];
+    if (i + 1 < docs.size()) {
+      out += separators[i % (sizeof(separators) / sizeof(separators[0]))];
+    }
+  }
+  out += "\n\t ";
+  return out;
+}
+
+inline std::string build_json_sequence_input(const std::vector<std::string> &docs) {
+  std::string out;
+  for (size_t i = 0; i < docs.size(); i++) {
+    out.push_back('\x1e');
+    out += docs[i];
+    out.push_back('\n');
+  }
+  return out;
+}
+
+inline std::string build_comma_delimited_input(const std::vector<std::string> &docs) {
+  std::string out;
+  for (size_t i = 0; i < docs.size(); i++) {
+    if (i > 0) {
+      out += (i % 3 == 0) ? ",\n" : ", ";
+    }
+    out += docs[i];
+  }
+  return out;
+}
+
+inline std::string build_comma_delimited_array_input(const std::vector<std::string> &docs) {
+  std::string out = " \t\n[";
+  for (size_t i = 0; i < docs.size(); i++) {
+    if (i > 0) {
+      out += (i % 4 == 0) ? ",\n" : ", ";
+    }
+    out += docs[i];
+  }
+  out += "]\r\n";
+  return out;
+}
+
+inline std::vector<stream_case> make_stream_cases(const std::vector<std::string> &docs) {
+  std::vector<std::string> whitespace_docs = make_wrapped_documents(docs);
+  return {
+    {"whitespace_delimited", simdjson::stream_format::whitespace_delimited, build_whitespace_input(whitespace_docs), whitespace_docs},
+    {"json_sequence", simdjson::stream_format::json_sequence, build_json_sequence_input(whitespace_docs), whitespace_docs},
+    {"comma_delimited", simdjson::stream_format::comma_delimited, build_comma_delimited_input(whitespace_docs), whitespace_docs},
+    {"comma_delimited_array", simdjson::stream_format::comma_delimited_array, build_comma_delimited_array_input(whitespace_docs), whitespace_docs}
+  };
+}
+
+} // namespace document_stream_fuzz
+
+#endif

tests/dom/CMakeLists.txt

@@ -7,6 +7,7 @@ if(NOT SIMDJSON_LEGACY_VISUAL_STUDIO AND NOT SIMDJSON_WINDOWS_DLL)
 endif()
 add_cpp_test(basictests                 LABELS dom acceptance per_implementation)
 add_cpp_test(document_stream_tests      LABELS dom acceptance per_implementation)
+add_cpp_test(document_stream_fuzz_tests LABELS dom acceptance per_implementation)
 add_cpp_test(document_tests             LABELS dom acceptance per_implementation)
 add_cpp_test(errortests                 LABELS dom acceptance per_implementation)
 add_cpp_test(extracting_values_example  LABELS dom acceptance per_implementation)

