summaryrefslogtreecommitdiffstats
path: root/contrib/diff/util.c
blob: 07b24a760e47ea60fd46af402ce95ddb0051d40a (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
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
/* Support routines for GNU DIFF.
   Copyright (C) 1988, 1989, 1992, 1993, 1994 Free Software Foundation, Inc.

This file is part of GNU DIFF.

GNU DIFF 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.

GNU DIFF 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 GNU DIFF; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "diff.h"

#ifndef PR_PROGRAM
#define PR_PROGRAM "/bin/pr"
#endif

/* Queue up one-line messages to be printed at the end,
   when -l is specified.  Each message is recorded with a `struct msg'.  */

struct msg
{
  struct msg *next;
  char const *format;
  char const *arg1;
  char const *arg2;
  char const *arg3;
  char const *arg4;
};

/* Head of the chain of queues messages.  */

static struct msg *msg_chain;

/* Tail of the chain of queues messages.  */

static struct msg **msg_chain_end = &msg_chain;

/* Use when a system call returns non-zero status.
   TEXT should normally be the file name.  */

void
perror_with_name (text)
     char const *text;
{
  int e = errno;
  fprintf (stderr, "%s: ", program_name);
  errno = e;
  perror (text);
}

/* Use when a system call returns non-zero status and that is fatal.  */

void
pfatal_with_name (text)
     char const *text;
{
  int e = errno;
  print_message_queue ();
  fprintf (stderr, "%s: ", program_name);
  errno = e;
  perror (text);
  exit (2);
}

/* Print an error message from the format-string FORMAT
   with args ARG1 and ARG2.  */

void
error (format, arg, arg1)
     char const *format, *arg, *arg1;
{
  fprintf (stderr, "%s: ", program_name);
  fprintf (stderr, format, arg, arg1);
  fprintf (stderr, "\n");
}

/* Print an error message containing the string TEXT, then exit.  */

void
fatal (m)
     char const *m;
{
  print_message_queue ();
  error ("%s", m, 0);
  exit (2);
}

/* Like printf, except if -l in effect then save the message and print later.
   This is used for things like "binary files differ" and "Only in ...".  */

void
message (format, arg1, arg2)
     char const *format, *arg1, *arg2;
{
  message5 (format, arg1, arg2, 0, 0);
}

void
message5 (format, arg1, arg2, arg3, arg4)
     char const *format, *arg1, *arg2, *arg3, *arg4;
{
  if (paginate_flag)
    {
      struct msg *new = (struct msg *) xmalloc (sizeof (struct msg));
      new->format = format;
      new->arg1 = concat (arg1, "", "");
      new->arg2 = concat (arg2, "", "");
      new->arg3 = arg3 ? concat (arg3, "", "") : 0;
      new->arg4 = arg4 ? concat (arg4, "", "") : 0;
      new->next = 0;
      *msg_chain_end = new;
      msg_chain_end = &new->next;
    }
  else
    {
      if (sdiff_help_sdiff)
	putchar (' ');
      printf (format, arg1, arg2, arg3, arg4);
    }
}

/* Output all the messages that were saved up by calls to `message'.  */

void
print_message_queue ()
{
  struct msg *m;

  for (m = msg_chain; m; m = m->next)
    printf (m->format, m->arg1, m->arg2, m->arg3, m->arg4);
}

/* Call before outputting the results of comparing files NAME0 and NAME1
   to set up OUTFILE, the stdio stream for the output to go to.

