From ccac6403d99a997814ec3e2ca13e49f53d448b25 Mon Sep 17 00:00:00 2001
From: Daniel Lemire <daniel@lemire.me>
Date: Sat, 1 Nov 2025 17:28:17 -0400
Subject: [PATCH] fixing support for pre-C++17

---
 include/simdjson/compiler_check.h                | 5 +++++
 include/simdjson/generic/numberparsing.h         | 4 ++--
 include/simdjson/internal/numberparsing_tables.h | 6 +++---
 src/internal/numberparsing_tables.cpp            | 4 ----
 4 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/include/simdjson/compiler_check.h b/include/simdjson/compiler_check.h
index b045f3b05..72400a30a 100644
--- a/include/simdjson/compiler_check.h
+++ b/include/simdjson/compiler_check.h
@@ -13,6 +13,11 @@
 #endif
 #endif
 
+// C++ 26
+#if !defined(SIMDJSON_CPLUSPLUS26) && (SIMDJSON_CPLUSPLUS >= 202402L) // update when the standard is finalized
+#define SIMDJSON_CPLUSPLUS26 1
+#endif
+
 // C++ 23
 #if !defined(SIMDJSON_CPLUSPLUS23) && (SIMDJSON_CPLUSPLUS >= 202302L)
 #define SIMDJSON_CPLUSPLUS23 1
diff --git a/include/simdjson/generic/numberparsing.h b/include/simdjson/generic/numberparsing.h
index c769f813e..35d574157 100644
--- a/include/simdjson/generic/numberparsing.h
+++ b/include/simdjson/generic/numberparsing.h
@@ -167,7 +167,7 @@ simdjson_inline bool compute_float_64(int64_t power, uint64_t i, bool negative,
   // with a returned value of type value128 with a "low component" corresponding to the
   // 64-bit least significant bits of the product and with a "high component" corresponding
   // to the 64-bit most significant bits of the product.
-#if SIMDJSON_CPLUSPLUS17
+#if SIMDJSON_CPLUSPLUS26
   simdjson::internal::value128 firstproduct = full_multiplication(i, simdjson::internal::powers_template<>::power_of_five_128[index]);
 #else
   simdjson::internal::value128 firstproduct = full_multiplication(i, simdjson::internal::power_of_five_128[index]);
@@ -205,7 +205,7 @@ simdjson_inline bool compute_float_64(int64_t power, uint64_t i, bool negative,
     // with a returned value of type value128 with a "low component" corresponding to the
     // 64-bit least significant bits of the product and with a "high component" corresponding
     // to the 64-bit most significant bits of the product.
-#if SIMDJSON_CPLUSPLUS17
+#if SIMDJSON_CPLUSPLUS26
     simdjson::internal::value128 secondproduct = full_multiplication(i, simdjson::internal::powers_template<>::power_of_five_128[index + 1]);
 #else
     simdjson::internal::value128 secondproduct = full_multiplication(i, simdjson::internal::power_of_five_128[index + 1]);
diff --git a/include/simdjson/internal/numberparsing_tables.h b/include/simdjson/internal/numberparsing_tables.h
index 4e6c38ef3..0f0d6f897 100644
--- a/include/simdjson/internal/numberparsing_tables.h
+++ b/include/simdjson/internal/numberparsing_tables.h
@@ -53,7 +53,7 @@ extern SIMDJSON_DLLIMPORTEXPORT const double power_of_ten[];
 // The mantissa is truncated to 128 bits, and
 // never rounded up. Uses about 10KB.
 // We use the template trick to allow inclusion in multiple translation units.
-#if SIMDJSON_CPLUSPLUS17
+#if SIMDJSON_CPLUSPLUS26
 template <typename unused = void>  struct powers_template {
 constexpr static uint64_t power_of_five_128[651*2]= {
         0xeef453d6923bd65a,0x113faa2906a13b3f,
@@ -708,9 +708,9 @@ constexpr static uint64_t power_of_five_128[651*2]= {
         0xe3d8f9e563a198e5,0x58180fddd97723a6,
         0x8e679c2f5e44ff8f,0x570f09eaa7ea7648,};
 };
-#else
+#endif // SIMDJSON_CPLUSPLUS26
+
 extern SIMDJSON_DLLIMPORTEXPORT const uint64_t power_of_five_128[651*2];
-#endif
 } // namespace internal
 } // namespace simdjson
 
diff --git a/src/internal/numberparsing_tables.cpp b/src/internal/numberparsing_tables.cpp
index e0686d559..143b27506 100644
--- a/src/internal/numberparsing_tables.cpp
+++ b/src/internal/numberparsing_tables.cpp
@@ -20,9 +20,6 @@ SIMDJSON_DLLIMPORTEXPORT const double simdjson::internal::power_of_ten[] = {
  * exactly using the binary notation, only the powers of five
  * affect the binary significand.
  */
-#if SIMDJSON_CPLUSPLUS17
-// See header file. We use the template trick to allow inclusion in multiple translation units.
-#else
 // The truncated powers of five from 5^-342 all the way to 5^308
 // The mantissa is truncated to 128 bits, and
 // never rounded up. Uses about 10KB.
@@ -678,7 +675,6 @@ SIMDJSON_DLLIMPORTEXPORT const uint64_t simdjson::internal::power_of_five_128[]=
         0xb6472e511c81471d,0xe0133fe4adf8e952,
         0xe3d8f9e563a198e5,0x58180fddd97723a6,
         0x8e679c2f5e44ff8f,0x570f09eaa7ea7648,};
-#endif // SIMDJSON_CPLUSPLUS17
 
 
 #endif // SIMDJSON_SRC_NUMBERPARSING_TABLES_CPP
\ No newline at end of file