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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-14 13:40:54 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-14 13:40:54 +0000 |
commit | 317c0644ccf108aa23ef3fd8358bd66c2840bfc0 (patch) | |
tree | c417b3d25c86b775989cb5ac042f37611b626c8a /src/crc16.c | |
parent | Initial commit. (diff) | |
download | redis-upstream/5%7.2.4.tar.xz redis-upstream/5%7.2.4.zip |
Adding upstream version 5:7.2.4.upstream/5%7.2.4
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/crc16.c')
-rw-r--r-- | src/crc16.c | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/src/crc16.c b/src/crc16.c new file mode 100644 index 0000000..7b8c1da --- /dev/null +++ b/src/crc16.c @@ -0,0 +1,88 @@ +#include "server.h" + +/* + * Copyright 2001-2010 Georges Menie (www.menie.org) + * Copyright 2010-2012 Salvatore Sanfilippo (adapted to Redis coding style) + * 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 the University of California, Berkeley 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 REGENTS 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 REGENTS AND 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. + */ + +/* CRC16 implementation according to CCITT standards. + * + * Note by @antirez: this is actually the XMODEM CRC 16 algorithm, using the + * following parameters: + * + * Name : "XMODEM", also known as "ZMODEM", "CRC-16/ACORN" + * Width : 16 bit + * Poly : 1021 (That is actually x^16 + x^12 + x^5 + 1) + * Initialization : 0000 + * Reflect Input byte : False + * Reflect Output CRC : False + * Xor constant to output CRC : 0000 + * Output for "123456789" : 31C3 + */ + +static const uint16_t crc16tab[256]= { + 0x0000,0x1021,0x2042,0x3063,0x4084,0x50a5,0x60c6,0x70e7, + 0x8108,0x9129,0xa14a,0xb16b,0xc18c,0xd1ad,0xe1ce,0xf1ef, + 0x1231,0x0210,0x3273,0x2252,0x52b5,0x4294,0x72f7,0x62d6, + 0x9339,0x8318,0xb37b,0xa35a,0xd3bd,0xc39c,0xf3ff,0xe3de, + 0x2462,0x3443,0x0420,0x1401,0x64e6,0x74c7,0x44a4,0x5485, + 0xa56a,0xb54b,0x8528,0x9509,0xe5ee,0xf5cf,0xc5ac,0xd58d, + 0x3653,0x2672,0x1611,0x0630,0x76d7,0x66f6,0x5695,0x46b4, + 0xb75b,0xa77a,0x9719,0x8738,0xf7df,0xe7fe,0xd79d,0xc7bc, + 0x48c4,0x58e5,0x6886,0x78a7,0x0840,0x1861,0x2802,0x3823, + 0xc9cc,0xd9ed,0xe98e,0xf9af,0x8948,0x9969,0xa90a,0xb92b, + 0x5af5,0x4ad4,0x7ab7,0x6a96,0x1a71,0x0a50,0x3a33,0x2a12, + 0xdbfd,0xcbdc,0xfbbf,0xeb9e,0x9b79,0x8b58,0xbb3b,0xab1a, + 0x6ca6,0x7c87,0x4ce4,0x5cc5,0x2c22,0x3c03,0x0c60,0x1c41, + 0xedae,0xfd8f,0xcdec,0xddcd,0xad2a,0xbd0b,0x8d68,0x9d49, + 0x7e97,0x6eb6,0x5ed5,0x4ef4,0x3e13,0x2e32,0x1e51,0x0e70, + 0xff9f,0xefbe,0xdfdd,0xcffc,0xbf1b,0xaf3a,0x9f59,0x8f78, + 0x9188,0x81a9,0xb1ca,0xa1eb,0xd10c,0xc12d,0xf14e,0xe16f, + 0x1080,0x00a1,0x30c2,0x20e3,0x5004,0x4025,0x7046,0x6067, + 0x83b9,0x9398,0xa3fb,0xb3da,0xc33d,0xd31c,0xe37f,0xf35e, + 0x02b1,0x1290,0x22f3,0x32d2,0x4235,0x5214,0x6277,0x7256, + 0xb5ea,0xa5cb,0x95a8,0x8589,0xf56e,0xe54f,0xd52c,0xc50d, + 0x34e2,0x24c3,0x14a0,0x0481,0x7466,0x6447,0x5424,0x4405, + 0xa7db,0xb7fa,0x8799,0x97b8,0xe75f,0xf77e,0xc71d,0xd73c, + 0x26d3,0x36f2,0x0691,0x16b0,0x6657,0x7676,0x4615,0x5634, + 0xd94c,0xc96d,0xf90e,0xe92f,0x99c8,0x89e9,0xb98a,0xa9ab, + 0x5844,0x4865,0x7806,0x6827,0x18c0,0x08e1,0x3882,0x28a3, + 0xcb7d,0xdb5c,0xeb3f,0xfb1e,0x8bf9,0x9bd8,0xabbb,0xbb9a, + 0x4a75,0x5a54,0x6a37,0x7a16,0x0af1,0x1ad0,0x2ab3,0x3a92, + 0xfd2e,0xed0f,0xdd6c,0xcd4d,0xbdaa,0xad8b,0x9de8,0x8dc9, + 0x7c26,0x6c07,0x5c64,0x4c45,0x3ca2,0x2c83,0x1ce0,0x0cc1, + 0xef1f,0xff3e,0xcf5d,0xdf7c,0xaf9b,0xbfba,0x8fd9,0x9ff8, + 0x6e17,0x7e36,0x4e55,0x5e74,0x2e93,0x3eb2,0x0ed1,0x1ef0 +}; + +uint16_t crc16(const char *buf, int len) { + int counter; + uint16_t crc = 0; + for (counter = 0; counter < len; counter++) + crc = (crc<<8) ^ crc16tab[((crc>>8) ^ *buf++)&0x00FF]; + return crc; +} |