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
  10/* BB_AUDIT SUSv3 compliant */
  11/* http://www.opengroup.org/onlinepubs/007904975/utilities/uniq.html */
  12
  13//usage:#define uniq_trivial_usage
  14//usage:       "[-cdu][-f,s,w N] [INPUT [OUTPUT]]"
  15//usage:#define uniq_full_usage "\n\n"
  16//usage:       "Discard duplicate lines\n"
  17//usage:     "\n        -c      Prefix lines by the number of occurrences"
  18//usage:     "\n        -d      Only print duplicate lines"
  19//usage:     "\n        -u      Only print unique lines"
  20//usage:     "\n        -f N    Skip first N fields"
  21//usage:     "\n        -s N    Skip first N chars (after any skipped fields)"
  22//usage:     "\n        -w N    Compare N characters in line"
  23//usage:
  24//usage:#define uniq_example_usage
  25//usage:       "$ echo -e \"a\\na\\nb\\nc\\nc\\na\" | sort | uniq\n"
  26//usage:       "a\n"
  27//usage:       "b\n"
  28//usage:       "c\n"
  29
  30#include "libbb.h"
  31
  32int uniq_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  33int uniq_main(int argc UNUSED_PARAM, char **argv)
  34{
  35        const char *input_filename;
  36        unsigned skip_fields, skip_chars, max_chars;
  37        unsigned opt;
  38        char *cur_line;
  39        const char *cur_compare;
  40
  41        enum {
  42                OPT_c = 0x1,
  43                OPT_d = 0x2, /* print only dups */
  44                OPT_u = 0x4, /* print only uniq */
  45                OPT_f = 0x8,
  46                OPT_s = 0x10,
  47                OPT_w = 0x20,
  48        };
  49
  50        skip_fields = skip_chars = 0;
  51        max_chars = INT_MAX;
  52
  53        opt_complementary = "f+:s+:w+";
  54        opt = getopt32(argv, "cduf:s:w:", &skip_fields, &skip_chars, &max_chars);
  55        argv += optind;
  56
  57        input_filename = argv[0];
  58        if (input_filename) {
  59                const char *output;
  60
  61                if (input_filename[0] != '-' || input_filename[1]) {
  62                        close(STDIN_FILENO); /* == 0 */
  63                        xopen(input_filename, O_RDONLY); /* fd will be 0 */
  64                }
  65                output = argv[1];
  66                if (output) {
  67                        if (argv[2])
  68                                bb_show_usage();
  69                        if (output[0] != '-' || output[1]) {
  70                                // Won't work with "uniq - FILE" and closed stdin:
  71                                //close(STDOUT_FILENO);
  72                                //xopen(output, O_WRONLY | O_CREAT | O_TRUNC);
  73                                xmove_fd(xopen(output, O_WRONLY | O_CREAT | O_TRUNC), STDOUT_FILENO);
  74                        }
  75                }
  76        }
  77
  78        cur_compare = cur_line = NULL; /* prime the pump */
  79
  80        do {
  81                unsigned i;
  82                unsigned long dups;
  83                char *old_line;
  84                const char *old_compare;
  85
  86                old_line = cur_line;
  87                old_compare = cur_compare;
  88                dups = 0;
  89
  90                /* gnu uniq ignores newlines */
  91                while ((cur_line = xmalloc_fgetline(stdin)) != NULL) {
  92                        cur_compare = cur_line;
  93                        for (i = skip_fields; i; i--) {
  94                                cur_compare = skip_whitespace(cur_compare);
  95                                cur_compare = skip_non_whitespace(cur_compare);
  96                        }
  97                        for (i = skip_chars; *cur_compare && i; i--) {
  98                                ++cur_compare;
  99                        }
 100
 101                        if (!old_line || strncmp(old_compare, cur_compare, max_chars)) {
 102                                break;
 103                        }
 104
 105                        free(cur_line);
 106                        ++dups;  /* testing for overflow seems excessive */
 107                }
 108
 109                if (old_line) {
 110                        if (!(opt & (OPT_d << !!dups))) { /* (if dups, opt & OPT_u) */
 111                                if (opt & OPT_c) {
 112                                        /* %7lu matches GNU coreutils 6.9 */
 113                                        printf("%7lu ", dups + 1);
 114                                }
 115                                printf("%s\n", old_line);
 116                        }
 117                        free(old_line);
 118                }
 119        } while (cur_line);
 120
 121        die_if_ferror(stdin, input_filename);
 122
 123        fflush_stdout_and_exit(EXIT_SUCCESS);
 124}
 125