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fastjson.hpp
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fastjson.hpp
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#ifndef FASTJSON_HPP_INCLUDED
#define FASTJSON_HPP_INCLUDED
// Copyright (C) 2013 Joshua M. Kriegshauser
// Version 1.0
// Revision $DateTime: 2013/09/21 18:24:00 $
//! \file fastjson.hpp This file contains the fastjson parser
// Disable warnings for MS VC++
#ifdef _MSC_VER
#pragma warning (push)
#pragma warning (disable : 4127) // Conditional expression is constant
#pragma warning (disable : 4702) // Unreachable code
#endif
// If no standard library, user must provide required functions and typedefs
#if !defined(FASTJSON_NO_STDLIB)
#include <cassert>
#include <new>
#include <cmath>
#include <sstream>
#endif
#define NOEXCEPT throw()
// Exceptions may be disabled completely by using FASTJSON_NO_EXCEPTIONS,
// however this will cause the default_error_handler to abort().
#if !defined(FASTJSON_NO_EXCEPTIONS)
#include <exception> // For std::exception
namespace fastjson
{
//! This exception is thrown by the parser when an error occurs when using fastjson::default_error_handler.
//! Use the what() function to get the human-readable error description.
//! Use the where() function to get a pointer to position within source text where the error
//! was detected.
//! <br><br>
//! If throwing exceptions is undesirable, exceptions can be disabled
//! by using <tt>\#define FASTJSON_NO_EXCEPTIONS</tt> before fastjson.hpp is included.
//! This will change the behavior of fastjson::default_error_handler to \c abort().
//! <br><br>
//! This class derives from <tt>std::exception</tt>.
class parse_error : public std::exception
{
public:
//! Constructor
parse_error(const char* what, void* where)
: what_(what)
, where_(where)
{}
//! Gets the human-readable description of the error
//! \return Pointer to a human-readable description of the error. This error
//! is always a static literal string.
virtual const char* what() const NOEXCEPT
{
return what_;
}
//! Gets the pointer to the character data where the error happened.
//! Ch should be the same as the character type of json_document that produced
//! the error.
//! \return Pointer to location within the parsed string where the error occurred.
template<class Ch> Ch* where() const NOEXCEPT
{
return reinterpret_cast<Ch*>(where_);
}
private:
const char* what_;
void* where_;
};
//! Defines an error handler functor to execute when a parse error occurs. The default
//! behavior is to throw the parse_error exception. If this is undesirable, implement
//! a custom error handler functor and pass it to the json_document::parse function.
//! <br><br>
//! A potential alternate to using exceptions would be to use \c setjmp() and \c longjmp().
//! <br><br>
//! If \c FASTJSON_NO_EXCEPTIONS is defined, the default behavior is to call \c abort().
//! NOTE: The functor must never return, otherwise \c abort() is called.
struct default_error_handler
{
//! \brief Handles the given error.
//! \param what A human-readable description of the error.
//! \param where The pointer offset into the buffer given to json_document::parse that generated the error.
void operator () (const char* what, void* where)
{
throw parse_error(what, where);
}
};
}
#else
namespace fastjson
{
struct default_error_handler
{
void operator () (const char*, void*)
{
abort();
}
};
}
#endif
#define FASTJSON_PARSE_ERROR(what, where) do { handler(what, where); abort(); } while (0)
#define FASTJSON_PARSE_ERROR_THIS(what, where) do { static_cast<error_handler&>(*this)(what, where); abort(); } while (0)
///////////////////////////////////////////////////////////////////////////////
// Pool size definitions
#if !defined(FASTJSON_STATIC_POOL_SIZE)
//! Size of the static memory block of memory_pool
//! Define FASTJSON_STATIC_POOL_SIZE before including fastjson.hpp if you want to override the default value.
//! The default value is 32 Kbytes.
//! No dynamic allocations are performed until the static pool is exhausted.
//! Value may be set to zero to disable static pool and cause all allocations to be from the heap.
#define FASTJSON_STATIC_POOL_SIZE (32 * 1024)
#endif
#if !defined(FASTJSON_DYNAMIC_POOL_SIZE)
//! Size of the dynamic memory block of memory_pool
//! Define FASTJSON_DYNAMIC_POOL_SIZE before including fastjson.hpp if you want to override the default value.
