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global: improve byte swapping functions (endian.h)

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Use platform's builtin byte swapping functions when available
This commit is contained in:
Hugues Delorme 2014-01-23 17:28:59 +01:00
parent 0539a111fd
commit 5f0f9f9273
2 changed files with 27 additions and 16 deletions
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37
src/endian.c
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@ -2,6 +2,9 @@
#include "convert.h"
#ifdef FOUG_HAVE_MSVC_BUILTIN_BSWAP_FUNC
# include <stdlib.h>
#endif
#include <string.h>
typedef union
@ -26,14 +29,19 @@ foug_endianness_t foug_host_endianness()
return FOUG_OTHER_ENDIAN;
}
uint16_t foug_uint16_swap(uint16_t val)
/*! Returns \p val with the order of bytes reversed.
*
* Uses compiler builtin functions if available
*/
uint16_t foug_uint16_bswap(uint16_t val)
{
#ifdef FOUG_HAVE_GCC_BUILTIN_BSWAP_FUNC
return __builtin_bswap16(val);
#elif defined(FOUG_HAVE_MSVC_BUILTIN_BSWAP_FUNC)
return _byteswap_ushort(val);
#else
return ((val & 0x00FF) << 8) | ((val >> 8) & 0x00FF);
}
uint16_t foug_uint16_noswap(uint16_t val)
{
return val;
#endif
}
/*! Read a 16bit integer from memory-location \p bytes (little-endian byte order) */
@ -59,18 +67,23 @@ void foug_encode_uint16_le(uint16_t val, uint8_t* bytes)
bytes[1] = (val >> 8) & 0xFF;
}
uint32_t foug_uint32_swap(uint32_t val)
/*! Returns \p val with the order of bytes reversed.
*
* Uses compiler builtin functions if available
*/
uint32_t foug_uint32_bswap(uint32_t val)
{
#ifdef FOUG_HAVE_GCC_BUILTIN_BSWAP_FUNC
return __builtin_bswap32(val);
#elif defined(FOUG_HAVE_MSVC_BUILTIN_BSWAP_FUNC)
return _byteswap_ulong(val);
#else
return
((val & 0x000000FF) << 24)
| ((val & 0x0000FF00) << 8)
| ((val >> 8) & 0x0000FF00)
| ((val >> 24) & 0x000000FF);
}
uint32_t foug_uint32_noswap(uint32_t val)
{
return val;
#endif
}
/*! Read a 32bit integer from memory-location \p bytes (little-endian byte order) */

6
src/endian.h
View File

@ -13,14 +13,12 @@ typedef enum
FOUG_LIB_EXPORT foug_endianness_t foug_host_endianness();
FOUG_LIB_EXPORT uint16_t foug_uint16_swap(uint16_t val);
FOUG_LIB_EXPORT uint16_t foug_uint16_noswap(uint16_t val);
FOUG_LIB_EXPORT uint16_t foug_uint16_bswap(uint16_t val);
FOUG_LIB_EXPORT uint16_t foug_decode_uint16_le(const uint8_t* bytes);
FOUG_LIB_EXPORT uint16_t foug_decode_uint16_be(const uint8_t* bytes);
FOUG_LIB_EXPORT void foug_encode_uint16_le(uint16_t val, uint8_t* bytes);
FOUG_LIB_EXPORT uint32_t foug_uint32_swap(uint32_t val);
FOUG_LIB_EXPORT uint32_t foug_uint32_noswap(uint32_t val);
FOUG_LIB_EXPORT uint32_t foug_uint32_bswap(uint32_t val);
FOUG_LIB_EXPORT uint32_t foug_decode_uint32_le(const uint8_t* bytes);
FOUG_LIB_EXPORT uint32_t foug_decode_uint32_me(const uint8_t* bytes);
FOUG_LIB_EXPORT uint32_t foug_decode_uint32_be(const uint8_t* bytes);