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      1 /*	$NetBSD: comm.c,v 1.20 2012/09/05 04:01:23 simonb Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1989, 1993, 1994
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Case Larsen.
      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 #ifndef lint
     37 __COPYRIGHT("@(#) Copyright (c) 1989, 1993, 1994\
     38  The Regents of the University of California.  All rights reserved.");
     39 #endif /* not lint */
     40 
     41 #ifndef lint
     42 #if 0
     43 static char sccsid[] = "@(#)comm.c	8.4 (Berkeley) 5/4/95";
     44 #endif
     45 __RCSID("$NetBSD: comm.c,v 1.20 2012/09/05 04:01:23 simonb Exp $");
     46 #endif /* not lint */
     47 
     48 #include <err.h>
     49 #include <limits.h>
     50 #include <locale.h>
     51 #include <stdio.h>
     52 #include <stdlib.h>
     53 #include <string.h>
     54 #include <unistd.h>
     55 
     56 #define	MAXLINELEN	(LINE_MAX + 1)
     57 
     58 static const char *tabs[] = { "", "\t", "\t\t" };
     59 
     60 static FILE   *file(const char *);
     61 static void	show(FILE *, const char *, char *);
     62 __dead static void	usage(void);
     63 static char   *getnextln(char *buf, FILE *);
     64 
     65 int
     66 main(int argc, char **argv)
     67 {
     68 	int comp, file1done, file2done, read1, read2;
     69 	int ch, flag1, flag2, flag3;
     70 	FILE *fp1, *fp2;
     71 	const char *col1, *col2, *col3, **p;
     72 	char line1[MAXLINELEN], line2[MAXLINELEN];
     73 	int (*compare)(const char*,const char*);
     74 
     75 	(void)setlocale(LC_ALL, "");
     76 
     77 	file1done = file2done = 0;
     78 	flag1 = flag2 = flag3 = 1;
     79 	compare = strcoll;
     80 	while ((ch = getopt(argc, argv, "123f")) != -1)
     81 		switch(ch) {
     82 		case '1':
     83 			flag1 = 0;
     84 			break;
     85 		case '2':
     86 			flag2 = 0;
     87 			break;
     88 		case '3':
     89 			flag3 = 0;
     90 			break;
     91 		case 'f':
     92 			compare = strcasecmp;
     93 			break;
     94 		case '?':
     95 		default:
     96 			usage();
     97 		}
     98 	argc -= optind;
     99 	argv += optind;
    100 
    101 	if (argc != 2)
    102 		usage();
    103 
    104 	fp1 = file(argv[0]);
    105 	fp2 = file(argv[1]);
    106 
    107 	/* for each column printed, add another tab offset */
    108 	p = tabs;
    109 	col1 = col2 = col3 = NULL;
    110 	if (flag1)
    111 		col1 = *p++;
    112 	if (flag2)
    113 		col2 = *p++;
    114 	if (flag3)
    115 		col3 = *p;
    116 
    117 	for (read1 = read2 = 1;;) {
    118 		/* read next line, check for EOF */
    119 		if (read1)
    120 			file1done = !getnextln(line1, fp1);
    121 		if (read2)
    122 			file2done = !getnextln(line2, fp2);
    123 
    124 		/* if one file done, display the rest of the other file */
    125 		if (file1done) {
    126 			if (!file2done && col2)
    127 				show(fp2, col2, line2);
    128 			break;
    129 		}
    130 		if (file2done) {
    131 			if (!file1done && col1)
    132 				show(fp1, col1, line1);
    133 			break;
    134 		}
    135 
    136 		/* lines are the same */
    137 		if (!(comp = compare(line1, line2))) {
    138 			read1 = read2 = 1;
    139 			if (col3)
    140 				if (printf("%s%s\n", col3, line1) < 0)
    141 					break;
    142 			continue;
    143 		}
    144 
    145 		/* lines are different */
    146 		if (comp < 0) {
    147 			read1 = 1;
    148 			read2 = 0;
    149 			if (col1)
    150 				if (printf("%s%s\n", col1, line1) < 0)
    151 					break;
    152 		} else {
    153 			read1 = 0;
    154 			read2 = 1;
    155 			if (col2)
    156 				if (printf("%s%s\n", col2, line2) < 0)
    157 					break;
    158 		}
    159 	}
    160 
    161 	if (ferror (stdout) || fclose (stdout) == EOF)
    162 		err(1, "stdout");
    163 
    164 	exit(0);
    165 }
    166 
    167 static void
    168 show(FILE *fp, const char *offset, char *buf)
    169 {
    170 	while (printf("%s%s\n", offset, buf) >= 0 && getnextln(buf, fp))
    171 		;
    172 }
    173 
    174 static FILE *
    175 file(const char *name)
    176 {
    177 	FILE *fp;
    178 
    179 	if (!strcmp(name, "-"))
    180 		return (stdin);
    181 	if ((fp = fopen(name, "r")) == NULL)
    182 		err(1, "%s", name);
    183 	return (fp);
    184 }
    185 
    186 static void
    187 usage(void)
    188 {
    189 
    190 	(void)fprintf(stderr, "usage: comm [-123f] file1 file2\n");
    191 	exit(1);
    192 }
    193 
    194 static char *
    195 getnextln(char *buf, FILE *fp)
    196 {
    197 	size_t i = 0;
    198 	int c;
    199 
    200 	while ((c = getc(fp)) != '\n' && c != EOF) {
    201 		buf[i++] = c;
    202 
    203 		if (i >= MAXLINELEN)
    204 			i--; /* consumes extra characters till newline */
    205 	}
    206 
    207 	if (c == EOF && !i)
    208 		return NULL;
    209 
    210 	buf[i] = 0;
    211 	return buf;
    212 }
    213 
    214