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crc64.c
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crc64.c
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/* Copyright (c) 2014, Matt Stancliff <matt@genges.com>
* Copyright (c) 2020, Amazon Web Services
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Redis nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE. */
#include "crc64.h"
#include "crcspeed.h"
static uint64_t crc64_table[8][256] = {{0}};
#define POLY UINT64_C(0xad93d23594c935a9)
/******************** BEGIN GENERATED PYCRC FUNCTIONS ********************/
/**
* Generated on Sun Dec 21 14:14:07 2014,
* by pycrc v0.8.2, https://www.tty1.net/pycrc/
*
* LICENSE ON GENERATED CODE:
* ==========================
* As of version 0.6, pycrc is released under the terms of the MIT licence.
* The code generated by pycrc is not considered a substantial portion of the
* software, therefore the author of pycrc will not claim any copyright on
* the generated code.
* ==========================
*
* CRC configuration:
* Width = 64
* Poly = 0xad93d23594c935a9
* XorIn = 0xffffffffffffffff
* ReflectIn = True
* XorOut = 0x0000000000000000
* ReflectOut = True
* Algorithm = bit-by-bit-fast
*
* Modifications after generation (by matt):
* - included finalize step in-line with update for single-call generation
* - re-worked some inner variable architectures
* - adjusted function parameters to match expected prototypes.
*****************************************************************************/
/**
* Reflect all bits of a \a data word of \a data_len bytes.
*
* \param data The data word to be reflected.
* \param data_len The width of \a data expressed in number of bits.
* \return The reflected data.
*****************************************************************************/
static inline uint_fast64_t crc_reflect(uint_fast64_t data, size_t data_len) {
uint_fast64_t ret = data & 0x01;
for (size_t i = 1; i < data_len; i++) {
data >>= 1;
ret = (ret << 1) | (data & 0x01);
}
return ret;
}
/**
* Update the crc value with new data.
*
* \param crc The current crc value.
* \param data Pointer to a buffer of \a data_len bytes.
* \param data_len Number of bytes in the \a data buffer.
* \return The updated crc value.
******************************************************************************/
uint64_t _crc64(uint_fast64_t crc, const void *in_data, const uint64_t len) {
const uint8_t *data = in_data;
unsigned long long bit;
for (uint64_t offset = 0; offset < len; offset++) {
uint8_t c = data[offset];
for (uint_fast8_t i = 0x01; i & 0xff; i <<= 1) {
bit = crc & 0x8000000000000000;
if (c & i) {
bit = !bit;
}
crc <<= 1;
if (bit) {
crc ^= POLY;
}
}
crc &= 0xffffffffffffffff;
}
crc = crc & 0xffffffffffffffff;
return crc_reflect(crc, 64) ^ 0x0000000000000000;
}
/******************** END GENERATED PYCRC FUNCTIONS ********************/
/* Initializes the 16KB lookup tables. */
void crc64_init(void) {
crcspeed64native_init(_crc64, crc64_table);
}
/* Compute crc64 */
uint64_t crc64(uint64_t crc, const unsigned char *s, uint64_t l) {
return crcspeed64native(crc64_table, crc, (void *) s, l);
}