git.maemo.org Git - busybox4maemo/blob - 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, int flags)
  18 {
  19         if (class == 0) {
  20                 if (flags & COMM_OPT_1)
  21                         return;
  22         } else if (class == 1) {
  23                 if (flags & COMM_OPT_2)
  24                         return;
  25                 if (!(flags & COMM_OPT_1))
  26                         putchar('\t');
  27         } else /*if (class == 2)*/ {
  28                 if (flags & COMM_OPT_3)
  29                         return;
  30                 if (!(flags & COMM_OPT_1))
  31                         putchar('\t');
  32                 if (!(flags & COMM_OPT_2))
  33                         putchar('\t');
  34         }
  35         fputs(line, stdout);
  36 }
  37
  38 int comm_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  39 int comm_main(int argc ATTRIBUTE_UNUSED, char **argv)
  40 {
  41 #define LINE_LEN 100
  42 #define BB_EOF_0 0x1
  43 #define BB_EOF_1 0x2
  44         char thisline[2][LINE_LEN];
  45         FILE *streams[2];
  46         int i;
  47         unsigned flags;
  48
  49         opt_complementary = "=2";
  50         flags = getopt32(argv, "123");
  51         argv += optind;
  52
  53         for (i = 0; i < 2; ++i) {
  54                 streams[i] = (argv[i][0] == '-' && !argv[i][1]) ? stdin : xfopen(argv[i], "r");
  55                 fgets(thisline[i], LINE_LEN, streams[i]);
  56         }
  57
  58         /* This is the real core of the program - lines are compared here */
  59
  60         while (*thisline[0] || *thisline[1]) {
  61                 int order = 0;
  62
  63                 i = 0;
  64                 if (feof(streams[0])) i |= BB_EOF_0;
  65                 if (feof(streams[1])) i |= BB_EOF_1;
  66
  67                 if (!*thisline[0])
  68                         order = 1;
  69                 else if (!*thisline[1])
  70                         order = -1;
  71                 else {
  72                         int tl0_len, tl1_len;
  73                         tl0_len = strlen(thisline[0]);
  74                         tl1_len = strlen(thisline[1]);
  75                         order = memcmp(thisline[0], thisline[1], tl0_len < tl1_len ? tl0_len : tl1_len);
  76                         if (!order)
  77                                 order = tl0_len < tl1_len ? -1 : tl0_len != tl1_len;
  78                 }
  79
  80                 if (order == 0 && !i)
  81                         writeline(thisline[1], 2, flags);
  82                 else if (order > 0 && !(i & BB_EOF_1))
  83                         writeline(thisline[1], 1, flags);
  84                 else if (order < 0 && !(i & BB_EOF_0))
  85                         writeline(thisline[0], 0, flags);
  86
  87                 if (i & BB_EOF_0 & BB_EOF_1) {
  88                         break;
  89
  90                 } else if (i) {
  91                         i = (i & BB_EOF_0 ? 1 : 0);
  92                         while (!feof(streams[i])) {
  93                                 if ((order < 0 && i) || (order > 0 && !i))
  94                                         writeline(thisline[i], i, flags);
  95                                 fgets(thisline[i], LINE_LEN, streams[i]);
  96                         }
  97                         break;
  98
  99                 } else {
 100                         if (order >= 0)
 101                                 fgets(thisline[1], LINE_LEN, streams[1]);
 102                         if (order <= 0)
 103                                 fgets(thisline[0], LINE_LEN, streams[0]);
 104                 }
 105         }
 106
 107         if (ENABLE_FEATURE_CLEAN_UP) {
 108                 fclose(streams[0]);
 109                 fclose(streams[1]);
 110         }
 111
 112         return EXIT_SUCCESS;
 113 }