tests/dom/document_stream_fuzz_tests.cpp

@@ -0,0 +1,97 @@
+#include <string>
+#include <vector>
+
+#include "simdjson.h"
+#include "test_macros.h"
+#include "test_main.h"
+#include "document_stream_fuzz_test_common.h"
+
+namespace document_stream_fuzz_tests {
+
+std::string strip_stream_artifacts(simdjson::stream_format format, std::string_view text) {
+  size_t start = 0;
+  size_t end = text.size();
+  while (start < end && (text[start] == ' ' || text[start] == '\t' || text[start] == '\n' || text[start] == '\r' || text[start] == '\x1e')) {
+    start++;
+  }
+  while (end > start && (text[end - 1] == ' ' || text[end - 1] == '\t' || text[end - 1] == '\n' || text[end - 1] == '\r' || text[end - 1] == '\x1e')) {
+    end--;
+  }
+  std::string cleaned(text.substr(start, end - start));
+  if (format == simdjson::stream_format::comma_delimited || format == simdjson::stream_format::comma_delimited_array) {
+    while (!cleaned.empty() && cleaned.back() == ',') {
+      cleaned.pop_back();
+      while (!cleaned.empty() && (cleaned.back() == ' ' || cleaned.back() == '\t' || cleaned.back() == '\n' || cleaned.back() == '\r')) {
+        cleaned.pop_back();
+      }
+    }
+  }
+  return cleaned;
+}
+
+std::string canonicalize_document(simdjson::stream_format format, std::string_view text) {
+  std::string cleaned = strip_stream_artifacts(format, text);
+  simdjson::dom::parser parser;
+  simdjson::dom::element doc;
+  if (parser.parse(cleaned).get(doc)) {
+    return std::string("PARSE_ERROR:") + cleaned;
+  }
+  return simdjson::minify(doc);
+}
+
+const std::vector<std::string> &expected_documents() {
+  static const std::vector<std::string> docs = document_stream_fuzz::make_documents();
+  return docs;
+}
+
+const std::vector<document_stream_fuzz::stream_case> &stream_cases() {
+  static const std::vector<document_stream_fuzz::stream_case> cases =
+      document_stream_fuzz::make_stream_cases(expected_documents());
+  return cases;
+}
+
+bool verify_case(const document_stream_fuzz::stream_case &test_case) {
+  TEST_START();
+  const auto &expected = test_case.expected_documents;
+  ASSERT_TRUE(test_case.input.size() > document_stream_fuzz::batch_size * 4);
+
+  simdjson::padded_string input(test_case.input);
+  simdjson::dom::parser parser;
+
+  for (int pass = 0; pass < 2; pass++) {
+    simdjson::dom::document_stream stream;
+    ASSERT_SUCCESS(parser.parse_many(input, document_stream_fuzz::batch_size, test_case.format).get(stream));
+
+    size_t index = 0;
+    for (auto doc : stream) {
+      ASSERT_SUCCESS(doc.error());
+      ASSERT_TRUE(index < expected.size());
+      simdjson::dom::element el;
+      ASSERT_SUCCESS(doc.get(el));
+      ASSERT_EQUAL(
+          canonicalize_document(test_case.format, simdjson::minify(el)),
+          canonicalize_document(test_case.format, expected[index])
+      );
+      index++;
+    }
+    ASSERT_EQUAL(index, expected.size());
+  }
+
+  TEST_SUCCEED();
+}
+
+bool run() {
+  for (const auto &test_case : stream_cases()) {
+    std::cout << "Running fuzz corpus against stream format: " << test_case.name << std::endl;
+    if (!verify_case(test_case)) {
+      return false;
+    }
+  }
+  return true;
+}
+
+} // namespace document_stream_fuzz_tests
+
+int main(int argc, char *argv[]) {
+  return test_main(argc, argv, document_stream_fuzz_tests::run);
+}

tests/memory_map_tests.cpp

@@ -1,13 +1,29 @@
+// On Windows, padded_memory_map is an opt-in feature gated on the
+// SIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS macro. When that macro is set, the
+// consumer must also include <windows.h> before <simdjson.h>. We include
+// the Win32 header here so that -- in configurations that turned the
+// feature on -- the test actually exercises the Windows path.
 #ifdef _WIN32
-#include <cstdlib>
+#ifndef WIN32_LEAN_AND_MEAN
-// This test is not supported on Windows because it relies on POSIX APIs like
+#define WIN32_LEAN_AND_MEAN
-// mmap. Please run it on a POSIX-compliant system.
+#endif
-int main() { return EXIT_SUCCESS; }
+#ifndef NOMINMAX
-#else
+#define NOMINMAX
+#endif
+#include <windows.h>
+#endif
 
 #include "simdjson.h"
 #include "test_macros.h"
 
