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 tarball for details.
   8  */
   9
  10 #include "libbb.h"
  11
  12 #define COMM_OPT_1 (1 << 0)
  13 #define COMM_OPT_2 (1 << 1)
  14 #define COMM_OPT_3 (1 << 2)
  15
  16 /* writeline outputs the input given, appropriately aligned according to class */
  17 static void writeline(char *line, int class)
  18 {
  19         int flags = option_mask32;
  20         if (class == 0) {
  21                 if (flags & COMM_OPT_1)
  22                         return;
  23         } else if (class == 1) {
  24                 if (flags & COMM_OPT_2)
  25                         return;
  26                 if (!(flags & COMM_OPT_1))
  27                         putchar('\t');
  28         } else /*if (class == 2)*/ {
  29                 if (flags & COMM_OPT_3)
  30                         return;
  31                 if (!(flags & COMM_OPT_1))
  32                         putchar('\t');
  33                 if (!(flags & COMM_OPT_2))
  34                         putchar('\t');
  35         }
  36         puts(line);
  37 }
  38
  39 int comm_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  40 int comm_main(int argc UNUSED_PARAM, char **argv)
  41 {
  42         char *thisline[2];
  43         FILE *stream[2];
  44         int i;
  45         int order;
  46
  47         opt_complementary = "=2";
  48         getopt32(argv, "123");
  49         argv += optind;
  50
  51         for (i = 0; i < 2; ++i) {
  52                 stream[i] = xfopen_stdin(argv[i]);
  53         }
  54
  55         order = 0;
  56         thisline[1] = thisline[0] = NULL;
  57         while (1) {
  58                 if (order <= 0) {
  59                         free(thisline[0]);
  60                         thisline[0] = xmalloc_fgetline(stream[0]);
  61                 }
  62                 if (order >= 0) {
  63                         free(thisline[1]);
  64                         thisline[1] = xmalloc_fgetline(stream[1]);
  65                 }
  66
  67                 i = !thisline[0] + (!thisline[1] << 1);
  68                 if (i)
  69                         break;
  70                 order = strcmp(thisline[0], thisline[1]);
  71
  72                 if (order >= 0)
  73                         writeline(thisline[1], order ? 1 : 2);
  74                 else
  75                         writeline(thisline[0], 0);
  76         }
  77
  78         /* EOF at least on one of the streams */
  79         i &= 1;
  80         if (thisline[i]) {
  81                 /* stream[i] is not at EOF yet */
  82                 /* we did not print thisline[i] yet */
  83                 char *p = thisline[i];
  84                 writeline(p, i);
  85                 while (1) {
  86                         free(p);
  87                         p = xmalloc_fgetline(stream[i]);
  88                         if (!p)
  89                                 break;
  90                         writeline(p, i);
  91                 }
  92         }
  93
  94         if (ENABLE_FEATURE_CLEAN_UP) {
  95                 fclose(stream[0]);
  96                 fclose(stream[1]);
  97         }
  98
  99         return EXIT_SUCCESS;
 100 }