aboutsummaryrefslogtreecommitdiff
path: root/coreutils/uniq.c
blob: 317f455311746674b6cee58f515ddd21d61b7ece (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
/* vi: set sw=4 ts=4: */
/*
 * uniq implementation for busybox
 *
 * Copyright (C) 2005  Manuel Novoa III  <mjn3@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */
//config:config UNIQ
//config:	bool "uniq (4.9 kb)"
//config:	default y
//config:	help
//config:	uniq is used to remove duplicate lines from a sorted file.

//applet:IF_UNIQ(APPLET(uniq, BB_DIR_USR_BIN, BB_SUID_DROP))

//kbuild:lib-$(CONFIG_UNIQ) += uniq.o

/* BB_AUDIT SUSv3 compliant */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/uniq.html */

//usage:#define uniq_trivial_usage
//usage:       "[-cdu][-f,s,w N] [INPUT [OUTPUT]]"
//usage:#define uniq_full_usage "\n\n"
//usage:       "Discard duplicate lines\n"
//usage:     "\n	-c	Prefix lines by the number of occurrences"
//usage:     "\n	-d	Only print duplicate lines"
//usage:     "\n	-u	Only print unique lines"
//usage:     "\n	-i	Ignore case"
//usage:     "\n	-f N	Skip first N fields"
//usage:     "\n	-s N	Skip first N chars (after any skipped fields)"
//usage:     "\n	-w N	Compare N characters in line"
//usage:
//usage:#define uniq_example_usage
//usage:       "$ echo -e \"a\\na\\nb\\nc\\nc\\na\" | sort | uniq\n"
//usage:       "a\n"
//usage:       "b\n"
//usage:       "c\n"

#include "libbb.h"

int uniq_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int uniq_main(int argc UNUSED_PARAM, char **argv)
{
	const char *input_filename;
	unsigned skip_fields, skip_chars, max_chars;
	unsigned opt;
	char *cur_line;
	const char *cur_compare;

	enum {
		OPT_c = 0x1,
		OPT_d = 0x2, /* print only dups */
		OPT_u = 0x4, /* print only uniq */
		OPT_f = 0x8,
		OPT_s = 0x10,
		OPT_w = 0x20,
		OPT_i = 0x40,
	};

	skip_fields = skip_chars = 0;
	max_chars = INT_MAX;

	opt = getopt32(argv, "cduf:+s:+w:+i", &skip_fields, &skip_chars, &max_chars);
	argv += optind;

	input_filename = argv[0];
	if (input_filename) {
		const char *output;

		if (input_filename[0] != '-' || input_filename[1]) {
			close(STDIN_FILENO); /* == 0 */
			xopen(input_filename, O_RDONLY); /* fd will be 0 */
		}
		output = argv[1];
		if (output) {
			if (argv[2])
				bb_show_usage();
			if (output[0] != '-' || output[1]) {
				// Won't work with "uniq - FILE" and closed stdin:
				//close(STDOUT_FILENO);
				//xopen(output, O_WRONLY | O_CREAT | O_TRUNC);
				xmove_fd(xopen(output, O_WRONLY | O_CREAT | O_TRUNC), STDOUT_FILENO);
			}
		}
	}

	cur_compare = cur_line = NULL; /* prime the pump */

	do {
		unsigned i;
		unsigned long dups;
		char *old_line;
		const char *old_compare;

		old_line = cur_line;
		old_compare = cur_compare;
		dups = 0;

		/* gnu uniq ignores newlines */
		while ((cur_line = xmalloc_fgetline(stdin)) != NULL) {
			cur_compare = cur_line;
			for (i = skip_fields; i; i--) {
				cur_compare = skip_whitespace(cur_compare);
				cur_compare = skip_non_whitespace(cur_compare);
			}
			for (i = skip_chars; *cur_compare && i; i--) {
				++cur_compare;
			}

			if (!old_line)
				break;
			if ((opt & OPT_i)
				? strncasecmp(old_compare, cur_compare, max_chars)
				: strncmp(old_compare, cur_compare, max_chars)
			) {
				break;
			}

			free(cur_line);
			++dups;  /* testing for overflow seems excessive */
		}

		if (old_line) {
			if (!(opt & (OPT_d << !!dups))) { /* (if dups, opt & OPT_u) */
				if (opt & OPT_c) {
					/* %7lu matches GNU coreutils 6.9 */
					printf("%7lu ", dups + 1);
				}
				puts(old_line);
			}
			free(old_line);
		}
	} while (cur_line);

	die_if_ferror(stdin, input_filename);

	fflush_stdout_and_exit(EXIT_SUCCESS);
}