1/* Copyright (c) 2014 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 "2sysincludes.h"
7#include "2crc8.h"
8
9uint8_t vb2_crc8(const void *vptr, uint32_t size)
10{
11	const uint8_t *data = vptr;
12	unsigned crc = 0;
13	uint32_t i, j;
14
15	/*
16	 * Calculate CRC-8 directly.  A table-based algorithm would be faster,
17	 * but for only a few bytes it isn't worth the code size.
18	 */
19	for (j = size; j; j--, data++) {
20		crc ^= (*data << 8);
21		for(i = 8; i; i--) {
22			if (crc & 0x8000)
23				crc ^= (0x1070 << 3);
24			crc <<= 1;
25		}
26	}
27
28	return (uint8_t)(crc >> 8);
29}
30