search.c 66.2 KB
Newer Older
Jim Blandy's avatar
Jim Blandy committed
1
/* String search routines for GNU Emacs.
Karl Heuer's avatar
Karl Heuer committed
2
   Copyright (C) 1985, 1986, 1987, 1993, 1994 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"
Karl Heuer's avatar
Karl Heuer committed
27
#include "charset.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 89
static int search_buffer ();

Jim Blandy's avatar
Jim Blandy committed
90 91 92 93 94 95 96 97 98 99 100 101
static void
matcher_overflow ()
{
  error ("Stack overflow in regexp matcher");
}

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

102 103 104 105 106 107 108 109 110
/* 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.
   TRANSLATE is a translation table for ignoring case, or NULL for none.
   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
111 112 113 114
   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
115

116
static void
Karl Heuer's avatar
Karl Heuer committed
117
compile_pattern_1 (cp, pattern, translate, regp, posix, multibyte)
118
     struct regexp_cache *cp;
Jim Blandy's avatar
Jim Blandy committed
119
     Lisp_Object pattern;
120
     Lisp_Object *translate;
121
     struct re_registers *regp;
122
     int posix;
Karl Heuer's avatar
Karl Heuer committed
123
     int multibyte;
Jim Blandy's avatar
Jim Blandy committed
124
{
125
  char *val;
126
  reg_syntax_t old;
Jim Blandy's avatar
Jim Blandy committed
127

128 129
  cp->regexp = Qnil;
  cp->buf.translate = translate;
130
  cp->posix = posix;
Karl Heuer's avatar
Karl Heuer committed
131
  cp->buf.multibyte = multibyte;
132
  BLOCK_INPUT;
133 134
  old = re_set_syntax (RE_SYNTAX_EMACS
		       | (posix ? 0 : RE_NO_POSIX_BACKTRACKING));
135 136
  val = (char *) re_compile_pattern ((char *) XSTRING (pattern)->data,
				     XSTRING (pattern)->size, &cp->buf);
137
  re_set_syntax (old);
138
  UNBLOCK_INPUT;
Jim Blandy's avatar
Jim Blandy committed
139
  if (val)
140
    Fsignal (Qinvalid_regexp, Fcons (build_string (val), Qnil));
Jim Blandy's avatar
Jim Blandy committed
141

142 143 144 145
  cp->regexp = Fcopy_sequence (pattern);
}

/* Compile a regexp if necessary, but first check to see if there's one in
146 147 148 149 150 151 152 153 154
   the cache.
   PATTERN is the pattern to compile.
   TRANSLATE is a translation table for ignoring case, or NULL for none.
   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.  */
155 156

struct re_pattern_buffer *
157
compile_pattern (pattern, regp, translate, posix, multibyte)
158 159
     Lisp_Object pattern;
     struct re_registers *regp;
160
     Lisp_Object *translate;
161
     int posix, multibyte;
162 163 164 165 166 167
{
  struct regexp_cache *cp, **cpp;

  for (cpp = &searchbuf_head; ; cpp = &cp->next)
    {
      cp = *cpp;
168 169
      if (XSTRING (cp->regexp)->size == XSTRING (pattern)->size
	  && !NILP (Fstring_equal (cp->regexp, pattern))
170
	  && cp->buf.translate == translate
Karl Heuer's avatar
Karl Heuer committed
171 172
	  && cp->posix == posix
	  && cp->buf.multibyte == multibyte)
173 174 175 176 177
	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
178
	  compile_pattern_1 (cp, pattern, translate, regp, posix, multibyte);
179 180 181 182 183 184 185 186 187 188
	  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
189

190 191 192 193 194
  /* 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);

195
  return &cp->buf;
Jim Blandy's avatar
Jim Blandy committed
196 197 198 199 200 201 202 203 204 205 206 207 208
}

