This repository has been archived by the owner on Jan 22, 2025. It is now read-only.
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathpcre_exec.c
7173 lines (6253 loc) · 213 KB
/
pcre_exec.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
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
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*************************************************
* Perl-Compatible Regular Expressions *
*************************************************/
/* PCRE is a library of functions to support regular expressions whose syntax
and semantics are as close as possible to those of the Perl 5 language.
Written by Philip Hazel
Copyright (c) 1997-2021 University of Cambridge
-----------------------------------------------------------------------------
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of the University of Cambridge nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
-----------------------------------------------------------------------------
*/
/* This module contains pcre_exec(), the externally visible function that does
pattern matching using an NFA algorithm, trying to mimic Perl as closely as
possible. There are also some static supporting functions. */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#define NLBLOCK md /* Block containing newline information */
#define PSSTART start_subject /* Field containing processed string start */
#define PSEND end_subject /* Field containing processed string end */
#include "pcre_internal.h"
/* Undefine some potentially clashing cpp symbols */
#undef min
#undef max
/* The md->capture_last field uses the lower 16 bits for the last captured
substring (which can never be greater than 65535) and a bit in the top half
to mean "capture vector overflowed". This odd way of doing things was
implemented when it was realized that preserving and restoring the overflow bit
whenever the last capture number was saved/restored made for a neater
interface, and doing it this way saved on (a) another variable, which would
have increased the stack frame size (a big NO-NO in PCRE) and (b) another
separate set of save/restore instructions. The following defines are used in
implementing this. */
#define CAPLMASK 0x0000ffff /* The bits used for last_capture */
#define OVFLMASK 0xffff0000 /* The bits used for the overflow flag */
#define OVFLBIT 0x00010000 /* The bit that is set for overflow */
/* Values for setting in md->match_function_type to indicate two special types
of call to match(). We do it this way to save on using another stack variable,
as stack usage is to be discouraged. */
#define MATCH_CONDASSERT 1 /* Called to check a condition assertion */
#define MATCH_CBEGROUP 2 /* Could-be-empty unlimited repeat group */
/* Non-error returns from the match() function. Error returns are externally
defined PCRE_ERROR_xxx codes, which are all negative. */
#define MATCH_MATCH 1
#define MATCH_NOMATCH 0
/* Special internal returns from the match() function. Make them sufficiently
negative to avoid the external error codes. */
#define MATCH_ACCEPT (-999)
#define MATCH_KETRPOS (-998)
#define MATCH_ONCE (-997)
/* The next 5 must be kept together and in sequence so that a test that checks
for any one of them can use a range. */
#define MATCH_COMMIT (-996)
#define MATCH_PRUNE (-995)
#define MATCH_SKIP (-994)
#define MATCH_SKIP_ARG (-993)
#define MATCH_THEN (-992)
#define MATCH_BACKTRACK_MAX MATCH_THEN
#define MATCH_BACKTRACK_MIN MATCH_COMMIT
/* Maximum number of ints of offset to save on the stack for recursive calls.
If the offset vector is bigger, malloc is used. This should be a multiple of 3,
because the offset vector is always a multiple of 3 long. */
#define REC_STACK_SAVE_MAX 30
/* Min and max values for the common repeats; for the maxima, 0 => infinity */
static const char rep_min[] = { 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, };
static const char rep_max[] = { 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, };
#ifdef PCRE_DEBUG
/*************************************************
* Debugging function to print chars *
*************************************************/
/* Print a sequence of chars in printable format, stopping at the end of the
subject if the requested.
Arguments:
p points to characters
length number to print
is_subject TRUE if printing from within md->start_subject
md pointer to matching data block, if is_subject is TRUE
Returns: nothing
*/
static void
pchars(const pcre_uchar *p, int length, BOOL is_subject, match_data *md)
{
pcre_uint32 c;
BOOL utf = md->utf;
if (is_subject && length > md->end_subject - p) length = md->end_subject - p;
while (length-- > 0)
if (isprint(c = UCHAR21INCTEST(p))) printf("%c", (char)c); else printf("\\x{%02x}", c);
}
#endif
/*************************************************
* Match a back-reference *
*************************************************/
/* Normally, if a back reference hasn't been set, the length that is passed is
negative, so the match always fails. However, in JavaScript compatibility mode,
the length passed is zero. Note that in caseless UTF-8 mode, the number of
subject bytes matched may be different to the number of reference bytes.
