1 // SPDX-License-Identifier: GPL-2.0-only 2 /* crc32hash.c - derived from linux/lib/crc32.c, GNU GPL v2 */ 3 /* Usage example: 4 $ ./crc32hash "Dual Speed" 5 */ 6 7 #include <string.h> 8 #include <stdio.h> 9 #include <ctype.h> 10 #include <stdlib.h> 11 12 static unsigned int crc32(unsigned char const *p, unsigned int len) 13 { 14 int i; 15 unsigned int crc = 0; 16 while (len--) { 17 crc ^= *p++; 18 for (i = 0; i < 8; i++) 19 crc = (crc >> 1) ^ ((crc & 1) ? 0xedb88320 : 0); 20 } 21 return crc; 22 } 23 24 int main(int argc, char **argv) { 25 unsigned int result; 26 if (argc != 2) { 27 printf("no string passed as argument\n"); 28 return -1; 29 } 30 result = crc32((unsigned char const *)argv[1], strlen(argv[1])); 31 printf("0x%x\n", result); 32 return 0; 33 } 34