/* 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;
}

209 210
static Lisp_Object
looking_at_1 (string, posix)
Jim Blandy's avatar
Jim Blandy committed
211
     Lisp_Object string;
212
     int posix;
Jim Blandy's avatar
Jim Blandy committed
213 214 215 216 217
{
  Lisp_Object val;
  unsigned char *p1, *p2;
  int s1, s2;
  register int i;
218
  struct re_pattern_buffer *bufp;
Jim Blandy's avatar
Jim Blandy committed
219

220 221 222
  if (running_asynch_code)
    save_search_regs ();

Jim Blandy's avatar
Jim Blandy committed
223
  CHECK_STRING (string, 0);
224 225
  bufp = compile_pattern (string, &search_regs,
			  (!NILP (current_buffer->case_fold_search)
226
			   ? XCHAR_TABLE (DOWNCASE_TABLE)->contents : 0),
227 228
			  posix,
			  !NILP (current_buffer->enable_multibyte_characters));
Jim Blandy's avatar
Jim Blandy committed
229 230 231 232 233 234 235 236

  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;
237
  s1 = GPT_BYTE - BEGV_BYTE;
Jim Blandy's avatar
Jim Blandy committed
238
  p2 = GAP_END_ADDR;
239
  s2 = ZV_BYTE - GPT_BYTE;
Jim Blandy's avatar
Jim Blandy committed
240 241 242
  if (s1 < 0)
    {
      p2 = p1;
243
      s2 = ZV_BYTE - BEGV_BYTE;
Jim Blandy's avatar
Jim Blandy committed
244 245 246 247
      s1 = 0;
    }
  if (s2 < 0)
    {
248
      s1 = ZV_BYTE - BEGV_BYTE;
Jim Blandy's avatar
Jim Blandy committed
249 250
      s2 = 0;
    }
251 252

  re_match_object = Qnil;
Jim Blandy's avatar
Jim Blandy committed
253
  
254
  i = re_match_2 (bufp, (char *) p1, s1, (char *) p2, s2,
255 256
		  PT_BYTE - BEGV_BYTE, &search_regs,
		  ZV_BYTE - BEGV_BYTE);
Jim Blandy's avatar
Jim Blandy committed
257 258 259 260
  if (i == -2)
    matcher_overflow ();

  val = (0 <= i ? Qt : Qnil);
261 262 263 264 265 266 267 268 269
  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);
	}
270
  XSETBUFFER (last_thing_searched, current_buffer);
Jim Blandy's avatar
Jim Blandy committed
271 272 273 274
  immediate_quit = 0;
  return val;
}

275
DEFUN ("looking-at", Flooking_at, Slooking_at, 1, 1, 0,
276
  "Return t if text after point matches regular expression REGEXP.\n\
277 278 279
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.")
280 281
  (regexp)
     Lisp_Object regexp;
282
{
283
  return looking_at_1 (regexp, 0);
284 285 286
}

DEFUN ("posix-looking-at", Fposix_looking_at, Sposix_looking_at, 1, 1, 0,
287
  "Return t if text after point matches regular expression REGEXP.\n\
288 289 290 291
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.")
292 293
  (regexp)
     Lisp_Object regexp;
294
{
295
  return looking_at_1 (regexp, 1);
296 297 298 299
}

static Lisp_Object
string_match_1 (regexp, string, start, posix)
Jim Blandy's avatar
Jim Blandy committed
300
     Lisp_Object regexp, string, start;
301
     int posix;
Jim Blandy's avatar
Jim Blandy committed
302 303
{
  int val;
304
  struct re_pattern_buffer *bufp;
305 306
  int pos, pos_byte;
  int i;
Jim Blandy's avatar
Jim Blandy committed
307

308 309 310
  if (running_asynch_code)
    save_search_regs ();

Jim Blandy's avatar
Jim Blandy committed
311 312 313 314
  CHECK_STRING (regexp, 0);
  CHECK_STRING (string, 1);

  if (NILP (start))
315
    pos = 0, pos_byte = 0;
Jim Blandy's avatar
Jim Blandy committed
316 317 318 319 320
  else
    {
      int len = XSTRING (string)->size;

