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31 lines
678 B
31 lines
678 B
/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include "sysincludes.h"
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#include "crc8.h"
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/**
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* Return CRC-8 of the data, using x^8 + x^2 + x + 1 polynomial. A table-based
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* algorithm would be faster, but for only a few bytes it isn't worth the code
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* size. */
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uint8_t Crc8(const void *vptr, int len)
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{
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const uint8_t *data = vptr;
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unsigned crc = 0;
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int i, j;
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for (j = len; j; j--, data++) {
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crc ^= (*data << 8);
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for(i = 8; i; i--) {
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if (crc & 0x8000)
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crc ^= (0x1070 << 3);
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crc <<= 1;
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}
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}
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return (uint8_t)(crc >> 8);
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}
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