//! The default value is 32 Kbytes.
//! Dynamic memory blocks of this size are allocated when necessary, and only after the static memory pool is exhausted.
//! If set to zero, all allocations will require a separate heap allocation.
#define FASTJSON_DYNAMIC_POOL_SIZE (32 * 1024)
#endif
#if !defined(FASTJSON_ALIGNMENT)
//! Memory allocation alignment
//! Define FASTJSON_ALIGNMENT before including fastjson.hpp if you want to override the default value.
//! The default value is pointer-size alignment.
//! Must be a power of two and at least 1, otherwise memory_pool will not work.
#define FASTJSON_ALIGNMENT (sizeof(void*))
#endif
///////////////////////////////////////////////////////////////////////////////
// Parser implementation
namespace fastjson
{
// Forward declarations and typedefs
template<class Ch, class error_handler, class pool> class json_document;
template<class Ch> class json_value;
template<class Ch> class json_object;
//! A single byte representation used by fastjson.
typedef unsigned char byte;
typedef unsigned char utf8_char;
typedef unsigned short utf16_char;
typedef unsigned int utf32_char;
//! \brief Enumeration of value types produced by the parser.
//! Given by the fastjson::json_value::type() function.
//! See fastjson::json_value for more information.
enum value_type
{
value_null, //!< The json null type.
value_bool, //!< A boolean value that may be true/false.
value_number, //!< A double-precision floating point value.
value_string, //!< A Unicode-encoded string. The encoding depends on the size of \c Ch.
value_array, //!< An array type. The class of the json_value is actually json_object.
value_object, //!< An object type. The class of the json_value is actually json_object.
};
namespace internal
{
//! Lookup tables used to speed lookups. These are defined as a template so that they
//! may be included in this header file without the linker complaining.
template<int Dummy>
struct lookup_tables
{
static const bool lookup_whitespace[256];
static const bool lookup_digit[256];
static const double lookup_double[10];
static const char lookup_hexchar[16];
static const std::size_t utf8_lengths[64];
static const std::ptrdiff_t encoding_sizes[5];
};
template<class Ch>
struct string_tables
{
static const Ch nullstr[5];
static const Ch truestr[5];
static const Ch falsestr[6];
};
// Internal parse flags
const int parse_do_swap = 1 << 30;
//! Returns an empty string.
template<class Ch>
Ch* emptystr() NOEXCEPT
{
static Ch nul = Ch('\0');
return &nul;
}
//! Returns the 'null' string
template<class Ch>
const Ch* nullstr() NOEXCEPT
{
return string_tables<Ch>::nullstr;
}
//! Returns the 'true' string
template<class Ch>
const Ch* truestr() NOEXCEPT
{
return string_tables<Ch>::truestr;
}
//! Returns the 'false' string
template<class Ch>
const Ch* falsestr() NOEXCEPT
{
return string_tables<Ch>::falsestr;
}
//! Measures the length of a NUL-terminated string of \c Ch characters.
//! A null pointer returns a zero length.
template<class Ch>
std::size_t length(const Ch* p) NOEXCEPT
{
const Ch* end = p;
if (end)
{
while (*end != Ch('\0'))
++end;
return (std::size_t)(end - p);
}
return 0;
}
// The read_helper struct performs a swap if necessary. The default implementation assumes no swap. The specialization does the swap.
template<bool swap>
struct read_helper
{
template<class Ch> static Ch read(Ch val)
{
return val;
}
};
template<>
struct read_helper<true>
{
template<class Ch> static Ch read(Ch val)
{
if (sizeof(Ch) == 2)
{
return (val >> 8) | (val << 8);
}
else if (sizeof(Ch) == 4)
{
byte* p = (byte*)&val;
std::swap(p[0], p[3]);
std::swap(p[1], p[2]);
return val;
}
else
{
assert(0); // Unsupported size for swapping
}
}
};
template<int Flags, class Ch>
Ch read(Ch text)
{
return read_helper<!!(Flags & internal::parse_do_swap)>::read(text);
}
//! Predicate for determining if \c ch is whitespace. Uses a look-up-table.
