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9c65ee15ee
The changes to make detection of endianness more portable had a bug that breaks on (at least) Solaris x86. The bug appears to be a simple copy/paste typo. It checks for _BIG_ENDIAN and not _LITTLE_ENDIAN for both the case where we would decide the system is big endian and little endian. Instead, the second test should be for _LITTLE_ENDIAN and not _BIG_ENDIAN. Two fixes were possible: 1. Change the negation order of the conditions in the second test. 2. Reverse the order of the conditions in the second test. Use the second option so that the condition we expect is always a positive check. Signed-off-by: Ben Walton <bdwalton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
176 lines
4.3 KiB
C
176 lines
4.3 KiB
C
/*
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* Let's make sure we always have a sane definition for ntohl()/htonl().
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* Some libraries define those as a function call, just to perform byte
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* shifting, bringing significant overhead to what should be a simple
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* operation.
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*/
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/*
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* Default version that the compiler ought to optimize properly with
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* constant values.
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*/
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static inline uint32_t default_swab32(uint32_t val)
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{
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return (((val & 0xff000000) >> 24) |
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((val & 0x00ff0000) >> 8) |
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((val & 0x0000ff00) << 8) |
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((val & 0x000000ff) << 24));
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}
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static inline uint64_t default_bswap64(uint64_t val)
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{
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return (((val & (uint64_t)0x00000000000000ffULL) << 56) |
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((val & (uint64_t)0x000000000000ff00ULL) << 40) |
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((val & (uint64_t)0x0000000000ff0000ULL) << 24) |
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((val & (uint64_t)0x00000000ff000000ULL) << 8) |
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((val & (uint64_t)0x000000ff00000000ULL) >> 8) |
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((val & (uint64_t)0x0000ff0000000000ULL) >> 24) |
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((val & (uint64_t)0x00ff000000000000ULL) >> 40) |
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((val & (uint64_t)0xff00000000000000ULL) >> 56));
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}
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#undef bswap32
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#undef bswap64
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#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
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#define bswap32 git_bswap32
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static inline uint32_t git_bswap32(uint32_t x)
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{
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uint32_t result;
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if (__builtin_constant_p(x))
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result = default_swab32(x);
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else
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__asm__("bswap %0" : "=r" (result) : "0" (x));
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return result;
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}
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#define bswap64 git_bswap64
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#if defined(__x86_64__)
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static inline uint64_t git_bswap64(uint64_t x)
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{
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uint64_t result;
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if (__builtin_constant_p(x))
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result = default_bswap64(x);
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else
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__asm__("bswap %q0" : "=r" (result) : "0" (x));
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return result;
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}
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#else
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static inline uint64_t git_bswap64(uint64_t x)
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{
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union { uint64_t i64; uint32_t i32[2]; } tmp, result;
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if (__builtin_constant_p(x))
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result.i64 = default_bswap64(x);
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else {
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tmp.i64 = x;
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result.i32[0] = git_bswap32(tmp.i32[1]);
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result.i32[1] = git_bswap32(tmp.i32[0]);
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}
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return result.i64;
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}
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#endif
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#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
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#include <stdlib.h>
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#define bswap32(x) _byteswap_ulong(x)
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#define bswap64(x) _byteswap_uint64(x)
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#endif
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#if defined(bswap32)
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#undef ntohl
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#undef htonl
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#define ntohl(x) bswap32(x)
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#define htonl(x) bswap32(x)
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#endif
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#if defined(bswap64)
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#undef ntohll
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#undef htonll
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#define ntohll(x) bswap64(x)
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#define htonll(x) bswap64(x)
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#else
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#undef ntohll
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#undef htonll
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#if defined(__BYTE_ORDER) && defined(__LITTLE_ENDIAN) && defined(__BIG_ENDIAN)
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# define GIT_BYTE_ORDER __BYTE_ORDER
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# define GIT_LITTLE_ENDIAN __LITTLE_ENDIAN
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# define GIT_BIG_ENDIAN __BIG_ENDIAN
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#elif defined(BYTE_ORDER) && defined(LITTLE_ENDIAN) && defined(BIG_ENDIAN)
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# define GIT_BYTE_ORDER BYTE_ORDER
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# define GIT_LITTLE_ENDIAN LITTLE_ENDIAN
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# define GIT_BIG_ENDIAN BIG_ENDIAN
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#else
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# define GIT_BIG_ENDIAN 4321
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# define GIT_LITTLE_ENDIAN 1234
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# if defined(_BIG_ENDIAN) && !defined(_LITTLE_ENDIAN)
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# define GIT_BYTE_ORDER GIT_BIG_ENDIAN
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# elif defined(_LITTLE_ENDIAN) && !defined(_BIG_ENDIAN)
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# define GIT_BYTE_ORDER GIT_LITTLE_ENDIAN
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# else
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# error "Cannot determine endianness"
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# endif
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#endif
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#if GIT_BYTE_ORDER == GIT_BIG_ENDIAN
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# define ntohll(n) (n)
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# define htonll(n) (n)
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#else
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# define ntohll(n) default_bswap64(n)
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# define htonll(n) default_bswap64(n)
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#endif
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#endif
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/*
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* Performance might be improved if the CPU architecture is OK with
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* unaligned 32-bit loads and a fast ntohl() is available.
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* Otherwise fall back to byte loads and shifts which is portable,
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* and is faster on architectures with memory alignment issues.
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*/
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#if defined(__i386__) || defined(__x86_64__) || \
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defined(_M_IX86) || defined(_M_X64) || \
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defined(__ppc__) || defined(__ppc64__) || \
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defined(__powerpc__) || defined(__powerpc64__) || \
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defined(__s390__) || defined(__s390x__)
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#define get_be16(p) ntohs(*(unsigned short *)(p))
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#define get_be32(p) ntohl(*(unsigned int *)(p))
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#define put_be32(p, v) do { *(unsigned int *)(p) = htonl(v); } while (0)
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#else
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#define get_be16(p) ( \
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(*((unsigned char *)(p) + 0) << 8) | \
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(*((unsigned char *)(p) + 1) << 0) )
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#define get_be32(p) ( \
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(*((unsigned char *)(p) + 0) << 24) | \
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(*((unsigned char *)(p) + 1) << 16) | \
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(*((unsigned char *)(p) + 2) << 8) | \
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(*((unsigned char *)(p) + 3) << 0) )
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#define put_be32(p, v) do { \
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unsigned int __v = (v); \
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*((unsigned char *)(p) + 0) = __v >> 24; \
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*((unsigned char *)(p) + 1) = __v >> 16; \
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*((unsigned char *)(p) + 2) = __v >> 8; \
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*((unsigned char *)(p) + 3) = __v >> 0; } while (0)
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#endif
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