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/* crc.h -- cyclic redundancy checks
Copyright (C) 2005, 2009-2019 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
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.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
/* Written by Simon Josefsson. */
#ifndef CRC_H
# define CRC_H 1
#include <stddef.h>
#include <stdint.h>
/* Compute CRC-32 value of LEN bytes long BUF, and return it. */
extern uint32_t crc32 (const char *buf, size_t len);
/* Incrementally update CRC-32 value CRC using LEN bytes long BUF. In
the first call, use 0 as the value for CRC. Return the updated
CRC-32 value. */
extern uint32_t crc32_update (uint32_t crc, const char *buf, size_t len);
/* Compute modified-CRC-32 value of LEN bytes long BUF, and return it.
The "modification" is to avoid the initial and final XOR operation.
Due to historic implementation errors, this variant is sometimes
used (i.e., in RFC 3961). */
extern uint32_t crc32_no_xor (const char *buf, size_t len);
/* Incrementally update modified-CRC-32 value CRC using LEN bytes long
BUF. In the first call, use 0 as the value for CRC. Return the
updated modified-CRC-32 value. The "modification" is to avoid the
initial and final XOR operation. Due to historic implementation
errors, this variant is sometimes used (i.e., in RFC 3961). */
extern uint32_t
crc32_update_no_xor (uint32_t crc, const char *buf, size_t len);
#endif /* CRC_H */
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