search.c 80.1 KB
Newer Older
Jim Blandy's avatar
Jim Blandy committed
1
/* String search routines for GNU Emacs.
Richard M. Stallman's avatar
Richard M. Stallman committed
2
   Copyright (C) 1985, 86, 87, 93, 94, 97, 1998 Free Software Foundation, Inc.
Jim Blandy's avatar
Jim Blandy committed
3 4 5 6 7

This file is part of GNU Emacs.

GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
Karl Heuer's avatar
Karl Heuer committed
8
the Free Software Foundation; either version 2, or (at your option)
Jim Blandy's avatar
Jim Blandy committed
9 10 11 12 13 14 15 16 17
any later version.

GNU Emacs 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 Emacs; see the file COPYING.  If not, write to
18 19
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */
Jim Blandy's avatar
Jim Blandy committed
20 21


22
#include <config.h>
Andreas Schwab's avatar
Andreas Schwab committed
23 24 25
#ifdef STDC_HEADERS
#include <stdlib.h>
#endif
Jim Blandy's avatar
Jim Blandy committed
26 27
#include "lisp.h"
#include "syntax.h"
Karl Heuer's avatar
Karl Heuer committed
28
#include "category.h"
Jim Blandy's avatar
Jim Blandy committed
29
#include "buffer.h"
Karl Heuer's avatar
Karl Heuer committed
30
#include "charset.h"
31
#include "region-cache.h"
Jim Blandy's avatar
Jim Blandy committed
32
#include "commands.h"
33
#include "blockinput.h"
34
#include "intervals.h"
Jim Blandy's avatar
Jim Blandy committed
35

Jim Blandy's avatar
Jim Blandy committed
36 37 38
#include <sys/types.h>
#include "regex.h"

39 40 41
#define min(a, b) ((a) < (b) ? (a) : (b))
#define max(a, b) ((a) > (b) ? (a) : (b))

42
#define REGEXP_CACHE_SIZE 20
Jim Blandy's avatar
Jim Blandy committed
43

44 45
/* If the regexp is non-nil, then the buffer contains the compiled form
   of that regexp, suitable for searching.  */
46 47
struct regexp_cache
{
48 49 50 51
  struct regexp_cache *next;
  Lisp_Object regexp;
  struct re_pattern_buffer buf;
  char fastmap[0400];
52 53
  /* Nonzero means regexp was compiled to do full POSIX backtracking.  */
  char posix;
54
};
Jim Blandy's avatar
Jim Blandy committed
55

56 57
/* The instances of that struct.  */
struct regexp_cache searchbufs[REGEXP_CACHE_SIZE];
Jim Blandy's avatar
Jim Blandy committed
58

59 60
/* The head of the linked list; points to the most recently used buffer.  */
struct regexp_cache *searchbuf_head;
Jim Blandy's avatar
Jim Blandy committed
61 62


Jim Blandy's avatar
Jim Blandy committed
63 64 65 66 67 68 69
/* Every call to re_match, etc., must pass &search_regs as the regs
   argument unless you can show it is unnecessary (i.e., if re_match
   is certainly going to be called again before region-around-match
   can be called).

   Since the registers are now dynamically allocated, we need to make
   sure not to refer to the Nth register before checking that it has
Jim Blandy's avatar
Jim Blandy committed
70 71 72
   been allocated by checking search_regs.num_regs.

   The regex code keeps track of whether it has allocated the search
73 74
   buffer using bits in the re_pattern_buffer.  This means that whenever
   you compile a new pattern, it completely forgets whether it has
Jim Blandy's avatar
Jim Blandy committed
75 76 77 78 79
   allocated any registers, and will allocate new registers the next
   time you call a searching or matching function.  Therefore, we need
   to call re_set_registers after compiling a new pattern or after
   setting the match registers, so that the regex functions will be
   able to free or re-allocate it properly.  */
Jim Blandy's avatar
Jim Blandy committed
80 81
static struct re_registers search_regs;

Jim Blandy's avatar
Jim Blandy committed
82 83 84 85
/* The buffer in which the last search was performed, or
   Qt if the last search was done in a string;
   Qnil if no searching has been done yet.  */
static Lisp_Object last_thing_searched;
Jim Blandy's avatar
Jim Blandy committed
86

Karl Heuer's avatar
Karl Heuer committed
87
/* error condition signaled when regexp compile_pattern fails */
Jim Blandy's avatar
Jim Blandy committed
88 89 90

Lisp_Object Qinvalid_regexp;

91
static void set_search_regs ();
92
static void save_search_regs ();
93 94
static int simple_search ();
static int boyer_moore ();
95 96
static int search_buffer ();

Jim Blandy's avatar
Jim Blandy committed
97 98 99 100 101 102 103 104 105 106 107 108
static void
matcher_overflow ()
{
  error ("Stack overflow in regexp matcher");
}

#ifdef __STDC__
#define CONST const
#else
#define CONST
#endif

109 110 111
/* Compile a regexp and signal a Lisp error if anything goes wrong.
   PATTERN is the pattern to compile.
   CP is the place to put the result.
112
   TRANSLATE is a translation table for ignoring case, or nil for none.
113 114 115 116 117
   REGP is the structure that says where to store the "register"
   values that will result from matching this pattern.
   If it is 0, we should compile the pattern not to record any
   subexpression bounds.
   POSIX is nonzero if we want full backtracking (POSIX style)
Karl Heuer's avatar
Karl Heuer committed
118 119 120 121
   for this pattern.  0 means backtrack only enough to get a valid match.
   MULTIBYTE is nonzero if we want to handle multibyte characters in
   PATTERN.  0 means all multibyte characters are recognized just as
   sequences of binary data.  */
Jim Blandy's avatar
Jim Blandy committed
122

