search.c 82.5 KB
Newer Older
Jim Blandy's avatar
Jim Blandy committed
1
/* String search routines for GNU Emacs.
2
   Copyright (C) 1985, 86,87,93,94,97,98, 1999 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>
Jim Blandy's avatar
Jim Blandy committed
23 24
#include "lisp.h"
#include "syntax.h"
Karl Heuer's avatar
Karl Heuer committed
25
#include "category.h"
Jim Blandy's avatar
Jim Blandy committed
26
#include "buffer.h"
27
#include "character.h"
28
#include "region-cache.h"
Jim Blandy's avatar
Jim Blandy committed
29
#include "commands.h"
30
#include "blockinput.h"
31
#include "intervals.h"
Jim Blandy's avatar
Jim Blandy committed
32

Jim Blandy's avatar
Jim Blandy committed
33 34 35
#include <sys/types.h>
#include "regex.h"

36
#define REGEXP_CACHE_SIZE 20
Jim Blandy's avatar
Jim Blandy committed
37

38 39
/* If the regexp is non-nil, then the buffer contains the compiled form
   of that regexp, suitable for searching.  */
40 41
struct regexp_cache
{
42 43 44 45
  struct regexp_cache *next;
  Lisp_Object regexp;
  struct re_pattern_buffer buf;
  char fastmap[0400];
46 47
  /* Nonzero means regexp was compiled to do full POSIX backtracking.  */
  char posix;
48
};
Jim Blandy's avatar
Jim Blandy committed
49

50 51
/* The instances of that struct.  */
struct regexp_cache searchbufs[REGEXP_CACHE_SIZE];
Jim Blandy's avatar
Jim Blandy committed
52

53 54
/* 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
55 56


Jim Blandy's avatar
Jim Blandy committed
57 58 59 60 61 62 63
/* 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
64 65 66
   been allocated by checking search_regs.num_regs.

   The regex code keeps track of whether it has allocated the search
67 68
   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
69 70 71 72 73
   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
74 75
static struct re_registers search_regs;

Jim Blandy's avatar
Jim Blandy committed
76 77 78 79
/* 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
80

Karl Heuer's avatar
Karl Heuer committed
81
/* error condition signaled when regexp compile_pattern fails */
Jim Blandy's avatar
Jim Blandy committed
82 83 84

Lisp_Object Qinvalid_regexp;

85
static void set_search_regs ();
86
static void save_search_regs ();
87 88
static int simple_search ();
static int boyer_moore ();
89 90
static int search_buffer ();

Jim Blandy's avatar
Jim Blandy committed
91 92 93 94 95 96
static void
matcher_overflow ()
{
  error ("Stack overflow in regexp matcher");
}

97 98 99
/* 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.
100
   TRANSLATE is a translation table for ignoring case, or nil for none.
101 102 103 104 105
   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
106 107 108 109
   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
110

111
static void
Karl Heuer's avatar
Karl Heuer committed
112
compile_pattern_1 (cp, pattern, translate, regp, posix, multibyte)
113
     struct regexp_cache *cp;
Jim Blandy's avatar
Jim Blandy committed
114
     Lisp_Object pattern;
115
     Lisp_Object translate;
116
     struct re_registers *regp;
117
     int posix;
Karl Heuer's avatar
Karl Heuer committed
118
     int multibyte;
Jim Blandy's avatar
Jim Blandy committed
119
{
120
  char *val;
121
  reg_syntax_t old;
Jim Blandy's avatar
Jim Blandy committed
122

123
  cp->regexp = Qnil;
124
  cp->buf.translate = (! NILP (translate) ? translate : make_number (0));
125
  cp->posix = posix;
126 127
  cp->buf.multibyte = STRING_MULTIBYTE (pattern);
  cp->buf.target_multibyte = multibyte;
128
  BLOCK_INPUT;
129
  old = re_set_syntax (RE_SYNTAX_EMACS
130
		       | (posix ? 0 : RE_NO_POSIX_BACKTRACKING));
131 132 133
  val = (char *) re_compile_pattern ((char *) (XSTRING (pattern)->data),
				     STRING_BYTES (XSTRING (pattern)),
				     &cp->buf);
134
  re_set_syntax (old);
135
  UNBLOCK_INPUT;
Jim Blandy's avatar
Jim Blandy committed
136
  if (val)
137
    Fsignal (Qinvalid_regexp, Fcons (build_string (val), Qnil));
Jim Blandy's avatar
Jim Blandy committed
138