template<class Ch>
struct whitespace_pred
{
bool operator () (Ch ch)
{
if (sizeof(ch) > 1 && (ch < 0 || ch >= 256)) return false;
return lookup_tables<0>::lookup_whitespace[(byte)ch];
}
};
//! Predicate for determining if \c ch is numeric. Uses a look-up-table.
template<class Ch>
struct digit_pred
{
bool operator () (Ch ch)
{
if (sizeof(ch) > 1 && (ch < 0 || ch >= 256)) return false;
return lookup_tables<0>::lookup_digit[(byte)ch];
}
};
//! Compares two strings. Assumes that \c first is NUL-terminated and
//! \c second is counted (\c secondend points to the first character following the string).
//! \return 0 if strings match fully (length must match)
//! \return -1 if first would be sorted lexicographically before second
//! \return 1 if first would be sorted lexicographically after second
template<class Ch>
int compare(const Ch* first, const Ch* second, const Ch* secondend) NOEXCEPT
{
assert(first); assert(second); assert(secondend);
while (*first && second != secondend)
{
if (*first < *second) return -1;
else if (*second < *first) return 1;
++first, ++second;
}
if (!*first && second == secondend) return 0;
return !!*first ? 1 : -1;
}
//! Compares two strings. Assumes that both strings are counted--the end character
//! points to the character immediately following the string.
//! \return 0 if strings match fully and are the same length
//! \return -1 if first would be sorted lexicographically before second
//! \return 1 if first would be sorted lexicographically after second
template<class Ch>
int compare(const Ch* first, const Ch* firstend, const Ch* second, const Ch* secondend) NOEXCEPT
{
assert(first && firstend && second && secondend);
while (first != firstend && second != secondend)
{
if (*first < *second) return -1;
else if (*second < *first) return 1;
++first; ++second;
}
if (first == firstend && second == secondend) return 0;
return first != firstend ? 1 : -1;
}
//! \brief Translates a \c Ch of a hex character to its numeric value.
//! \param text the character to convert
//! \param handler an error handler that is called if \c text is not a valid hex character
//! \return the numeric representation of the given character
template<int Flags, class Ch, class error_handler>
byte hex_value(Ch* text, error_handler handler)
{
Ch ch = read<Flags>(*text);
switch (ch)
{
case Ch('0'): case Ch('1'): case Ch('2'): case Ch('3'): case Ch('4'):
case Ch('5'): case Ch('6'): case Ch('7'): case Ch('8'): case Ch('9'):
return ((byte)ch) - '0';
case Ch('a'): case Ch('A'): return byte(10);
case Ch('b'): case Ch('B'): return byte(11);
case Ch('c'): case Ch('C'): return byte(12);
case Ch('d'): case Ch('D'): return byte(13);
case Ch('e'): case Ch('E'): return byte(14);
case Ch('f'): case Ch('F'): return byte(15);
default:
FASTJSON_PARSE_ERROR("Expected hex character (0-9, a-f, A-F)", text);
return byte(0);
}
}
//! \brief Translates a numeric value to a hex character
//! \param value The value to translate. Must be less than 16.
//! \return The hex character that represents the value.
template<class Ch>
Ch hex_char(byte value)
{
assert(value < 16);
return Ch(lookup_tables<0>::lookup_hexchar[value]);
}
//! \brief Converts a string value to a double.
//! Numeric string values are converted to a double floating-point number. A string value of 'true' returns 1.0. Other strings return 0.0.
//! \return The double value of the given string. As much of the string as possible is processed.
//! \return Processing stops when the string is no longer formatted as a double value.
template<class Ch>
double value_to_number(const Ch* start, const Ch* end) NOEXCEPT
{
if (start == end) return 0.0;
// Convert 'true' to 1.0
if ((end - start) == 4 && start[0] == Ch('t') && start[1] == Ch('r') && start[2] == Ch('u') && start[3] == Ch('e'))
{
return 1.0;
}
double num = 0.0, fact = 1.0;
if (*start == Ch('-'))
{
fact = -1.0;
++start;
}
bool period = false;
while (start < end)
{
switch (*start)
{
case Ch('0'): case Ch('1'): case Ch('2'): case Ch('3'): case Ch('4'):
case Ch('5'): case Ch('6'): case Ch('7'): case Ch('8'): case Ch('9'):
num *= 10.0;
num += lookup_tables<0>::lookup_double[*start - '0'];
if (period) fact /= 10.0;
++start;
break;
case Ch('.'):
if (!period) { period = true; ++start; }
else start = end; // Done.