      CHECK_NUMBER (start, 2);
321 322 323 324
      pos = XINT (start);
      if (pos < 0 && -pos <= len)
	pos = len + pos;
      else if (0 > pos || pos > len)
Jim Blandy's avatar
Jim Blandy committed
325
	args_out_of_range (string, start);
326
      pos_byte = string_char_to_byte (string, pos);
Jim Blandy's avatar
Jim Blandy committed
327 328
    }

329 330
  bufp = compile_pattern (regexp, &search_regs,
			  (!NILP (current_buffer->case_fold_search)
331
			   ? XCHAR_TABLE (DOWNCASE_TABLE)->contents : 0),
332 333
			  posix,
			  STRING_MULTIBYTE (string));
Jim Blandy's avatar
Jim Blandy committed
334
  immediate_quit = 1;
335 336
  re_match_object = string;
  
337
  val = re_search (bufp, (char *) XSTRING (string)->data,
338 339
		   XSTRING (string)->size_byte, pos_byte,
		   XSTRING (string)->size_byte - pos_byte,
Jim Blandy's avatar
Jim Blandy committed
340 341
		   &search_regs);
  immediate_quit = 0;
Jim Blandy's avatar
Jim Blandy committed
342
  last_thing_searched = Qt;
Jim Blandy's avatar
Jim Blandy committed
343 344 345
  if (val == -2)
    matcher_overflow ();
  if (val < 0) return Qnil;
346 347 348 349 350 351 352 353 354 355 356

  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
357
}
Richard M. Stallman's avatar
Richard M. Stallman committed
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
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
384 385 386 387 388 389 390 391 392
/* 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;
393
  struct re_pattern_buffer *bufp;
Richard M. Stallman's avatar
Richard M. Stallman committed
394

395
  bufp = compile_pattern (regexp, 0, 0, 0, STRING_MULTIBYTE (string));
Richard M. Stallman's avatar
Richard M. Stallman committed
396
  immediate_quit = 1;
397 398
  re_match_object = string;
  
399
  val = re_search (bufp, (char *) XSTRING (string)->data,
Richard M. Stallman's avatar
Richard M. Stallman committed
400 401 402 403 404
		   XSTRING (string)->size, 0, XSTRING (string)->size,
		   0);
  immediate_quit = 0;
  return val;
}
Karl Heuer's avatar
Karl Heuer committed
405 406 407

/* Match REGEXP against STRING, searching all of STRING ignoring case,
   and return the index of the match, or negative on failure.
408 409
   This does not clobber the match data.
   We assume that STRING contains single-byte characters.  */
Karl Heuer's avatar
Karl Heuer committed
410 411 412 413

extern Lisp_Object Vascii_downcase_table;

int
414
fast_c_string_match_ignore_case (regexp, string)
Karl Heuer's avatar
Karl Heuer committed
415 416 417 418 419 420 421
     Lisp_Object regexp;
     char *string;
{
  int val;
  struct re_pattern_buffer *bufp;
  int len = strlen (string);

422
  regexp = string_make_unibyte (regexp);
423
  re_match_object = Qt;
Karl Heuer's avatar
Karl Heuer committed
424
  bufp = compile_pattern (regexp, 0,
425 426
			  XCHAR_TABLE (Vascii_downcase_table)->contents, 0,
			  1);
Karl Heuer's avatar
Karl Heuer committed
427 428 429 430 431
  immediate_quit = 1;
  val = re_search (bufp, string, len, 0, len, 0);
  immediate_quit = 0;
  return val;
}
Jim Blandy's avatar
Jim Blandy committed
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
/* max and min.  */

static int
max (a, b)
     int a, b;
{
  return ((a > b) ? a : b);
}

static int
min (a, b)
     int a, b;
{
  return ((a < b) ? a : b);
}


/* 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
487 488

   If we find COUNT instances, set *SHORTAGE to zero, and return the
Richard M. Stallman's avatar
Richard M. Stallman committed
489 490
   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
491

