Home | History | Annotate | Line # | Download | only in cmp 
      1 /*	$NetBSD: regular.c,v 1.26 2025/01/12 06:38:21 simonb Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1991, 1993, 1994
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #ifndef lint
     34 #if 0
     35 static char sccsid[] = "@(#)regular.c	8.3 (Berkeley) 4/2/94";
     36 #else
     37 __RCSID("$NetBSD: regular.c,v 1.26 2025/01/12 06:38:21 simonb Exp $");
     38 #endif
     39 #endif /* not lint */
     40 
     41 #include <sys/param.h>
     42 #include <sys/mman.h>
     43 #include <sys/stat.h>
     44 
     45 #include <err.h>
     46 #include <limits.h>
     47 #include <stdlib.h>
     48 #include <stdint.h>
     49 #include <stdio.h>
     50 #include <string.h>
     51 
     52 #include "extern.h"
     53 
     54 void
     55 c_regular(int fd1, const char *file1, off_t skip1, off_t len1,
     56     int fd2, const char *file2, off_t skip2, off_t len2)
     57 {
     58 	u_char ch, *p1, *p2;
     59 	off_t byte, length, line;
     60 	int dfound;
     61 	size_t blk_sz, blk_cnt;
     62 
     63 	if (skip1 > len1)
     64 		eofmsg(file1, len1 + 1, 0);
     65 	len1 -= skip1;
     66 	if (skip2 > len2)
     67 		eofmsg(file2, len2 + 1, 0);
     68 	len2 -= skip2;
     69 
     70 	if (sflag && len1 != len2)
     71 		exit(DIFF_EXIT);
     72 
     73 	byte = line = 1;
     74 	dfound = 0;
     75 	length = MIN(len1, len2);
     76 	for (blk_sz = 1024 * 1024; length != 0; length -= blk_sz) {
     77 		if ((uintmax_t)blk_sz > (uintmax_t)length)
     78 			blk_sz = length;
     79 		p1 = mmap(NULL, blk_sz, PROT_READ, MAP_FILE|MAP_SHARED,
     80 		    fd1, skip1);
     81 		if (p1 == MAP_FAILED)
     82 			goto mmap_failed;
     83 
     84 		p2 = mmap(NULL, blk_sz, PROT_READ, MAP_FILE|MAP_SHARED,
     85 		    fd2, skip2);
     86 		if (p2 == MAP_FAILED) {
     87 			munmap(p1, blk_sz);
     88 			goto mmap_failed;
     89 		}
     90 
     91 		blk_cnt = blk_sz;
     92 		if ((lflag || sflag) && (memcmp(p1, p2, blk_sz) == 0)) {
     93 			/*
     94 			 * If the two blocks are the same and we are
     95 			 * using the -l or -s flags, we don't need to
     96 			 * count lines.  There is nothing else to do
     97 			 * except advance the pointers for munmap()
     98 			 * below.
     99 			 */
    100 			p1 += blk_sz;
    101 			p2 += blk_sz;
    102 		} else {
    103 			for (; blk_cnt--; ++p1, ++p2, ++byte) {
    104 				if ((ch = *p1) != *p2) {
    105 					if (!lflag) {
    106 						diffmsg(file1, file2, byte, line);
    107 						/* NOTREACHED */
    108 					}
    109 					dfound = 1;
    110 					(void)printf("%6lld %3o %3o\n",
    111 					    (long long)byte, ch, *p2);
    112 				}
    113 				if (ch == '\n')
    114 					++line;
    115 			}
    116 		}
    117 		munmap(p1 - blk_sz, blk_sz);
    118 		munmap(p2 - blk_sz, blk_sz);
    119 		skip1 += blk_sz;
    120 		skip2 += blk_sz;
    121 	}
    122 
    123 	if (len1 != len2)
    124 		eofmsg(len1 > len2 ? file2 : file1, byte, line);
    125 	if (dfound)
    126 		exit(DIFF_EXIT);
    127 	return;
    128 
    129 mmap_failed:
    130 	c_special(fd1, file1, skip1, fd2, file2, skip2);
    131 }
    132