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///////////////////////////////////////////////////////////////////////////////
//
/// \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;
}
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