util-linux/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 the GPL v2 or later, see the file LICENSE in this tarball.
   8  */
   9
  10 /* BB_AUDIT SUSv3 compliant */
  11 /* http://www.opengroup.org/onlinepubs/007904975/utilities/uniq.html */
  12
  13 #include "libbb.h"
  14
  15 int uniq_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  16 int uniq_main(int argc UNUSED_PARAM, char **argv)
  17 {
  18         const char *input_filename;
  19         unsigned skip_fields, skip_chars, max_chars;
  20         unsigned opt;
  21         char *cur_line;
  22         const char *cur_compare;
  23
  24         enum {
  25                 OPT_c = 0x1,
  26                 OPT_d = 0x2, /* print only dups */
  27                 OPT_u = 0x4, /* print only uniq */
  28                 OPT_f = 0x8,
  29                 OPT_s = 0x10,
  30                 OPT_w = 0x20,
  31         };
  32
  33         skip_fields = skip_chars = 0;
  34         max_chars = INT_MAX;
  35
  36         opt_complementary = "f+:s+:w+";
  37         opt = getopt32(argv, "cduf:s:w:", &skip_fields, &skip_chars, &max_chars);
  38         argv += optind;
  39
  40         input_filename = argv[0];
  41         if (input_filename) {
  42                 const char *output;
  43
  44                 if (input_filename[0] != '-' || input_filename[1]) {
  45                         close(STDIN_FILENO); /* == 0 */
  46                         xopen(input_filename, O_RDONLY); /* fd will be 0 */
  47                 }
  48                 output = argv[1];
  49                 if (output) {
  50                         if (argv[2])
  51                                 bb_show_usage();
  52                         if (output[0] != '-' || output[1]) {
  53                                 // Won't work with "uniq - FILE" and closed stdin:
  54                                 //close(STDOUT_FILENO);
  55                                 //xopen3(output, O_WRONLY | O_CREAT | O_TRUNC, 0666);
  56                                 xmove_fd(xopen3(output, O_WRONLY | O_CREAT | O_TRUNC, 0666), STDOUT_FILENO);
  57                         }
  58                 }
  59         }
  60
  61         cur_compare = cur_line = NULL; /* prime the pump */
  62
  63         do {
  64                 unsigned i;
  65                 unsigned long dups;
  66                 char *old_line;
  67                 const char *old_compare;
  68
  69                 old_line = cur_line;
  70                 old_compare = cur_compare;
  71                 dups = 0;
  72
  73                 /* gnu uniq ignores newlines */
  74                 while ((cur_line = xmalloc_fgetline(stdin)) != NULL) {
  75                         cur_compare = cur_line;
  76                         for (i = skip_fields; i; i--) {
  77                                 cur_compare = skip_whitespace(cur_compare);
  78                                 cur_compare = skip_non_whitespace(cur_compare);
  79                         }
  80                         for (i = skip_chars; *cur_compare && i; i--) {
  81                                 ++cur_compare;
  82                         }
  83
  84                         if (!old_line || strncmp(old_compare, cur_compare, max_chars)) {
  85                                 break;
  86                         }
  87
  88                         free(cur_line);
  89                         ++dups;  /* testing for overflow seems excessive */
  90                 }
  91
  92                 if (old_line) {
  93                         if (!(opt & (OPT_d << !!dups))) { /* (if dups, opt & OPT_u) */
  94                                 if (opt & OPT_c) {
  95                                         /* %7lu matches GNU coreutils 6.9 */
  96                                         printf("%7lu ", dups + 1);
  97                                 }
  98                                 printf("%s\n", old_line);
  99                         }
 100                         free(old_line);
 101                 }
 102         } while (cur_line);
 103
 104         die_if_ferror(stdin, input_filename);
 105
 106         fflush_stdout_and_exit(EXIT_SUCCESS);
 107 }