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https://github.com/eledio-devices/thirdparty-littlefs.git
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26 lines
706 B
C
26 lines
706 B
C
/*
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* lfs util functions
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*
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* Copyright (c) 2017 Christopher Haster
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* Distributed under the Apache 2.0 license
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*/
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#include "lfs_util.h"
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void lfs_crc(uint32_t *restrict crc, const void *buffer, size_t size) {
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static const uint32_t rtable[16] = {
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0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
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0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
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0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
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0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c,
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};
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const uint8_t *data = buffer;
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for (size_t i = 0; i < size; i++) {
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*crc = (*crc >> 4) ^ rtable[(*crc ^ (data[i] >> 0)) & 0xf];
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*crc = (*crc >> 4) ^ rtable[(*crc ^ (data[i] >> 4)) & 0xf];
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}
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}
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