LXR busybox/coreutils/uniq.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * uniq implementation for busybox
   4 *
   5 * Copyright (C) 2005  Manuel Novoa III  <mjn3@codepoet.org>
   6 *
   7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8 */
   9//config:config UNIQ
  10//config:       bool "uniq (4.9 kb)"
  11//config:       default y
  12//config:       help
  13//config:       uniq is used to remove duplicate lines from a sorted file.
  14
  15//applet:IF_UNIQ(APPLET(uniq, BB_DIR_USR_BIN, BB_SUID_DROP))
  16
  17//kbuild:lib-$(CONFIG_UNIQ) += uniq.o
  18
  19/* BB_AUDIT SUSv3 compliant */
  20/* http://www.opengroup.org/onlinepubs/007904975/utilities/uniq.html */
  21
  22//usage:#define uniq_trivial_usage
  23//usage:       "[-cduiz] [-f,s,w N] [FILE [OUTFILE]]"
  24//usage:#define uniq_full_usage "\n\n"
  25//usage:       "Discard duplicate lines\n"
  26//usage:     "\n        -c      Prefix lines by the number of occurrences"
  27//usage:     "\n        -d      Only print duplicate lines"
  28//usage:     "\n        -u      Only print unique lines"
  29//usage:     "\n        -i      Ignore case"
  30//usage:     "\n        -z      NUL terminated output"
  31//usage:     "\n        -f N    Skip first N fields"
  32//usage:     "\n        -s N    Skip first N chars (after any skipped fields)"
  33//usage:     "\n        -w N    Compare N characters in line"
  34//usage:
  35//usage:#define uniq_example_usage
  36//usage:       "$ echo -e \"a\\na\\nb\\nc\\nc\\na\" | sort | uniq\n"
  37//usage:       "a\n"
  38//usage:       "b\n"
  39//usage:       "c\n"
  40
  41#include "libbb.h"
  42
  43int uniq_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  44int uniq_main(int argc UNUSED_PARAM, char **argv)
  45{
  46        const char *input_filename;
  47        unsigned skip_fields, skip_chars, max_chars;
  48        unsigned opt;
  49        char eol;
  50        char *cur_line;
  51        const char *cur_compare;
  52
  53        enum {
  54                OPT_c = 1 << 0,
  55                OPT_d = 1 << 1, /* print only dups */
  56                OPT_u = 1 << 2, /* print only uniq */
  57                OPT_f = 1 << 3,
  58                OPT_s = 1 << 4,
  59                OPT_w = 1 << 5,
  60                OPT_i = 1 << 6,
  61                OPT_z = 1 << 7,
  62        };
  63
  64        skip_fields = skip_chars = 0;
  65        max_chars = INT_MAX;
  66
  67        opt = getopt32(argv, "cduf:+s:+w:+iz", &skip_fields, &skip_chars, &max_chars);
  68        argv += optind;
  69
  70        input_filename = argv[0];
  71        if (input_filename) {
  72                const char *output;
  73
  74                if (input_filename[0] != '-' || input_filename[1]) {
  75                        close(STDIN_FILENO); /* == 0 */
  76                        xopen(input_filename, O_RDONLY); /* fd will be 0 */
  77                }
  78                output = argv[1];
  79                if (output) {
  80                        if (argv[2])
  81                                bb_show_usage();
  82                        if (output[0] != '-' || output[1]) {
  83                                // Won't work with "uniq - FILE" and closed stdin:
  84                                //close(STDOUT_FILENO);
  85                                //xopen(output, O_WRONLY | O_CREAT | O_TRUNC);
  86                                xmove_fd(xopen(output, O_WRONLY | O_CREAT | O_TRUNC), STDOUT_FILENO);
  87                        }
  88                }
  89        }
  90
  91        cur_compare = cur_line = NULL; /* prime the pump */
  92        eol = (opt & OPT_z) ? 0 : '\n';
  93
  94        do {
  95                unsigned i;
  96                unsigned long dups;
  97                char *old_line;
  98                const char *old_compare;
  99
 100                old_line = cur_line;
 101                old_compare = cur_compare;
 102                dups = 0;
 103
 104                /* gnu uniq ignores newlines */
 105                while ((cur_line = xmalloc_fgetline(stdin)) != NULL) {
 106                        cur_compare = cur_line;
 107                        for (i = skip_fields; i; i--) {
 108                                cur_compare = skip_whitespace(cur_compare);
 109                                cur_compare = skip_non_whitespace(cur_compare);
 110                        }
 111                        for (i = skip_chars; *cur_compare && i; i--) {
 112                                ++cur_compare;
 113                        }
 114
 115                        if (!old_line)
 116                                break;
 117                        if ((opt & OPT_i)
 118                                ? strncasecmp(old_compare, cur_compare, max_chars)
 119                                : strncmp(old_compare, cur_compare, max_chars)
 120                        ) {
 121                                break;
 122                        }
 123
 124                        free(cur_line);
 125                        ++dups;  /* testing for overflow seems excessive */
 126                }
 127
 128                if (old_line) {
 129                        if (!(opt & (OPT_d << !!dups))) { /* (if dups, opt & OPT_u) */
 130                                if (opt & OPT_c) {
 131                                        /* %7lu matches GNU coreutils 6.9 */
 132                                        printf("%7lu ", dups + 1);
 133                                }
 134                                printf("%s%c", old_line, eol);
 135                        }
 136                        free(old_line);
 137                }
 138        } while (cur_line);
 139
 140        die_if_ferror(stdin, input_filename);
 141
 142        fflush_stdout_and_exit(EXIT_SUCCESS);
 143}
 144