+// When SIMDJSON_HAS_PADDED_MEMORY_MAP is 0 (e.g. Windows builds without
+// SIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS, or MinGW configurations that lack
+// the required SDK gating), compile the test body out and make main()
+// report success so the test suite still runs as a no-op. This is not a
+// silent downgrade: users who want the Windows path must explicitly
+// enable the CMake option `SIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS`.
+#if SIMDJSON_HAS_PADDED_MEMORY_MAP
+
 #if SIMDJSON_EXCEPTIONS
 bool test_memory_map_exception() {
   TEST_START();
@@ -37,11 +53,89 @@ bool test_memory_map_noexception() {
     TEST_SUCCEED();
 }
 
+// Verifies that padded_memory_map can feed a streaming parser (iterate_many)
+// with JSON documents read from a file. This exercises the API that parse_many
+// / iterate_many users typically want: no extra copy on POSIX, portable fallback
+// on Windows. The AMAZON_CELLPHONES_NDJSON resource is an NDJSON file so it is
+// a realistic stress-test for streaming from a memory-mapped file.
+bool test_memory_map_iterate_many() {
+    TEST_START();
+    simdjson::padded_memory_map map(AMAZON_CELLPHONES_NDJSON);
+    if (!map.is_valid()) {
+        std::cerr << "Failed to memory-map the file " << AMAZON_CELLPHONES_NDJSON << std::endl;
+        return false;
+    }
+    simdjson::padded_string_view view = map.view();
+    simdjson::ondemand::parser parser;
+    simdjson::ondemand::document_stream stream;
+    ASSERT_SUCCESS( parser.iterate_many(view).get(stream) );
+    size_t count = 0;
+    for (auto doc : stream) {
+        ASSERT_SUCCESS( doc.error() );
+        count++;
+    }
+    if (count == 0) {
+        std::cerr << "Expected at least one document in " << AMAZON_CELLPHONES_NDJSON << std::endl;
+        return false;
+    }
+    TEST_SUCCEED();
+}
+
+// Verifies that padded_memory_map also works with the DOM streaming parser
+// (parse_many). Same rationale as the ondemand variant above.
+bool test_memory_map_parse_many() {
+    TEST_START();
+    simdjson::padded_memory_map map(AMAZON_CELLPHONES_NDJSON);
+    if (!map.is_valid()) {
+        std::cerr << "Failed to memory-map the file " << AMAZON_CELLPHONES_NDJSON << std::endl;
+        return false;
+    }
+    simdjson::padded_string_view view = map.view();
+    simdjson::dom::parser parser;
+    simdjson::dom::document_stream stream;
+    ASSERT_SUCCESS( parser.parse_many(view).get(stream) );
+    size_t count = 0;
+    for (auto doc : stream) {
+        ASSERT_SUCCESS( doc.error() );
+        count++;
+    }
+    if (count == 0) {
+        std::cerr << "Expected at least one document in " << AMAZON_CELLPHONES_NDJSON << std::endl;
+        return false;
+    }
+    TEST_SUCCEED();
+}
+
+// Ensures that trying to memory-map a file that does not exist leaves the map
+// in the "invalid" state rather than crashing. This is important on Windows
+// where the underlying implementation path differs from POSIX.
+bool test_memory_map_missing_file() {
+    TEST_START();
+    simdjson::padded_memory_map map("this_file_definitely_does_not_exist_123456789.json");
+    if (map.is_valid()) {
+        std::cerr << "Expected is_valid() == false for missing file" << std::endl;
+        return false;
+    }
+    TEST_SUCCEED();
+}
+
+#endif // SIMDJSON_HAS_PADDED_MEMORY_MAP
+
 int main() {
+#if SIMDJSON_HAS_PADDED_MEMORY_MAP
+    bool ok = true;
 #if SIMDJSON_EXCEPTIONS
-    return (test_memory_map_exception() && test_memory_map_noexception()) ? EXIT_SUCCESS : EXIT_FAILURE;
+    ok = ok && test_memory_map_exception();
+#endif
+    ok = ok && test_memory_map_noexception();
+    ok = ok && test_memory_map_iterate_many();
+    ok = ok && test_memory_map_parse_many();
+    ok = ok && test_memory_map_missing_file();
+    return ok ? EXIT_SUCCESS : EXIT_FAILURE;
 #else
-    return test_memory_map_noexception() ? EXIT_SUCCESS : EXIT_FAILURE;
+    std::cout << "padded_memory_map is disabled in this configuration; "
+                 "set SIMDJSON_ENABLE_MEMORY_FILE_MAPPING_ON_WINDOWS=ON in CMake to "
+                 "enable it on Windows. Test skipped." << std::endl;
+    return EXIT_SUCCESS;
 #endif
 }
-#endif

