TheAlgorithms-C/hash/hash_crc32.c

59 lines
1.1 KiB
C

/**
* @addtogroup hash Hash algorithms
* @{
* @file hash_crc32.c
* @author [Christian Bender](https://github.com/christianbender)
* @brief 32-bit [CRC
* hash](https://en.wikipedia.org/wiki/Cyclic_redundancy_check#CRC-32_algorithm)
* algorithm
*/
#include <assert.h>
#include <inttypes.h>
#include <stdio.h>
/**
* @brief 32-bit CRC algorithm implementation
*
* @param s NULL terminated ASCII string to hash
* @return 32-bit hash result
*/
uint32_t crc32(const char* s)
{
uint32_t crc = 0xffffffff;
size_t i = 0;
while (s[i] != '\0')
{
uint8_t byte = s[i];
crc = crc ^ byte;
for (uint8_t j = 8; j > 0; --j)
{
crc = (crc >> 1) ^ (0xEDB88320 & (-(crc & 1)));
}
i++;
}
return crc ^ 0xffffffff;
}
/**
* @brief Test function for ::crc32
* \returns None
*/
void test_crc32()
{
assert(crc32("Hello World") == 1243066710);
assert(crc32("Hello World!") == 472456355);
assert(crc32("Hello world") == 2346098258);
assert(crc32("Hello world!") == 461707669);
printf("Tests passed\n");
}
/** @} */
/** Main function */
int main()
{
test_crc32();
return 0;
}