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Use compiler intrinsics to swap bytes

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This commit is contained in:
Matias Fontanini
2016-02-18 20:35:37 -08:00
parent bd31b3648f
commit 5c22cc7985
5 changed files with 50 additions and 6 deletions
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3
include/tins/config.h.in
View File

@@ -16,4 +16,7 @@
/* Have TCP ACK tracking */
#cmakedefine HAVE_ACK_TRACKER
/* Have GCC builtin swap */
#cmakedefine HAVE_GCC_BUILTIN_SWAP
#endif // TINS_CONFIG_H

36
include/tins/endianness.h
View File

@@ -42,6 +42,7 @@
#define TINS_IS_LITTLE_ENDIAN (_BYTE_ORDER == _LITTLE_ENDIAN)
#define TINS_IS_BIG_ENDIAN (_BYTE_ORDER == _BIG_ENDIAN)
#elif defined(_WIN32)
#include <cstdlib>
// Assume windows == little endian. fixme later
#define TINS_IS_LITTLE_ENDIAN 1
#define TINS_IS_BIG_ENDIAN 0
@@ -51,6 +52,19 @@
#define TINS_IS_BIG_ENDIAN (__BYTE_ORDER == __BIG_ENDIAN)
#endif
// Define macros to swap bytes using compiler intrinsics when possible
#if defined(_MSC_VER)
#define TINS_BYTE_SWAP_16(data) _byteswap_ushort(data)
#define TINS_BYTE_SWAP_32(data) _byteswap_ulong(data)
#define TINS_BYTE_SWAP_64(data) _byteswap_uint64(data)
#elif defined(HAVE_GCC_BUILTIN_SWAP)
#define TINS_BYTE_SWAP_16(data) __builtin_bswap16(data)
#define TINS_BYTE_SWAP_32(data) __builtin_bswap32(data)
#define TINS_BYTE_SWAP_64(data) __builtin_bswap64(data)
#else
#define TINS_NO_BYTE_SWAP_INTRINSICS
#endif
namespace Tins {
namespace Endian {
@@ -70,7 +84,11 @@ inline uint8_t do_change_endian(uint8_t data) {
* \param data The data to convert.
*/
inline uint16_t do_change_endian(uint16_t data) {
return ((data & 0xff00) >> 8) | ((data & 0x00ff) << 8);
#ifdef TINS_NO_BYTE_SWAP_INTRINSICS
return ((data & 0xff00) >> 8) | ((data & 0x00ff) << 8);
#else
return TINS_BYTE_SWAP_16(data);
#endif
}
/**
@@ -79,8 +97,12 @@ inline uint16_t do_change_endian(uint16_t data) {
* \param data The data to convert.
*/
inline uint32_t do_change_endian(uint32_t data) {
return (((data & 0xff000000) >> 24) | ((data & 0x00ff0000) >> 8) |
((data & 0x0000ff00) << 8) | ((data & 0x000000ff) << 24));
#ifdef TINS_NO_BYTE_SWAP_INTRINSICS
return (((data & 0xff000000) >> 24) | ((data & 0x00ff0000) >> 8) |
((data & 0x0000ff00) << 8) | ((data & 0x000000ff) << 24));
#else
return TINS_BYTE_SWAP_32(data);
#endif
}
/**
@@ -89,8 +111,12 @@ inline uint32_t do_change_endian(uint32_t data) {
* \param data The data to convert.
*/
inline uint64_t do_change_endian(uint64_t data) {
return (((uint64_t)(do_change_endian((uint32_t)(data & 0xffffffff))) << 32) |
(do_change_endian(((uint32_t)(data >> 32)))));
#ifdef TINS_NO_BYTE_SWAP_INTRINSICS
return (((uint64_t)(do_change_endian((uint32_t)(data & 0xffffffff))) << 32) |
(do_change_endian(((uint32_t)(data >> 32)))));
#else
return TINS_BYTE_SWAP_64(data);
#endif
}
/**