1/* vi: set sw=4 ts=4: */
2/*
3 * Mini comm implementation for busybox
4 *
5 * Copyright (C) 2005 by Robert Sullivan <cogito.ergo.cogito@gmail.com>
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
8 */
9
10#include "libbb.h"
11
12#define COMM_OPT_1 (1 << 0)
13#define COMM_OPT_2 (1 << 1)
14#define COMM_OPT_3 (1 << 2)
15
16/* writeline outputs the input given, appropriately aligned according to class */
17static void writeline(char *line, int class, int flags)
18{
19	if (class == 0) {
20		if (flags & COMM_OPT_1)
21			return;
22	} else if (class == 1) {
23		if (flags & COMM_OPT_2)
24			return;
25		if (!(flags & COMM_OPT_1))
26			putchar('\t');
27	} else /*if (class == 2)*/ {
28		if (flags & COMM_OPT_3)
29			return;
30		if (!(flags & COMM_OPT_1))
31			putchar('\t');
32		if (!(flags & COMM_OPT_2))
33			putchar('\t');
34	}
35	fputs(line, stdout);
36}
37
38int comm_main(int argc, char **argv);
39int comm_main(int argc, char **argv)
40{
41#define LINE_LEN 100
42#define BB_EOF_0 0x1
43#define BB_EOF_1 0x2
44	char thisline[2][LINE_LEN];
45	FILE *streams[2];
46	int i;
47	unsigned flags;
48
49	opt_complementary = "=2";
50	flags = getopt32(argv, "123");
51	argv += optind;
52
53	for (i = 0; i < 2; ++i) {
54		streams[i] = (argv[i][0] == '-' && !argv[i][1]) ? stdin : xfopen(argv[i], "r");
55		fgets(thisline[i], LINE_LEN, streams[i]);
56	}
57
58	/* This is the real core of the program - lines are compared here */
59
60	while (*thisline[0] || *thisline[1]) {
61		int order = 0;
62
63		i = 0;
64		if (feof(streams[0])) i |= BB_EOF_0;
65		if (feof(streams[1])) i |= BB_EOF_1;
66
67		if (!*thisline[0])
68			order = 1;
69		else if (!*thisline[1])
70			order = -1;
71		else {
72			int tl0_len, tl1_len;
73			tl0_len = strlen(thisline[0]);
74			tl1_len = strlen(thisline[1]);
75			order = memcmp(thisline[0], thisline[1], tl0_len < tl1_len ? tl0_len : tl1_len);
76			if (!order)
77				order = tl0_len < tl1_len ? -1 : tl0_len != tl1_len;
78		}
79
80		if (order == 0 && !i)
81			writeline(thisline[1], 2, flags);
82		else if (order > 0 && !(i & BB_EOF_1))
83			writeline(thisline[1], 1, flags);
84		else if (order < 0 && !(i & BB_EOF_0))
85			writeline(thisline[0], 0, flags);
86
87		if (i & BB_EOF_0 & BB_EOF_1) {
88			break;
89
90		} else if (i) {
91			i = (i & BB_EOF_0 ? 1 : 0);
92			while (!feof(streams[i])) {
93				if ((order < 0 && i) || (order > 0 && !i))
94					writeline(thisline[i], i, flags);
95				fgets(thisline[i], LINE_LEN, streams[i]);
96			}
97			break;
98
99		} else {
100			if (order >= 0)
101				fgets(thisline[1], LINE_LEN, streams[1]);
102			if (order <= 0)
103				fgets(thisline[0], LINE_LEN, streams[0]);
104		}
105	}
106
107	if (ENABLE_FEATURE_CLEAN_UP) {
108		fclose(streams[0]);
109		fclose(streams[1]);
110	}
111
112	return EXIT_SUCCESS;
113}
114