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"
  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-$(CONFIG_UNIQ) += uniq.o
  18
  19/* BB_AUDIT SUSv3 compliant */
  20/* http://www.opengroup.org/onlinepubs/007904975/utilities/uniq.html */
  21
  22//usage:#define uniq_trivial_usage
  23//usage:       "[-cdu][-f,s,w N] [INPUT [OUTPUT]]"
  24//usage:#define uniq_full_usage "\n\n"
  25//usage:       "Discard duplicate lines\n"
  26//usage:     "\n        -c      Prefix lines by the number of occurrences"
  27//usage:     "\n        -d      Only print duplicate lines"
  28//usage:     "\n        -u      Only print unique lines"
  29//usage:     "\n        -f N    Skip first N fields"
  30//usage:     "\n        -s N    Skip first N chars (after any skipped fields)"
  31//usage:     "\n        -w N    Compare N characters in line"
  32//usage:
  33//usage:#define uniq_example_usage
  34//usage:       "$ echo -e \"a\\na\\nb\\nc\\nc\\na\" | sort | uniq\n"
  35//usage:       "a\n"
  36//usage:       "b\n"
  37//usage:       "c\n"
  38
  39#include "libbb.h"
  40
  41int uniq_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  42int uniq_main(int argc UNUSED_PARAM, char **argv)
  43{
  44        const char *input_filename;
  45        unsigned skip_fields, skip_chars, max_chars;
  46        unsigned opt;
  47        char *cur_line;
  48        const char *cur_compare;
  49
  50        enum {
  51                OPT_c = 0x1,
  52                OPT_d = 0x2, /* print only dups */
  53                OPT_u = 0x4, /* print only uniq */
  54                OPT_f = 0x8,
  55                OPT_s = 0x10,
  56                OPT_w = 0x20,
  57        };
  58
  59        skip_fields = skip_chars = 0;
  60        max_chars = INT_MAX;
  61
  62        opt = getopt32(argv, "cduf:+s:+w:+", &skip_fields, &skip_chars, &max_chars);
  63        argv += optind;
  64
  65        input_filename = argv[0];
  66        if (input_filename) {
  67                const char *output;
  68
  69                if (input_filename[0] != '-' || input_filename[1]) {
  70                        close(STDIN_FILENO); /* == 0 */
  71                        xopen(input_filename, O_RDONLY); /* fd will be 0 */
  72                }
  73                output = argv[1];
  74                if (output) {
  75                        if (argv[2])
  76                                bb_show_usage();
  77                        if (output[0] != '-' || output[1]) {
  78                                // Won't work with "uniq - FILE" and closed stdin:
  79                                //close(STDOUT_FILENO);
  80                                //xopen(output, O_WRONLY | O_CREAT | O_TRUNC);
  81                                xmove_fd(xopen(output, O_WRONLY | O_CREAT | O_TRUNC), STDOUT_FILENO);
  82                        }
  83                }
  84        }
  85
  86        cur_compare = cur_line = NULL; /* prime the pump */
  87
  88        do {
  89                unsigned i;
  90                unsigned long dups;
  91                char *old_line;
  92                const char *old_compare;
  93
  94                old_line = cur_line;
  95                old_compare = cur_compare;
  96                dups = 0;
  97
  98                /* gnu uniq ignores newlines */
  99                while ((cur_line = xmalloc_fgetline(stdin)) != NULL) {
 100                        cur_compare = cur_line;
 101                        for (i = skip_fields; i; i--) {
 102                                cur_compare = skip_whitespace(cur_compare);
 103                                cur_compare = skip_non_whitespace(cur_compare);
 104                        }
 105                        for (i = skip_chars; *cur_compare && i; i--) {
 106                                ++cur_compare;
 107                        }
 108
 109                        if (!old_line || strncmp(old_compare, cur_compare, max_chars)) {
 110                                break;
 111                        }
 112
 113                        free(cur_line);
 114                        ++dups;  /* testing for overflow seems excessive */
 115                }
 116
 117                if (old_line) {
 118                        if (!(opt & (OPT_d << !!dups))) { /* (if dups, opt & OPT_u) */
 119                                if (opt & OPT_c) {
 120                                        /* %7lu matches GNU coreutils 6.9 */
 121                                        printf("%7lu ", dups + 1);
 122                                }
 123                                puts(old_line);
 124                        }
 125                        free(old_line);
 126                }
 127        } while (cur_line);
 128
 129        die_if_ferror(stdin, input_filename);
 130
 131        fflush_stdout_and_exit(EXIT_SUCCESS);
 132}
 133