123
static void
Karl Heuer's avatar
Karl Heuer committed
124
compile_pattern_1 (cp, pattern, translate, regp, posix, multibyte)
125
     struct regexp_cache *cp;
Jim Blandy's avatar
Jim Blandy committed
126
     Lisp_Object pattern;
127
     Lisp_Object translate;
128
     struct re_registers *regp;
129
     int posix;
Karl Heuer's avatar
Karl Heuer committed
130
     int multibyte;
Jim Blandy's avatar
Jim Blandy committed
131
{
132 133
  char *raw_pattern;
  int raw_pattern_size;
134
  char *val;
135
  reg_syntax_t old;
Jim Blandy's avatar
Jim Blandy committed
136

137 138 139 140 141 142 143
  /* MULTIBYTE says whether the text to be searched is multibyte.
     We must convert PATTERN to match that, or we will not really
     find things right.  */

  if (multibyte == STRING_MULTIBYTE (pattern))
    {
      raw_pattern = (char *) XSTRING (pattern)->data;
144
      raw_pattern_size = STRING_BYTES (XSTRING (pattern));
145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164
    }
  else if (multibyte)
    {
      raw_pattern_size = count_size_as_multibyte (XSTRING (pattern)->data,
						  XSTRING (pattern)->size);
      raw_pattern = (char *) alloca (raw_pattern_size + 1);
      copy_text (XSTRING (pattern)->data, raw_pattern,
		 XSTRING (pattern)->size, 0, 1);
    }
  else
    {
      /* Converting multibyte to single-byte.

	 ??? Perhaps this conversion should be done in a special way
	 by subtracting nonascii-insert-offset from each non-ASCII char,
	 so that only the multibyte chars which really correspond to
	 the chosen single-byte character set can possibly match.  */
      raw_pattern_size = XSTRING (pattern)->size;
      raw_pattern = (char *) alloca (raw_pattern_size + 1);
      copy_text (XSTRING (pattern)->data, raw_pattern,
165
		 STRING_BYTES (XSTRING (pattern)), 1, 0);
166 167
    }

168
  cp->regexp = Qnil;
169
  cp->buf.translate = (! NILP (translate) ? translate : make_number (0));
170
  cp->posix = posix;
Karl Heuer's avatar
Karl Heuer committed
171
  cp->buf.multibyte = multibyte;
172
  BLOCK_INPUT;
173 174
  old = re_set_syntax (RE_SYNTAX_EMACS
		       | (posix ? 0 : RE_NO_POSIX_BACKTRACKING));
175
  val = (char *) re_compile_pattern (raw_pattern, raw_pattern_size, &cp->buf);
176
  re_set_syntax (old);
177
  UNBLOCK_INPUT;
Jim Blandy's avatar
Jim Blandy committed
178
  if (val)
179
    Fsignal (Qinvalid_regexp, Fcons (build_string (val), Qnil));
Jim Blandy's avatar
Jim Blandy committed
180

181 182 183 184
  cp->regexp = Fcopy_sequence (pattern);
}

/* Compile a regexp if necessary, but first check to see if there's one in
185 186
   the cache.
   PATTERN is the pattern to compile.
187
   TRANSLATE is a translation table for ignoring case, or nil for none.
188 189 190 191 192 193
   REGP is the structure that says where to store the "register"
   values that will result from matching this pattern.
   If it is 0, we should compile the pattern not to record any
   subexpression bounds.
   POSIX is nonzero if we want full backtracking (POSIX style)
   for this pattern.  0 means backtrack only enough to get a valid match.  */
194 195

struct re_pattern_buffer *
196
compile_pattern (pattern, regp, translate, posix, multibyte)
197 198
     Lisp_Object pattern;
     struct re_registers *regp;
199
     Lisp_Object translate;
200
     int posix, multibyte;
201 202 203 204 205 206
{
  struct regexp_cache *cp, **cpp;

  for (cpp = &searchbuf_head; ; cpp = &cp->next)
    {
      cp = *cpp;
207 208
      if (XSTRING (cp->regexp)->size == XSTRING (pattern)->size
	  && !NILP (Fstring_equal (cp->regexp, pattern))
209
	  && EQ (cp->buf.translate, (! NILP (translate) ? translate : make_number (0)))
Karl Heuer's avatar
Karl Heuer committed
210 211
	  && cp->posix == posix
	  && cp->buf.multibyte == multibyte)
212 213 214 215 216
	break;

      /* If we're at the end of the cache, compile into the last cell.  */
      if (cp->next == 0)
	{
Karl Heuer's avatar
Karl Heuer committed
217
	  compile_pattern_1 (cp, pattern, translate, regp, posix, multibyte);
218 219 220 221 222 223 224 225 226 227
	  break;
	}
    }

  /* When we get here, cp (aka *cpp) contains the compiled pattern,
     either because we found it in the cache or because we just compiled it.
     Move it to the front of the queue to mark it as most recently used.  */
  *cpp = cp->next;
  cp->next = searchbuf_head;
  searchbuf_head = cp;
Jim Blandy's avatar
Jim Blandy committed
228

229 230 231 232 233
  /* Advise the searching functions about the space we have allocated
     for register data.  */
  if (regp)
    re_set_registers (&cp->buf, regp, regp->num_regs, regp->start, regp->end);

234
  return &cp->buf;
Jim Blandy's avatar
Jim Blandy committed
235 236 237 238 239 240 241 242 243 244 245 246 247
}

