1 /* Copyright (c) 2013 The Chromium OS Authors. All rights reserved. 2 * Use of this source code is governed by a BSD-style license that can be 3 * found in the LICENSE file. 4 */ 5 6 #include "sysincludes.h" 7 8 #include "crc8.h" 9 10 /** 11 * Return CRC-8 of the data, using x^8 + x^2 + x + 1 polynomial. A table-based 12 * algorithm would be faster, but for only a few bytes it isn't worth the code 13 * size. */ 14 uint8_t Crc8(const void *vptr, int len) 15 { 16 const uint8_t *data = vptr; 17 unsigned crc = 0; 18 int i, j; 19 20 for (j = len; j; j--, data++) { 21 crc ^= (*data << 8); 22 for(i = 8; i; i--) { 23 if (crc & 0x8000) 24 crc ^= (0x1070 << 3); 25 crc <<= 1; 26 } 27 } 28 29 return (uint8_t)(crc >> 8); 30 } 31
