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#include <stdint.h>
#include <stddef.h>
#define CRC32_POLYNOMIAL 0x04C11DB7
unsigned int CRCTable[ 256 ];
static uint32_t Reflect(uint32_t ref, char ch )
{
char i;
uint32_t value = 0;
/* Swap bit 0 for bit 7.
* bit 1 for bit 6, etc.
*/
for (i = 1; i < (ch + 1); i++)
{
if(ref & 1)
value |= 1 << (ch - i);
ref >>= 1;
}
return value;
}
void CRC_BuildTable(void)
{
int i, j;
uint32_t crc;
for (i = 0; i < 256; i++)
{
crc = Reflect( i, 8 ) << 24;
for (j = 0; j < 8; j++)
crc = (crc << 1) ^ (crc & (1 << 31) ? CRC32_POLYNOMIAL : 0);
CRCTable[i] = Reflect( crc, 32 );
}
}
unsigned int CRC32( unsigned int crc, void *buffer, unsigned int count )
{
uint8_t *p = (uint8_t*) buffer;
while (count--)
crc = (crc >> 8) ^ CRCTable[(crc & 0xFF) ^ *p++];
return ~crc;
}
uint32_t CRC_Calculate(void *buffer, uint32_t count)
{
uint32_t crc = 0xffffffff;
uint8_t *p = (uint8_t*) buffer;
while (count--)
crc = (crc >> 8) ^ CRCTable[(crc & 0xFF) ^ *p++];
return ~crc;
}
uint32_t adler32(uint32_t adler, void *buf, int len)
{
return CRC32(adler, buf, len);
}
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