simdjson-simdjson/include/simdjson/jsonparser.h

#ifndef SIMDJSON_JSONPARSER_H
#define SIMDJSON_JSONPARSER_H
#include <string>
#include "simdjson/common_defs.h"
#include "simdjson/padded_string.h"
#include "simdjson/jsonioutil.h"
#include "simdjson/parsedjson.h"
#include "simdjson/stage1_find_marks.h"
#include "simdjson/stage2_build_tape.h"
#include "simdjson/simdjson.h"
#ifdef _MSC_VER
#include <windows.h>
#include <sysinfoapi.h>
#else
#include <unistd.h>
#endif

// The function that users are expected to call is json_parse.
// We have more than one such function because we want to support several 
// instruction sets.

// function pointer type for json_parse
using json_parse_functype = int (const uint8_t *buf, size_t len, ParsedJson &pj, bool reallocifneeded);

// Pointer that holds the json_parse implementation corresponding to the available SIMD instruction set
extern json_parse_functype *json_parse_ptr;


// json_parse_implementation is the generic function, it is specialized for various 
// SIMD instruction sets, e.g., as json_parse_implementation<simdjson::instruction_set::avx2>
// or json_parse_implementation<simdjson::instruction_set::neon> 
template<simdjson::instruction_set T>
int json_parse_implementation(const uint8_t *buf, size_t len, ParsedJson &pj, bool reallocifneeded = true) {
  if (pj.bytecapacity < len) {
    return simdjson::CAPACITY;
  }
  bool reallocated = false;
  if(reallocifneeded) {
#ifdef ALLOW_SAME_PAGE_BUFFER_OVERRUN
    // realloc is needed if the end of the memory crosses a page
#ifdef _MSC_VER
    SYSTEM_INFO sysInfo; 
    GetSystemInfo(&sysInfo); 
    long pagesize = sysInfo.dwPageSize;
#else
    long pagesize = sysconf (_SC_PAGESIZE); 
#endif
    //////////////
    // We want to check that buf + len - 1 and buf + len - 1 + SIMDJSON_PADDING
    // are in the same page.
    // That is, we want to check that  
    // (buf + len - 1) / pagesize == (buf + len - 1 + SIMDJSON_PADDING) / pagesize
    // That's true if (buf + len - 1) % pagesize + SIMDJSON_PADDING < pagesize.
    ///////////
    if ( (reinterpret_cast<uintptr_t>(buf + len - 1) % pagesize ) + SIMDJSON_PADDING < static_cast<uintptr_t>(pagesize) ) {
#else // SIMDJSON_SAFE_SAME_PAGE_READ_OVERRUN
    if(true) { // if not SIMDJSON_SAFE_SAME_PAGE_READ_OVERRUN, we always reallocate
#endif
      const uint8_t *tmpbuf  = buf;
      buf = (uint8_t *) allocate_padded_buffer(len);
      if(buf == NULL) return simdjson::MEMALLOC;
      memcpy((void*)buf,tmpbuf,len);
      reallocated = true;
    } // if (true) OR if ( (reinterpret_cast<uintptr_t>(buf + len - 1) % pagesize ) + SIMDJSON_PADDING < static_cast<uintptr_t>(pagesize) ) {
  } // if(reallocifneeded) {
  int stage1_is_ok = find_structural_bits<T>(buf, len, pj);
  if(stage1_is_ok != simdjson::SUCCESS) {
    pj.errorcode = stage1_is_ok;
    return pj.errorcode;
  } 
  int res = unified_machine(buf, len, pj);
  if(reallocated) { aligned_free((void*)buf);}
  return res;
}

// Parse a document found in buf. 
// You need to preallocate ParsedJson with a capacity of len (e.g., pj.allocateCapacity(len)).
//
// The function returns simdjson::SUCCESS (an integer = 0) in case of a success or an error code from 
// simdjson/simdjson.h in case of failure such as  simdjson::CAPACITY, simdjson::MEMALLOC, 
// simdjson::DEPTH_ERROR and so forth; the simdjson::errorMsg function converts these error codes 
// into a string). 
//
// You can also check validity by calling pj.isValid(). The same ParsedJson can be reused for other documents.
//
// If reallocifneeded is true (default) then a temporary buffer is created when needed during processing
// (a copy of the input string is made).
// The input buf should be readable up to buf + len + SIMDJSON_PADDING if reallocifneeded is false,
// all bytes at and after buf + len  are ignored (can be garbage).
// The ParsedJson object can be reused.

inline int json_parse(const uint8_t *buf, size_t len, ParsedJson &pj, bool reallocifneeded = true) {
  return json_parse_ptr(buf, len, pj, reallocifneeded);
}

