/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include <stdint.h>
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/* Calculate CRC32 how the STM32F4xx family does */
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static unsigned int crc_table[] =
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{
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0x00000000, 0x04C11DB7, 0x09823B6E, 0x0D4326D9,
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0x130476DC ,0x17C56B6B ,0x1A864DB2 ,0x1E475005,
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0x2608EDB8, 0x22C9F00F, 0x2F8AD6D6, 0x2B4BCB61,
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0x350C9B64, 0x31CD86D3, 0x3C8EA00A, 0x384FBDBD
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};
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static uint32_t crc32_word(uint32_t crc, uint32_t data)
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{
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crc = crc ^ data;
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crc = (crc << 4) ^ crc_table[crc >> 28];
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crc = (crc << 4) ^ crc_table[crc >> 28];
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crc = (crc << 4) ^ crc_table[crc >> 28];
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crc = (crc << 4) ^ crc_table[crc >> 28];
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crc = (crc << 4) ^ crc_table[crc >> 28];
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crc = (crc << 4) ^ crc_table[crc >> 28];
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crc = (crc << 4) ^ crc_table[crc >> 28];
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crc = (crc << 4) ^ crc_table[crc >> 28];
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return crc;
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}
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uint32_t stm32f4_crc32(uint8_t *buffer, int length)
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{
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uint32_t *data = (uint32_t *)buffer;
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uint32_t word;
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uint32_t crc = ~0;
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int i;
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/* word by word crc32 */
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for (i=0; i<(length>>2); i++) {
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crc = crc32_word(crc, data[i]);
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}
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/* zero pad last word if required */
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if (length & 0x3) {
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for (i*=4, word=0; i<length; i++)
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word |= buffer[i] << ((i & 0x3) * 8);
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crc = crc32_word(crc, word);
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}
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return crc;
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}
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