   Usually, OUTFILE is just stdout.  But when -l was specified
   we fork off a `pr' and make OUTFILE a pipe to it.
   `pr' then outputs to our stdout.  */

static char const *current_name0;
static char const *current_name1;
static int current_depth;

void
setup_output (name0, name1, depth)
     char const *name0, *name1;
     int depth;
{
  current_name0 = name0;
  current_name1 = name1;
  current_depth = depth;
  outfile = 0;
}

#if HAVE_FORK
static pid_t pr_pid;
#endif

void
begin_output ()
{
  char *name;

  if (outfile != 0)
    return;

  /* Construct the header of this piece of diff.  */
  name = xmalloc (strlen (current_name0) + strlen (current_name1)
		  + strlen (switch_string) + 7);
  /* Posix.2 section 4.17.6.1.1 specifies this format.  But there is a
     bug in the first printing (IEEE Std 1003.2-1992 p 251 l 3304):
     it says that we must print only the last component of the pathnames.
     This requirement is silly and does not match historical practice.  */
  sprintf (name, "diff%s %s %s", switch_string, current_name0, current_name1);

  if (paginate_flag)
    {
      /* Make OUTFILE a pipe to a subsidiary `pr'.  */

#if HAVE_FORK
      int pipes[2];

      if (pipe (pipes) != 0)
	pfatal_with_name ("pipe");

      fflush (stdout);

      pr_pid = vfork ();
      if (pr_pid < 0)
	pfatal_with_name ("vfork");

      if (pr_pid == 0)
	{
	  close (pipes[1]);
	  if (pipes[0] != STDIN_FILENO)
	    {
	      if (dup2 (pipes[0], STDIN_FILENO) < 0)
		pfatal_with_name ("dup2");
	      close (pipes[0]);
	    }
#ifdef __FreeBSD__
	  execl (PR_PROGRAM, PR_PROGRAM, "-F", "-h", name, 0);
#else
	  execl (PR_PROGRAM, PR_PROGRAM, "-f", "-h", name, 0);
#endif
	  pfatal_with_name (PR_PROGRAM);
	}
      else
	{
	  close (pipes[0]);
	  outfile = fdopen (pipes[1], "w");
	  if (!outfile)
	    pfatal_with_name ("fdopen");
	}
#else /* ! HAVE_FORK */
      char *command = xmalloc (4 * strlen (name) + strlen (PR_PROGRAM) + 10);
      char *p;
      char const *a = name;
      sprintf (command, "%s -f -h ", PR_PROGRAM);
      p = command + strlen (command);
      SYSTEM_QUOTE_ARG (p, a);
      *p = 0;
      outfile = popen (command, "w");
      if (!outfile)
	pfatal_with_name (command);
      free (command);
#endif /* ! HAVE_FORK */
    }
  else
    {

      /* If -l was not specified, output the diff straight to `stdout'.  */

      outfile = stdout;

      /* If handling multiple files (because scanning a directory),
	 print which files the following output is about.  */
      if (current_depth > 0)
	printf ("%s\n", name);
    }

  free (name);

  /* A special header is needed at the beginning of context output.  */
  switch (output_style)
    {
    case OUTPUT_CONTEXT:
      print_context_header (files, 0);
      break;

    case OUTPUT_UNIFIED:
      print_context_header (files, 1);
      break;

    default:
      break;
    }
}

/* Call after the end of output of diffs for one file.
   Close OUTFILE and get rid of the `pr' subfork.  */

void
finish_output ()
{
  if (outfile != 0 && outfile != stdout)
    {
      int wstatus;
      if (ferror (outfile))
	fatal ("write error");
#if ! HAVE_FORK
      wstatus = pclose (outfile);
#else /* HAVE_FORK */
      if (fclose (outfile) != 0)
	pfatal_with_name ("write error");
      if (waitpid (pr_pid, &wstatus, 0) < 0)
	pfatal_with_name ("waitpid");
#endif /* HAVE_FORK */
      if (wstatus != 0)
	fatal ("subsidiary pr failed");
    }

  outfile = 0;
}

/* Compare two lines (typically one from each input file)
   according to the command line options.
   For efficiency, this is invoked only when the lines do not match exactly
   but an option like -i might cause us to ignore the difference.
   Return nonzero if the lines differ.  */

int
line_cmp (s1, s2)
     char const *s1, *s2;
{
  register unsigned char const *t1 = (unsigned char const *) s1;
  register unsigned char const *t2 = (unsigned char const *) s2;

  while (1)
    {
      register unsigned char c1 = *t1++;
      register unsigned char c2 = *t2++;