break;
case Ch('e'):
case Ch('E'):
num *= fact;
if (++start < end)
{
bool neg = false;
if (*start == Ch('+') || *start == Ch('-'))
{
neg = (*start == Ch('-'));
++start;
}
double exp = 0.0;
while (start < end)
{
switch (*start)
{
case Ch('0'): case Ch('1'): case Ch('2'): case Ch('3'): case Ch('4'):
case Ch('5'): case Ch('6'): case Ch('7'): case Ch('8'): case Ch('9'):
exp *= 10.0;
exp += lookup_tables<0>::lookup_double[*start - '0'];
++start;
break;
default:
start = end; // Done
}
}
num *= pow(10.0, neg ? -exp : exp);
}
start = end; // Done
return num;
default:
break;
}
}
return num * fact;
}
//! A union for a double that breaks it apart into mantissa, exponent and sign bits.
union udouble
{
double d;
unsigned long long ull;
struct sdouble
{
const static unsigned Bias = 1023;
const static unsigned NonFiniteExp = (1u << 11)-1;
unsigned long long mantissa: 52;
unsigned long long exponent: 11;
unsigned long long sign: 1;
} s;
};
//! \brief Converts a double to a json-compatible number string.
//! Absolute values smaller than 0.0000000000001 are rounded to zero.
//! Absolute values smaller than 0.0000000001 or larger than 1,000,000,000,000 are represented using scientific notation.
//! Up to 12 digits of fractional precision are used.
//! \return true if the value could be represented as a json number.
//! \return false if the value is non-finite (infinite or not-a-number) and must be represented as a json string
template<class Ch>
bool number_to_string(const double& val, Ch* buf, Ch*& bufend)
{
assert(buf < bufend);
udouble u; u.d = val;
const bool neg = (u.s.sign != 0);
u.s.sign = 0;
if (u.d < 1.0e-12) // Very small
{
// Zero
*buf++ = Ch('0');
*(bufend = buf) = Ch('\0');
return true;
}
else if (u.s.exponent == udouble::sdouble::NonFiniteExp)
{
if (u.s.mantissa == 0)
{
// Infinite. Convert to string.
if (neg) { *buf++ = Ch('-'); assert(buf < bufend); }
*buf++ = Ch('I'); assert(buf < bufend);
*buf++ = Ch('n'); assert(buf < bufend);
*buf++ = Ch('f'); assert(buf < bufend);
*(bufend = buf) = Ch('\0');
}
else
{
// Not a number. Convert to string.
*buf++ = Ch('N'); assert(buf < bufend);
*buf++ = Ch('a'); assert(buf < bufend);
*buf++ = Ch('N'); assert(buf < bufend);
*(bufend = buf) = Ch('\0');
}
return false; // as a string
}
// Double to float is beyond the scope of fastjson. However, json is very clear about the rules.
const bool scientific = u.d < 1.0e-9 || u.d > 1.0e12;
char temp[128]; int len;
#if defined (_MSC_VER)
len = ::sprintf_s<sizeof(temp)>(temp, scientific ? "%.12g" : "%.12f", neg ? -u.d : u.d);
#else
len = ::snprintf(temp, sizeof(temp), scientific ? "%.12g" : "%.12f", neg ? -u.d : u.d);
#endif
if (!scientific)
{
// Strip trailing zeros
for (char* p = temp + len - 1; p > temp; --p)
{
if (*p != '0') break;
*p = '\0';
--len;
}
if (temp[len-1] == '.') temp[--len] = '\0';
}
assert(len < (bufend - buf));
for (char* p = temp; *p; ++p)
{
*buf++ = Ch(*p);
}
*(bufend = buf) = Ch('\0');
return true;
}
//! \brief Converts a text string to a boolean value.
//! This works with all json values. A json string of "true" will return true.
//! A string that starts with a non-zero number will also return true.
//! A null value will return false.