139 140 141
  cp->regexp = Fcopy_sequence (pattern);
}

142 143 144 145 146 147 148
/* Shrink each compiled regexp buffer in the cache
   to the size actually used right now.
   This is called from garbage collection.  */

void
shrink_regexp_cache ()
{
149
  struct regexp_cache *cp;
150 151 152 153 154 155 156 157 158

  for (cp = searchbuf_head; cp != 0; cp = cp->next)
    {
      cp->buf.allocated = cp->buf.used;
      cp->buf.buffer
	= (unsigned char *) realloc (cp->buf.buffer, cp->buf.used);
    }
}

159
/* Compile a regexp if necessary, but first check to see if there's one in
160 161
   the cache.
   PATTERN is the pattern to compile.
162
   TRANSLATE is a translation table for ignoring case, or nil for none.
163 164 165 166 167 168
   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.  */
169 170

struct re_pattern_buffer *
171
compile_pattern (pattern, regp, translate, posix, multibyte)
172 173
     Lisp_Object pattern;
     struct re_registers *regp;
174
     Lisp_Object translate;
175
     int posix, multibyte;
176 177 178 179 180 181
{
  struct regexp_cache *cp, **cpp;

  for (cpp = &searchbuf_head; ; cpp = &cp->next)
    {
      cp = *cpp;
182 183 184 185 186
      /* Entries are initialized to nil, and may be set to nil by
	 compile_pattern_1 if the pattern isn't valid.  Don't apply
	 XSTRING in those cases.  However, compile_pattern_1 is only
	 applied to the cache entry we pick here to reuse.  So nil
	 should never appear before a non-nil entry.  */
187
      if (NILP (cp->regexp))
188
	goto compile_it;
189
      if (XSTRING (cp->regexp)->size == XSTRING (pattern)->size
190
	  && STRING_MULTIBYTE (cp->regexp) == STRING_MULTIBYTE (pattern)
191
	  && !NILP (Fstring_equal (cp->regexp, pattern))
192
	  && EQ (cp->buf.translate, (! NILP (translate) ? translate : make_number (0)))
Karl Heuer's avatar
Karl Heuer committed
193 194
	  && cp->posix == posix
	  && cp->buf.multibyte == multibyte)
195 196
	break;

197 198 199
      /* If we're at the end of the cache, compile into the nil cell
	 we found, or the last (least recently used) cell with a
	 string value.  */
200 201
      if (cp->next == 0)
	{
202
	compile_it:
Karl Heuer's avatar
Karl Heuer committed
203
	  compile_pattern_1 (cp, pattern, translate, regp, posix, multibyte);
204 205 206 207 208 209 210 211 212 213
	  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
214

215 216 217 218 219
  /* 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);

220
  return &cp->buf;
Jim Blandy's avatar
Jim Blandy committed
221 222 223 224 225 226 227 228 229 230 231 232 233
}

/* 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;
}

234 235
static Lisp_Object
looking_at_1 (string, posix)
Jim Blandy's avatar
Jim Blandy committed
236
     Lisp_Object string;
237
     int posix;
Jim Blandy's avatar
Jim Blandy committed
238 239 240 241 242
{
  Lisp_Object val;
  unsigned char *p1, *p2;
  int s1, s2;
  register int i;
243
  struct re_pattern_buffer *bufp;
Jim Blandy's avatar
Jim Blandy committed
244

245 246 247
  if (running_asynch_code)
    save_search_regs ();

248
  CHECK_STRING (string);
249 250
  bufp = compile_pattern (string, &search_regs,
			  (!NILP (current_buffer->case_fold_search)
251
			   ? DOWNCASE_TABLE : Qnil),
252 253
			  posix,
			  !NILP (current_buffer->enable_multibyte_characters));
Jim Blandy's avatar
Jim Blandy committed
254 255 256 257 258 259 260 261

