coreutils/comm.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini comm implementation for busybox
   4  *
   5  * Copyright (C) 2005 by Robert Sullivan <cogito.ergo.cogito@gmail.com>
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8  */
   9
  10 //usage:#define comm_trivial_usage
  11 //usage:       "[-123] FILE1 FILE2"
  12 //usage:#define comm_full_usage "\n\n"
  13 //usage:       "Compare FILE1 with FILE2\n"
  14 //usage:     "\n        -1      Suppress lines unique to FILE1"
  15 //usage:     "\n        -2      Suppress lines unique to FILE2"
  16 //usage:     "\n        -3      Suppress lines common to both files"
  17
  18 #include "libbb.h"
  19
  20 #define COMM_OPT_1 (1 << 0)
  21 #define COMM_OPT_2 (1 << 1)
  22 #define COMM_OPT_3 (1 << 2)
  23
  24 /* writeline outputs the input given, appropriately aligned according to class */
  25 static void writeline(char *line, int class)
  26 {
  27         int flags = option_mask32;
  28         if (class == 0) {
  29                 if (flags & COMM_OPT_1)
  30                         return;
  31         } else if (class == 1) {
  32                 if (flags & COMM_OPT_2)
  33                         return;
  34                 if (!(flags & COMM_OPT_1))
  35                         putchar('\t');
  36         } else /*if (class == 2)*/ {
  37                 if (flags & COMM_OPT_3)
  38                         return;
  39                 if (!(flags & COMM_OPT_1))
  40                         putchar('\t');
  41                 if (!(flags & COMM_OPT_2))
  42                         putchar('\t');
  43         }
  44         puts(line);
  45 }
  46
  47 int comm_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  48 int comm_main(int argc UNUSED_PARAM, char **argv)
  49 {
  50         char *thisline[2];
  51         FILE *stream[2];
  52         int i;
  53         int order;
  54
  55         opt_complementary = "=2";
  56         getopt32(argv, "123");
  57         argv += optind;
  58
  59         for (i = 0; i < 2; ++i) {
  60                 stream[i] = xfopen_stdin(argv[i]);
  61         }
  62
  63         order = 0;
  64         thisline[1] = thisline[0] = NULL;
  65         while (1) {
  66                 if (order <= 0) {
  67                         free(thisline[0]);
  68                         thisline[0] = xmalloc_fgetline(stream[0]);
  69                 }
  70                 if (order >= 0) {
  71                         free(thisline[1]);
  72                         thisline[1] = xmalloc_fgetline(stream[1]);
  73                 }
  74
  75                 i = !thisline[0] + (!thisline[1] << 1);
  76                 if (i)
  77                         break;
  78                 order = strcmp(thisline[0], thisline[1]);
  79
  80                 if (order >= 0)
  81                         writeline(thisline[1], order ? 1 : 2);
  82                 else
  83                         writeline(thisline[0], 0);
  84         }
  85
  86         /* EOF at least on one of the streams */
  87         i &= 1;
  88         if (thisline[i]) {
  89                 /* stream[i] is not at EOF yet */
  90                 /* we did not print thisline[i] yet */
  91                 char *p = thisline[i];
  92                 writeline(p, i);
  93                 while (1) {
  94                         free(p);
  95                         p = xmalloc_fgetline(stream[i]);
  96                         if (!p)
  97                                 break;
  98                         writeline(p, i);
  99                 }
 100         }
 101
 102         if (ENABLE_FEATURE_CLEAN_UP) {
 103                 fclose(stream[0]);
 104                 fclose(stream[1]);
 105         }
 106
 107         return EXIT_SUCCESS;
 108 }