492 493
   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
494

495 496 497
   If ALLOW_QUIT is non-zero, set immediate_quit.  That's good to do
   except when inside redisplay.  */

498 499 500 501 502
scan_buffer (target, start, end, count, shortage, allow_quit)
     register int target;
     int start, end;
     int count;
     int *shortage;
503
     int allow_quit;
Jim Blandy's avatar
Jim Blandy committed
504
{
505 506
  struct region_cache *newline_cache;
  int direction; 
Jim Blandy's avatar
Jim Blandy committed
507

508 509 510 511 512 513 514 515 516 517
  if (count > 0)
    {
      direction = 1;
      if (! end) end = ZV;
    }
  else
    {
      direction = -1;
      if (! end) end = BEGV;
    }
Jim Blandy's avatar
Jim Blandy committed
518

519 520
  newline_cache_on_off (current_buffer);
  newline_cache = current_buffer->newline_cache;
Jim Blandy's avatar
Jim Blandy committed
521 522 523 524

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

525
  immediate_quit = allow_quit;
Jim Blandy's avatar
Jim Blandy committed
526

Jim Blandy's avatar
Jim Blandy committed
527
  if (count > 0)
528
    while (start != end)
Jim Blandy's avatar
Jim Blandy committed
529
      {
530 531 532 533 534
        /* 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.  */
535 536
	int ceiling_byte = CHAR_TO_BYTE (end) - 1;
	int start_byte = CHAR_TO_BYTE (start);
537 538 539 540 541 542 543 544

        /* 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
545 546
                   (current_buffer, newline_cache, start_byte, &next_change))
              start_byte = next_change;
547
            immediate_quit = allow_quit;
548

549 550 551
            /* START should never be after END.  */
            if (start_byte > ceiling_byte)
              start_byte = ceiling_byte;
552 553 554

            /* Now the text after start is an unknown region, and
               next_change is the position of the next known region. */
555
            ceiling_byte = min (next_change - 1, ceiling_byte);
556 557 558 559 560 561
          }

        /* 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.  */
562
        ceiling_byte = min (BUFFER_CEILING_OF (start_byte), ceiling_byte);
563 564 565

        {
          /* The termination address of the dumb loop.  */ 
566 567 568 569
          register unsigned char *ceiling_addr
	    = BYTE_POS_ADDR (ceiling_byte) + 1;
          register unsigned char *cursor
	    = BYTE_POS_ADDR (start_byte);
570 571 572 573 574 575 576 577 578 579 580 581 582 583
          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,
584 585
                                   start_byte + scan_start - base,
                                   start_byte + cursor - base);
586 587 588 589 590 591 592

              /* Did we find the target character?  */
              if (cursor < ceiling_addr)
                {
                  if (--count == 0)
                    {
                      immediate_quit = 0;
593
                      return BYTE_TO_CHAR (start_byte + cursor - base + 1);
594 595 596 597 598
                    }
                  cursor++;
                }
            }

599
          start = BYTE_TO_CHAR (start_byte + cursor - base);
600
        }
Jim Blandy's avatar
Jim Blandy committed
601 602
      }
  else
603 604 605
    while (start > end)
      {
        /* The last character to check before the next obstacle.  */
606 607
	int ceiling_byte = CHAR_TO_BYTE (end);
	int start_byte = CHAR_TO_BYTE (start);
608 609 610 611 612 613 614

        /* Consult the newline cache, if appropriate.  */
        if (target == '\n' && newline_cache)
          {
            int next_change;
            immediate_quit = 0;
            while (region_cache_backward
615 616
                   (current_buffer, newline_cache, start_byte, &next_change))
              start_byte = next_change;
617
            immediate_quit = allow_quit;
618 619