//! No errors or exceptions are thrown. Invalid values will return false.
template<class Ch>
bool value_to_boolean(const Ch* start, const Ch* end) NOEXCEPT
{
if (start == end) return false;
if (start[0] == Ch('t') && start[1] == Ch('r') && start[2] == Ch('u') && start[3] == Ch('e')) return true;
if (start[0] == Ch('f') && start[1] == Ch('a') && start[2] == Ch('l') && start[3] == Ch('s') && start[4] == Ch('e')) return false;
return value_to_number(start, end) != 0.0;
}
//! \brief Reads a json-style UTF-16 character in the format \\u1234
//! \param ptr the current parsing location. The pointer is advanced by the parsing of the UTF-16 value.
//! \param handler if parsing fails, the function is invoked.
//! \return The UTF-16 character represented by the string.
template<int Flags, class Ch, class error_handler>
utf16_char read_utf16(Ch*& ptr, error_handler handler)
{
if (read<Flags>(*ptr++) != Ch('\\')) FASTJSON_PARSE_ERROR("Expected \\uXXXX", ptr - 1);
if (read<Flags>(*ptr++) != Ch('u')) FASTJSON_PARSE_ERROR("Expected \\uXXXX", ptr - 2);
// hex_value will throw if not a hex character
utf16_char c =
(hex_value<Flags>(ptr + 0, handler) << 12) |
(hex_value<Flags>(ptr + 1, handler) << 8) |
(hex_value<Flags>(ptr + 2, handler) << 4) |
(hex_value<Flags>(ptr + 3, handler));
ptr += 4;
return c;
}
// These structures provide specializations that convert between any two types of encodings (UTF-8, UTF-16 BE/LE, UTF-32 BE/LE)
template<int Flags, class Ch, std::size_t S = sizeof(Ch)> struct to_utf32
{};
template<int Flags, class Ch>
struct to_utf32<Flags, Ch, 1> // UTF-8 to UTF-32
{
template<class error_handler> static utf32_char convert(Ch*& ch, const Ch* end, error_handler handler)
{
assert(ch < end);
utf32_char out = 0;
const utf8_char* p = (const utf8_char*)ch;
switch (lookup_tables<0>::utf8_lengths[*p >> 2])
{
default:
FASTJSON_PARSE_ERROR("Invalid UTF-8 sequence", ch);
break;
case 1:
out = utf32_char(*p);
++ch;
break;
case 2:
if ((end - ch) < 2)
{
FASTJSON_PARSE_ERROR("Invalid UTF-8 sequence", ch);
}
out = utf32_char(p[0] & 0x1f) << 6;
out |= utf32_char(p[1] & 0x3f);
ch += 2;
break;
case 3:
if ((end - ch) < 3)
{
FASTJSON_PARSE_ERROR("Invalid UTF-8 sequence", ch);
}
out = utf32_char(p[0] & 0xf) << 12;
out |= utf32_char(p[1] & 0x3f) << 6;
out |= utf32_char(p[2] & 0x3f);
ch += 3;
break;
case 4:
if ((end - ch) < 4)
{
FASTJSON_PARSE_ERROR("Invalid UTF-8 sequence", ch);
}
out = utf32_char(p[0] & 0x7) << 18;
out |= utf32_char(p[1] & 0x3f) << 12;
out |= utf32_char(p[2] & 0x3f) << 6;
out |= utf32_char(p[3] & 0x3f);
ch += 4;
break;
}
assert(out <= 0x10ffff);
return out;
}
};
template<int Flags, class Ch>
struct to_utf32<Flags, Ch, 2> // UTF-16 to UTF-32
{
template<class error_handler> static utf32_char convert(Ch*& ch, const Ch* end, error_handler handler)
{
assert(ch < end);
utf32_char out = 0;
const utf16_char* p = (const utf16_char*)ch;
utf16_char c = read<Flags>(p[0]);
if (c < 0xd800 || c > 0xdfff)
{
out = utf32_char(c);
++ch;
}
else if (c < 0xdc00)
{
// Surrogate pair
if ((end - ch) < 2)
{
FASTJSON_PARSE_ERROR("Invalid UTF-16 surrogate pair",ch);
}
utf16_char c2 = read<Flags>(p[1]);
