1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
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 <err.h>
36#include <limits.h>
37#include <locale.h>
38#include <stdint.h>
39#include <stdio.h>
40#include <stdlib.h>
41#include <string.h>
42#include <unistd.h>
43#include <wchar.h>
44#include <wctype.h>
45
46static int iflag;
47static const char *tabs[] = { "", "\t", "\t\t" };
48
49static FILE	*file(const char *);
50static wchar_t	*convert(const char *);
51static void	show(FILE *, const char *, const char *, char **, size_t *);
52static void	usage(void);
53
54int
55main(int argc, char *argv[])
56{
57	int comp, read1, read2;
58	int ch, flag1, flag2, flag3;
59	FILE *fp1, *fp2;
60	const char *col1, *col2, *col3;
61	size_t line1len, line2len;
62	char *line1, *line2;
63	ssize_t n1, n2;
64	wchar_t *tline1, *tline2;
65	const char **p;
66
67	(void) setlocale(LC_ALL, "");
68
69	flag1 = flag2 = flag3 = 1;
70
71	while ((ch = getopt(argc, argv, "123i")) != -1)
72		switch(ch) {
73		case '1':
74			flag1 = 0;
75			break;
76		case '2':
77			flag2 = 0;
78			break;
79		case '3':
80			flag3 = 0;
81			break;
82		case 'i':
83			iflag = 1;
84			break;
85		case '?':
86		default:
87			usage();
88		}
89	argc -= optind;
90	argv += optind;
91
92	if (argc != 2)
93		usage();
94
95	fp1 = file(argv[0]);
96	fp2 = file(argv[1]);
97
98	/* for each column printed, add another tab offset */
99	p = tabs;
100	col1 = col2 = col3 = NULL;
101	if (flag1)
102		col1 = *p++;
103	if (flag2)
104		col2 = *p++;
105	if (flag3)
106		col3 = *p;
107
108	line1len = line2len = 0;
109	line1 = line2 = NULL;
110	n1 = n2 = -1;
111
112	for (read1 = read2 = 1;;) {
113		/* read next line, check for EOF */
114		if (read1) {
115			n1 = getline(&line1, &line1len, fp1);
116			if (n1 < 0 && ferror(fp1))
117				err(1, "%s", argv[0]);
118			if (n1 > 0 && line1[n1 - 1] == '\n')
119				line1[n1 - 1] = '\0';
120
121		}
122		if (read2) {
123			n2 = getline(&line2, &line2len, fp2);
124			if (n2 < 0 && ferror(fp2))
125				err(1, "%s", argv[1]);
126			if (n2 > 0 && line2[n2 - 1] == '\n')
127				line2[n2 - 1] = '\0';
128		}
129
130		/* if one file done, display the rest of the other file */
131		if (n1 < 0) {
132			if (n2 >= 0 && col2 != NULL)
133				show(fp2, argv[1], col2, &line2, &line2len);
134			break;
135		}
136		if (n2 < 0) {
137			if (n1 >= 0 && col1 != NULL)
138				show(fp1, argv[0], col1, &line1, &line1len);
139			break;
140		}
141
142		tline2 = NULL;
143		if ((tline1 = convert(line1)) != NULL)
144			tline2 = convert(line2);
145		if (tline1 == NULL || tline2 == NULL)
146			comp = strcmp(line1, line2);
147		else
148			comp = wcscoll(tline1, tline2);
149		if (tline1 != NULL)
150			free(tline1);
151		if (tline2 != NULL)
152			free(tline2);
153
154		/* lines are the same */
155		if (!comp) {
156			read1 = read2 = 1;
157			if (col3 != NULL)
158				(void)printf("%s%s\n", col3, line1);
159			continue;
160		}
161
162		/* lines are different */
163		if (comp < 0) {
164			read1 = 1;
165			read2 = 0;
166			if (col1 != NULL)
167				(void)printf("%s%s\n", col1, line1);
168		} else {
169			read1 = 0;
170			read2 = 1;
171			if (col2 != NULL)
172				(void)printf("%s%s\n", col2, line2);
173		}
174	}
175	exit(0);
176}
177
178static wchar_t *
179convert(const char *str)
180{
181	size_t n;
182	wchar_t *buf, *p;
183
184	if ((n = mbstowcs(NULL, str, 0)) == (size_t)-1)
185		return (NULL);
186	if (SIZE_MAX / sizeof(*buf) < n + 1)
187		errx(1, "conversion buffer length overflow");
188	if ((buf = malloc((n + 1) * sizeof(*buf))) == NULL)
189		err(1, "malloc");
190	if (mbstowcs(buf, str, n + 1) != n)
191		errx(1, "internal mbstowcs() error");
192
193	if (iflag) {
194		for (p = buf; *p != L'\0'; p++)
195			*p = towlower(*p);
196	}
197
198	return (buf);
199}
200
201static void
202show(FILE *fp, const char *fn, const char *offset, char **bufp, size_t *buflenp)
203{
204	ssize_t n;
205
206	do {
207		(void)printf("%s%s\n", offset, *bufp);
208		if ((n = getline(bufp, buflenp, fp)) < 0)
209			break;
210		if (n > 0 && (*bufp)[n - 1] == '\n')
211			(*bufp)[n - 1] = '\0';
212	} while (1);
213	if (ferror(fp))
214		err(1, "%s", fn);
215}
216
217static FILE *
218file(const char *name)
219{
220	FILE *fp;
221
222	if (!strcmp(name, "-"))
223		return (stdin);
224	if ((fp = fopen(name, "r")) == NULL) {
225		err(1, "%s", name);
226	}
227	return (fp);
228}
229
230static void
231usage(void)
232{
233	(void)fprintf(stderr, "usage: comm [-123i] file1 file2\n");
234	exit(1);
235}
236