tests/ondemand/CMakeLists.txt

@@ -12,6 +12,7 @@ add_cpp_test(ondemand_array_tests                    LABELS ondemand acceptance
 add_cpp_test(ondemand_array_error_tests              LABELS ondemand acceptance per_implementation)
 add_cpp_test(ondemand_compilation_tests              LABELS ondemand acceptance per_implementation)
 add_cpp_test(ondemand_document_stream_tests          LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_document_stream_fuzz_tests     LABELS ondemand acceptance per_implementation)
 add_cpp_test(ondemand_error_tests                    LABELS ondemand acceptance per_implementation)
 add_cpp_test(ondemand_error_location_tests           LABELS ondemand acceptance per_implementation)
 add_cpp_test(ondemand_json_pointer_tests             LABELS ondemand acceptance per_implementation)
@@ -24,6 +25,7 @@ add_cpp_test(ondemand_misc_tests                     LABELS ondemand acceptance
 add_cpp_test(ondemand_number_tests                   LABELS ondemand acceptance per_implementation)
 add_cpp_test(ondemand_number_in_string_tests         LABELS ondemand acceptance per_implementation)
 add_cpp_test(ondemand_object_tests                   LABELS ondemand acceptance per_implementation)
+add_cpp_test(ondemand_object_find_field_tests        LABELS ondemand acceptance per_implementation)
 add_cpp_test(ondemand_object_error_tests             LABELS ondemand acceptance per_implementation)
 add_cpp_test(ondemand_ordering_tests                 LABELS ondemand acceptance per_implementation)
 add_cpp_test(ondemand_parse_api_tests                LABELS ondemand acceptance per_implementation)