/* Error condition used for failing searches */
Lisp_Object Qsearch_failed;

Lisp_Object
signal_failure (arg)
     Lisp_Object arg;
{
  Fsignal (Qsearch_failed, Fcons (arg, Qnil));
  return Qnil;
}

248 249
static Lisp_Object
looking_at_1 (string, posix)
Jim Blandy's avatar
Jim Blandy committed
250
     Lisp_Object string;
251
     int posix;
Jim Blandy's avatar
Jim Blandy committed
252 253 254 255 256
{
  Lisp_Object val;
  unsigned char *p1, *p2;
  int s1, s2;
  register int i;
257
  struct re_pattern_buffer *bufp;
Jim Blandy's avatar
Jim Blandy committed
258

259 260 261
  if (running_asynch_code)
    save_search_regs ();

Jim Blandy's avatar
Jim Blandy committed
262
  CHECK_STRING (string, 0);
263 264
  bufp = compile_pattern (string, &search_regs,
			  (!NILP (current_buffer->case_fold_search)
265
			   ? DOWNCASE_TABLE : Qnil),
266 267
			  posix,
			  !NILP (current_buffer->enable_multibyte_characters));
Jim Blandy's avatar
Jim Blandy committed
268 269 270 271 272 273 274 275

  immediate_quit = 1;
  QUIT;			/* Do a pending quit right away, to avoid paradoxical behavior */

  /* Get pointers and sizes of the two strings
     that make up the visible portion of the buffer. */

  p1 = BEGV_ADDR;
276
  s1 = GPT_BYTE - BEGV_BYTE;
Jim Blandy's avatar
Jim Blandy committed
277
  p2 = GAP_END_ADDR;
278
  s2 = ZV_BYTE - GPT_BYTE;
Jim Blandy's avatar
Jim Blandy committed
279 280 281
  if (s1 < 0)
    {
      p2 = p1;
282
      s2 = ZV_BYTE - BEGV_BYTE;
Jim Blandy's avatar
Jim Blandy committed
283 284 285 286
      s1 = 0;
    }
  if (s2 < 0)
    {
287
      s1 = ZV_BYTE - BEGV_BYTE;
Jim Blandy's avatar
Jim Blandy committed
288 289
      s2 = 0;
    }
290 291

  re_match_object = Qnil;
Jim Blandy's avatar
Jim Blandy committed
292
  
293
  i = re_match_2 (bufp, (char *) p1, s1, (char *) p2, s2,
294 295
		  PT_BYTE - BEGV_BYTE, &search_regs,
		  ZV_BYTE - BEGV_BYTE);
Jim Blandy's avatar
Jim Blandy committed
296 297 298 299
  if (i == -2)
    matcher_overflow ();

  val = (0 <= i ? Qt : Qnil);
300 301 302 303 304 305 306 307 308
  if (i >= 0)
    for (i = 0; i < search_regs.num_regs; i++)
      if (search_regs.start[i] >= 0)
	{
	  search_regs.start[i]
	    = BYTE_TO_CHAR (search_regs.start[i] + BEGV_BYTE);
	  search_regs.end[i]
	    = BYTE_TO_CHAR (search_regs.end[i] + BEGV_BYTE);
	}
309
  XSETBUFFER (last_thing_searched, current_buffer);
Jim Blandy's avatar
Jim Blandy committed
310 311 312 313
  immediate_quit = 0;
  return val;
}

314
DEFUN ("looking-at", Flooking_at, Slooking_at, 1, 1, 0,
315
  "Return t if text after point matches regular expression REGEXP.\n\
316 317 318
This function modifies the match data that `match-beginning',\n\
`match-end' and `match-data' access; save and restore the match\n\
data if you want to preserve them.")
319 320
  (regexp)
     Lisp_Object regexp;
321
{
322
  return looking_at_1 (regexp, 0);
323 324 325
}

DEFUN ("posix-looking-at", Fposix_looking_at, Sposix_looking_at, 1, 1, 0,
326
  "Return t if text after point matches regular expression REGEXP.\n\
327 328 329 330
Find the longest match, in accord with Posix regular expression rules.\n\
This function modifies the match data that `match-beginning',\n\
`match-end' and `match-data' access; save and restore the match\n\
data if you want to preserve them.")
331 332
  (regexp)
     Lisp_Object regexp;
333
{
334
  return looking_at_1 (regexp, 1);
335 336 337 338
}

static Lisp_Object
string_match_1 (regexp, string, start, posix)
Jim Blandy's avatar
Jim Blandy committed
339
     Lisp_Object regexp, string, start;
340
     int posix;
Jim Blandy's avatar
Jim Blandy committed
341 342
{
  int val;
343
  struct re_pattern_buffer *bufp;
344 345
  int pos, pos_byte;
  int i;
Jim Blandy's avatar
Jim Blandy committed
346

347 348 349
  if (running_asynch_code)
    save_search_regs ();

Jim Blandy's avatar
Jim Blandy committed
350 351 352 353
  CHECK_STRING (regexp, 0);
  CHECK_STRING (string, 1);

  if (NILP (start))
354
    pos = 0, pos_byte = 0;
Jim Blandy's avatar
Jim Blandy committed
355 356 357 358 359
  else
    {
      int len = XSTRING (string)->size;

      CHECK_NUMBER (start, 2);
360 361 362 363
      pos = XINT (start);
      if (pos < 0 && -pos <= len)
	pos = len + pos;
      else if (0 > pos || pos > len)
Jim Blandy's avatar
Jim Blandy committed
364
	args_out_of_range (string, start);
365
      pos_byte = string_char_to_byte (string, pos);
Jim Blandy's avatar
Jim Blandy committed
366 367
    }