// Parse a document found in buf.
// You need to preallocate ParsedJson with a capacity of len (e.g., pj.allocateCapacity(len)).
//
// The function returns simdjson::SUCCESS (an integer = 0) in case of a success or an error code from 
// simdjson/simdjson.h in case of failure such as  simdjson::CAPACITY, simdjson::MEMALLOC, 
// simdjson::DEPTH_ERROR and so forth; the simdjson::errorMsg function converts these error codes 
// into a string). 
//
// You can also check validity
// by calling pj.isValid(). The same ParsedJson can be reused for other documents.
//
// If reallocifneeded is true (default) then a temporary buffer is created when needed during processing
// (a copy of the input string is made).
// The input buf should be readable up to buf + len + SIMDJSON_PADDING  if reallocifneeded is false,
// all bytes at and after buf + len  are ignored (can be garbage).
// The ParsedJson object can be reused.
inline int json_parse(const char * buf, size_t len, ParsedJson &pj, bool reallocifneeded = true) {
  return json_parse_ptr(reinterpret_cast<const uint8_t *>(buf), len, pj, reallocifneeded);
}

// We do not want to allow implicit conversion from C string to std::string.
int json_parse(const char * buf, ParsedJson &pj) = delete;

// Parse a document found in in string s.
// You need to preallocate ParsedJson with a capacity of len (e.g., pj.allocateCapacity(len)).
//
// The function returns simdjson::SUCCESS (an integer = 0) in case of a success or an error code from 
// simdjson/simdjson.h in case of failure such as  simdjson::CAPACITY, simdjson::MEMALLOC, 
// simdjson::DEPTH_ERROR and so forth; the simdjson::errorMsg function converts these error codes 
// into a string). 
//
// A temporary buffer is created when needed during processing
// (a copy of the input string is made).
inline int json_parse(const std::string &s, ParsedJson &pj) {
  return json_parse(s.data(), s.length(), pj, true);
}

// Parse a document found in in string s.
// You need to preallocate ParsedJson with a capacity of len (e.g., pj.allocateCapacity(len)).
//
// The function returns simdjson::SUCCESS (an integer = 0) in case of a success or an error code from 
// simdjson/simdjson.h in case of failure such as  simdjson::CAPACITY, simdjson::MEMALLOC, 
// simdjson::DEPTH_ERROR and so forth; the simdjson::errorMsg function converts these error codes 
// into a string). 
//
// You can also check validity
// by calling pj.isValid(). The same ParsedJson can be reused for other documents.
inline int json_parse(const padded_string &s, ParsedJson &pj) {
  return json_parse(s.data(), s.length(), pj, false);
}


// Build a ParsedJson object. You can check validity
// by calling pj.isValid(). This does the memory allocation needed for ParsedJson.
// If reallocifneeded is true (default) then a temporary buffer is created when needed during processing
// (a copy of the input string is made).
//
// the input buf should be readable up to buf + len + SIMDJSON_PADDING  if reallocifneeded is false,
// all bytes at and after buf + len  are ignored (can be garbage).
//
// This is a convenience function which calls json_parse.
WARN_UNUSED
ParsedJson build_parsed_json(const uint8_t *buf, size_t len, bool reallocifneeded = true);

WARN_UNUSED
// Build a ParsedJson object. You can check validity
// by calling pj.isValid(). This does the memory allocation needed for ParsedJson.
// If reallocifneeded is true (default) then a temporary buffer is created when needed during processing
// (a copy of the input string is made).
// The input buf should be readable up to buf + len + SIMDJSON_PADDING if reallocifneeded is false,
// all bytes at and after buf + len  are ignored (can be garbage).
//
// This is a convenience function which calls json_parse.
inline ParsedJson build_parsed_json(const char * buf, size_t len, bool reallocifneeded = true) {
  return build_parsed_json(reinterpret_cast<const uint8_t *>(buf), len, reallocifneeded);
}


// We do not want to allow implicit conversion from C string to std::string.
ParsedJson build_parsed_json(const char *buf) = delete;


// Parse a document found in in string s.
// You need to preallocate ParsedJson with a capacity of len (e.g., pj.allocateCapacity(len)).
// Return SUCCESS (an integer = 0) in case of a success. You can also check validity
// by calling pj.isValid(). The same ParsedJson can be reused for other documents.
//
// A temporary buffer is created when needed during processing
// (a copy of the input string is made).
//
// This is a convenience function which calls json_parse.
WARN_UNUSED
inline ParsedJson build_parsed_json(const std::string &s) {
  return build_parsed_json(s.data(), s.length(), true);
}


// Parse a document found in in string s.
// You need to preallocate ParsedJson with a capacity of len (e.g., pj.allocateCapacity(len)).
// Return SUCCESS (an integer = 0) in case of a success. You can also check validity
// by calling pj.isValid(). The same ParsedJson can be reused for other documents.
//
// This is a convenience function which calls json_parse.
WARN_UNUSED
inline ParsedJson build_parsed_json(const padded_string &s) {
  return build_parsed_json(s.data(), s.length(), false);
}



#endif