Viewing file:  pycore_byteswap.h (2.56 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/* Bytes swap functions, reverse order of bytes:
- _Py_bswap16(uint16_t)
- _Py_bswap32(uint32_t)
- _Py_bswap64(uint64_t)
*/
#ifndef Py_INTERNAL_BSWAP_H
#define Py_INTERNAL_BSWAP_H
#ifdef __cplusplus
extern "C" {
#endif
#ifndef Py_BUILD_CORE
# error "this header requires Py_BUILD_CORE define"
#endif
#if defined(__GNUC__) \
&& ((__GNUC__ >= 5) || (__GNUC__ == 4) && (__GNUC_MINOR__ >= 8))
/* __builtin_bswap16() is available since GCC 4.8,
__builtin_bswap32() is available since GCC 4.3,
__builtin_bswap64() is available since GCC 4.3. */
# define _PY_HAVE_BUILTIN_BSWAP
#endif
#ifdef _MSC_VER
/* Get _byteswap_ushort(), _byteswap_ulong(), _byteswap_uint64() */
# include <intrin.h>
#endif
static inline uint16_t
_Py_bswap16(uint16_t word)
{
#if defined(_PY_HAVE_BUILTIN_BSWAP) || _Py__has_builtin(__builtin_bswap16)
return __builtin_bswap16(word);
#elif defined(_MSC_VER)
Py_BUILD_ASSERT(sizeof(word) == sizeof(unsigned short));
return _byteswap_ushort(word);
#else
// Portable implementation which doesn't rely on circular bit shift
return ( ((word & UINT16_C(0x00FF)) << 8)
| ((word & UINT16_C(0xFF00)) >> 8));
#endif
}
static inline uint32_t
_Py_bswap32(uint32_t word)
{
#if defined(_PY_HAVE_BUILTIN_BSWAP) || _Py__has_builtin(__builtin_bswap32)
return __builtin_bswap32(word);
#elif defined(_MSC_VER)
Py_BUILD_ASSERT(sizeof(word) == sizeof(unsigned long));
return _byteswap_ulong(word);
#else
// Portable implementation which doesn't rely on circular bit shift
return ( ((word & UINT32_C(0x000000FF)) << 24)
| ((word & UINT32_C(0x0000FF00)) << 8)
| ((word & UINT32_C(0x00FF0000)) >> 8)
| ((word & UINT32_C(0xFF000000)) >> 24));
#endif
}
static inline uint64_t
_Py_bswap64(uint64_t word)
{
#if defined(_PY_HAVE_BUILTIN_BSWAP) || _Py__has_builtin(__builtin_bswap64)
return __builtin_bswap64(word);
#elif defined(_MSC_VER)
return _byteswap_uint64(word);
#else
// Portable implementation which doesn't rely on circular bit shift
return ( ((word & UINT64_C(0x00000000000000FF)) << 56)
| ((word & UINT64_C(0x000000000000FF00)) << 40)
| ((word & UINT64_C(0x0000000000FF0000)) << 24)
| ((word & UINT64_C(0x00000000FF000000)) << 8)
| ((word & UINT64_C(0x000000FF00000000)) >> 8)
| ((word & UINT64_C(0x0000FF0000000000)) >> 24)
| ((word & UINT64_C(0x00FF000000000000)) >> 40)
| ((word & UINT64_C(0xFF00000000000000)) >> 56));
#endif
}
#ifdef __cplusplus
}
#endif
#endif /* !Py_INTERNAL_BSWAP_H */
|