368 369
  bufp = compile_pattern (regexp, &search_regs,
			  (!NILP (current_buffer->case_fold_search)
370
			   ? DOWNCASE_TABLE : Qnil),
371 372
			  posix,
			  STRING_MULTIBYTE (string));
Jim Blandy's avatar
Jim Blandy committed
373
  immediate_quit = 1;
374 375
  re_match_object = string;
  
376
  val = re_search (bufp, (char *) XSTRING (string)->data,
377 378
		   STRING_BYTES (XSTRING (string)), pos_byte,
		   STRING_BYTES (XSTRING (string)) - pos_byte,
Jim Blandy's avatar
Jim Blandy committed
379 380
		   &search_regs);
  immediate_quit = 0;
Jim Blandy's avatar
Jim Blandy committed
381
  last_thing_searched = Qt;
Jim Blandy's avatar
Jim Blandy committed
382 383 384
  if (val == -2)
    matcher_overflow ();
  if (val < 0) return Qnil;
385 386 387 388 389 390 391 392 393 394 395

  for (i = 0; i < search_regs.num_regs; i++)
    if (search_regs.start[i] >= 0)
      {
	search_regs.start[i]
	  = string_byte_to_char (string, search_regs.start[i]);
	search_regs.end[i]
	  = string_byte_to_char (string, search_regs.end[i]);
      }

  return make_number (string_byte_to_char (string, val));
Jim Blandy's avatar
Jim Blandy committed
396
}
Richard M. Stallman's avatar
Richard M. Stallman committed
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
DEFUN ("string-match", Fstring_match, Sstring_match, 2, 3, 0,
  "Return index of start of first match for REGEXP in STRING, or nil.\n\
If third arg START is non-nil, start search at that index in STRING.\n\
For index of first char beyond the match, do (match-end 0).\n\
`match-end' and `match-beginning' also give indices of substrings\n\
matched by parenthesis constructs in the pattern.")
  (regexp, string, start)
     Lisp_Object regexp, string, start;
{
  return string_match_1 (regexp, string, start, 0);
}

DEFUN ("posix-string-match", Fposix_string_match, Sposix_string_match, 2, 3, 0,
  "Return index of start of first match for REGEXP in STRING, or nil.\n\
Find the longest match, in accord with Posix regular expression rules.\n\
If third arg START is non-nil, start search at that index in STRING.\n\
For index of first char beyond the match, do (match-end 0).\n\
`match-end' and `match-beginning' also give indices of substrings\n\
matched by parenthesis constructs in the pattern.")
  (regexp, string, start)
     Lisp_Object regexp, string, start;
{
  return string_match_1 (regexp, string, start, 1);
}

Richard M. Stallman's avatar
Richard M. Stallman committed
423 424 425 426 427 428 429 430 431
/* Match REGEXP against STRING, searching all of STRING,
   and return the index of the match, or negative on failure.
   This does not clobber the match data.  */

int
fast_string_match (regexp, string)
     Lisp_Object regexp, string;
{
  int val;
432
  struct re_pattern_buffer *bufp;
Richard M. Stallman's avatar
Richard M. Stallman committed
433

434 435
  bufp = compile_pattern (regexp, 0, Qnil,
			  0, STRING_MULTIBYTE (string));
Richard M. Stallman's avatar
Richard M. Stallman committed
436
  immediate_quit = 1;
437 438
  re_match_object = string;
  
439
  val = re_search (bufp, (char *) XSTRING (string)->data,
440 441
		   STRING_BYTES (XSTRING (string)), 0,
		   STRING_BYTES (XSTRING (string)), 0);
Richard M. Stallman's avatar
Richard M. Stallman committed
442 443 444
  immediate_quit = 0;
  return val;
}
Karl Heuer's avatar
Karl Heuer committed
445 446 447

/* Match REGEXP against STRING, searching all of STRING ignoring case,
   and return the index of the match, or negative on failure.
448 449
   This does not clobber the match data.
   We assume that STRING contains single-byte characters.  */
Karl Heuer's avatar
Karl Heuer committed
450 451 452 453

extern Lisp_Object Vascii_downcase_table;

int
454
fast_c_string_match_ignore_case (regexp, string)
Karl Heuer's avatar
Karl Heuer committed
455 456 457 458 459 460 461
     Lisp_Object regexp;
     char *string;
{
  int val;
  struct re_pattern_buffer *bufp;
  int len = strlen (string);

462
  regexp = string_make_unibyte (regexp);
463
  re_match_object = Qt;
Karl Heuer's avatar
Karl Heuer committed
464
  bufp = compile_pattern (regexp, 0,
465
			  Vascii_downcase_table, 0,
466
			  0);
Karl Heuer's avatar
Karl Heuer committed
467 468 469 470 471
  immediate_quit = 1;
  val = re_search (bufp, string, len, 0, len, 0);
  immediate_quit = 0;
  return val;
}
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

/* The newline cache: remembering which sections of text have no newlines.  */

/* If the user has requested newline caching, make sure it's on.
   Otherwise, make sure it's off.
   This is our cheezy way of associating an action with the change of
   state of a buffer-local variable.  */
static void
newline_cache_on_off (buf)
     struct buffer *buf;
{
  if (NILP (buf->cache_long_line_scans))
    {
      /* It should be off.  */
      if (buf->newline_cache)
        {
          free_region_cache (buf->newline_cache);
          buf->newline_cache = 0;
        }
    }
  else
    {
      /* It should be on.  */
      if (buf->newline_cache == 0)
        buf->newline_cache = new_region_cache ();
    }
}


/* Search for COUNT instances of the character TARGET between START and END.