      /* Test for exact char equality first, since it's a common case.  */
      if (c1 != c2)
	{
	  /* Ignore horizontal white space if -b or -w is specified.  */

	  if (ignore_all_space_flag)
	    {
	      /* For -w, just skip past any white space.  */
	      while (ISSPACE (c1) && c1 != '\n') c1 = *t1++;
	      while (ISSPACE (c2) && c2 != '\n') c2 = *t2++;
	    }
	  else if (ignore_space_change_flag)
	    {
	      /* For -b, advance past any sequence of white space in line 1
		 and consider it just one Space, or nothing at all
		 if it is at the end of the line.  */
	      if (ISSPACE (c1))
		{
		  while (c1 != '\n')
		    {
		      c1 = *t1++;
		      if (! ISSPACE (c1))
			{
			  --t1;
			  c1 = ' ';
			  break;
			}
		    }
		}

	      /* Likewise for line 2.  */
	      if (ISSPACE (c2))
		{
		  while (c2 != '\n')
		    {
		      c2 = *t2++;
		      if (! ISSPACE (c2))
			{
			  --t2;
			  c2 = ' ';
			  break;
			}
		    }
		}

	      if (c1 != c2)
		{
		  /* If we went too far when doing the simple test
		     for equality, go back to the first non-white-space
		     character in both sides and try again.  */
		  if (c2 == ' ' && c1 != '\n'
		      && (unsigned char const *) s1 + 1 < t1
		      && ISSPACE(t1[-2]))
		    {
		      --t1;
		      continue;
		    }
		  if (c1 == ' ' && c2 != '\n'
		      && (unsigned char const *) s2 + 1 < t2
		      && ISSPACE(t2[-2]))
		    {
		      --t2;
		      continue;
		    }
		}
	    }

	  /* Lowercase all letters if -i is specified.  */

	  if (ignore_case_flag)
	    {
	      if (ISUPPER (c1))
		c1 = tolower (c1);
	      if (ISUPPER (c2))
		c2 = tolower (c2);
	    }

	  if (c1 != c2)
	    break;
	}
      if (c1 == '\n')
	return 0;
    }

  return (1);
}

/* Find the consecutive changes at the start of the script START.
   Return the last link before the first gap.  */

struct change *
find_change (start)
     struct change *start;
{
  return start;
}

struct change *
find_reverse_change (start)
     struct change *start;
{
  return start;
}

/* Divide SCRIPT into pieces by calling HUNKFUN and
   print each piece with PRINTFUN.
   Both functions take one arg, an edit script.

   HUNKFUN is called with the tail of the script
   and returns the last link that belongs together with the start
   of the tail.

   PRINTFUN takes a subscript which belongs together (with a null
   link at the end) and prints it.  */

void
print_script (script, hunkfun, printfun)
     struct change *script;
     struct change * (*hunkfun) PARAMS((struct change *));
     void (*printfun) PARAMS((struct change *));
{
  struct change *next = script;

  while (next)
    {
      struct change *this, *end;

      /* Find a set of changes that belong together.  */
      this = next;
      end = (*hunkfun) (next);

      /* Disconnect them from the rest of the changes,
	 making them a hunk, and remember the rest for next iteration.  */
      next = end->link;
      end->link = 0;
#ifdef DEBUG
      debug_script (this);
#endif

      /* Print this hunk.  */
      (*printfun) (this);

      /* Reconnect the script so it will all be freed properly.  */
      end->link = next;
    }
}

/* Print the text of a single line LINE,
   flagging it with the characters in LINE_FLAG (which say whether
   the line is inserted, deleted, changed, etc.).  */

void
print_1_line (line_flag, line)
     char const *line_flag;
     char const * const *line;
{
  char const *text = line[0], *limit = line[1]; /* Help the compiler.  */
  FILE *out = outfile; /* Help the compiler some more.  */
  char const *flag_format = 0;