if (c2 < 0xdc00 || c2 > 0xdfff)
{
FASTJSON_PARSE_ERROR("Invalid UTF-16 surrogate pair", ch);
}
out = utf32_char(c & 0x3ff) << 10;
out |= utf32_char(c & 0x3fff);
out += 0x10000;
ch += 2;
}
else
{
FASTJSON_PARSE_ERROR("Invalid UTF-16 character", ch);
}
return out;
}
};
template<int Flags, class Ch>
struct to_utf32<Flags, Ch, 4> // UTF-32 to UTF-32
{
template<class error_handler> static utf32_char convert(Ch*& ch, const Ch* end, error_handler handler)
{
static_cast<void>(handler);
assert(ch < end);
utf32_char out = read<Flags>(*(const utf32_char*)ch);
++ch;
return out;
}
};
template<class Ch, std::size_t S = sizeof(Ch)> struct from_utf32
{};
template<class Ch>
struct from_utf32<Ch, 1>
{
template<class error_handler> static void convert(utf32_char c, Ch*& out, const Ch* end, error_handler handler)
{
static_cast<void>(handler);
assert(out < end);
if (c <= 0x7f)
{
*out++ = Ch(c);
}
else if (c <= 0x7ff)
{
assert((end - out) >= 2);
*out++ = Ch(0xc0 + ((c >> 6) & 0x3f));
*out++ = Ch(0x80 + ( c & 0x3f));
}
else if (c < 0x10000)
{
assert((end - out) >= 3);
*out++ = Ch(0xe0 + ((c >> 12) & 0x0f));
*out++ = Ch(0x80 + ((c >> 6) & 0x3f));
*out++ = Ch(0x80 + ( c & 0x3f));
}
else
{
assert((end - out) >= 4);
*out++ = Ch(0xf0 + ((c >> 18) & 0x07));
*out++ = Ch(0x80 + ((c >> 12) & 0x3f));
*out++ = Ch(0x80 + ((c >> 6) & 0x3f));
*out++ = Ch(0x80 + ( c & 0x3f));
}
}
};
template<class Ch>
struct from_utf32<Ch, 2>
{
template<class error_handler> static void convert(utf32_char c, Ch*& out, const Ch* end, error_handler handler)
{
static_cast<void>(handler);
assert(out < end);
if (c < 0x10000)
{
assert(c < 0xd800 || c > 0xdfff);
*out++ = Ch(c);
}
else
{
assert((end - out) >= 2);
c -= 0x10000;
*out++ = Ch(0xd800 | (c >> 10));
*out++ = Ch(0xdc00 | (c & 0x3ff));
}
}
};
template<class Ch>
struct from_utf32<Ch, 4>
{
template<class error_handler> static void convert(utf32_char c, Ch*& out, const Ch* end, error_handler handler)
{
static_cast<void>(handler);
assert(out < end);
*out++ = c;
}
};
template<int Flags, class ChIn, class ChOut, std::size_t SIn = sizeof(ChIn), std::size_t SOut = sizeof(ChOut)>
struct unicode_converter
{
template<class error_handler> static void convert(ChIn*& in, const ChIn* end, ChOut*& out, const ChOut* outend, error_handler handler)
{
const utf32_char c = to_utf32<Flags, ChIn>::convert(in, end, handler);
from_utf32<ChOut>::convert(c, out, outend, handler);
}
template<class error_handler> static std::size_t measure(ChIn*& in, const ChIn* end, error_handler handler)
{
const utf32_char c = to_utf32<Flags, ChIn>::convert(in, end, handler);
ChOut buf[6];
ChOut* p = buf;
// Do the conversion to actually measure
from_utf32<ChOut>::convert(c, p, &buf[6], handler);
return p - buf;
}
};
template<int Flags, class ChIn, class ChOut>
struct unicode_converter<Flags, ChIn, ChOut, 1, 1> // UTF-8 to UTF-8 converter
{
template<class error_handler> static void convert(ChIn*& in, const ChIn* end, ChOut*& out, const ChOut* outend, error_handler handler)
{
assert(in != end);
const utf8_char* p = (const utf8_char*)in;
utf8_char c = read<Flags>(p[0]);
const std::size_t size = lookup_tables<0>::utf8_lengths[c >> 2];