   If COUNT is positive, search forwards; END must be >= START.
   If COUNT is negative, search backwards for the -COUNTth instance;
      END must be <= START.
   If COUNT is zero, do anything you please; run rogue, for all I care.

   If END is zero, use BEGV or ZV instead, as appropriate for the
   direction indicated by COUNT.
Jim Blandy's avatar
Jim Blandy committed
510 511

   If we find COUNT instances, set *SHORTAGE to zero, and return the
Richard M. Stallman's avatar
Richard M. Stallman committed
512 513
   position after the COUNTth match.  Note that for reverse motion
   this is not the same as the usual convention for Emacs motion commands.
Jim Blandy's avatar
Jim Blandy committed
514

515 516
   If we don't find COUNT instances before reaching END, set *SHORTAGE
   to the number of TARGETs left unfound, and return END.
Jim Blandy's avatar
Jim Blandy committed
517

518 519 520
   If ALLOW_QUIT is non-zero, set immediate_quit.  That's good to do
   except when inside redisplay.  */

Andreas Schwab's avatar
Andreas Schwab committed
521
int
522 523 524 525 526
scan_buffer (target, start, end, count, shortage, allow_quit)
     register int target;
     int start, end;
     int count;
     int *shortage;
527
     int allow_quit;
Jim Blandy's avatar
Jim Blandy committed
528
{
529 530
  struct region_cache *newline_cache;
  int direction; 
Jim Blandy's avatar
Jim Blandy committed
531

532 533 534 535 536 537 538 539 540 541
  if (count > 0)
    {
      direction = 1;
      if (! end) end = ZV;
    }
  else
    {
      direction = -1;
      if (! end) end = BEGV;
    }
Jim Blandy's avatar
Jim Blandy committed
542

543 544
  newline_cache_on_off (current_buffer);
  newline_cache = current_buffer->newline_cache;
Jim Blandy's avatar
Jim Blandy committed
545 546 547 548

  if (shortage != 0)
    *shortage = 0;

549
  immediate_quit = allow_quit;
Jim Blandy's avatar
Jim Blandy committed
550

Jim Blandy's avatar
Jim Blandy committed
551
  if (count > 0)
552
    while (start != end)
Jim Blandy's avatar
Jim Blandy committed
553
      {
554 555 556 557 558
        /* Our innermost scanning loop is very simple; it doesn't know
           about gaps, buffer ends, or the newline cache.  ceiling is
           the position of the last character before the next such
           obstacle --- the last character the dumb search loop should
           examine.  */
559 560
	int ceiling_byte = CHAR_TO_BYTE (end) - 1;
	int start_byte = CHAR_TO_BYTE (start);
561
	int tem;
562 563 564 565 566 567 568 569

        /* If we're looking for a newline, consult the newline cache
           to see where we can avoid some scanning.  */
        if (target == '\n' && newline_cache)
          {
            int next_change;
            immediate_quit = 0;
            while (region_cache_forward
570 571
                   (current_buffer, newline_cache, start_byte, &next_change))
              start_byte = next_change;
572
            immediate_quit = allow_quit;
573

574 575 576
            /* START should never be after END.  */
            if (start_byte > ceiling_byte)
              start_byte = ceiling_byte;
577 578 579

            /* Now the text after start is an unknown region, and
               next_change is the position of the next known region. */
580
            ceiling_byte = min (next_change - 1, ceiling_byte);
581 582 583 584 585 586
          }

        /* The dumb loop can only scan text stored in contiguous
           bytes. BUFFER_CEILING_OF returns the last character
           position that is contiguous, so the ceiling is the
           position after that.  */
587 588
	tem = BUFFER_CEILING_OF (start_byte);
	ceiling_byte = min (tem, ceiling_byte);
589 590 591

        {
          /* The termination address of the dumb loop.  */ 
592 593 594 595
          register unsigned char *ceiling_addr
	    = BYTE_POS_ADDR (ceiling_byte) + 1;
          register unsigned char *cursor
	    = BYTE_POS_ADDR (start_byte);
596 597 598 599 600 601 602 603 604 605 606 607 608 609
          unsigned char *base = cursor;

          while (cursor < ceiling_addr)
            {
              unsigned char *scan_start = cursor;

              /* The dumb loop.  */
              while (*cursor != target && ++cursor < ceiling_addr)
                ;

              /* If we're looking for newlines, cache the fact that
                 the region from start to cursor is free of them. */
              if (target == '\n' && newline_cache)
                know_region_cache (current_buffer, newline_cache,
610 611
                                   start_byte + scan_start - base,
                                   start_byte + cursor - base);
612 613 614 615 616 617 618

              /* Did we find the target character?  */
              if (cursor < ceiling_addr)
                {
                  if (--count == 0)
                    {
                      immediate_quit = 0;
619
                      return BYTE_TO_CHAR (start_byte + cursor - base + 1);
620 621 622 623 624
                    }
                  cursor++;
                }
            }

625
          start = BYTE_TO_CHAR (start_byte + cursor - base);
626
        }
Jim Blandy's avatar
Jim Blandy committed
627 628
      }
  else
629 630 631
    while (start > end)
      {
        /* The last character to check before the next obstacle.  */
632 633
	int ceiling_byte = CHAR_TO_BYTE (end);
	int start_byte = CHAR_TO_BYTE (start);
634
	int tem;
635 636 637 638 639 640 641

