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author | Brad King <brad.king@kitware.com> | 2014-07-21 18:31:04 (GMT) |
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committer | Brad King <brad.king@kitware.com> | 2014-07-21 19:54:44 (GMT) |
commit | 133d42fe59e2f15610afaed287ef80ec4ff6f888 (patch) | |
tree | ea0831dc0601b3e91c3881d9f182c085ad4fffe2 /Utilities/cmliblzma/liblzma/check/crc64_small.c | |
parent | 8510533f0e713abeedf53a737c702d683b636ecb (diff) | |
parent | c289e63491982dd8aed7c6b6f54d390df91aaf95 (diff) | |
download | CMake-133d42fe59e2f15610afaed287ef80ec4ff6f888.zip CMake-133d42fe59e2f15610afaed287ef80ec4ff6f888.tar.gz CMake-133d42fe59e2f15610afaed287ef80ec4ff6f888.tar.bz2 |
Merge branch 'liblzma-upstream' into add-liblzma
Diffstat (limited to 'Utilities/cmliblzma/liblzma/check/crc64_small.c')
-rw-r--r-- | Utilities/cmliblzma/liblzma/check/crc64_small.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/Utilities/cmliblzma/liblzma/check/crc64_small.c b/Utilities/cmliblzma/liblzma/check/crc64_small.c new file mode 100644 index 0000000..55d7231 --- /dev/null +++ b/Utilities/cmliblzma/liblzma/check/crc64_small.c @@ -0,0 +1,53 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file crc64_small.c +/// \brief CRC64 calculation (size-optimized) +// +// Author: Lasse Collin +// +// This file has been put into the public domain. +// You can do whatever you want with this file. +// +/////////////////////////////////////////////////////////////////////////////// + +#include "check.h" + + +static uint64_t crc64_table[256]; + + +static void +crc64_init(void) +{ + static const uint64_t poly64 = UINT64_C(0xC96C5795D7870F42); + + for (size_t b = 0; b < 256; ++b) { + uint64_t r = b; + for (size_t i = 0; i < 8; ++i) { + if (r & 1) + r = (r >> 1) ^ poly64; + else + r >>= 1; + } + + crc64_table[b] = r; + } + + return; +} + + +extern LZMA_API(uint64_t) +lzma_crc64(const uint8_t *buf, size_t size, uint64_t crc) +{ + mythread_once(crc64_init); + + crc = ~crc; + + while (size != 0) { + crc = crc64_table[*buf++ ^ (crc & 0xFF)] ^ (crc >> 8); + --size; + } + + return ~crc; +} |