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// Copyright 2017 Daniel Parker
// Distributed under the Boost license, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
// See https://github.com/danielaparker/jsoncons for latest version
#ifndef JSONCONS_CONFIG_BINARY_CONFIG_HPP
#define JSONCONS_CONFIG_BINARY_CONFIG_HPP
#include <cfloat>
#include <cstddef>
#include <cstdint>
#include <cstring> // std::memcpy
#include <memory>
#include <type_traits> // std::enable_if
// The definitions below follow the definitions in compiler_support_p.h, https://github.com/01org/tinycbor
// MIT license
#ifdef __F16C__
# include <immintrin.h>
#endif
#ifndef __has_builtin
# define __has_builtin(x) 0
#endif
#if defined(__GNUC__)
#if (__GNUC__ * 100 + __GNUC_MINOR__ >= 403) || (__has_builtin(__builtin_bswap64) && __has_builtin(__builtin_bswap32))
# define JSONCONS_BYTE_SWAP_64 __builtin_bswap64
# define JSONCONS_BYTE_SWAP_32 __builtin_bswap32
# ifdef __INTEL_COMPILER
# define JSONCONS_BYTE_SWAP_16 _bswap16
# elif (__GNUC__ * 100 + __GNUC_MINOR__ >= 608) || __has_builtin(__builtin_bswap16)
# define JSONCONS_BYTE_SWAP_16 __builtin_bswap16
# endif
#endif
#elif defined(__sun)
# include <sys/byteorder.h>
#elif defined(_MSC_VER)
// MSVC, which implies sizeof(long) == 4
# define JSONCONS_BYTE_SWAP_64 _byteswap_uint64
# define JSONCONS_BYTE_SWAP_32 _byteswap_ulong
# define JSONCONS_BYTE_SWAP_16 _byteswap_ushort
#endif
namespace jsoncons {
namespace binary {
struct uint128_holder
{
uint64_t lo;
uint64_t hi;
};
static inline bool add_check_overflow(std::size_t v1, std::size_t v2, std::size_t *r)
{
#if ((defined(__GNUC__) && (__GNUC__ >= 5)) && !defined(__INTEL_COMPILER)) || __has_builtin(__builtin_add_overflow)
return __builtin_add_overflow(v1, v2, r);
#else
// unsigned additions are well-defined
*r = v1 + v2;
return v1 > v1 + v2;
#endif
}
#if defined(__apple_build_version__) && ((__clang_major__ < 8) || ((__clang_major__ == 8) && (__clang_minor__ < 1)))
#define APPLE_MISSING_INTRINSICS 1
#endif
inline
uint16_t encode_half(double val)
{
#if defined(__F16C__) && !defined(APPLE_MISSING_INTRINSICS)
return _cvtss_sh((float)val, 3);
#else
uint64_t v;
std::memcpy(&v, &val, sizeof(v));
int64_t sign = static_cast<int64_t>(v >> 63 << 15);
int64_t exp = (v >> 52) & 0x7ff;
int64_t mant = v << 12 >> 12 >> (53-11); /* keep only the 11 most significant bits of the mantissa */
exp -= 1023;
if (exp == 1024) {
/* infinity or NaN */
exp = 16;
mant >>= 1;
} else if (exp >= 16) {
/* overflow, as largest number */
exp = 15;
mant = 1023;
} else if (exp >= -14) {
/* regular normal */
} else if (exp >= -24) {
/* subnormal */
mant |= 1024;
mant >>= -(exp + 14);
exp = -15;
} else {
/* underflow, make zero */
return 0;
}
/* safe cast here as bit operations above guarantee not to overflow */
return static_cast<uint16_t>(sign | ((exp + 15) << 10) | mant);
#endif
}
/* this function was copied & adapted from RFC 7049 Appendix D */