        /* Consult the newline cache, if appropriate.  */
        if (target == '\n' && newline_cache)
          {
            int next_change;
            immediate_quit = 0;
            while (region_cache_backward
642 643
                   (current_buffer, newline_cache, start_byte, &next_change))
              start_byte = next_change;
644
            immediate_quit = allow_quit;
645 646

            /* Start should never be at or before end.  */
647 648
            if (start_byte <= ceiling_byte)
              start_byte = ceiling_byte + 1;
649 650 651

            /* Now the text before start is an unknown region, and
               next_change is the position of the next known region. */
652
            ceiling_byte = max (next_change, ceiling_byte);
653 654 655
          }

        /* Stop scanning before the gap.  */
656 657
	tem = BUFFER_FLOOR_OF (start_byte - 1);
	ceiling_byte = max (tem, ceiling_byte);
658 659 660

        {
          /* The termination address of the dumb loop.  */
661 662
          register unsigned char *ceiling_addr = BYTE_POS_ADDR (ceiling_byte);
          register unsigned char *cursor = BYTE_POS_ADDR (start_byte - 1);
663 664 665 666 667 668 669 670 671 672 673 674 675
          unsigned char *base = cursor;

          while (cursor >= ceiling_addr)
            {
              unsigned char *scan_start = cursor;

              while (*cursor != target && --cursor >= ceiling_addr)
                ;

              /* If we're looking for newlines, cache the fact that
                 the region from after the cursor to start is free of them.  */
              if (target == '\n' && newline_cache)
                know_region_cache (current_buffer, newline_cache,
676 677
                                   start_byte + cursor - base,
                                   start_byte + scan_start - base);
678 679 680 681 682 683 684

              /* Did we find the target character?  */
              if (cursor >= ceiling_addr)
                {
                  if (++count >= 0)
                    {
                      immediate_quit = 0;
685
                      return BYTE_TO_CHAR (start_byte + cursor - base);
686 687 688 689 690
                    }
                  cursor--;
                }
            }

691
	  start = BYTE_TO_CHAR (start_byte + cursor - base);
692 693 694
        }
      }

Jim Blandy's avatar
Jim Blandy committed
695 696
  immediate_quit = 0;
  if (shortage != 0)
Jim Blandy's avatar
Jim Blandy committed
697
    *shortage = count * direction;
698
  return start;
Jim Blandy's avatar
Jim Blandy committed
699
}
700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715

/* Search for COUNT instances of a line boundary, which means either a
   newline or (if selective display enabled) a carriage return.
   Start at START.  If COUNT is negative, search backwards.

   We report the resulting position by calling TEMP_SET_PT_BOTH.

   If we find COUNT instances. we position after (always after,
   even if scanning backwards) the COUNTth match, and return 0.

   If we don't find COUNT instances before reaching the end of the
   buffer (or the beginning, if scanning backwards), we return
   the number of line boundaries left unfound, and position at
   the limit we bumped up against.

   If ALLOW_QUIT is non-zero, set immediate_quit.  That's good to do
716
   except in special cases.  */
Jim Blandy's avatar
Jim Blandy committed
717

718
int
719 720 721 722 723
scan_newline (start, start_byte, limit, limit_byte, count, allow_quit)
     int start, start_byte;
     int limit, limit_byte;
     register int count;
     int allow_quit;
724
{
725 726 727 728 729 730 731 732
  int direction = ((count > 0) ? 1 : -1);

  register unsigned char *cursor;
  unsigned char *base;

  register int ceiling;
  register unsigned char *ceiling_addr;

733 734
  int old_immediate_quit = immediate_quit;

735 736 737 738 739 740 741 742
  /* If we are not in selective display mode,
     check only for newlines.  */
  int selective_display = (!NILP (current_buffer->selective_display)
			   && !INTEGERP (current_buffer->selective_display));

  /* The code that follows is like scan_buffer
     but checks for either newline or carriage return.  */

743 744
  if (allow_quit)
    immediate_quit++;
745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764

  start_byte = CHAR_TO_BYTE (start);

  if (count > 0)
    {
      while (start_byte < limit_byte)
	{
	  ceiling =  BUFFER_CEILING_OF (start_byte);
	  ceiling = min (limit_byte - 1, ceiling);
	  ceiling_addr = BYTE_POS_ADDR (ceiling) + 1;
	  base = (cursor = BYTE_POS_ADDR (start_byte));
	  while (1)
	    {
	      while (*cursor != '\n' && ++cursor != ceiling_addr)
		;

	      if (cursor != ceiling_addr)
		{
		  if (--count == 0)
		    {
765
		      immediate_quit = old_immediate_quit;
766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797
		      start_byte = start_byte + cursor - base + 1;
		      start = BYTE_TO_CHAR (start_byte);
		      TEMP_SET_PT_BOTH (start, start_byte);
		      return 0;
		    }
		  else
		    if (++cursor == ceiling_addr)
		      break;
		}
	      else
		break;
	    }
	  start_byte += cursor - base;
	}
    }
  else
    {
      while (start_byte > limit_byte)
	{
	  ceiling = BUFFER_FLOOR_OF (start_byte - 1);
	  ceiling = max (limit_byte, ceiling);
	  ceiling_addr = BYTE_POS_ADDR (ceiling) - 1;
	  base = (cursor = BYTE_POS_ADDR (start_byte - 1) + 1);
	  while (1)
	    {
	      while (--cursor != ceiling_addr && *cursor != '\n')
		;

	      if (cursor != ceiling_addr)
		{
		  if (++count == 0)
		    {
798
		      immediate_quit = old_immediate_quit;
799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815
		      /* Return the position AFTER the match we found.  */
		      start_byte = start_byte + cursor - base + 1;
		      start = BYTE_TO_CHAR (start_byte);
		      TEMP_SET_PT_BOTH (start, start_byte);
		      return 0;
		    }
		}
	      else
		break;
	    }
	  /* Here we add 1 to compensate for the last decrement
	     of CURSOR, which took it past the valid range.  */
	  start_byte += cursor - base + 1;
	}
    }

