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 //config:config COMM
  10 //config:       bool "comm (3.9 kb)"
  11 //config:       default y
  12 //config:       help
  13 //config:       comm is used to compare two files line by line and return
  14 //config:       a three-column output.
  15
  16 //applet:IF_COMM(APPLET(comm, BB_DIR_USR_BIN, BB_SUID_DROP))
  17
  18 //kbuild:lib-$(CONFIG_COMM) += comm.o
  19
  20 //usage:#define comm_trivial_usage
  21 //usage:       "[-123] FILE1 FILE2"
  22 //usage:#define comm_full_usage "\n\n"
  23 //usage:       "Compare FILE1 with FILE2\n"
  24 //usage:     "\n        -1      Suppress lines unique to FILE1"
  25 //usage:     "\n        -2      Suppress lines unique to FILE2"
  26 //usage:     "\n        -3      Suppress lines common to both files"
  27
  28 #include "libbb.h"
  29
  30 #define COMM_OPT_1 (1 << 0)
  31 #define COMM_OPT_2 (1 << 1)
  32 #define COMM_OPT_3 (1 << 2)
  33
  34 /* writeline outputs the input given, appropriately aligned according to class */
  35 static void writeline(char *line, int class)
  36 {
  37         int flags = option_mask32;
  38         if (class == 0) {
  39                 if (flags & COMM_OPT_1)
  40                         return;
  41         } else if (class == 1) {
  42                 if (flags & COMM_OPT_2)
  43                         return;
  44                 if (!(flags & COMM_OPT_1))
  45                         putchar('\t');
  46         } else /*if (class == 2)*/ {
  47                 if (flags & COMM_OPT_3)
  48                         return;
  49                 if (!(flags & COMM_OPT_1))
  50                         putchar('\t');
  51                 if (!(flags & COMM_OPT_2))
  52                         putchar('\t');
  53         }
  54         puts(line);
  55 }
  56
  57 int comm_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  58 int comm_main(int argc UNUSED_PARAM, char **argv)
  59 {
  60         char *thisline[2];
  61         FILE *stream[2];
  62         int i;
  63         int order;
  64
  65         opt_complementary = "=2";
  66         getopt32(argv, "123");
  67         argv += optind;
  68
  69         for (i = 0; i < 2; ++i) {
  70                 stream[i] = xfopen_stdin(argv[i]);
  71         }
  72
  73         order = 0;
  74         thisline[1] = thisline[0] = NULL;
  75         while (1) {
  76                 if (order <= 0) {
  77                         free(thisline[0]);
  78                         thisline[0] = xmalloc_fgetline(stream[0]);
  79                 }
  80                 if (order >= 0) {
  81                         free(thisline[1]);
  82                         thisline[1] = xmalloc_fgetline(stream[1]);
  83                 }
  84
  85                 i = !thisline[0] + (!thisline[1] << 1);
  86                 if (i)
  87                         break;
  88                 order = strcmp(thisline[0], thisline[1]);
  89
  90                 if (order >= 0)
  91                         writeline(thisline[1], order ? 1 : 2);
  92                 else
  93                         writeline(thisline[0], 0);
  94         }
  95
  96         /* EOF at least on one of the streams */
  97         i &= 1;
  98         if (thisline[i]) {
  99                 /* stream[i] is not at EOF yet */
 100                 /* we did not print thisline[i] yet */
 101                 char *p = thisline[i];
 102                 writeline(p, i);
 103                 while (1) {
 104                         free(p);
 105                         p = xmalloc_fgetline(stream[i]);
 106                         if (!p)
 107                                 break;
 108                         writeline(p, i);
 109                 }
 110         }
 111
 112         if (ENABLE_FEATURE_CLEAN_UP) {
 113                 fclose(stream[0]);
 114                 fclose(stream[1]);
 115         }
 116
 117         return EXIT_SUCCESS;
 118 }