  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;
262
  s1 = GPT_BYTE - BEGV_BYTE;
Jim Blandy's avatar
Jim Blandy committed
263
  p2 = GAP_END_ADDR;
264
  s2 = ZV_BYTE - GPT_BYTE;
Jim Blandy's avatar
Jim Blandy committed
265 266 267
  if (s1 < 0)
    {
      p2 = p1;
268
      s2 = ZV_BYTE - BEGV_BYTE;
Jim Blandy's avatar
Jim Blandy committed
269 270 271 272
      s1 = 0;
    }
  if (s2 < 0)
    {
273
      s1 = ZV_BYTE - BEGV_BYTE;
Jim Blandy's avatar
Jim Blandy committed
274 275
      s2 = 0;
    }
276 277

  re_match_object = Qnil;
Jim Blandy's avatar
Jim Blandy committed
278
  
279
  i = re_match_2 (bufp, (char *) p1, s1, (char *) p2, s2,
280 281
		  PT_BYTE - BEGV_BYTE, &search_regs,
		  ZV_BYTE - BEGV_BYTE);
282 283
  immediate_quit = 0;
  
Jim Blandy's avatar
Jim Blandy committed
284 285 286 287
  if (i == -2)
    matcher_overflow ();

  val = (0 <= i ? Qt : Qnil);
288 289 290 291 292 293 294 295 296
  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);
	}
297
  XSETBUFFER (last_thing_searched, current_buffer);
Jim Blandy's avatar
Jim Blandy committed
298 299 300
  return val;
}

301
DEFUN ("looking-at", Flooking_at, Slooking_at, 1, 1, 0,
302 303 304 305 306
       doc: /* Return t if text after point matches regular expression REGEXP.
This function modifies the match data that `match-beginning',
`match-end' and `match-data' access; save and restore the match
data if you want to preserve them.  */)
     (regexp)
307
     Lisp_Object regexp;
308
{
309
  return looking_at_1 (regexp, 0);
310 311 312
}

DEFUN ("posix-looking-at", Fposix_looking_at, Sposix_looking_at, 1, 1, 0,
313 314 315 316 317 318
       doc: /* Return t if text after point matches regular expression REGEXP.
Find the longest match, in accord with Posix regular expression rules.
This function modifies the match data that `match-beginning',
`match-end' and `match-data' access; save and restore the match
data if you want to preserve them.  */)
     (regexp)
319
     Lisp_Object regexp;
320
{
321
  return looking_at_1 (regexp, 1);
322 323 324 325
}

static Lisp_Object
string_match_1 (regexp, string, start, posix)
Jim Blandy's avatar
Jim Blandy committed
326
     Lisp_Object regexp, string, start;
327
     int posix;
Jim Blandy's avatar
Jim Blandy committed
328 329
{
  int val;
330
  struct re_pattern_buffer *bufp;
331 332
  int pos, pos_byte;
  int i;
Jim Blandy's avatar
Jim Blandy committed
333

334 335 336
  if (running_asynch_code)
    save_search_regs ();

337 338
  CHECK_STRING (regexp);
  CHECK_STRING (string);
Jim Blandy's avatar
Jim Blandy committed
339 340

  if (NILP (start))
341
    pos = 0, pos_byte = 0;
Jim Blandy's avatar
Jim Blandy committed
342 343 344 345
  else
    {
      int len = XSTRING (string)->size;

346
      CHECK_NUMBER (start);
347 348 349 350
      pos = XINT (start);
      if (pos < 0 && -pos <= len)
	pos = len + pos;
      else if (0 > pos || pos > len)
Jim Blandy's avatar
Jim Blandy committed
351
	args_out_of_range (string, start);
352
      pos_byte = string_char_to_byte (string, pos);
Jim Blandy's avatar
Jim Blandy committed
353 354
    }

355 356
  bufp = compile_pattern (regexp, &search_regs,
			  (!NILP (current_buffer->case_fold_search)
357
			   ? DOWNCASE_TABLE : Qnil),
358 359
			  posix,
			  STRING_MULTIBYTE (string));
Jim Blandy's avatar
Jim Blandy committed
360
  immediate_quit = 1;
361 362
  re_match_object = string;
  