inline
double decode_half(uint16_t half)
{
#if defined(__F16C__) && !defined(APPLE_MISSING_INTRINSICS)
return _cvtsh_ss(half);
#else
int64_t exp = (half >> 10) & 0x1f;
int64_t mant = half & 0x3ff;
double val;
if (exp == 0)
{
val = ldexp(static_cast<double>(mant), -24);
}
else if (exp != 31)
{
val = ldexp(static_cast<double>(mant) + 1024.0, static_cast<int>(exp - 25));
}
else
{
val = mant == 0 ? std::numeric_limits<double>::infinity() : std::nan("");
}
return half & 0x8000 ? -val : val;
#endif
}
// byte_swap
template<class T>
typename std::enable_if<std::is_integral<T>::value && sizeof(T) == sizeof(uint8_t),T>::type
byte_swap(T val)
{
return val;
}
template<class T>
typename std::enable_if<std::is_integral<T>::value && sizeof(T) == sizeof(uint16_t),T>::type
byte_swap(T val)
{
#if defined(JSONCONS_BYTE_SWAP_16)
return JSONCONS_BYTE_SWAP_16(val);
#else
return (static_cast<uint16_t>(val) >> 8) | (static_cast<uint16_t>(val) << 8);
#endif
}
template<class T>
typename std::enable_if<std::is_integral<T>::value && sizeof(T) == sizeof(uint32_t),T>::type
byte_swap(T val)
{
#if defined(JSONCONS_BYTE_SWAP_32)
return JSONCONS_BYTE_SWAP_32(val);
#else
uint32_t tmp = ((static_cast<uint32_t>(val) << 8) & 0xff00ff00) | ((static_cast<uint32_t>(val) >> 8) & 0xff00ff);
return (tmp << 16) | (tmp >> 16);
#endif
}
template<class T>
typename std::enable_if<std::is_integral<T>::value && sizeof(T) == sizeof(uint64_t),T>::type
byte_swap(T val)
{
#if defined(JSONCONS_BYTE_SWAP_64)
return JSONCONS_BYTE_SWAP_64(val);
#else
uint64_t tmp = ((static_cast<uint64_t>(val) & 0x00000000ffffffffull) << 32) | ((static_cast<uint64_t>(val) & 0xffffffff00000000ull) >> 32);
tmp = ((tmp & 0x0000ffff0000ffffull) << 16) | ((tmp & 0xffff0000ffff0000ull) >> 16);
return ((tmp & 0x00ff00ff00ff00ffull) << 8) | ((tmp & 0xff00ff00ff00ff00ull) >> 8);
#endif
}
template<class T>
typename std::enable_if<std::is_floating_point<T>::value && sizeof(T) == sizeof(uint32_t),T>::type
byte_swap(T val)
{
uint32_t x;
std::memcpy(&x,&val,sizeof(uint32_t));
uint32_t y = byte_swap(x);
T val2;
std::memcpy(&val2,&y,sizeof(uint32_t));
return val2;
}
template<class T>
typename std::enable_if<std::is_floating_point<T>::value && sizeof(T) == sizeof(uint64_t),T>::type
byte_swap(T val)
{
uint64_t x;
std::memcpy(&x,&val,sizeof(uint64_t));
uint64_t y = byte_swap(x);
T val2;
std::memcpy(&val2,&y,sizeof(uint64_t));
return val2;
}
template<class T>
typename std::enable_if<std::is_floating_point<T>::value && sizeof(T) == 2*sizeof(uint64_t),T>::type
byte_swap(T val)
{
uint128_holder x;
uint8_t buf[2*sizeof(uint64_t)];
std::memcpy(buf,&val,2*sizeof(uint64_t));
std::memcpy(&x.lo,buf,sizeof(uint64_t));
std::memcpy(&x.hi,buf+sizeof(uint64_t),sizeof(uint64_t));
uint128_holder y;
y.lo = byte_swap(x.hi);
y.hi = byte_swap(x.lo);
T val2;
std::memcpy(&val2,&y,2*sizeof(uint64_t));
return val2;
}
} // binary
} // jsoncons
#endif
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