Arguments:
offset index into the offset vector
eptr pointer into the subject
length length of reference to be matched (number of bytes)
md points to match data block
caseless TRUE if caseless
Returns: >= 0 the number of subject bytes matched
-1 no match
-2 partial match; always given if at end subject
*/
static int
match_ref(int offset, register PCRE_PUCHAR eptr, int length, match_data *md,
BOOL caseless)
{
PCRE_PUCHAR eptr_start = eptr;
register PCRE_PUCHAR p = md->start_subject + md->offset_vector[offset];
#if defined SUPPORT_UTF && defined SUPPORT_UCP
BOOL utf = md->utf;
#endif
#ifdef PCRE_DEBUG
if (eptr >= md->end_subject)
printf("matching subject <null>");
else
{
printf("matching subject ");
pchars(eptr, length, TRUE, md);
}
printf(" against backref ");
pchars(p, length, FALSE, md);
printf("\n");
#endif
/* Always fail if reference not set (and not JavaScript compatible - in that
case the length is passed as zero). */
if (length < 0) return -1;
/* Separate the caseless case for speed. In UTF-8 mode we can only do this
properly if Unicode properties are supported. Otherwise, we can check only
ASCII characters. */
if (caseless)
{
#if defined SUPPORT_UTF && defined SUPPORT_UCP
if (utf)
{
/* Match characters up to the end of the reference. NOTE: the number of
data units matched may differ, because in UTF-8 there are some characters
whose upper and lower case versions code have different numbers of bytes.
For example, U+023A (2 bytes in UTF-8) is the upper case version of U+2C65
(3 bytes in UTF-8); a sequence of 3 of the former uses 6 bytes, as does a
sequence of two of the latter. It is important, therefore, to check the
length along the reference, not along the subject (earlier code did this
wrong). */
PCRE_PUCHAR endptr = p + length;
while (p < endptr)
{
pcre_uint32 c, d;
const ucd_record *ur;
if (eptr >= md->end_subject) return -2; /* Partial match */
GETCHARINC(c, eptr);
GETCHARINC(d, p);
ur = GET_UCD(d);
if (c != d && c != d + ur->other_case)
{
const pcre_uint32 *pp = PRIV(ucd_caseless_sets) + ur->caseset;
for (;;)
{
if (c < *pp) return -1;
if (c == *pp++) break;
}
}
}
}
else
#endif
/* The same code works when not in UTF-8 mode and in UTF-8 mode when there
is no UCP support. */
{
while (length-- > 0)
{
pcre_uint32 cc, cp;
if (eptr >= md->end_subject) return -2; /* Partial match */
cc = UCHAR21TEST(eptr);
cp = UCHAR21TEST(p);
if (TABLE_GET(cp, md->lcc, cp) != TABLE_GET(cc, md->lcc, cc)) return -1;
p++;
eptr++;
}
}
}
/* In the caseful case, we can just compare the bytes, whether or not we
are in UTF-8 mode. */
else
{
while (length-- > 0)
{
if (eptr >= md->end_subject) return -2; /* Partial match */
if (UCHAR21INCTEST(p) != UCHAR21INCTEST(eptr)) return -1;
}
}
return (int)(eptr - eptr_start);
}
/***************************************************************************
****************************************************************************
RECURSION IN THE match() FUNCTION
The match() function is highly recursive, though not every recursive call
increases the recursive depth. Nevertheless, some regular expressions can cause
it to recurse to a great depth. I was writing for Unix, so I just let it call
itself recursively. This uses the stack for saving everything that has to be
saved for a recursive call. On Unix, the stack can be large, and this works
fine.
It turns out that on some non-Unix-like systems there are problems with
programs that use a lot of stack. (This despite the fact that every last chip
has oodles of memory these days, and techniques for extending the stack have
been known for decades.) So....
There is a fudge, triggered by defining NO_RECURSE, which avoids recursive
calls by keeping local variables that need to be preserved in blocks of memory
obtained from malloc() instead instead of on the stack. Macros are used to
achieve this so that the actual code doesn't look very different to what it
always used to.
The original heap-recursive code used longjmp(). However, it seems that this
can be very slow on some operating systems. Following a suggestion from Stan
Switzer, the use of longjmp() has been abolished, at the cost of having to
provide a unique number for each call to RMATCH. There is no way of generating
a sequence of numbers at compile time in C. I have given them names, to make
them stand out more clearly.
Crude tests on x86 Linux show a small speedup of around 5-8%. However, on
FreeBSD, avoiding longjmp() more than halves the time taken to run the standard
tests. Furthermore, not using longjmp() means that local dynamic variables
don't have indeterminate values; this has meant that the frame size can be
reduced because the result can be "passed back" by straight setting of the
variable instead of being passed in the frame.