if (size == 0 || (in + size) > end)
{
FASTJSON_PARSE_ERROR("Invalid UTF-8 sequence", in);
}
assert((std::size_t)(outend - out) >= size);
switch (size)
{
default:
FASTJSON_PARSE_ERROR("Invalid UTF-8 sequence", in);
break;
case 4: *out++ = ChOut(read<Flags>(*in++)); // Fall through
case 3: *out++ = ChOut(read<Flags>(*in++)); // Fall through
case 2: *out++ = ChOut(read<Flags>(*in++)); // Fall through
case 1: *out++ = ChOut(read<Flags>(*in++)); // Fall through
}
}
template<class error_handler> static std::size_t measure(ChIn*& in, const ChIn* end, error_handler handler)
{
assert(in != end);
const utf8_char* p = (const utf8_char*)in;
const std::size_t size = lookup_tables<0>::utf8_lengths[read<Flags>(*p) >> 2];
if (size == 0 || (std::size_t)(end - in) < size)
{
FASTJSON_PARSE_ERROR("Invalid UTF-8 sequence", in);
}
in += size;
return size;
}
};
template<int Flags, class ChIn, class ChOut>
struct unicode_converter<Flags, ChIn, ChOut, 2, 2> // UTF-16 to UTF-16 converter
{
template<class error_handler> static void convert(ChIn*& in, const ChIn* end, ChOut*& out, const ChOut* outend, error_handler handler)
{
assert(in != end); assert(out != outend);
const utf16_char* p = (const utf16_char*)in;
utf16_char c = read<Flags>(*p);
*out++ = (ChOut)c;
++in;
if (c >= 0xd800 && c < 0xdc00)
{
assert(in != end);
assert(out != outend);
c = read<Flags>(p[1]);
if (c < 0xdc00 || c > 0xdfff)
{
FASTJSON_PARSE_ERROR("Invalid UTF-16 surrogate pair", in);
}
*out++ = c;
++in;
}
}
template<class error_handler> static std::size_t measure(ChIn*& in, const ChIn* end, error_handler handler)
{
assert(in != end);
const utf16_char* p = (const utf16_char*)in;
++in;
utf16_char c = read<Flags>(p[0]);
if (c >= 0xd800 && c < 0xdc00)
{
assert(in != end);
c = read<Flags>(p[1]);
if (c < 0xdc00 || c > 0xdfff)
{
FASTJSON_PARSE_ERROR("Invalid UTF-16 surrogate pair", in);
}
++in;
return 2;
}
return 1;
}
};
template<int Flags, class ChIn, class ChOut>
struct unicode_converter<Flags, ChIn, ChOut, 4, 4> // UTF-32 to UTF-32 converter
{
template<class error_handler> static void convert(ChIn*& in, const ChIn* end, ChOut*& out, const ChOut* outend, error_handler handler)
{
static_cast<void>(handler);
assert(in != end);
assert(out != outend);
*out++ = ChOut(read<Flags>(*in++));
}
template<class error_handler> static std::size_t measure(ChIn*& in, const ChIn* end, error_handler handler)
{
static_cast<void>(handler);
assert(in != end);
++in;
return 1;
}
};
template<int Flags, class ChIn, class ChOut, class error_handler>
void convert(ChIn*& in, const ChIn* end, ChOut*& out, const ChOut* outend, error_handler handler)
{
unicode_converter<Flags, ChIn, ChOut>::convert(in, end, out, outend, handler);
}
template<int Flags, class ChOut, class ChIn, class error_handler>
std::size_t measure(ChIn*& in, const ChIn* end, error_handler handler)
{
return unicode_converter<Flags, ChIn, ChOut>::measure(in, end, handler);
}
} // namespace internal
///////////////////////////////////////////////////////////////////////////
// Parsing flags
//! Parse flags which represent the default behavior of the parser.
//! This is always zero, so that flags may be or'd together.
