summaryrefslogtreecommitdiff
path: root/src/comm.c
blob: 972aefbbec1857ca46d1a1e2ae8a69704407ec40 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
/* comm -- compare two sorted files line by line.
   Copyright (C) 86, 90, 91, 1995-2004 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

/* Written by Richard Stallman and David MacKenzie. */

#include <config.h>

#include <stdio.h>
#include <getopt.h>
#include <sys/types.h>
#include "system.h"
#include "linebuffer.h"
#include "error.h"
#include "hard-locale.h"
#include "quote.h"
#include "xmemcoll.h"

/* The official name of this program (e.g., no `g' prefix).  */
#define PROGRAM_NAME "comm"

#define AUTHORS "Richard Stallman", "David MacKenzie"

/* Undefine, to avoid warning about redefinition on some systems.  */
#undef min
#define min(x, y) ((x) < (y) ? (x) : (y))

/* The name this program was run with. */
char *program_name;

/* True if the LC_COLLATE locale is hard.  */
static bool hard_LC_COLLATE;

/* If true, print lines that are found only in file 1. */
static bool only_file_1;

/* If true, print lines that are found only in file 2. */
static bool only_file_2;

/* If true, print lines that are found in both files. */
static bool both;

static struct option const long_options[] =
{
  {GETOPT_HELP_OPTION_DECL},
  {GETOPT_VERSION_OPTION_DECL},
  {0, 0, 0, 0}
};



void
usage (int status)
{
  if (status != EXIT_SUCCESS)
    fprintf (stderr, _("Try `%s --help' for more information.\n"),
	     program_name);
  else
    {
      printf (_("\
Usage: %s [OPTION]... FILE1 FILE2\n\
"),
	      program_name);
      fputs (_("\
Compare sorted files FILE1 and FILE2 line by line.\n\
"), stdout);
      fputs (_("\
\n\
With no options, produce three-column output.  Column one contains\n\
lines unique to FILE1, column two contains lines unique to FILE2,\n\
and column three contains lines common to both files.\n\
"), stdout);
      fputs (_("\
\n\
  -1              suppress lines unique to FILE1\n\
  -2              suppress lines unique to FILE2\n\
  -3              suppress lines that appear in both files\n\
"), stdout);
      fputs (HELP_OPTION_DESCRIPTION, stdout);
      fputs (VERSION_OPTION_DESCRIPTION, stdout);
      printf (_("\nReport bugs to <%s>.\n"), PACKAGE_BUGREPORT);
    }
  exit (status);
}

/* Output the line in linebuffer LINE to stream STREAM
   provided the switches say it should be output.
   CLASS is 1 for a line found only in file 1,
   2 for a line only in file 2, 3 for a line in both. */

static void
writeline (const struct linebuffer *line, FILE *stream, int class)
{
  switch (class)
    {
    case 1:
      if (!only_file_1)
	return;
      break;

    case 2:
      if (!only_file_2)
	return;
      /* Print a TAB if we are printing lines from file 1.  */
      if (only_file_1)
	putc ('\t', stream);
      break;

    case 3:
      if (!both)
	return;
      /* Print a TAB if we are printing lines from file 1.  */
      if (only_file_1)
	putc ('\t', stream);
      /* Print a TAB if we are printing lines from file 2.  */
      if (only_file_2)
	putc ('\t', stream);
      break;
    }

  fwrite (line->buffer, sizeof (char), line->length, stream);
}

/* Compare INFILES[0] and INFILES[1].
   If either is "-", use the standard input for that file.
   Assume that each input file is sorted;
   merge them and output the result.
   Return true if successful.  */

static bool
compare_files (char **infiles)
{
  /* For each file, we have one linebuffer in lb1.  */
  struct linebuffer lb1[2];

  /* thisline[i] points to the linebuffer holding the next available line
     in file i, or is NULL if there are no lines left in that file.  */
  struct linebuffer *thisline[2];