  /* If -T was specified, use a Tab between the line-flag and the text.
     Otherwise use a Space (as Unix diff does).
     Print neither space nor tab if line-flags are empty.  */

  if (line_flag && *line_flag)
    {
      flag_format = tab_align_flag ? "%s\t" : "%s ";
      fprintf (out, flag_format, line_flag);
    }

  output_1_line (text, limit, flag_format, line_flag);

  if ((!line_flag || line_flag[0]) && limit[-1] != '\n')
    fprintf (out, "\n\\ No newline at end of file\n");
}

/* Output a line from TEXT up to LIMIT.  Without -t, output verbatim.
   With -t, expand white space characters to spaces, and if FLAG_FORMAT
   is nonzero, output it with argument LINE_FLAG after every
   internal carriage return, so that tab stops continue to line up.  */

void
output_1_line (text, limit, flag_format, line_flag)
     char const *text, *limit, *flag_format, *line_flag;
{
  if (!tab_expand_flag)
    fwrite (text, sizeof (char), limit - text, outfile);
  else
    {
      register FILE *out = outfile;
      register unsigned char c;
      register char const *t = text;
      register unsigned column = 0;

      while (t < limit)
	switch ((c = *t++))
	  {
	  case '\t':
	    {
	      unsigned spaces = TAB_WIDTH - column % TAB_WIDTH;
	      column += spaces;
	      do
		putc (' ', out);
	      while (--spaces);
	    }
	    break;

	  case '\r':
	    putc (c, out);
	    if (flag_format && t < limit && *t != '\n')
	      fprintf (out, flag_format, line_flag);
	    column = 0;
	    break;

	  case '\b':
	    if (column == 0)
	      continue;
	    column--;
	    putc (c, out);
	    break;

	  default:
	    if (ISPRINT (c))
	      column++;
	    putc (c, out);
	    break;
	  }
    }
}

int
change_letter (inserts, deletes)
     int inserts, deletes;
{
  if (!inserts)
    return 'd';
  else if (!deletes)
    return 'a';
  else
    return 'c';
}

/* Translate an internal line number (an index into diff's table of lines)
   into an actual line number in the input file.
   The internal line number is LNUM.  FILE points to the data on the file.

   Internal line numbers count from 0 starting after the prefix.
   Actual line numbers count from 1 within the entire file.  */

int
translate_line_number (file, lnum)
     struct file_data const *file;
     int lnum;
{
  return lnum + file->prefix_lines + 1;
}

void
translate_range (file, a, b, aptr, bptr)
     struct file_data const *file;
     int a, b;
     int *aptr, *bptr;
{
  *aptr = translate_line_number (file, a - 1) + 1;
  *bptr = translate_line_number (file, b + 1) - 1;
}

/* Print a pair of line numbers with SEPCHAR, translated for file FILE.
   If the two numbers are identical, print just one number.

   Args A and B are internal line numbers.
   We print the translated (real) line numbers.  */

void
print_number_range (sepchar, file, a, b)
     int sepchar;
     struct file_data *file;
     int a, b;
{
  int trans_a, trans_b;
  translate_range (file, a, b, &trans_a, &trans_b);

  /* Note: we can have B < A in the case of a range of no lines.
     In this case, we should print the line number before the range,
     which is B.  */
  if (trans_b > trans_a)
    fprintf (outfile, "%d%c%d", trans_a, sepchar, trans_b);
  else
    fprintf (outfile, "%d", trans_b);
}

/* Look at a hunk of edit script and report the range of lines in each file
   that it applies to.  HUNK is the start of the hunk, which is a chain
   of `struct change'.  The first and last line numbers of file 0 are stored in
   *FIRST0 and *LAST0, and likewise for file 1 in *FIRST1 and *LAST1.
   Note that these are internal line numbers that count from 0.

   If no lines from file 0 are deleted, then FIRST0 is LAST0+1.