            /* Start should never be at or before end.  */
620 621
            if (start_byte <= ceiling_byte)
              start_byte = ceiling_byte + 1;
622 623 624

            /* Now the text before start is an unknown region, and
               next_change is the position of the next known region. */
625
            ceiling_byte = max (next_change, ceiling_byte);
626 627 628
          }

        /* Stop scanning before the gap.  */
629
        ceiling_byte = max (BUFFER_FLOOR_OF (start_byte - 1), ceiling_byte);
630 631 632

        {
          /* The termination address of the dumb loop.  */
633 634
          register unsigned char *ceiling_addr = BYTE_POS_ADDR (ceiling_byte);
          register unsigned char *cursor = BYTE_POS_ADDR (start_byte - 1);
635 636 637 638 639 640 641 642 643 644 645 646 647
          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,
648 649
                                   start_byte + cursor - base,
                                   start_byte + scan_start - base);
650 651 652 653 654 655 656

              /* Did we find the target character?  */
              if (cursor >= ceiling_addr)
                {
                  if (++count >= 0)
                    {
                      immediate_quit = 0;
657
                      return BYTE_TO_CHAR (start_byte + cursor - base);
658 659 660 661 662
                    }
                  cursor--;
                }
            }

663
	  start = BYTE_TO_CHAR (start_byte + cursor - base);
664 665 666
        }
      }

Jim Blandy's avatar
Jim Blandy committed
667 668
  immediate_quit = 0;
  if (shortage != 0)
Jim Blandy's avatar
Jim Blandy committed
669
    *shortage = count * direction;
670
  return start;
Jim Blandy's avatar
Jim Blandy committed
671
}
672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687

/* 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
688
   except in special cases.  */
Jim Blandy's avatar
Jim Blandy committed
689

690
int
691 692 693 694 695
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;
696
{
697 698 699 700 701 702 703 704
  int direction = ((count > 0) ? 1 : -1);

  register unsigned char *cursor;
  unsigned char *base;

  register int ceiling;
  register unsigned char *ceiling_addr;

705 706
  int old_immediate_quit = immediate_quit;

707 708 709 710 711 712 713 714
  /* 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.  */

715 716
  if (allow_quit)
    immediate_quit++;
717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736

  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)
		    {
737
		      immediate_quit = old_immediate_quit;
738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770
		      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
    {
      int start_byte = CHAR_TO_BYTE (start);
      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)
		    {
771
		      immediate_quit = old_immediate_quit;
772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788
		      /* 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);
789
  immediate_quit = old_immediate_quit;
790 791

  return count * direction;
792 793
}

Jim Blandy's avatar
Jim Blandy committed
794
int
795
find_next_newline_no_quit (from, cnt)
Jim Blandy's avatar
Jim Blandy committed
796 797
     register int from, cnt;
{
798
  return scan_buffer ('\n', from, 0, cnt, (int *) 0, 0);
799 800 801 802 803
}

/* 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.  */
804

805 806
int
find_before_next_newline (from, to, cnt)
807
     int from, to, cnt;
808 809 810 811 812 813 814 815
{
  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
816 817 818 819 820
}

/* Subroutines of Lisp buffer search functions. */

static Lisp_Object
821
search_command (string, bound, noerror, count, direction, RE, posix)
Jim Blandy's avatar
Jim Blandy committed
822 823 824
     Lisp_Object string, bound, noerror, count;
     int direction;
     int RE;
825
     int posix;
Jim Blandy's avatar
Jim Blandy committed
826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843
{
  register int np;
  int lim;
  int n = direction;

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

  CHECK_STRING (string, 0);
  if (NILP (bound))
    lim = n > 0 ? ZV : BEGV;
  else
    {
      CHECK_NUMBER_COERCE_MARKER (bound, 1);
      lim = XINT (bound);
844
      if (n > 0 ? lim < PT : lim > PT)
Jim Blandy's avatar
Jim Blandy committed
845 846 847 848 849 850 851
	error ("Invalid search bound (wrong side of point)");
      if (lim > ZV)
	lim = ZV;
      if (lim < BEGV)
	lim = BEGV;
    }

