hush/coreutils/uniq.c

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/* vi: set sw=4 ts=4: */
/*
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* 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"
//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-$(CONFIG_UNIQ) += uniq.o
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/* BB_AUDIT SUSv3 compliant */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/uniq.html */
//usage:#define uniq_trivial_usage
//usage: "[-cdu][-f,s,w N] [INPUT [OUTPUT]]"
//usage:#define uniq_full_usage "\n\n"
//usage: "Discard duplicate lines\n"
//usage: "\n -c Prefix lines by the number of occurrences"
//usage: "\n -d Only print duplicate lines"
//usage: "\n -u Only print unique lines"
//usage: "\n -f N Skip first N fields"
//usage: "\n -s N Skip first N chars (after any skipped fields)"
//usage: "\n -w N Compare N characters in line"
//usage:
//usage:#define uniq_example_usage
//usage: "$ 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;
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int uniq_main(int argc UNUSED_PARAM, char **argv)
{
const char *input_filename;
unsigned skip_fields, skip_chars, max_chars;
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unsigned opt;
char *cur_line;
const char *cur_compare;
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enum {
OPT_c = 0x1,
OPT_d = 0x2, /* print only dups */
OPT_u = 0x4, /* print only uniq */
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OPT_f = 0x8,
OPT_s = 0x10,
OPT_w = 0x20,
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};
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skip_fields = skip_chars = 0;
max_chars = INT_MAX;
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opt = getopt32(argv, "cduf:+s:+w:+", &skip_fields, &skip_chars, &max_chars);
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argv += optind;
input_filename = argv[0];
if (input_filename) {
const char *output;
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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);
}
}
}
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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;
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/* gnu uniq ignores newlines */
while ((cur_line = xmalloc_fgetline(stdin)) != NULL) {
cur_compare = cur_line;
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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 || strncmp(old_compare, cur_compare, max_chars)) {
break;
}
free(cur_line);
++dups; /* testing for overflow seems excessive */
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}
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);
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}
free(old_line);
}
} while (cur_line);
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die_if_ferror(stdin, input_filename);
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fflush_stdout_and_exit(EXIT_SUCCESS);
}