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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 21:12:04 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 21:12:04 +0000 |
commit | eac54b7c4aec25060d7bd856f7cdc290943d6aae (patch) | |
tree | 9a6d81c9f88df4698e746d63d14ddafeddd918b8 /src/liblzma/check/crc32_small.c | |
parent | Initial commit. (diff) | |
download | xz-utils-eac54b7c4aec25060d7bd856f7cdc290943d6aae.tar.xz xz-utils-eac54b7c4aec25060d7bd856f7cdc290943d6aae.zip |
Adding upstream version 5.4.1.upstream/5.4.1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/liblzma/check/crc32_small.c')
-rw-r--r-- | src/liblzma/check/crc32_small.c | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/src/liblzma/check/crc32_small.c b/src/liblzma/check/crc32_small.c new file mode 100644 index 0000000..186966e --- /dev/null +++ b/src/liblzma/check/crc32_small.c @@ -0,0 +1,68 @@ +/////////////////////////////////////////////////////////////////////////////// +// +/// \file crc32_small.c +/// \brief CRC32 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" + + +uint32_t lzma_crc32_table[1][256]; + + +#ifdef HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR +__attribute__((__constructor__)) +#endif +static void +crc32_init(void) +{ + static const uint32_t poly32 = UINT32_C(0xEDB88320); + + for (size_t b = 0; b < 256; ++b) { + uint32_t r = b; + for (size_t i = 0; i < 8; ++i) { + if (r & 1) + r = (r >> 1) ^ poly32; + else + r >>= 1; + } + + lzma_crc32_table[0][b] = r; + } + + return; +} + + +#ifndef HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR +extern void +lzma_crc32_init(void) +{ + mythread_once(crc32_init); + return; +} +#endif + + +extern LZMA_API(uint32_t) +lzma_crc32(const uint8_t *buf, size_t size, uint32_t crc) +{ +#ifndef HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR + lzma_crc32_init(); +#endif + + crc = ~crc; + + while (size != 0) { + crc = lzma_crc32_table[0][*buf++ ^ (crc & 0xFF)] ^ (crc >> 8); + --size; + } + + return ~crc; +} |