Sha256: c05b26e1196d02ebc333b8fa3012e71cb2aef4e890abfc2189be5fe59634f2f4
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Contents
/////////////////////////////////////////////////////////////////////////////// // /// \file crc64.c /// \brief CRC64 calculation /// /// Calculate the CRC64 using the slice-by-four algorithm. This is the same /// idea that is used in crc32_fast.c, but for CRC64 we use only four tables /// instead of eight to avoid increasing CPU cache usage. // // Author: Lasse Collin // // This file has been put into the public domain. // You can do whatever you want with this file. // /////////////////////////////////////////////////////////////////////////////// #include "check.h" #include "crc_macros.h" #ifdef WORDS_BIGENDIAN # define A1(x) ((x) >> 56) #else # define A1 A #endif // See the comments in crc32_fast.c. They aren't duplicated here. extern LZMA_API(uint64_t) lzma_crc64(const uint8_t *buf, size_t size, uint64_t crc) { crc = ~crc; #ifdef WORDS_BIGENDIAN crc = bswap64(crc); #endif if (size > 4) { while ((uintptr_t)(buf) & 3) { crc = lzma_crc64_table[0][*buf++ ^ A1(crc)] ^ S8(crc); --size; } const uint8_t *const limit = buf + (size & ~(size_t)(3)); size &= (size_t)(3); while (buf < limit) { #ifdef WORDS_BIGENDIAN const uint32_t tmp = (crc >> 32) ^ *(const uint32_t *)(buf); #else const uint32_t tmp = crc ^ *(const uint32_t *)(buf); #endif buf += 4; crc = lzma_crc64_table[3][A(tmp)] ^ lzma_crc64_table[2][B(tmp)] ^ S32(crc) ^ lzma_crc64_table[1][C(tmp)] ^ lzma_crc64_table[0][D(tmp)]; } } while (size-- != 0) crc = lzma_crc64_table[0][*buf++ ^ A1(crc)] ^ S8(crc); #ifdef WORDS_BIGENDIAN crc = bswap64(crc); #endif return ~crc; }
Version data entries
1 entries across 1 versions & 1 rubygems
Version | Path |
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laag-xz-5.2.4.0 | vendor/git.tukaani.org/xz/src/liblzma/check/crc64_fast.c |