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/* Calculate crc32. Little endian.
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/* Calculate crc32. Little endian.
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 * Standard seed is 0xffffffff or 0.
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 * Standard seed is 0xffffffff or 0.
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 * Some implementations xor result with 0xffffffff after calculation.
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 * Some implementations xor result with 0xffffffff after calculation.
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 */
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 */
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uint32_t crc32(void *data, unsigned int len, uint32_t seed) {
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uint32_t crc32(void *data, unsigned int len, uint32_t seed)
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{
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	uint8_t *d = data;
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    uint8_t *d = data;
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	while (len--) {
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    while (len--)
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    {
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		seed = ((seed >> 8) & 0x00FFFFFF) ^ crc32table [(seed ^ *d++) & 0xFF];
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        seed = ((seed >> 8) & 0x00FFFFFF) ^ crc32table [(seed ^ *d++) & 0xFF];
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	}
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    }
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	return seed;
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    return seed;
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}
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}
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/* Calculate crc32table */
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/* Calculate crc32table */
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void crc32_init() {
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void crc32_init()
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{
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	uint32_t poly = 0xEDB88320L;
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    uint32_t poly = 0xEDB88320L;
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	uint32_t crc;
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    uint32_t crc;
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	int i, j;
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    int i, j;
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	for (i = 0; i < 256; ++i) {
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    for (i = 0; i < 256; ++i)
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    {
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		crc = i;
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        crc = i;
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		for (j = 8; j > 0; --j) {
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        for (j = 8; j > 0; --j)
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        {
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			crc = (crc >> 1) ^ ((crc & 1) ? poly : 0);
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            crc = (crc >> 1) ^ ((crc & 1) ? poly : 0);
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		}
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        }
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		crc32table[i] = crc;
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        crc32table[i] = crc;
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	}
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    }
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}
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}