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