****************************************************************************
***************************************************************************/
/* Numbers for RMATCH calls. When this list is changed, the code at HEAP_RETURN
below must be updated in sync. */
enum { RM1=1, RM2, RM3, RM4, RM5, RM6, RM7, RM8, RM9, RM10,
RM11, RM12, RM13, RM14, RM15, RM16, RM17, RM18, RM19, RM20,
RM21, RM22, RM23, RM24, RM25, RM26, RM27, RM28, RM29, RM30,
RM31, RM32, RM33, RM34, RM35, RM36, RM37, RM38, RM39, RM40,
RM41, RM42, RM43, RM44, RM45, RM46, RM47, RM48, RM49, RM50,
RM51, RM52, RM53, RM54, RM55, RM56, RM57, RM58, RM59, RM60,
RM61, RM62, RM63, RM64, RM65, RM66, RM67 };
/* These versions of the macros use the stack, as normal. There are debugging
versions and production versions. Note that the "rw" argument of RMATCH isn't
actually used in this definition. */
#ifndef NO_RECURSE
#define REGISTER register
#ifdef PCRE_DEBUG
#define RMATCH(ra,rb,rc,rd,re,rw) \
{ \
printf("match() called in line %d\n", __LINE__); \
rrc = match(ra,rb,mstart,rc,rd,re,rdepth+1); \
printf("to line %d\n", __LINE__); \
}
#define RRETURN(ra) \
{ \
printf("match() returned %d from line %d\n", ra, __LINE__); \
return ra; \
}
#else
#define RMATCH(ra,rb,rc,rd,re,rw) \
rrc = match(ra,rb,mstart,rc,rd,re,rdepth+1)
#define RRETURN(ra) return ra
#endif
#else
/* These versions of the macros manage a private stack on the heap. Note that
the "rd" argument of RMATCH isn't actually used in this definition. It's the md
argument of match(), which never changes. */
#define REGISTER
#define RMATCH(ra,rb,rc,rd,re,rw)\
{\
heapframe *newframe = frame->Xnextframe;\
if (newframe == NULL)\
{\
newframe = (heapframe *)(PUBL(stack_malloc))(sizeof(heapframe));\
if (newframe == NULL) RRETURN(PCRE_ERROR_NOMEMORY);\
newframe->Xnextframe = NULL;\
frame->Xnextframe = newframe;\
}\
frame->Xwhere = rw;\
newframe->Xeptr = ra;\
newframe->Xecode = rb;\
newframe->Xmstart = mstart;\
newframe->Xoffset_top = rc;\
newframe->Xeptrb = re;\
newframe->Xrdepth = frame->Xrdepth + 1;\
newframe->Xprevframe = frame;\
frame = newframe;\
DPRINTF(("restarting from line %d\n", __LINE__));\
goto HEAP_RECURSE;\
L_##rw:\
DPRINTF(("jumped back to line %d\n", __LINE__));\
}
#define RRETURN(ra)\
{\
heapframe *oldframe = frame;\
frame = oldframe->Xprevframe;\
if (frame != NULL)\
{\
rrc = ra;\
goto HEAP_RETURN;\
}\
return ra;\
}
/* Structure for remembering the local variables in a private frame */
typedef struct heapframe {
struct heapframe *Xprevframe;
struct heapframe *Xnextframe;
/* Function arguments that may change */
PCRE_PUCHAR Xeptr;
const pcre_uchar *Xecode;
PCRE_PUCHAR Xmstart;
int Xoffset_top;
eptrblock *Xeptrb;
unsigned int Xrdepth;
/* Function local variables */
PCRE_PUCHAR Xcallpat;
#ifdef SUPPORT_UTF
PCRE_PUCHAR Xcharptr;
#endif
PCRE_PUCHAR Xdata;
PCRE_PUCHAR Xnext;
PCRE_PUCHAR Xpp;
PCRE_PUCHAR Xprev;
PCRE_PUCHAR Xsaved_eptr;
recursion_info Xnew_recursive;
BOOL Xcur_is_word;
BOOL Xcondition;
BOOL Xprev_is_word;
#ifdef SUPPORT_UCP
int Xprop_type;
unsigned int Xprop_value;
int Xprop_fail_result;
int Xoclength;
pcre_uchar Xocchars[6];
#endif
int Xcodelink;
int Xctype;
unsigned int Xfc;
int Xfi;
int Xlength;
int Xmax;
int Xmin;
unsigned int Xnumber;
int Xoffset;
unsigned int Xop;
pcre_int32 Xsave_capture_last;
int Xsave_offset1, Xsave_offset2, Xsave_offset3;
int Xstacksave[REC_STACK_SAVE_MAX];
eptrblock Xnewptrb;
/* Where to jump back to */
int Xwhere;
} heapframe;
#endif
/***************************************************************************
***************************************************************************/
/*************************************************
* Match from current position *
*************************************************/
/* This function is called recursively in many circumstances. Whenever it
returns a negative (error) response, the outer incarnation must also return the
same response. */
/* These macros pack up tests that are used for partial matching, and which
appear several times in the code. We set the "hit end" flag if the pointer is
at the end of the subject and also past the start of the subject (i.e.