852
  np = search_buffer (string, PT, lim, n, RE,
Jim Blandy's avatar
Jim Blandy committed
853
		      (!NILP (current_buffer->case_fold_search)
854 855
		       ? XCHAR_TABLE (current_buffer->case_canon_table)->contents
		       : 0),
Jim Blandy's avatar
Jim Blandy committed
856
		      (!NILP (current_buffer->case_fold_search)
857 858
		       ? XCHAR_TABLE (current_buffer->case_eqv_table)->contents
		       : 0),
859
		      posix);
Jim Blandy's avatar
Jim Blandy committed
860 861 862 863 864 865 866 867
  if (np <= 0)
    {
      if (NILP (noerror))
	return signal_failure (string);
      if (!EQ (noerror, Qt))
	{
	  if (lim < BEGV || lim > ZV)
	    abort ();
868 869 870 871
	  SET_PT (lim);
	  return Qnil;
#if 0 /* This would be clean, but maybe programs depend on
	 a value of nil here.  */
872
	  np = lim;
873
#endif
Jim Blandy's avatar
Jim Blandy committed
874
	}
875 876
      else
	return Qnil;
Jim Blandy's avatar
Jim Blandy committed
877 878 879 880 881 882 883 884 885 886
    }

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

  SET_PT (np);

  return make_number (np);
}

887 888
/* Return 1 if REGEXP it matches just one constant string.  */

Karl Heuer's avatar
Karl Heuer committed
889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908
static int
trivial_regexp_p (regexp)
     Lisp_Object regexp;
{
  int len = XSTRING (regexp)->size;
  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':
909
	    case 'S': case '=':
Karl Heuer's avatar
Karl Heuer committed
910
	    case 'c': case 'C':	/* for categoryspec and notcategoryspec */
911
	    case '1': case '2': case '3': case '4': case '5':
Karl Heuer's avatar
Karl Heuer committed
912 913 914 915 916 917 918 919
	    case '6': case '7': case '8': case '9':
	      return 0;
	    }
	}
    }
  return 1;
}

920
/* Search for the n'th occurrence of STRING in the current buffer,
Jim Blandy's avatar
Jim Blandy committed
921
   starting at position POS and stopping at position LIM,
922
   treating STRING as a literal string if RE is false or as
Jim Blandy's avatar
Jim Blandy committed
923 924 925 926 927 928 929
   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.

   Returns -x if only N-x occurrences found (x > 0),
   or else the position at the beginning of the Nth occurrence
930 931 932 933
   (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
934

935 936
static int
search_buffer (string, pos, lim, n, RE, trt, inverse_trt, posix)
Jim Blandy's avatar
Jim Blandy committed
937 938 939 940 941
     Lisp_Object string;
     int pos;
     int lim;
     int n;
     int RE;
942 943
     Lisp_Object *trt;
     Lisp_Object *inverse_trt;
944
     int posix;
Jim Blandy's avatar
Jim Blandy committed
945 946
{
  int len = XSTRING (string)->size;
947
  int len_byte = XSTRING (string)->size_byte;
Jim Blandy's avatar
Jim Blandy committed
948 949 950 951 952 953 954 955 956 957 958
  unsigned char *base_pat = XSTRING (string)->data;
  register int *BM_tab;
  int *BM_tab_base;
  register int direction = ((n > 0) ? 1 : -1);
  register int dirlen;
  int infinity, limit, k, stride_for_teases;
  register unsigned char *pat, *cursor, *p_limit;  
  register int i, j;
  unsigned char *p1, *p2;
  int s1, s2;

959 960 961
  if (running_asynch_code)
    save_search_regs ();

Jim Blandy's avatar
Jim Blandy committed
962
  /* Null string is found at starting position.  */
963
  if (len == 0)
964 965 966 967
    {
      set_search_regs (pos, 0);
      return pos;
    }
968 969 970

