crc.c revision 1.1.1.2
1 1.1 cgd /*- 2 1.1.1.2 glass * Copyright (c) 1991, 1993 3 1.1.1.2 glass * The Regents of the University of California. All rights reserved. 4 1.1 cgd * 5 1.1 cgd * This code is derived from software contributed to Berkeley by 6 1.1.1.2 glass * James W. Williams of NASA Goddard Space Flight Center. 7 1.1 cgd * 8 1.1 cgd * Redistribution and use in source and binary forms, with or without 9 1.1 cgd * modification, are permitted provided that the following conditions 10 1.1 cgd * are met: 11 1.1 cgd * 1. Redistributions of source code must retain the above copyright 12 1.1 cgd * notice, this list of conditions and the following disclaimer. 13 1.1 cgd * 2. Redistributions in binary form must reproduce the above copyright 14 1.1 cgd * notice, this list of conditions and the following disclaimer in the 15 1.1 cgd * documentation and/or other materials provided with the distribution. 16 1.1 cgd * 3. All advertising materials mentioning features or use of this software 17 1.1 cgd * must display the following acknowledgement: 18 1.1 cgd * This product includes software developed by the University of 19 1.1 cgd * California, Berkeley and its contributors. 20 1.1 cgd * 4. Neither the name of the University nor the names of its contributors 21 1.1 cgd * may be used to endorse or promote products derived from this software 22 1.1 cgd * without specific prior written permission. 23 1.1 cgd * 24 1.1 cgd * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 1.1 cgd * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 1.1 cgd * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 1.1 cgd * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 1.1 cgd * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 1.1 cgd * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 1.1 cgd * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 1.1 cgd * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 1.1 cgd * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 1.1 cgd * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 1.1 cgd * SUCH DAMAGE. 35 1.1 cgd */ 36 1.1 cgd 37 1.1 cgd #ifndef lint 38 1.1.1.2 glass static char sccsid[] = "@(#)crc.c 8.1 (Berkeley) 6/17/93"; 39 1.1 cgd #endif /* not lint */ 40 1.1 cgd 41 1.1 cgd #include <sys/types.h> 42 1.1 cgd #include <unistd.h> 43 1.1 cgd 44 1.1.1.2 glass static u_long crctab[] = { 45 1.1.1.2 glass 0x0, 46 1.1.1.2 glass 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b, 47 1.1.1.2 glass 0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 48 1.1.1.2 glass 0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd, 49 1.1.1.2 glass 0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac, 50 1.1.1.2 glass 0x5bd4b01b, 0x569796c2, 0x52568b75, 0x6a1936c8, 0x6ed82b7f, 51 1.1.1.2 glass 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a, 52 1.1.1.2 glass 0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039, 53 1.1.1.2 glass 0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58, 54 1.1.1.2 glass 0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 55 1.1.1.2 glass 0xa4ad16ea, 0xa06c0b5d, 0xd4326d90, 0xd0f37027, 0xddb056fe, 56 1.1.1.2 glass 0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95, 57 1.1.1.2 glass 0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4, 58 1.1.1.2 glass 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0, 59 1.1.1.2 glass 0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, 60 1.1.1.2 glass 0x2ac12072, 0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 61 1.1.1.2 glass 0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca, 0x7897ab07, 62 1.1.1.2 glass 0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c, 63 1.1.1.2 glass 0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 64 1.1.1.2 glass 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba, 65 1.1.1.2 glass 0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, 66 1.1.1.2 glass 0xbb60adfc, 0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698, 67 1.1.1.2 glass 0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d, 68 1.1.1.2 glass 0x94ea7b2a, 0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e, 69 1.1.1.2 glass 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2, 0xc6bcf05f, 70 1.1.1.2 glass 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34, 71 1.1.1.2 glass 0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80, 72 1.1.1.2 glass 0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb, 73 1.1.1.2 glass 0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a, 74 1.1.1.2 glass 0x58c1663d, 0x558240e4, 0x51435d53, 0x251d3b9e, 0x21dc2629, 75 1.1.1.2 glass 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c, 76 1.1.1.2 glass 0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff, 77 1.1.1.2 glass 0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e, 78 1.1.1.2 glass 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 79 1.1.1.2 glass 0xeba91bbc, 0xef68060b, 0xd727bbb6, 0xd3e6a601, 0xdea580d8, 80 1.1.1.2 glass 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3, 81 1.1.1.2 glass 0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2, 82 1.1.1.2 glass 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71, 83 1.1.1.2 glass 0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, 84 1.1.1.2 glass 0x857130c3, 0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 85 1.1.1.2 glass 0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c, 0x7b827d21, 86 1.1.1.2 glass 0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a, 87 1.1.1.2 glass 0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e, 0x18197087, 88 1.1.1.2 glass 0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec, 89 1.1.1.2 glass 0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, 90 1.1.1.2 glass 0x2056cd3a, 0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce, 91 1.1.1.2 glass 0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 92 1.1.1.2 glass 0xdbee767c, 0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18, 93 1.1.1.2 glass 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4, 0x89b8fd09, 94 1.1.1.2 glass 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662, 95 1.1.1.2 glass 0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf, 96 1.1.1.2 glass 0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4 97 1.1 cgd }; 98 1.1 cgd 99 1.1 cgd /* 100 1.1.1.2 glass * Compute a POSIX 1003.2 checksum. This routine has been broken out so that 101 1.1.1.2 glass * other programs can use it. It takes a file descriptor to read from and 102 1.1.1.2 glass * locations to store the crc and the number of bytes read. It returns 0 on 103 1.1.1.2 glass * success and 1 on failure. Errno is set on failure. 104 1.1 cgd */ 105 1.1.1.2 glass u_long crc_total = ~0; /* The crc over a number of files. */ 106 1.1.1.2 glass 107 1.1.1.2 glass int 108 1.1 cgd crc(fd, cval, clen) 109 1.1 cgd register int fd; 110 1.1 cgd u_long *cval, *clen; 111 1.1 cgd { 112 1.1 cgd register u_char *p; 113 1.1.1.2 glass register int nr; 114 1.1.1.2 glass register u_long crc, len; 115 1.1.1.2 glass u_char buf[16 * 1024]; 116 1.1.1.2 glass 117 1.1.1.2 glass #define COMPUTE(var, ch) (var) = (var) << 8 ^ crctab[(var) >> 24 ^ (ch)] 118 1.1 cgd 119 1.1.1.2 glass crc = len = 0; 120 1.1.1.2 glass crc_total = ~crc_total; 121 1.1 cgd while ((nr = read(fd, buf, sizeof(buf))) > 0) 122 1.1.1.2 glass for (len += nr, p = buf; nr--; ++p) { 123 1.1.1.2 glass COMPUTE(crc, *p); 124 1.1.1.2 glass COMPUTE(crc_total, *p); 125 1.1 cgd } 126 1.1 cgd if (nr < 0) 127 1.1.1.2 glass return (1); 128 1.1.1.2 glass 129 1.1.1.2 glass *clen = len; 130 1.1 cgd 131 1.1.1.2 glass /* Include the length of the file. */ 132 1.1.1.2 glass for (; len != 0; len >>= 8) { 133 1.1.1.2 glass COMPUTE(crc, len & 0xff); 134 1.1.1.2 glass COMPUTE(crc_total, len & 0xff); 135 1.1.1.2 glass } 136 1.1.1.2 glass 137 1.1.1.2 glass *cval = ~crc; 138 1.1.1.2 glass crc_total = ~crc_total; 139 1.1.1.2 glass return (0); 140 1.1 cgd } 141
Indexes created Sat Oct 25 16:10:12 GMT 2025