mirror of
https://github.com/git/git.git
synced 2024-10-31 14:27:54 +01:00
bfb0e6fcd2
There is no /usr/include/endian.h equivalent on z/OS, but the compiler will define macros to indicate endianness on host and target hardware. This adds a test for these macros as a last resort for determining byte order. Signed-off-by: David Michael <fedora.dm0@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
179 lines
4.6 KiB
C
179 lines
4.6 KiB
C
/*
|
|
* Let's make sure we always have a sane definition for ntohl()/htonl().
|
|
* Some libraries define those as a function call, just to perform byte
|
|
* shifting, bringing significant overhead to what should be a simple
|
|
* operation.
|
|
*/
|
|
|
|
/*
|
|
* Default version that the compiler ought to optimize properly with
|
|
* constant values.
|
|
*/
|
|
static inline uint32_t default_swab32(uint32_t val)
|
|
{
|
|
return (((val & 0xff000000) >> 24) |
|
|
((val & 0x00ff0000) >> 8) |
|
|
((val & 0x0000ff00) << 8) |
|
|
((val & 0x000000ff) << 24));
|
|
}
|
|
|
|
static inline uint64_t default_bswap64(uint64_t val)
|
|
{
|
|
return (((val & (uint64_t)0x00000000000000ffULL) << 56) |
|
|
((val & (uint64_t)0x000000000000ff00ULL) << 40) |
|
|
((val & (uint64_t)0x0000000000ff0000ULL) << 24) |
|
|
((val & (uint64_t)0x00000000ff000000ULL) << 8) |
|
|
((val & (uint64_t)0x000000ff00000000ULL) >> 8) |
|
|
((val & (uint64_t)0x0000ff0000000000ULL) >> 24) |
|
|
((val & (uint64_t)0x00ff000000000000ULL) >> 40) |
|
|
((val & (uint64_t)0xff00000000000000ULL) >> 56));
|
|
}
|
|
|
|
#undef bswap32
|
|
#undef bswap64
|
|
|
|
#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
|
|
|
|
#define bswap32 git_bswap32
|
|
static inline uint32_t git_bswap32(uint32_t x)
|
|
{
|
|
uint32_t result;
|
|
if (__builtin_constant_p(x))
|
|
result = default_swab32(x);
|
|
else
|
|
__asm__("bswap %0" : "=r" (result) : "0" (x));
|
|
return result;
|
|
}
|
|
|
|
#define bswap64 git_bswap64
|
|
#if defined(__x86_64__)
|
|
static inline uint64_t git_bswap64(uint64_t x)
|
|
{
|
|
uint64_t result;
|
|
if (__builtin_constant_p(x))
|
|
result = default_bswap64(x);
|
|
else
|
|
__asm__("bswap %q0" : "=r" (result) : "0" (x));
|
|
return result;
|
|
}
|
|
#else
|
|
static inline uint64_t git_bswap64(uint64_t x)
|
|
{
|
|
union { uint64_t i64; uint32_t i32[2]; } tmp, result;
|
|
if (__builtin_constant_p(x))
|
|
result.i64 = default_bswap64(x);
|
|
else {
|
|
tmp.i64 = x;
|
|
result.i32[0] = git_bswap32(tmp.i32[1]);
|
|
result.i32[1] = git_bswap32(tmp.i32[0]);
|
|
}
|
|
return result.i64;
|
|
}
|
|
#endif
|
|
|
|
#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
|
|
|
|
#include <stdlib.h>
|
|
|
|
#define bswap32(x) _byteswap_ulong(x)
|
|
#define bswap64(x) _byteswap_uint64(x)
|
|
|
|
#endif
|
|
|
|
#if defined(bswap32)
|
|
|
|
#undef ntohl
|
|
#undef htonl
|
|
#define ntohl(x) bswap32(x)