363
  val = re_search (bufp, (char *) XSTRING (string)->data,
364 365
		   STRING_BYTES (XSTRING (string)), pos_byte,
		   STRING_BYTES (XSTRING (string)) - pos_byte,
Jim Blandy's avatar
Jim Blandy committed
366 367
		   &search_regs);
  immediate_quit = 0;
Jim Blandy's avatar
Jim Blandy committed
368
  last_thing_searched = Qt;
Jim Blandy's avatar
Jim Blandy committed
369 370 371
  if (val == -2)
    matcher_overflow ();
  if (val < 0) return Qnil;
372 373 374 375 376 377 378 379 380 381 382

  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
383
}
Richard M. Stallman's avatar
Richard M. Stallman committed
384

385
DEFUN ("string-match", Fstring_match, Sstring_match, 2, 3, 0,
386 387 388 389 390 391 392
       doc: /* Return index of start of first match for REGEXP in STRING, or nil.
Case is ignored if `case-fold-search' is non-nil in the current buffer.
If third arg START is non-nil, start search at that index in STRING.
For index of first char beyond the match, do (match-end 0).
`match-end' and `match-beginning' also give indices of substrings
matched by parenthesis constructs in the pattern.  */)
     (regexp, string, start)
393 394 395 396 397 398
     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,
399 400 401 402 403 404 405 406
       doc: /* Return index of start of first match for REGEXP in STRING, or nil.
Find the longest match, in accord with Posix regular expression rules.
Case is ignored if `case-fold-search' is non-nil in the current buffer.
If third arg START is non-nil, start search at that index in STRING.
For index of first char beyond the match, do (match-end 0).
`match-end' and `match-beginning' also give indices of substrings
matched by parenthesis constructs in the pattern.  */)
     (regexp, string, start)
407 408 409 410 411
     Lisp_Object regexp, string, start;
{
  return string_match_1 (regexp, string, start, 1);
}

Richard M. Stallman's avatar
Richard M. Stallman committed
412 413 414 415 416 417 418 419 420
/* 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;
421
  struct re_pattern_buffer *bufp;
Richard M. Stallman's avatar
Richard M. Stallman committed
422

423 424
  bufp = compile_pattern (regexp, 0, Qnil,
			  0, STRING_MULTIBYTE (string));
Richard M. Stallman's avatar
Richard M. Stallman committed
425
  immediate_quit = 1;
426 427
  re_match_object = string;
  
428
  val = re_search (bufp, (char *) XSTRING (string)->data,
429 430
		   STRING_BYTES (XSTRING (string)), 0,
		   STRING_BYTES (XSTRING (string)), 0);
Richard M. Stallman's avatar
Richard M. Stallman committed
431 432 433
  immediate_quit = 0;
  return val;
}
Karl Heuer's avatar
Karl Heuer committed
434 435 436

/* Match REGEXP against STRING, searching all of STRING ignoring case,
   and return the index of the match, or negative on failure.
437 438
   This does not clobber the match data.
   We assume that STRING contains single-byte characters.  */
Karl Heuer's avatar
Karl Heuer committed
439 440 441 442

extern Lisp_Object Vascii_downcase_table;

int
443
fast_c_string_match_ignore_case (regexp, string)
Karl Heuer's avatar
Karl Heuer committed
444 445 446 447 448 449 450
     Lisp_Object regexp;
     char *string;
{
  int val;
  struct re_pattern_buffer *bufp;
  int len = strlen (string);

451
  regexp = string_make_unibyte (regexp);
452
  re_match_object = Qt;
Karl Heuer's avatar
Karl Heuer committed
453
  bufp = compile_pattern (regexp, 0,
454
			  Vascii_downcase_table, 0,
455
			  0);
Karl Heuer's avatar
Karl Heuer committed
456 457 458 459 460
  immediate_quit = 1;
  val = re_search (bufp, string, len, 0, len, 0);
  immediate_quit = 0;
  return val;
}
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

/* 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
499 500

   If we find COUNT instances, set *SHORTAGE to zero, and return the
Richard M. Stallman's avatar
Richard M. Stallman committed
501 502
   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
503

