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crc32: sb8: remove some unneeded stuff, use hashindex byteorder detection

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This commit is contained in:
Marian Beermann 2017-01-13 00:30:17 +01:00
parent 292fb1e2a9
commit f482c32423
1 changed files with 16 additions and 48 deletions
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64
src/borg/_crc32/slice_by_8.c
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@ -12,8 +12,6 @@
/// compute CRC32 (Slicing-by-8 algorithm), unroll inner loop 4 times
uint32_t crc32_4x8bytes(const void* data, size_t length, uint32_t previousCrc32);
// //////////////////////////////////////////////////////////
// Crc32.cpp
// Copyright (c) 2011-2016 Stephan Brumme. All rights reserved.
@ -22,55 +20,25 @@ uint32_t crc32_4x8bytes(const void* data, size_t length, uint32_t previousCrc32)
// see http://create.stephan-brumme.com/disclaimer.html
//
// if running on an embedded system, you might consider shrinking the
// big Crc32Lookup table:
// - crc32_bitwise doesn't need it at all
// - crc32_halfbyte has its own small lookup table
// - crc32_1byte needs only Crc32Lookup[0]
// - crc32_4bytes needs only Crc32Lookup[0..3]
// - crc32_8bytes needs only Crc32Lookup[0..7]
// - crc32_4x8bytes needs only Crc32Lookup[0..7]
// - crc32_16bytes needs all of Crc32Lookup
// define endianess and some integer data types
#if defined(_MSC_VER) || defined(__MINGW32__)
#define __LITTLE_ENDIAN 1234
#define __BIG_ENDIAN 4321
#define __BYTE_ORDER __LITTLE_ENDIAN
#include <xmmintrin.h>
#ifdef __MINGW32__
#define PREFETCH(location) __builtin_prefetch(location)
#else
#define PREFETCH(location) _mm_prefetch(location, _MM_HINT_T0)
#endif
#else
// defines __BYTE_ORDER as __LITTLE_ENDIAN or __BIG_ENDIAN
#include <sys/param.h>
#ifdef __GNUC__
#define PREFETCH(location) __builtin_prefetch(location)
#else
#define PREFETCH(location) ;
#endif
#endif
/// zlib's CRC32 polynomial
const uint32_t Polynomial = 0xEDB88320;
/// swap endianess
static inline uint32_t swap(uint32_t x)
{
#if defined(__GNUC__) || defined(__clang__)
return __builtin_bswap32(x);
#else
return (x >> 24) |
((x >> 8) & 0x0000FF00) |
((x << 8) & 0x00FF0000) |
(x << 24);
#if defined (__SVR4) && defined (__sun)
#include <sys/isa_defs.h>
#endif
#if (defined(BYTE_ORDER)&&(BYTE_ORDER == BIG_ENDIAN)) || \
(defined(_BIG_ENDIAN)&&defined(__SVR4)&&defined(__sun))
#define _le32toh(x) __builtin_bswap32(x)
#define BORG_BIG_ENDIAN
#elif (defined(BYTE_ORDER)&&(BYTE_ORDER == LITTLE_ENDIAN)) || \
(defined(_LITTLE_ENDIAN)&&defined(__SVR4)&&defined(__sun))
#define _le32toh(x) (x)
#define BORG_LITTLE_ENDIAN
#else
#error Unknown byte order
#endif
}
// //////////////////////////////////////////////////////////
// constants
@ -389,8 +357,8 @@ uint32_t crc32_slice_by_8(const void* data, size_t length, uint32_t previousCrc3
size_t unrolling;
for (unrolling = 0; unrolling < Unroll; unrolling++)
{
#if __BYTE_ORDER == __BIG_ENDIAN
uint32_t one = *current++ ^ swap(crc);
#ifdef BORG_BIG_ENDIAN
uint32_t one = *current++ ^ _le32toh(crc);
uint32_t two = *current++;
crc = Crc32Lookup[0][ two & 0xFF] ^
Crc32Lookup[1][(two>> 8) & 0xFF] ^