  /* streams[i] holds the input stream for file i.  */
  FILE *streams[2];

  /* errno values for each stream.  */
  int saved_errno[2];

  int i;
  bool ret = true;

  /* Initialize the storage. */
  for (i = 0; i < 2; i++)
    {
      initbuffer (&lb1[i]);
      thisline[i] = &lb1[i];
      streams[i] = (STREQ (infiles[i], "-") ? stdin : fopen (infiles[i], "r"));
      if (!streams[i])
	{
	  error (0, errno, "%s", infiles[i]);
	  return false;
	}

      thisline[i] = readlinebuffer (thisline[i], streams[i]);
      saved_errno[i] = errno;
    }

  while (thisline[0] || thisline[1])
    {
      int order;

      /* Compare the next available lines of the two files.  */

      if (!thisline[0])
	order = 1;
      else if (!thisline[1])
	order = -1;
      else
	{
	  if (HAVE_SETLOCALE && hard_LC_COLLATE)
	    order = xmemcoll (thisline[0]->buffer, thisline[0]->length - 1,
			      thisline[1]->buffer, thisline[1]->length - 1);
	  else
	    {
	      size_t len = min (thisline[0]->length, thisline[1]->length) - 1;
	      order = memcmp (thisline[0]->buffer, thisline[1]->buffer, len);
	      if (order == 0)
		order = (thisline[0]->length < thisline[1]->length
			 ? -1
			 : thisline[0]->length != thisline[1]->length);
	    }
	}

      /* Output the line that is lesser. */
      if (order == 0)
	writeline (thisline[1], stdout, 3);
      else if (order > 0)
	writeline (thisline[1], stdout, 2);
      else
	writeline (thisline[0], stdout, 1);

      /* Step the file the line came from.
	 If the files match, step both files.  */
      if (order >= 0)
	{
	  thisline[1] = readlinebuffer (thisline[1], streams[1]);
	  saved_errno[1] = errno;
	}
      if (order <= 0)
	{
	  thisline[0] = readlinebuffer (thisline[0], streams[0]);
	  saved_errno[0] = errno;
	}
    }

  /* Free all storage and close all input streams. */
  for (i = 0; i < 2; i++)
    {
      free (lb1[i].buffer);
      if (ferror (streams[i]))
	{
	  error (0, saved_errno[i], "%s", infiles[i]);
	  ret = false;
	}
      if (fclose (streams[i]) != 0)
	{
	  error (0, errno, "%s", infiles[i]);
	  ret = false;
	}
    }
  return ret;
}

int
main (int argc, char **argv)
{
  int c;

  initialize_main (&argc, &argv);
  program_name = argv[0];
  setlocale (LC_ALL, "");
  bindtextdomain (PACKAGE, LOCALEDIR);
  textdomain (PACKAGE);
  hard_LC_COLLATE = hard_locale (LC_COLLATE);

  atexit (close_stdout);

  only_file_1 = true;
  only_file_2 = true;
  both = true;

  while ((c = getopt_long (argc, argv, "123", long_options, NULL)) != -1)
    switch (c)
      {
      case '1':
	only_file_1 = false;
	break;

      case '2':
	only_file_2 = false;
	break;

      case '3':
	both = false;
	break;

      case_GETOPT_HELP_CHAR;

      case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);

      default:
	usage (EXIT_FAILURE);
      }

  if (argc - optind < 2)
    {
      if (argc <= optind)
	error (0, 0, _("missing operand"));
      else
	error (0, 0, _("missing operand after %s"), quote (argv[argc - 1]));
      usage (EXIT_FAILURE);
    }

  if (2 < argc - optind)
    {
      error (0, 0, _("extra operand %s"), quote (argv[optind + 2]));
      usage (EXIT_FAILURE);
    }

  exit (compare_files (argv + optind)
	? EXIT_SUCCESS : EXIT_FAILURE);
}