Home | History | Annotate | Line # | Download | only in mtree
crc.c revision 1.5 
      1 /*	$NetBSD: crc.c,v 1.5 2003/08/07 11:25:35 agc Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1991, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * James W. Williams of NASA Goddard Space Flight Center.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  */
     34 
     35 #include <sys/cdefs.h>
     36 #if defined(__RCSID) && !defined(lint)
     37 #if 0
     38 static char sccsid[] = "@(#)crc.c	8.1 (Berkeley) 6/17/93";
     39 #else
     40 __RCSID("$NetBSD: crc.c,v 1.5 2003/08/07 11:25:35 agc Exp $");
     41 #endif
     42 #endif /* not lint */
     43 
     44 #include <sys/types.h>
     45 
     46 #include <stdio.h>
     47 #include <time.h>
     48 #include <unistd.h>
     49 
     50 #include "extern.h"
     51 
     52 static const u_int32_t crctab[] = {
     53 	0x0,
     54 	0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b,
     55 	0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6,
     56 	0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
     57 	0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac,
     58 	0x5bd4b01b, 0x569796c2, 0x52568b75, 0x6a1936c8, 0x6ed82b7f,
     59 	0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a,
     60 	0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
     61 	0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58,
     62 	0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033,
     63 	0xa4ad16ea, 0xa06c0b5d, 0xd4326d90, 0xd0f37027, 0xddb056fe,
     64 	0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
     65 	0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4,
     66 	0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0,
     67 	0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5,
     68 	0x2ac12072, 0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16,
     69 	0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca, 0x7897ab07,
     70 	0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c,
     71 	0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1,
     72 	0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
     73 	0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b,
     74 	0xbb60adfc, 0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698,
     75 	0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d,
     76 	0x94ea7b2a, 0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e,
     77 	0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2, 0xc6bcf05f,
     78 	0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34,
     79 	0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80,
     80 	0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
     81 	0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a,
     82 	0x58c1663d, 0x558240e4, 0x51435d53, 0x251d3b9e, 0x21dc2629,
     83 	0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c,
     84 	0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
     85 	0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e,
     86 	0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65,
     87 	0xeba91bbc, 0xef68060b, 0xd727bbb6, 0xd3e6a601, 0xdea580d8,
     88 	0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
     89 	0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2,
     90 	0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71,
     91 	0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74,
     92 	0x857130c3, 0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640,
     93 	0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c, 0x7b827d21,
     94 	0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a,
     95 	0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e, 0x18197087,
     96 	0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
     97 	0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d,
     98 	0x2056cd3a, 0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce,
     99 	0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb,
    100 	0xdbee767c, 0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18,
    101 	0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4, 0x89b8fd09,
    102 	0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662,
    103 	0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf,
    104 	0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
    105 };
    106 
    107 /*
    108  * Compute a POSIX 1003.2 checksum.  This routine has been broken out so that
    109  * other programs can use it.  It takes a file descriptor to read from and
    110  * locations to store the crc and the number of bytes read.  It returns 0 on
    111  * success and 1 on failure.  Errno is set on failure.
    112  */
    113 extern int sflag;
    114 u_int32_t crc_total = ~0;		/* The crc over a number of files. */
    115 
    116 int
    117 crc(fd, cval, clen)
    118 	register int fd;
    119 	u_int32_t *cval, *clen;
    120 {
    121 	register u_char *p;
    122 	register int nr;
    123 	register u_int32_t thecrc, len;
    124 	register u_int32_t crctot;
    125 	u_char buf[16 * 1024];
    126 
    127 #define	COMPUTE(var, ch)	(var) = (var) << 8 ^ crctab[(var) >> 24 ^ (ch)]
    128 
    129 	thecrc = len = 0;
    130 	if (sflag)
    131 		crctot = ~crc_total;
    132 	while ((nr = read(fd, buf, sizeof(buf))) > 0)
    133 		if (sflag) {
    134 			for (len += nr, p = buf; nr--; ++p) {
    135 				COMPUTE(thecrc, *p);
    136 				COMPUTE(crctot, *p);
    137 			}
    138 		} else {
    139 			for (len += nr, p = buf; nr--; ++p)
    140 				COMPUTE(thecrc, *p);
    141 		}
    142 	if (nr < 0)
    143 		return (1);
    144 
    145 	*clen = len;
    146 
    147 	/* Include the length of the file. */
    148 	if (sflag) {
    149 		for (; len != 0; len >>= 8) {
    150 			COMPUTE(thecrc, len & 0xff);
    151 			COMPUTE(crctot, len & 0xff);
    152 		}
    153 	} else {
    154 		for (; len != 0; len >>= 8)
    155 			COMPUTE(thecrc, len & 0xff);
    156 	}
    157 
    158 	*cval = ~thecrc;
    159 	if (sflag)
    160 		crc_total = ~crctot;
    161 	return (0);
    162 }
    163