Annotation of libelwix/src/crc_tbl.c, revision 1.2

1.2     ! misho       1: /*************************************************************************
        !             2: * (C) 2014 AITNET ltd - Sofia/Bulgaria - <misho@aitbg.com>
        !             3: *  by Michael Pounov <misho@openbsd-bg.org>
        !             4: *
        !             5: * $Author: misho $
        !             6: * $Id: crc_tbl.c,v 1.1.2.3 2014/01/29 14:11:45 misho Exp $
        !             7: *
        !             8: **************************************************************************
        !             9: The ELWIX and AITNET software is distributed under the following
        !            10: terms:
        !            11: 
        !            12: All of the documentation and software included in the ELWIX and AITNET
        !            13: Releases is copyrighted by ELWIX - Sofia/Bulgaria <info@elwix.org>
        !            14: 
        !            15: Copyright 2004 - 2014
        !            16:        by Michael Pounov <misho@elwix.org>.  All rights reserved.
        !            17: 
        !            18: Redistribution and use in source and binary forms, with or without
        !            19: modification, are permitted provided that the following conditions
        !            20: are met:
        !            21: 1. Redistributions of source code must retain the above copyright
        !            22:    notice, this list of conditions and the following disclaimer.
        !            23: 2. Redistributions in binary form must reproduce the above copyright
        !            24:    notice, this list of conditions and the following disclaimer in the
        !            25:    documentation and/or other materials provided with the distribution.
        !            26: 3. All advertising materials mentioning features or use of this software
        !            27:    must display the following acknowledgement:
        !            28: This product includes software developed by Michael Pounov <misho@elwix.org>
        !            29: ELWIX - Embedded LightWeight unIX and its contributors.
        !            30: 4. Neither the name of AITNET nor the names of its contributors
        !            31:    may be used to endorse or promote products derived from this software
        !            32:    without specific prior written permission.
        !            33: 
        !            34: THIS SOFTWARE IS PROVIDED BY AITNET AND CONTRIBUTORS ``AS IS'' AND
        !            35: ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
        !            36: IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
        !            37: ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
        !            38: FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
        !            39: DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
        !            40: OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
        !            41: HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
        !            42: LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
        !            43: OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
        !            44: SUCH DAMAGE.
        !            45: */
        !            46: #include "global.h"
        !            47: 
        !            48: 
        !            49: /* 
        !            50:  * Table of CRC-32's of all single-byte values
        !            51:  */
        !            52: static const uint32_t crc32_table[256] = {
        !            53:   0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419,
        !            54:   0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4,
        !            55:   0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07,
        !            56:   0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
        !            57:   0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856,
        !            58:   0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
        !            59:   0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4,
        !            60:   0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
        !            61:   0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3,
        !            62:   0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a,
        !            63:   0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599,
        !            64:   0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
        !            65:   0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190,
        !            66:   0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f,
        !            67:   0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e,
        !            68:   0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
        !            69:   0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed,
        !            70:   0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
        !            71:   0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3,
        !            72:   0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
        !            73:   0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a,
        !            74:   0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5,
        !            75:   0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010,
        !            76:   0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
        !            77:   0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17,
        !            78:   0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6,
        !            79:   0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615,
        !            80:   0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
        !            81:   0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344,
        !            82:   0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
        !            83:   0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a,
        !            84:   0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
        !            85:   0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1,
        !            86:   0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c,
        !            87:   0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef,
        !            88:   0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
        !            89:   0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe,
        !            90:   0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31,
        !            91:   0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c,
        !            92:   0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
        !            93:   0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b,
        !            94:   0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
        !            95:   0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1,
        !            96:   0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
        !            97:   0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278,
        !            98:   0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7,
        !            99:   0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66,
        !           100:   0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
        !           101:   0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605,
        !           102:   0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8,
        !           103:   0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b,
        !           104:   0x2d02ef8d
        !           105: };
        !           106: 
        !           107: #define DO1(crc, buf)  (crc) = crc32_table[((crc) ^ (*(buf)++)) & 0xff] ^ ((crc) >> 8);
        !           108: #define DO2(crc, buf)  DO1(crc, buf); DO1(crc, buf);
        !           109: #define DO4(crc, buf)  DO2(crc, buf); DO2(crc, buf);
        !           110: #define DO8(crc, buf)  DO4(crc, buf); DO4(crc, buf);
        !           111: 
        !           112: /*
        !           113:  * crc32() - CRC32 calculation from table
        !           114:  *
        !           115:  * @crc = Initial crc value
        !           116:  * @buf = Data for calculation
        !           117:  * @len = Length of data
        !           118:  * return: calculated CRC32
        !           119:  */
        !           120: uint32_t
        !           121: crc32(uint32_t crc, const uint8_t * __restrict buf, uint32_t len)
        !           122: {
        !           123:        crc = crc ^ 0xffffffff;
        !           124:        while (len >= 8) {
        !           125:                DO8(crc, buf);
        !           126:                len -= 8;
        !           127:        }
        !           128:        if (len)
        !           129:                do {
        !           130:                        DO1(crc, buf);
        !           131:                } while (--len);
        !           132:        return crc ^ 0xffffffff;
        !           133: }

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