//! See json_document::parse() function.
const int parse_default = 0;
const int parse_no_string_terminators = 1 << 0; //!< Don't terminate string values with NUL characters. Use json_value::nameend() to get the end of the string. Mutually exclusive with parse_force_string_terminators.
const int parse_no_inline_translation = 1 << 1; //!< Don't translate strings in-line with the given data buffer. Instead, a copy is made and strings are fixed there.
const int parse_force_string_terminators = 1 << 2; //<! Ensures that all strings are copied, so that translation is not inline but string terminators are present. This ensures a non-destructive parse but is less efficient than parse_non_destructive. Mutually exclusive with parse_no_string_terminators.
const int parse_non_destructive = (parse_no_string_terminators|parse_no_inline_translation); //!< Ensures that the buffer passed to json_document::parse is not modified. Does not always terminate strings; use json_value::nameend() to get the end of the string.
const int parse_non_destructive_nul = (parse_force_string_terminators); //!< Ensures that the buffer passed to json_document::parse is not modified. Strings are copied and NUL-terminated. Slightly less efficient than parse_non_destructive.
// These flags are non-RFC-7159 compliant, but helpful
const int parse_trailing_commas = 1 << 3; //<! Allows commas to exist at the end of objects and arrays
const int parse_comments = 1 << 4; //<! Allows comments (//, /**/, #) to exist
///////////////////////////////////////////////////////////////////////////
// Allocator interface
//! \class default_allocator
//! Uses new/delete to allocate pool memory. Used by memory_pool to handle dynamic allocations.
class default_allocator
{
public:
//! Constructor
default_allocator() {}
//! Destructor
~default_allocator() {}
//! \brief Allocates memory from the heap.
//! \param size the number of bytes to allocate from the heap
//! \return memory allocated from the heap or NULL if allocation failed
//! \exception std::bad_alloc may be thrown if memory cannot be allocated
byte* raw_heap_alloc(std::size_t size)
{
return new byte[size];
}
//! \brief Frees memory previously allocated with raw_heap_alloc
//! \param p the memory previously allocated with raw_heap_alloc
void raw_heap_free(byte* p)
{
delete[] p;
}
};
///////////////////////////////////////////////////////////////////////////
// Memory pool
// Implements the statically-sized pool. This pool is consumed first.
template<std::size_t static_size>
class static_pool
{
byte static_pool_[static_size];
protected:
byte* static_pool_start() NOEXCEPT { return static_pool_; }
byte* static_pool_end() NOEXCEPT { return static_pool_ + static_size; }
};
// Specialization of static_pool that is zero bytes
template <>
class static_pool<0>
{
protected:
byte* static_pool_start() NOEXCEPT { return 0; }
byte* static_pool_end() NOEXCEPT { return 0; }
};
//! \class memory_pool
//! \brief Allocates and tracks memory used by a json_document.
//!
//! The memory_pool uses a two-stage allocation system. First a static pool of size \c static_size is used. This is actually reserved as part of the size of
//! the object and therefore does not require a heap allocation. Once the static pool is exhausted, dynamic pools of size \c dynamic_size
//! (or larger as necessary) are allocated whenever additional memory is needed. The \c T_ALLOC template parameter is used for the dynamic pool
//! allocation.
//! \tparam T_ALLOC the allocator to use for dynamic allocations. See default_allocator for more info.
//! \tparam static_size Defaults to FASTJSON_STATIC_POOL_SIZE (32 KBytes). Specifies the size of memory to be included in the memory_pool for initial allocations. May be zero to force all allocations to be dynamic (reduces \c sizeof(memory_pool) ).
//! \tparam dynamic_size Defaults to FASTJSON_DYNAMIC_POOL_SIZE (32 KBytes). Specifies the size of each additional needed dynamic pool from the heap. If set to zero, all requested allocations are passed through to the heap (no pooling occurs).
template<class T_ALLOC = default_allocator, std::size_t static_size = FASTJSON_STATIC_POOL_SIZE, std::size_t dynamic_size = FASTJSON_DYNAMIC_POOL_SIZE>
class memory_pool : public T_ALLOC, public static_pool<static_size>
{
typedef static_pool<static_size> pool_type;
public:
//! Constructor
memory_pool() NOEXCEPT { init(); }
//! Destructor. Frees all of the memory used by this memory_pool.
~memory_pool() { clear(); }
//! \brief Clears all allocations from this memory pool back to the heap.
void clear()
{
while (pool_ != pool_type::static_pool_start())
{