504 505
   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
506

507 508 509
   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
510
int
511 512 513 514 515
scan_buffer (target, start, end, count, shortage, allow_quit)
     register int target;
     int start, end;
     int count;
     int *shortage;
516
     int allow_quit;
Jim Blandy's avatar
Jim Blandy committed
517
{
518 519
  struct region_cache *newline_cache;
  int direction; 
Jim Blandy's avatar
Jim Blandy committed
520

521 522 523 524 525 526 527 528 529 530
  if (count > 0)
    {
      direction = 1;
      if (! end) end = ZV;
    }
  else
    {
      direction = -1;
      if (! end) end = BEGV;
    }
Jim Blandy's avatar
Jim Blandy committed
531

532 533
  newline_cache_on_off (current_buffer);
  newline_cache = current_buffer->newline_cache;
Jim Blandy's avatar
Jim Blandy committed
534 535 536 537

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

538
  immediate_quit = allow_quit;
Jim Blandy's avatar
Jim Blandy committed
539

Jim Blandy's avatar
Jim Blandy committed
540
  if (count > 0)
541
    while (start != end)
Jim Blandy's avatar
Jim Blandy committed
542
      {
543 544 545 546 547
        /* 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.  */
548 549
	int ceiling_byte = CHAR_TO_BYTE (end) - 1;
	int start_byte = CHAR_TO_BYTE (start);
550
	int tem;
551 552 553 554 555 556 557 558

        /* 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
559 560
                   (current_buffer, newline_cache, start_byte, &next_change))
              start_byte = next_change;
561
            immediate_quit = allow_quit;
562

563 564 565
            /* START should never be after END.  */
            if (start_byte > ceiling_byte)
              start_byte = ceiling_byte;
566 567 568

            /* Now the text after start is an unknown region, and
               next_change is the position of the next known region. */
569
            ceiling_byte = min (next_change - 1, ceiling_byte);
570 571 572 573 574 575
          }

        /* 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.  */
576 577
	tem = BUFFER_CEILING_OF (start_byte);
	ceiling_byte = min (tem, ceiling_byte);
578 579 580

        {
          /* The termination address of the dumb loop.  */ 
581 582 583 584
          register unsigned char *ceiling_addr
	    = BYTE_POS_ADDR (ceiling_byte) + 1;
          register unsigned char *cursor
	    = BYTE_POS_ADDR (start_byte);
585 586 587 588 589 590 591 592 593 594 595 596 597 598
          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,
599 600
                                   start_byte + scan_start - base,
                                   start_byte + cursor - base);
601 602 603 604 605 606 607

              /* Did we find the target character?  */
              if (cursor < ceiling_addr)
                {
                  if (--count == 0)
                    {
                      immediate_quit = 0;
608
                      return BYTE_TO_CHAR (start_byte + cursor - base + 1);
609 610 611 612 613
                    }
                  cursor++;
                }
            }

614
          start = BYTE_TO_CHAR (start_byte + cursor - base);
615
        }
Jim Blandy's avatar
Jim Blandy committed
616 617
      }
  else
618 619 620
    while (start > end)
      {
        /* The last character to check before the next obstacle.  */
621 622
	int ceiling_byte = CHAR_TO_BYTE (end);
	int start_byte = CHAR_TO_BYTE (start);
623
	int tem;
624 625 626 627 628 629 630

        /* Consult the newline cache, if appropriate.  */
        if (target == '\n' && newline_cache)
          {
            int next_change;
            immediate_quit = 0;
            while (region_cache_backward
631 632
                   (current_buffer, newline_cache, start_byte, &next_change))
              start_byte = next_change;
633
            immediate_quit = allow_quit;
634 635

            /* Start should never be at or before end.  */
636 637
            if (start_byte <= ceiling_byte)
              start_byte = ceiling_byte + 1;
638 639 640

            /* Now the text before start is an unknown region, and
               next_change is the position of the next known region. */
641
            ceiling_byte = max (next_change, ceiling_byte);
642 643 644
          }

        /* Stop scanning before the gap.  */
645 646
	tem = BUFFER_FLOOR_OF (start_byte - 1);
	ceiling_byte = max (tem, ceiling_byte);
647 648 649

