summaryrefslogtreecommitdiff
path: root/coreutils/comm.c
blob: 6b7b9554c4b8ac5ef4353e7018a6fb6eb8d687d0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
/* vi: set sw=4 ts=4: */
/*
 * Mini comm implementation for busybox
 *
 * Copyright (C) 2005 by Robert Sullivan <cogito.ergo.cogito@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 * 02111-1307 USA
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "busybox.h"

#define COMM_OPT_1 0x01
#define COMM_OPT_2 0x02
#define COMM_OPT_3 0x04

/* These three variables control behaviour if non-zero */

static int only_file_1;
static int only_file_2;
static int both;

/* writeline outputs the input given, appropriately aligned according to class */
static void writeline (char *line, int class)
{
	switch (class) {
		case 1:
			if (!only_file_1)
				return;
			break;
		case 2:
			if (!only_file_2)
				return;
			if (only_file_1)
				putchar('\t');
			break;
		case 3:
			if (!both)
				return;
			if (only_file_1)
				putchar('\t');
			if (only_file_2)
				putchar('\t');
			break;
	}
	fputs(line, stdout);
}

/* This is the real core of the program - lines are compared here */
static int cmp_files(char **infiles)
{
	char thisline[2][100];
	FILE *streams[2];
	int i = 0;

	for (i = 0; i < 2; i++) {
		streams[i] = (strcmp(infiles[i], "=") == 0 ? stdin : fopen(infiles[i], "r"));
		fgets(thisline[i], 100, streams[i]);
	}

	while (thisline[0] || thisline[1]) {
		int order = 0;
		int tl0_len = strlen(thisline[0]);
		int tl1_len = strlen(thisline[1]);

		if (!thisline[0])
			order = 1;
		else if (!thisline[1])
			order = -1;
		else {
			order = memcmp(thisline[0], thisline[1], tl0_len < tl1_len ? tl0_len : tl1_len);
			if (!order)
				order = tl0_len < tl1_len ? -1 : tl0_len != tl1_len;
		}

		if ((order == 0) && (!feof(streams[0])) && (!feof(streams[1])))
			writeline(thisline[1], 3);
		else if ((order > 0) && (!feof(streams[1])))
			writeline(thisline[1], 2);
		else if ((order < 0) && (!feof(streams[0])))
			writeline(thisline[0], 1);

		if (feof(streams[0]) && feof(streams[1])) {
			fclose(streams[0]);
			fclose(streams[1]);
			break;

		} else if (feof(streams[0])) {
			while (!feof(streams[1])) {
				if (order < 0)
					writeline(thisline[1], 2);
				fgets(thisline[1], 100, streams[1]);
			}
			fclose(streams[0]);
			fclose(streams[1]);
			break;

		} else if (feof(streams[1])) {
			while (!feof(streams[0])) {
				if (order > 0)
					writeline(thisline[0], 1);
				fgets(thisline[0], 100, streams[0]);
			}
			fclose(streams[0]);
			fclose(streams[1]);
			break;

		} else {
			if (order >= 0)
				fgets(thisline[1], 100, streams[1]);
			if (order <= 0)
				fgets(thisline[0], 100, streams[0]);
		}
	}

	return 0;
}

int comm_main (int argc, char **argv)
{
	unsigned long opt;
	only_file_1 = 1;
	only_file_2 = 1;
	both = 1;

	opt = bb_getopt_ulflags(argc, argv, "123");

	if ((opt & 0x80000000UL) || (optind == argc))
		bb_show_usage();

	if (opt & COMM_OPT_1)
		only_file_1 = 0;
	if (opt & COMM_OPT_2)
		only_file_2 = 0;
	if (opt & COMM_OPT_3)
		both = 0;

	exit(cmp_files(argv + optind) == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
}