  TEMP_SET_PT_BOTH (limit, limit_byte);
816
  immediate_quit = old_immediate_quit;
817 818

  return count * direction;
819 820
}

Jim Blandy's avatar
Jim Blandy committed
821
int
822
find_next_newline_no_quit (from, cnt)
Jim Blandy's avatar
Jim Blandy committed
823 824
     register int from, cnt;
{
825
  return scan_buffer ('\n', from, 0, cnt, (int *) 0, 0);
826 827 828 829 830
}

/* Like find_next_newline, but returns position before the newline,
   not after, and only search up to TO.  This isn't just
   find_next_newline (...)-1, because you might hit TO.  */
831

832 833
int
find_before_next_newline (from, to, cnt)
834
     int from, to, cnt;
835 836 837 838 839 840 841 842
{
  int shortage;
  int pos = scan_buffer ('\n', from, to, cnt, &shortage, 1);

  if (shortage == 0)
    pos--;
  
  return pos;
Jim Blandy's avatar
Jim Blandy committed
843 844 845 846 847
}

/* Subroutines of Lisp buffer search functions. */

static Lisp_Object
848
search_command (string, bound, noerror, count, direction, RE, posix)
Jim Blandy's avatar
Jim Blandy committed
849 850 851
     Lisp_Object string, bound, noerror, count;
     int direction;
     int RE;
852
     int posix;
Jim Blandy's avatar
Jim Blandy committed
853 854
{
  register int np;
855
  int lim, lim_byte;
Jim Blandy's avatar
Jim Blandy committed
856 857 858 859 860 861 862 863 864 865
  int n = direction;

  if (!NILP (count))
    {
      CHECK_NUMBER (count, 3);
      n *= XINT (count);
    }

  CHECK_STRING (string, 0);
  if (NILP (bound))
866 867 868 869 870 871
    {
      if (n > 0)
	lim = ZV, lim_byte = ZV_BYTE;
      else
	lim = BEGV, lim_byte = BEGV_BYTE;
    }
Jim Blandy's avatar
Jim Blandy committed
872 873 874 875
  else
    {
      CHECK_NUMBER_COERCE_MARKER (bound, 1);
      lim = XINT (bound);
876
      if (n > 0 ? lim < PT : lim > PT)
Jim Blandy's avatar
Jim Blandy committed
877 878
	error ("Invalid search bound (wrong side of point)");
      if (lim > ZV)
879
	lim = ZV, lim_byte = ZV_BYTE;
880
      else if (lim < BEGV)
881
	lim = BEGV, lim_byte = BEGV_BYTE;
882 883
      else
	lim_byte = CHAR_TO_BYTE (lim);
Jim Blandy's avatar
Jim Blandy committed
884 885
    }

886
  np = search_buffer (string, PT, PT_BYTE, lim, lim_byte, n, RE,
Jim Blandy's avatar
Jim Blandy committed
887
		      (!NILP (current_buffer->case_fold_search)
888
		       ? current_buffer->case_canon_table
889
		       : Qnil),
Jim Blandy's avatar
Jim Blandy committed
890
		      (!NILP (current_buffer->case_fold_search)
891
		       ? current_buffer->case_eqv_table
892
		       : Qnil),
893
		      posix);
Jim Blandy's avatar
Jim Blandy committed
894 895 896 897 898 899 900 901
  if (np <= 0)
    {
      if (NILP (noerror))
	return signal_failure (string);
      if (!EQ (noerror, Qt))
	{
	  if (lim < BEGV || lim > ZV)
	    abort ();
902
	  SET_PT_BOTH (lim, lim_byte);
903 904 905
	  return Qnil;
#if 0 /* This would be clean, but maybe programs depend on
	 a value of nil here.  */
906
	  np = lim;
907
#endif
Jim Blandy's avatar
Jim Blandy committed
908
	}
909 910
      else
	return Qnil;
Jim Blandy's avatar
Jim Blandy committed
911 912 913 914 915 916 917 918 919 920
    }

  if (np < BEGV || np > ZV)
    abort ();

  SET_PT (np);

  return make_number (np);
}

921 922
/* Return 1 if REGEXP it matches just one constant string.  */

Karl Heuer's avatar
Karl Heuer committed
923 924 925 926
static int
trivial_regexp_p (regexp)
     Lisp_Object regexp;
{
927
  int len = STRING_BYTES (XSTRING (regexp));
Karl Heuer's avatar
Karl Heuer committed
928 929 930 931 932 933 934 935 936 937 938 939 940 941 942
  unsigned char *s = XSTRING (regexp)->data;
  unsigned char c;
  while (--len >= 0)
    {
      switch (*s++)
	{
	case '.': case '*': case '+': case '?': case '[': case '^': case '$':
	  return 0;
	case '\\':
	  if (--len < 0)
	    return 0;
	  switch (*s++)
	    {
	    case '|': case '(': case ')': case '`': case '\'': case 'b':
	    case 'B': case '<': case '>': case 'w': case 'W': case 's':
943
	    case 'S': case '=':
Karl Heuer's avatar
Karl Heuer committed
944
	    case 'c': case 'C':	/* for categoryspec and notcategoryspec */
945
	    case '1': case '2': case '3': case '4': case '5':
Karl Heuer's avatar
Karl Heuer committed
946 947 948 949 950 951 952 953
	    case '6': case '7': case '8': case '9':
	      return 0;
	    }
	}
    }
  return 1;
}

954
/* Search for the n'th occurrence of STRING in the current buffer,
Jim Blandy's avatar
Jim Blandy committed
955
   starting at position POS and stopping at position LIM,
956
   treating STRING as a literal string if RE is false or as
Jim Blandy's avatar
Jim Blandy committed
957 958 959 960 961
   a regular expression if RE is true.

