src/comm.c

   1 /* comm -- compare two sorted files line by line.
   2    Copyright (C) 1986, 1990, 1991, 1995, 1996 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 2, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program; if not, write to the Free Software
  16    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  17
  18 /* Written by Richard Stallman and David MacKenzie. */
  19 \f
  20 #include <config.h>
  21
  22 #include <stdio.h>
  23 #include <getopt.h>
  24 #include <sys/types.h>
  25 #include "system.h"
  26 #include "linebuffer.h"
  27 #include "error.h"
  28
  29 /* Undefine, to avoid warning about redefinition on some systems.  */
  30 #undef min
  31 #define min(x, y) ((x) < (y) ? (x) : (y))
  32
  33 /* The name this program was run with. */
  34 char *program_name;
  35
  36 /* If nonzero, print lines that are found only in file 1. */
  37 static int only_file_1;
  38
  39 /* If nonzero, print lines that are found only in file 2. */
  40 static int only_file_2;
  41
  42 /* If nonzero, print lines that are found in both files. */
  43 static int both;
  44
  45 /* If nonzero, display usage information and exit.  */
  46 static int show_help;
  47
  48 /* If nonzero, print the version on standard output then exit.  */
  49 static int show_version;
  50
  51 static struct option const long_options[] =
  52 {
  53   {"help", no_argument, &show_help, 1},
  54   {"version", no_argument, &show_version, 1},
  55   {0, 0, 0, 0}
  56 };
  57
  58 \f
  59
  60 static void
  61 usage (int status)
  62 {
  63   if (status != 0)
  64     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  65              program_name);
  66   else
  67     {
  68       printf (_("\
  69 Usage: %s [OPTION]... LEFT_FILE RIGHT_FILE\n\
  70 "),
  71               program_name);
  72       printf (_("\
  73 Compare sorted files LEFT_FILE and RIGHT_FILE line by line.\n\
  74 \n\
  75   -1              suppress lines unique to left file\n\
  76   -2              suppress lines unique to right file\n\
  77   -3              suppress lines unique to both files\n\
  78       --help      display this help and exit\n\
  79       --version   output version information and exit\n\
  80 "));
  81     }
  82   exit (status == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
  83 }
  84
  85 /* Output the line in linebuffer LINE to stream STREAM
  86    provided the switches say it should be output.
  87    CLASS is 1 for a line found only in file 1,
  88    2 for a line only in file 2, 3 for a line in both. */
  89
  90 static void
  91 writeline (struct linebuffer *line, FILE *stream, int class)
  92 {
  93   switch (class)
  94     {
  95     case 1:
  96       if (!only_file_1)
  97         return;
  98       break;
  99
 100     case 2:
 101       if (!only_file_2)
 102         return;
 103       /* Skip the tab stop for case 1, if we are printing case 1.  */
 104       if (only_file_1)
 105         putc ('\t', stream);
 106       break;
 107
 108     case 3:
 109       if (!both)
 110         return;
 111       /* Skip the tab stop for case 1, if we are printing case 1.  */
 112       if (only_file_1)
 113         putc ('\t', stream);
 114       /* Skip the tab stop for case 2, if we are printing case 2.  */
 115       if (only_file_2)
 116         putc ('\t', stream);
 117       break;
 118     }
 119
 120   fwrite (line->buffer, sizeof (char), line->length, stream);
 121   putc ('\n', stream);
 122 }
 123
 124 /* Compare INFILES[0] and INFILES[1].
 125    If either is "-", use the standard input for that file.
 126    Assume that each input file is sorted;
 127    merge them and output the result.
 128    Return 0 if successful, 1 if any errors occur. */
 129
 130 static int
 131 compare_files (char **infiles)
 132 {
 133   /* For each file, we have one linebuffer in lb1.  */
 134   struct linebuffer lb1[2];
 135
 136   /* thisline[i] points to the linebuffer holding the next available line
 137      in file i, or is NULL if there are no lines left in that file.  */
 138   struct linebuffer *thisline[2];
 139
 140   /* streams[i] holds the input stream for file i.  */
 141   FILE *streams[2];
 142
 143   int i, ret = 0;
 144
 145   /* Initialize the storage. */
 146   for (i = 0; i < 2; i++)
 147     {
 148       initbuffer (&lb1[i]);
 149       thisline[i] = &lb1[i];
 150       streams[i] = strcmp (infiles[i], "-")
 151         ? fopen (infiles[i], "r") : stdin;
 152       if (!streams[i])
 153         {
 154           error (0, errno, "%s", infiles[i]);
 155           return 1;
 156         }
 157
 158       thisline[i] = readline (thisline[i], streams[i]);
 159     }
 160
 161   while (thisline[0] || thisline[1])
 162     {
 163       int order;
 164
 165       /* Compare the next available lines of the two files.  */
 166
 167       if (!thisline[0])
 168         order = 1;
 169       else if (!thisline[1])
 170         order = -1;
 171       else
 172         {
 173           /* Cannot use bcmp -- it only returns a boolean value. */
 174           order = memcmp (thisline[0]->buffer, thisline[1]->buffer,
 175                           min (thisline[0]->length, thisline[1]->length));
 176           if (order == 0)
 177             order = thisline[0]->length - thisline[1]->length;
 178         }
 179
 180       /* Output the line that is lesser. */
 181       if (order == 0)
 182         writeline (thisline[1], stdout, 3);
 183       else if (order > 0)
 184         writeline (thisline[1], stdout, 2);
 185       else
 186         writeline (thisline[0], stdout, 1);
 187
 188       /* Step the file the line came from.
 189          If the files match, step both files.  */
 190       if (order >= 0)
 191         thisline[1] = readline (thisline[1], streams[1]);
 192       if (order <= 0)
 193         thisline[0] = readline (thisline[0], streams[0]);
 194     }
 195
 196   /* Free all storage and close all input streams. */
 197   for (i = 0; i < 2; i++)
 198     {
 199       free (lb1[i].buffer);
 200       if (ferror (streams[i]) || fclose (streams[i]) == EOF)
 201         {
 202           error (0, errno, "%s", infiles[i]);
 203           ret = 1;
 204         }
 205     }
 206   if (ferror (stdout) || fclose (stdout) == EOF)
 207     {
 208       error (0, errno, _("write error"));
 209       ret = 1;
 210     }
 211   return ret;
 212 }
 213
 214 int
 215 main (int argc, char **argv)
 216 {
 217   int c;
 218
 219   program_name = argv[0];
 220   setlocale (LC_ALL, "");
 221   bindtextdomain (PACKAGE, LOCALEDIR);
 222   textdomain (PACKAGE);
 223
 224   only_file_1 = 1;
 225   only_file_2 = 1;
 226   both = 1;
 227
 228   while ((c = getopt_long (argc, argv, "123", long_options, (int *) 0)) != EOF)
 229     switch (c)
 230       {
 231       case 0:
 232         break;
 233
 234       case '1':
 235         only_file_1 = 0;
 236         break;
 237
 238       case '2':
 239         only_file_2 = 0;
 240         break;
 241
 242       case '3':
 243         both = 0;
 244         break;
 245
 246       default:
 247         usage (1);
 248       }
 249
 250   if (show_version)
 251     {
 252       printf ("comm - %s\n", PACKAGE_VERSION);
 253       exit (EXIT_SUCCESS);
 254     }
 255
 256   if (show_help)
 257     usage (0);
 258
 259   if (optind + 2 != argc)
 260     usage (1);
 261
 262   exit (compare_files (argv + optind) == 0
 263         ? EXIT_SUCCESS : EXIT_FAILURE);
 264 }