tests/ondemand/ondemand_document_stream_fuzz_tests.cpp

@@ -0,0 +1,101 @@
+#include <string>
+#include <vector>
+
+#include "simdjson.h"
+#include "test_ondemand.h"
+#include "document_stream_fuzz_test_common.h"
+
+namespace document_stream_fuzz_tests {
+
+std::string strip_stream_artifacts(simdjson::stream_format format, std::string_view text) {
+  size_t start = 0;
+  size_t end = text.size();
+  while (start < end && (text[start] == ' ' || text[start] == '\t' || text[start] == '\n' || text[start] == '\r' || text[start] == '\x1e')) {
+    start++;
+  }
+  while (end > start && (text[end - 1] == ' ' || text[end - 1] == '\t' || text[end - 1] == '\n' || text[end - 1] == '\r' || text[end - 1] == '\x1e')) {
+    end--;
+  }
+  std::string cleaned(text.substr(start, end - start));
+  if (format == simdjson::stream_format::comma_delimited || format == simdjson::stream_format::comma_delimited_array) {
+    while (!cleaned.empty() && cleaned.back() == ',') {
+      cleaned.pop_back();
+      while (!cleaned.empty() && (cleaned.back() == ' ' || cleaned.back() == '\t' || cleaned.back() == '\n' || cleaned.back() == '\r')) {
+        cleaned.pop_back();
+      }
+    }
+  }
+  return cleaned;
+}
+
+std::string canonicalize_document(simdjson::stream_format format, std::string_view text) {
+  std::string cleaned = strip_stream_artifacts(format, text);
+  simdjson::dom::parser parser;
+  simdjson::dom::element doc;
+  if (parser.parse(cleaned).get(doc)) {
+    return std::string("PARSE_ERROR:") + cleaned;
+  }
+  return simdjson::minify(doc);
+}
+
+const std::vector<std::string> &expected_documents() {
+  static const std::vector<std::string> docs = document_stream_fuzz::make_documents();
+  return docs;
+}
+
+const std::vector<document_stream_fuzz::stream_case> &stream_cases() {
+  static const std::vector<document_stream_fuzz::stream_case> cases =
+      document_stream_fuzz::make_stream_cases(expected_documents());
+  return cases;
+}
+
+bool verify_case(const document_stream_fuzz::stream_case &test_case) {
+  TEST_START();
+  const auto &expected = test_case.expected_documents;
+  ASSERT_TRUE(test_case.input.size() > document_stream_fuzz::batch_size * 4);
+
+  simdjson::padded_string input(test_case.input);
+  simdjson::ondemand::parser parser;
+
+  for (int pass = 0; pass < 2; pass++) {
+    simdjson::ondemand::document_stream stream;
+    ASSERT_SUCCESS(parser.iterate_many(input, document_stream_fuzz::batch_size, test_case.format).get(stream));
+
+    size_t index = 0;
+    for (auto it = stream.begin(); it != stream.end(); ++it) {
+      auto doc_result = *it;
+      ASSERT_SUCCESS(doc_result.error());
+      ASSERT_TRUE(index < expected.size());
+
+      simdjson::ondemand::document_reference doc;
+      ASSERT_SUCCESS(doc_result.get(doc));
+
+      std::string_view actual;
+      ASSERT_SUCCESS(simdjson::to_json_string(doc).get(actual));
+      ASSERT_EQUAL(
+          canonicalize_document(test_case.format, actual),
+          canonicalize_document(test_case.format, expected[index])
+      );
+      index++;
+    }
+    ASSERT_EQUAL(index, expected.size());
+  }
+
+  TEST_SUCCEED();
+}
+
+bool run() {
+  for (const auto &test_case : stream_cases()) {
+    std::cout << "Running fuzz corpus against stream format: " << test_case.name << std::endl;
+    if (!verify_case(test_case)) {
+      return false;
+    }
+  }
+  return true;
+}
+
+} // namespace document_stream_fuzz_tests
+
+int main(int argc, char *argv[]) {
+  return test_main(argc, argv, document_stream_fuzz_tests::run);
+}

tests/ondemand/ondemand_iterate_many_csv.cpp

@@ -13,7 +13,7 @@ bool normal() {
   auto json = R"( 1, 2, 3, 4, "a", "b", "c", {"hello": "world"} , [1, 2, 3])"_padded;
   ondemand::parser parser;
   ondemand::document_stream doc_stream;
-  ASSERT_SUCCESS(parser.iterate_many(json, json.size(), true).get(doc_stream));
+  ASSERT_SUCCESS(parser.iterate_many(json, json.size(), stream_format::comma_delimited).get(doc_stream));
 
   for (auto doc : doc_stream)
   {
@@ -28,7 +28,7 @@ bool small_batch_size() {
   auto json = R"( 1, 2, 3, 4, "a", "b", "c", {"hello": "world"} , [1, 2, 3])"_padded;
   ondemand::parser parser;
   ondemand::document_stream doc_stream;
-  ASSERT_SUCCESS(parser.iterate_many(json, 32, true).get(doc_stream));
+  ASSERT_SUCCESS(parser.iterate_many(json, 32, stream_format::comma_delimited).get(doc_stream));
 
   for (auto doc : doc_stream)
   {
@@ -43,7 +43,7 @@ bool trailing_comma() {
   auto json = R"(1,)"_padded;
   ondemand::parser parser;
   ondemand::document_stream doc_stream;
-  ASSERT_SUCCESS(parser.iterate_many(json, json.size(), true).get(doc_stream));
+  ASSERT_SUCCESS(parser.iterate_many(json, json.size(), stream_format::comma_delimited).get(doc_stream));
 