|
|
#define htonl(x) bswap32(x)
|
|
|
|
#endif
|
|
|
|
#if defined(bswap64)
|
|
|
|
#undef ntohll
|
|
#undef htonll
|
|
#define ntohll(x) bswap64(x)
|
|
#define htonll(x) bswap64(x)
|
|
|
|
#else
|
|
|
|
#undef ntohll
|
|
#undef htonll
|
|
|
|
#if defined(__BYTE_ORDER) && defined(__LITTLE_ENDIAN) && defined(__BIG_ENDIAN)
|
|
|
|
# define GIT_BYTE_ORDER __BYTE_ORDER
|
|
# define GIT_LITTLE_ENDIAN __LITTLE_ENDIAN
|
|
# define GIT_BIG_ENDIAN __BIG_ENDIAN
|
|
|
|
#elif defined(BYTE_ORDER) && defined(LITTLE_ENDIAN) && defined(BIG_ENDIAN)
|
|
|
|
# define GIT_BYTE_ORDER BYTE_ORDER
|
|
# define GIT_LITTLE_ENDIAN LITTLE_ENDIAN
|
|
# define GIT_BIG_ENDIAN BIG_ENDIAN
|
|
|
|
#else
|
|
|
|
# define GIT_BIG_ENDIAN 4321
|
|
# define GIT_LITTLE_ENDIAN 1234
|
|
|
|
# if defined(_BIG_ENDIAN) && !defined(_LITTLE_ENDIAN)
|
|
# define GIT_BYTE_ORDER GIT_BIG_ENDIAN
|
|
# elif defined(_LITTLE_ENDIAN) && !defined(_BIG_ENDIAN)
|
|
# define GIT_BYTE_ORDER GIT_LITTLE_ENDIAN
|
|
# elif defined(__THW_BIG_ENDIAN__) && !defined(__THW_LITTLE_ENDIAN__)
|
|
# define GIT_BYTE_ORDER GIT_BIG_ENDIAN
|
|
# elif defined(__THW_LITTLE_ENDIAN__) && !defined(__THW_BIG_ENDIAN__)
|
|
# define GIT_BYTE_ORDER GIT_LITTLE_ENDIAN
|
|
# else
|
|
# error "Cannot determine endianness"
|
|
# endif
|
|
|
|
#endif
|
|
|
|
#if GIT_BYTE_ORDER == GIT_BIG_ENDIAN
|
|
# define ntohll(n) (n)
|
|
# define htonll(n) (n)
|
|
#else
|
|
# define ntohll(n) default_bswap64(n)
|
|
# define htonll(n) default_bswap64(n)
|
|
#endif
|
|
|
|
#endif
|
|
|
|
/*
|
|
* Performance might be improved if the CPU architecture is OK with
|
|
* unaligned 32-bit loads and a fast ntohl() is available.
|
|
* Otherwise fall back to byte loads and shifts which is portable,
|
|
* and is faster on architectures with memory alignment issues.
|
|
*/
|
|
|
|
#if defined(__i386__) || defined(__x86_64__) || \
|
|
defined(_M_IX86) || defined(_M_X64) || \
|
|
defined(__ppc__) || defined(__ppc64__) || \
|
|
defined(__powerpc__) || defined(__powerpc64__) || \
|
|
defined(__s390__) || defined(__s390x__)
|
|
|
|
#define get_be16(p) ntohs(*(unsigned short *)(p))
|
|
#define get_be32(p) ntohl(*(unsigned int *)(p))
|
|
#define put_be32(p, v) do { *(unsigned int *)(p) = htonl(v); } while (0)
|
|
|
|
#else
|
|
|
|
#define get_be16(p) ( \
|
|
(*((unsigned char *)(p) + 0) << 8) | \
|
|
(*((unsigned char *)(p) + 1) << 0) )
|
|
#define get_be32(p) ( \
|
|
(*((unsigned char *)(p) + 0) << 24) | \
|
|
(*((unsigned char *)(p) + 1) << 16) | \
|
|
(*((unsigned char *)(p) + 2) << 8) | \
|
|
(*((unsigned char *)(p) + 3) << 0) )
|
|
#define put_be32(p, v) do { \
|
|
unsigned int __v = (v); \
|
|
*((unsigned char *)(p) + 0) = __v >> 24; \
|
|
*((unsigned char *)(p) + 1) = __v >> 16; \
|
|
*((unsigned char *)(p) + 2) = __v >> 8; \
|
|
*((unsigned char *)(p) + 3) = __v >> 0; } while (0)
|
|
|
|
#endif
|