   If N is positive, searching is forward and LIM must be greater than POS.
   If N is negative, searching is backward and LIM must be less than POS.

962
   Returns -x if x occurrences remain to be found (x > 0),
Jim Blandy's avatar
Jim Blandy committed
963
   or else the position at the beginning of the Nth occurrence
964 965 966 967
   (if searching backward) or the end (if searching forward).

   POSIX is nonzero if we want full backtracking (POSIX style)
   for this pattern.  0 means backtrack only enough to get a valid match.  */
Jim Blandy's avatar
Jim Blandy committed
968

969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984
#define TRANSLATE(out, trt, d)			\
do						\
  {						\
    if (! NILP (trt))				\
      {						\
	Lisp_Object temp;			\
	temp = Faref (trt, make_number (d));	\
	if (INTEGERP (temp))			\
	  out = XINT (temp);			\
	else					\
	  out = d;				\
      }						\
    else					\
      out = d;					\
  }						\
while (0)
985

986
static int
987 988
search_buffer (string, pos, pos_byte, lim, lim_byte, n,
	       RE, trt, inverse_trt, posix)
Jim Blandy's avatar
Jim Blandy committed
989 990
     Lisp_Object string;
     int pos;
991
     int pos_byte;
Jim Blandy's avatar
Jim Blandy committed
992
     int lim;
993
     int lim_byte;
Jim Blandy's avatar
Jim Blandy committed
994 995
     int n;
     int RE;
996 997
     Lisp_Object trt;
     Lisp_Object inverse_trt;
998
     int posix;
Jim Blandy's avatar
Jim Blandy committed
999 1000
{
  int len = XSTRING (string)->size;
1001
  int len_byte = STRING_BYTES (XSTRING (string));
1002
  register int i;
Jim Blandy's avatar
Jim Blandy committed
1003

1004 1005 1006
  if (running_asynch_code)
    save_search_regs ();

Jim Blandy's avatar
Jim Blandy committed
1007
  /* Null string is found at starting position.  */
1008
  if (len == 0)
1009 1010 1011 1012
    {
      set_search_regs (pos, 0);
      return pos;
    }
1013 1014 1015

  /* Searching 0 times means don't move.  */
  if (n == 0)
Jim Blandy's avatar
Jim Blandy committed
1016 1017
    return pos;

Karl Heuer's avatar
Karl Heuer committed
1018
  if (RE && !trivial_regexp_p (string))
Jim Blandy's avatar
Jim Blandy committed
1019
    {
1020 1021
      unsigned char *p1, *p2;
      int s1, s2;
1022 1023
      struct re_pattern_buffer *bufp;

1024 1025
      bufp = compile_pattern (string, &search_regs, trt, posix,
			      !NILP (current_buffer->enable_multibyte_characters));
Jim Blandy's avatar
Jim Blandy committed
1026 1027 1028 1029 1030 1031 1032 1033 1034 1035

      immediate_quit = 1;	/* Quit immediately if user types ^G,
				   because letting this function finish
				   can take too long. */
      QUIT;			/* Do a pending quit right away,
				   to avoid paradoxical behavior */
      /* Get pointers and sizes of the two strings
	 that make up the visible portion of the buffer. */

      p1 = BEGV_ADDR;
1036
      s1 = GPT_BYTE - BEGV_BYTE;
Jim Blandy's avatar
Jim Blandy committed
1037
      p2 = GAP_END_ADDR;
1038
      s2 = ZV_BYTE - GPT_BYTE;
Jim Blandy's avatar
Jim Blandy committed
1039 1040 1041
      if (s1 < 0)
	{
	  p2 = p1;
1042
	  s2 = ZV_BYTE - BEGV_BYTE;
Jim Blandy's avatar
Jim Blandy committed
1043 1044 1045 1046
	  s1 = 0;
	}
      if (s2 < 0)
	{
1047
	  s1 = ZV_BYTE - BEGV_BYTE;
Jim Blandy's avatar
Jim Blandy committed
1048 1049
	  s2 = 0;
	}
1050 1051
      re_match_object = Qnil;
  
Jim Blandy's avatar
Jim Blandy committed
1052 1053
      while (n < 0)
	{
1054
	  int val;
1055
	  val = re_search_2 (bufp, (char *) p1, s1, (char *) p2, s2,
1056 1057
			     pos_byte - BEGV_BYTE, lim_byte - pos_byte,
			     &search_regs,
1058
			     /* Don't allow match past current point */
1059
			     pos_byte - BEGV_BYTE);
Jim Blandy's avatar
Jim Blandy committed
1060
	  if (val == -2)
Karl Heuer's avatar
Karl Heuer committed
1061 1062 1063
	    {
	      matcher_overflow ();
	    }
Jim Blandy's avatar
Jim Blandy committed
1064 1065
	  if (val >= 0)
	    {
1066
	      pos_byte = search_regs.start[0] + BEGV_BYTE;
Jim Blandy's avatar
Jim Blandy committed
1067
	      for (i = 0; i < search_regs.num_regs; i++)