   for (auto doc : doc_stream)
   {
@@ -59,7 +59,7 @@ bool check_parsed_values() {
   auto json = R"(  1  , "a" , [100, 1]  , {"hello"  :    "world"}  , )"_padded;
   ondemand::parser parser;
   ondemand::document_stream doc_stream;
-  ASSERT_SUCCESS(parser.iterate_many(json, json.size(), true).get(doc_stream));
+  ASSERT_SUCCESS(parser.iterate_many(json, json.size(), stream_format::comma_delimited).get(doc_stream));
 
   auto begin = doc_stream.begin();
   auto end = doc_stream.end();
@@ -127,7 +127,7 @@ bool leading_comma() {
   auto json = R"(,1)"_padded;
   ondemand::parser parser;
   ondemand::document_stream doc_stream;
-  ASSERT_SUCCESS(parser.iterate_many(json, json.size(), true).get(doc_stream));
+  ASSERT_SUCCESS(parser.iterate_many(json, json.size(), stream_format::comma_delimited).get(doc_stream));
 
   try {
     auto begin = doc_stream.begin();

tests/ondemand/ondemand_object_find_field_tests.cpp

@@ -173,6 +173,36 @@ namespace object_tests {
     TEST_SUCCEED();
   }
 
+#if SIMDJSON_SUPPORTS_CONCEPTS
+  bool object_find_field_key_selector() {
+    TEST_START();
+    auto json = R"({ "name": "John", "age": 30, "city": "New York" })"_padded;
+    constexpr std::array<std::string_view, 3> keys = {"name", "age", "city"};
+    constexpr auto selector = ondemand::key_selector<3>(keys);
+
+    SUBTEST("ondemand::object with key_selector", test_ondemand_doc(json, [&](auto doc_result) {
+      ondemand::object object;
+      ASSERT_SUCCESS( doc_result.get(object) );
+
+      auto [index, value_result] = object.find_field(selector);
+      ASSERT_TRUE(index < 3);
+      ASSERT_SUCCESS(value_result);
+      std::string_view str_val;
+      ASSERT_SUCCESS(value_result.get(str_val));
+      ASSERT_EQUAL(str_val, "John");
+
+      // Test that we can find different keys
+      ASSERT_EQUAL(selector.index_of("name"), 0);
+      ASSERT_EQUAL(selector.index_of("age"), 1);
+      ASSERT_EQUAL(selector.index_of("city"), 2);
+      ASSERT_EQUAL(selector.index_of("invalid"), 3); // Not found
+
+      return true;
+    }));
+    TEST_SUCCEED();
+  }
+#endif
+
   bool run() {
     return
            object_find_field_unordered() &&
@@ -181,6 +211,9 @@ namespace object_tests {
            object_find_field() &&
            document_object_find_field() &&
            value_object_find_field() &&
+#if SIMDJSON_SUPPORTS_CONCEPTS
+           object_find_field_key_selector() &&
+#endif
            true;
   }
 

tests/ondemand/ondemand_readme_examples.cpp

@@ -1706,10 +1706,7 @@ bool allow_comma_separated_example() {
   auto json = R"( 1, 2, 3, 4, "a", "b", "c", {"hello": "world"} , [1, 2, 3])"_padded;
   ondemand::parser parser;
   ondemand::document_stream doc_stream;
-  // We pass '32' as the batch size, but it is a bogus parameter because, since
+  auto error = parser.iterate_many(json, 32, simdjson::stream_format::comma_delimited).get(doc_stream);
-  // we pass 'true' to the allow_comma parameter, the batch size will be set to at least
-  // the document size.
-  auto error = parser.iterate_many(json, 32, true).get(doc_stream);
   if(error) { std::cerr << error << std::endl; return false; }
   for (auto doc : doc_stream) {
     std::cout << doc.type() << std::endl;