A C language implementation of the CRC-32 algorithm using the polynomial 0xEDB88320. Includes a pre-computed lookup table for efficient checksum computation.
#include <stdio.h>
#include "crc32.h"
int main() {
unsigned char data[] = "halloweeks";
crc32_t crc = crc32(data, sizeof(data) - 1);
printf("crc: %08x\n", crc);
return 0;
}#include <stdio.h>
#include "crc32.h"
int main() {
unsigned char data1[] = "hallo";
unsigned char data2[] = "weeks";
crc32_t crc = crc32_init();
crc = crc32_update(crc, data1, 5);
crc = crc32_update(crc, data2, 5);
crc = crc32_final(crc);
printf("crc: %08x\n", crc);
return 0;
}unsigned int crc32_table[256] = {0};
void make_crc_table(unsigned int crcTable[]) {
const unsigned int POLYNOMIAL = 0xEDB88320;
for (unsigned int b = 0; b < 256; ++b) {
unsigned int remainder = b;
for (unsigned int bit = 0; bit < 8; ++bit) {
if (remainder & 1)
4B34
remainder = (remainder >> 1) ^ POLYNOMIAL;
else
remainder >>= 1;
}
crcTable[b] = remainder;
}
}