        {
          /* The termination address of the dumb loop.  */
650 651
          register unsigned char *ceiling_addr = BYTE_POS_ADDR (ceiling_byte);
          register unsigned char *cursor = BYTE_POS_ADDR (start_byte - 1);
652 653 654 655 656 657 658 659 660 661 662 663 664
          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,
665 666
                                   start_byte + cursor - base,
                                   start_byte + scan_start - base);
667 668 669 670 671 672 673

              /* Did we find the target character?  */
              if (cursor >= ceiling_addr)
                {
                  if (++count >= 0)
                    {
                      immediate_quit = 0;
674
                      return BYTE_TO_CHAR (start_byte + cursor - base);
675 676 677 678 679
                    }
                  cursor--;
                }
            }

680
	  start = BYTE_TO_CHAR (start_byte + cursor - base);
681 682 683
        }
      }

Jim Blandy's avatar
Jim Blandy committed
684 685
  immediate_quit = 0;
  if (shortage != 0)
Jim Blandy's avatar
Jim Blandy committed
686
    *shortage = count * direction;
687
  return start;
Jim Blandy's avatar
Jim Blandy committed
688
}
689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704

/* 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
705
   except in special cases.  */
Jim Blandy's avatar
Jim Blandy committed
706

707
int
708 709 710 711 712
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;
713
{
714 715 716 717 718 719 720 721
  int direction = ((count > 0) ? 1 : -1);

  register unsigned char *cursor;
  unsigned char *base;

  register int ceiling;
  register unsigned char *ceiling_addr;

722 723
  int old_immediate_quit = immediate_quit;

724 725 726
  /* The code that follows is like scan_buffer
     but checks for either newline or carriage return.  */

727 728
  if (allow_quit)
    immediate_quit++;
729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748

  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)
		    {
749
		      immediate_quit = old_immediate_quit;
750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781
		      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)
		    {
782
		      immediate_quit = old_immediate_quit;
783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799
		      /* 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);
800
  immediate_quit = old_immediate_quit;
801 802

  return count * direction;
803 804
}

Jim Blandy's avatar
Jim Blandy committed
805
int
806
find_next_newline_no_quit (from, cnt)
Jim Blandy's avatar
Jim Blandy committed
807 808
     register int from, cnt;
{
809
  return scan_buffer ('\n', from, 0, cnt, (int *) 0, 0);
810 811 812 813 814
}

/* 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.  */
815

816 817
int
find_before_next_newline (from, to, cnt)
818
     int from, to, cnt;
819 820 821 822 823 824 825 826
{
  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
827 828 829 830 831
}

/* Subroutines of Lisp buffer search functions. */

static Lisp_Object
832
search_command (string, bound, noerror, count, direction, RE, posix)
Jim Blandy's avatar
Jim Blandy committed
833 834 835
     Lisp_Object string, bound, noerror, count;
     int direction;
     int RE;
836
     int posix;
Jim Blandy's avatar
Jim Blandy committed
837 838
{
  register int np;
839
  int lim, lim_byte;
Jim Blandy's avatar
Jim Blandy committed
840 841 842 843
  int n = direction;

  if (!NILP (count))
    {
844
      CHECK_NUMBER (count);
Jim Blandy's avatar
Jim Blandy committed
845 846 847
      n *= XINT (count);
    }

848
  CHECK_STRING (string);
Jim Blandy's avatar
Jim Blandy committed
849
  if (NILP (bound))
850 851 852 853 854 855
    {
      if (n > 0)
	lim = ZV, lim_byte = ZV_BYTE;
      else
	lim = BEGV, lim_byte = BEGV_BYTE;
    }
Jim Blandy's avatar
Jim Blandy committed
856 857
  else
    {
858
      CHECK_NUMBER_COERCE_MARKER (bound);
Jim Blandy's avatar
Jim Blandy committed
859
      lim = XINT (bound);
860
      if (n > 0 ? lim < PT : lim > PT)
Jim Blandy's avatar
Jim Blandy committed
861 862
	error ("Invalid search bound (wrong side of point)");
      if (lim > ZV)
863
	lim = ZV, lim_byte = ZV_BYTE;
864
      else if (lim < BEGV)
865
	lim = BEGV, lim_byte = BEGV_BYTE;
866 867
      else
	lim_byte = CHAR_TO_BYTE (lim);
Jim Blandy's avatar
Jim Blandy committed
868 869
    }