  /* Searching 0 times means don't move.  */
  if (n == 0)
Jim Blandy's avatar
Jim Blandy committed
971 972
    return pos;

Karl Heuer's avatar
Karl Heuer committed
973
  if (RE && !trivial_regexp_p (string))
Jim Blandy's avatar
Jim Blandy committed
974
    {
975 976
      struct re_pattern_buffer *bufp;

977 978
      bufp = compile_pattern (string, &search_regs, trt, posix,
			      !NILP (current_buffer->enable_multibyte_characters));
Jim Blandy's avatar
Jim Blandy committed
979 980 981 982 983 984 985 986 987 988

      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;
989
      s1 = GPT_BYTE - BEGV_BYTE;
Jim Blandy's avatar
Jim Blandy committed
990
      p2 = GAP_END_ADDR;
991
      s2 = ZV_BYTE - GPT_BYTE;
Jim Blandy's avatar
Jim Blandy committed
992 993 994
      if (s1 < 0)
	{
	  p2 = p1;
995
	  s2 = ZV_BYTE - BEGV_BYTE;
Jim Blandy's avatar
Jim Blandy committed
996 997 998 999
	  s1 = 0;
	}
      if (s2 < 0)
	{
1000
	  s1 = ZV_BYTE - BEGV_BYTE;
Jim Blandy's avatar
Jim Blandy committed
1001 1002
	  s2 = 0;
	}
1003 1004
      re_match_object = Qnil;
  
Jim Blandy's avatar
Jim Blandy committed
1005 1006
      while (n < 0)
	{
1007
	  int val;
1008
	  val = re_search_2 (bufp, (char *) p1, s1, (char *) p2, s2,
1009 1010 1011
			     pos - BEGV, lim - pos, &search_regs,
			     /* Don't allow match past current point */
			     pos - BEGV);
Jim Blandy's avatar
Jim Blandy committed
1012
	  if (val == -2)
Karl Heuer's avatar
Karl Heuer committed
1013 1014 1015
	    {
	      matcher_overflow ();
	    }
Jim Blandy's avatar
Jim Blandy committed
1016 1017
	  if (val >= 0)
	    {
Jim Blandy's avatar
Jim Blandy committed
1018
	      for (i = 0; i < search_regs.num_regs; i++)
Jim Blandy's avatar
Jim Blandy committed
1019 1020
		if (search_regs.start[i] >= 0)
		  {
1021 1022 1023 1024
		    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);
Jim Blandy's avatar
Jim Blandy committed
1025
		  }
1026
	      XSETBUFFER (last_thing_searched, current_buffer);
Jim Blandy's avatar
Jim Blandy committed
1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038
	      /* Set pos to the new position. */
	      pos = search_regs.start[0];
	    }
	  else
	    {
	      immediate_quit = 0;
	      return (n);
	    }
	  n++;
	}
      while (n > 0)
	{
1039
	  int val;
1040
	  val = re_search_2 (bufp, (char *) p1, s1, (char *) p2, s2,
1041 1042
			     pos - BEGV, lim - pos, &search_regs,
			     lim - BEGV);
Jim Blandy's avatar
Jim Blandy committed
1043
	  if (val == -2)
Karl Heuer's avatar
Karl Heuer committed
1044 1045 1046
	    {
	      matcher_overflow ();
	    }
Jim Blandy's avatar
Jim Blandy committed
1047 1048
	  if (val >= 0)
	    {
Jim Blandy's avatar
Jim Blandy committed
1049
	      for (i = 0; i < search_regs.num_regs; i++)
Jim Blandy's avatar
Jim Blandy committed
1050 1051
		if (search_regs.start[i] >= 0)
		  {
1052 1053 1054 1055
		    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);
Jim Blandy's avatar
Jim Blandy committed
1056
		  }
1057
	      XSETBUFFER (last_thing_searched, current_buffer);