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/*
* Copyright (C) 2016 Felix Fietkau <nbd@nbd.name>
*
* Based on busybox code:
* CRC32 table fill function
* Copyright (C) 2006 by Rob Sullivan <cogito.ergo.cogito@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef __BB_CRC32_H
#define __BB_CRC32_H
static inline void
crc32_filltable(uint32_t *crc_table)
{
uint32_t polynomial = 0xedb88320;
uint32_t c;
int i, j;
for (i = 0; i < 256; i++) {
c = i;
for (j = 8; j; j--)
c = (c&1) ? ((c >> 1) ^ polynomial) : (c >> 1);
*crc_table++ = c;
}
}
static inline uint32_t
crc32_block(uint32_t val, const void *buf, unsigned len, uint32_t *crc_table)
{
const void *end = (uint8_t*)buf + len;
while (buf != end) {
val = crc_table[(uint8_t)val ^ *(uint8_t*)buf] ^ (val >> 8);
buf = (uint8_t*)buf + 1;
}
return val;
}
#endif
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