870
  np = search_buffer (string, PT, PT_BYTE, lim, lim_byte, n, RE,
Jim Blandy's avatar
Jim Blandy committed
871
		      (!NILP (current_buffer->case_fold_search)
872
		       ? current_buffer->case_canon_table
873
		       : Qnil),
Jim Blandy's avatar
Jim Blandy committed
874
		      (!NILP (current_buffer->case_fold_search)
875
		       ? current_buffer->case_eqv_table
876
		       : Qnil),
877
		      posix);
Jim Blandy's avatar
Jim Blandy committed
878 879 880 881 882 883 884 885
  if (np <= 0)
    {
      if (NILP (noerror))
	return signal_failure (string);
      if (!EQ (noerror, Qt))
	{
	  if (lim < BEGV || lim > ZV)
	    abort ();
886
	  SET_PT_BOTH (lim, lim_byte);
887 888 889
	  return Qnil;
#if 0 /* This would be clean, but maybe programs depend on
	 a value of nil here.  */
890
	  np = lim;
891
#endif
Jim Blandy's avatar
Jim Blandy committed
892
	}
893 894
      else
	return Qnil;
Jim Blandy's avatar
Jim Blandy committed
895 896 897 898 899 900 901 902 903 904
    }

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

  SET_PT (np);

  return make_number (np);
}

905 906
/* Return 1 if REGEXP it matches just one constant string.  */

Karl Heuer's avatar
Karl Heuer committed
907 908 909 910
static int
trivial_regexp_p (regexp)
     Lisp_Object regexp;
{
911
  int len = STRING_BYTES (XSTRING (regexp));
Karl Heuer's avatar
Karl Heuer committed
912 913 914 915 916 917 918 919 920 921 922 923 924 925
  unsigned char *s = XSTRING (regexp)->data;
  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':
926
	    case 'S': case '=': case '{': case '}':
Karl Heuer's avatar
Karl Heuer committed
927
	    case 'c': case 'C':	/* for categoryspec and notcategoryspec */
928
	    case '1': case '2': case '3': case '4': case '5':
Karl Heuer's avatar
Karl Heuer committed
929 930 931 932 933 934 935 936
	    case '6': case '7': case '8': case '9':
	      return 0;
	    }
	}
    }
  return 1;
}

937
/* Search for the n'th occurrence of STRING in the current buffer,
Jim Blandy's avatar
Jim Blandy committed
938
   starting at position POS and stopping at position LIM,
939
   treating STRING as a literal string if RE is false or as
Jim Blandy's avatar
Jim Blandy committed
940 941 942 943 944
   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.

945
   Returns -x if x occurrences remain to be found (x > 0),
Jim Blandy's avatar
Jim Blandy committed
946
   or else the position at the beginning of the Nth occurrence
947 948 949 950
   (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
951

952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967
#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)
968

969
static int
970 971
search_buffer (string, pos, pos_byte, lim, lim_byte, n,
	       RE, trt, inverse_trt, posix)
Jim Blandy's avatar
Jim Blandy committed
972 973
     Lisp_Object string;
     int pos;
974
     int pos_byte;
Jim Blandy's avatar
Jim Blandy committed
975
     int lim;
976
     int lim_byte;
Jim Blandy's avatar
Jim Blandy committed
977 978
     int n;
     int RE;
979 980
     Lisp_Object trt;
     Lisp_Object inverse_trt;
981
     int posix;
Jim Blandy's avatar
Jim Blandy committed
982 983
{
  int len = XSTRING (string)->size;
984
  int len_byte = STRING_BYTES (XSTRING (string));
985
  register int i;
Jim Blandy's avatar
Jim Blandy committed
986

987 988 989
  if (running_asynch_code)
    save_search_regs ();

990
  /* Searching 0 times means don't move.  */
Jim Blandy's avatar
Jim Blandy committed
991
  /* Null string is found at starting position.  */
992
  if (len == 0 || n == 0)
993
    {
994
      set_search_regs (pos_byte, 0);
995 996
      return pos;
    }