   Also set *DELETES nonzero if any lines of file 0 are deleted
   and set *INSERTS nonzero if any lines of file 1 are inserted.
   If only ignorable lines are inserted or deleted, both are
   set to 0.  */

void
analyze_hunk (hunk, first0, last0, first1, last1, deletes, inserts)
     struct change *hunk;
     int *first0, *last0, *first1, *last1;
     int *deletes, *inserts;
{
  int l0, l1, show_from, show_to;
  int i;
  int trivial = ignore_blank_lines_flag || ignore_regexp_list;
  struct change *next;

  show_from = show_to = 0;

  *first0 = hunk->line0;
  *first1 = hunk->line1;

  next = hunk;
  do
    {
      l0 = next->line0 + next->deleted - 1;
      l1 = next->line1 + next->inserted - 1;
      show_from += next->deleted;
      show_to += next->inserted;

      for (i = next->line0; i <= l0 && trivial; i++)
	if (!ignore_blank_lines_flag || files[0].linbuf[i][0] != '\n')
	  {
	    struct regexp_list *r;
	    char const *line = files[0].linbuf[i];
	    int len = files[0].linbuf[i + 1] - line;

	    for (r = ignore_regexp_list; r; r = r->next)
	      if (0 <= re_search (&r->buf, line, len, 0, len, 0))
		break;	/* Found a match.  Ignore this line.  */
	    /* If we got all the way through the regexp list without
	       finding a match, then it's nontrivial.  */
	    if (!r)
	      trivial = 0;
	  }

      for (i = next->line1; i <= l1 && trivial; i++)
	if (!ignore_blank_lines_flag || files[1].linbuf[i][0] != '\n')
	  {
	    struct regexp_list *r;
	    char const *line = files[1].linbuf[i];
	    int len = files[1].linbuf[i + 1] - line;

	    for (r = ignore_regexp_list; r; r = r->next)
	      if (0 <= re_search (&r->buf, line, len, 0, len, 0))
		break;	/* Found a match.  Ignore this line.  */
	    /* If we got all the way through the regexp list without
	       finding a match, then it's nontrivial.  */
	    if (!r)
	      trivial = 0;
	  }
    }
  while ((next = next->link) != 0);

  *last0 = l0;
  *last1 = l1;

  /* If all inserted or deleted lines are ignorable,
     tell the caller to ignore this hunk.  */

  if (trivial)
    show_from = show_to = 0;

  *deletes = show_from;
  *inserts = show_to;
}

/* malloc a block of memory, with fatal error message if we can't do it. */

VOID *
xmalloc (size)
     size_t size;
{
  register VOID *value;

  if (size == 0)
    size = 1;

  value = (VOID *) malloc (size);

  if (!value)
    fatal ("memory exhausted");
  return value;
}

/* realloc a block of memory, with fatal error message if we can't do it. */

VOID *
xrealloc (old, size)
     VOID *old;
     size_t size;
{
  register VOID *value;

  if (size == 0)
    size = 1;

  value = (VOID *) realloc (old, size);

  if (!value)
    fatal ("memory exhausted");
  return value;
}

/* Concatenate three strings, returning a newly malloc'd string.  */

char *
concat (s1, s2, s3)
     char const *s1, *s2, *s3;
{
  size_t len = strlen (s1) + strlen (s2) + strlen (s3);
  char *new = xmalloc (len + 1);
  sprintf (new, "%s%s%s", s1, s2, s3);
  return new;
}

/* Yield the newly malloc'd pathname
   of the file in DIR whose filename is FILE.  */

char *
dir_file_pathname (dir, file)
     char const *dir, *file;
{
  char const *p = filename_lastdirchar (dir);
  return concat (dir, "/" + (p && !p[1]), file);
}

void
debug_script (sp)
     struct change *sp;
{
  fflush (stdout);
  for (; sp; sp = sp->link)
    fprintf (stderr, "%3d %3d delete %d insert %d\n",
	     sp->line0, sp->line1, sp->deleted, sp->inserted);
  fflush (stderr);
}
OpenPOWER on IntegriCloud