something has been matched). For hard partial matching, we then return
immediately. The second one is used when we already know we are past the end of
the subject. */
#define CHECK_PARTIAL()\
if (md->partial != 0 && eptr >= md->end_subject && \
eptr > md->start_used_ptr) \
{ \
md->hitend = TRUE; \
if (md->partial > 1) RRETURN(PCRE_ERROR_PARTIAL); \
}
#define SCHECK_PARTIAL()\
if (md->partial != 0 && eptr > md->start_used_ptr) \
{ \
md->hitend = TRUE; \
if (md->partial > 1) RRETURN(PCRE_ERROR_PARTIAL); \
}
/* Performance note: It might be tempting to extract commonly used fields from
the md structure (e.g. utf, end_subject) into individual variables to improve
performance. Tests using gcc on a SPARC disproved this; in the first case, it
made performance worse.
Arguments:
eptr pointer to current character in subject
ecode pointer to current position in compiled code
mstart pointer to the current match start position (can be modified
by encountering \K)
offset_top current top pointer
md pointer to "static" info for the match
eptrb pointer to chain of blocks containing eptr at start of
brackets - for testing for empty matches
rdepth the recursion depth
Returns: MATCH_MATCH if matched ) these values are >= 0
MATCH_NOMATCH if failed to match )
a negative MATCH_xxx value for PRUNE, SKIP, etc
a negative PCRE_ERROR_xxx value if aborted by an error condition
(e.g. stopped by repeated call or recursion limit)
*/
static int
match(REGISTER PCRE_PUCHAR eptr, REGISTER const pcre_uchar *ecode,
PCRE_PUCHAR mstart, int offset_top, match_data *md, eptrblock *eptrb,
unsigned int rdepth)
{
/* These variables do not need to be preserved over recursion in this function,
so they can be ordinary variables in all cases. Mark some of them with
"register" because they are used a lot in loops. */
register int rrc; /* Returns from recursive calls */
register int i; /* Used for loops not involving calls to RMATCH() */
register pcre_uint32 c; /* Character values not kept over RMATCH() calls */
register BOOL utf; /* Local copy of UTF flag for speed */
BOOL minimize, possessive; /* Quantifier options */
BOOL caseless;
int condcode;
/* When recursion is not being used, all "local" variables that have to be
preserved over calls to RMATCH() are part of a "frame". We set up the top-level
frame on the stack here; subsequent instantiations are obtained from the heap
whenever RMATCH() does a "recursion". See the macro definitions above. Putting
the top-level on the stack rather than malloc-ing them all gives a performance
boost in many cases where there is not much "recursion". */
#ifdef NO_RECURSE
heapframe *frame = (heapframe *)md->match_frames_base;
/* Copy in the original argument variables */
frame->Xeptr = eptr;
frame->Xecode = ecode;
frame->Xmstart = mstart;
frame->Xoffset_top = offset_top;
frame->Xeptrb = eptrb;
frame->Xrdepth = rdepth;
/* This is where control jumps back to to effect "recursion" */
HEAP_RECURSE:
/* Macros make the argument variables come from the current frame */
#define eptr frame->Xeptr
#define ecode frame->Xecode
#define mstart frame->Xmstart
#define offset_top frame->Xoffset_top
#define eptrb frame->Xeptrb
#define rdepth frame->Xrdepth
/* Ditto for the local variables */
#ifdef SUPPORT_UTF
#define charptr frame->Xcharptr
#endif
#define callpat frame->Xcallpat
#define codelink frame->Xcodelink
#define data frame->Xdata
#define next frame->Xnext
#define pp frame->Xpp
#define prev frame->Xprev
#define saved_eptr frame->Xsaved_eptr
#define new_recursive frame->Xnew_recursive
#define cur_is_word frame->Xcur_is_word
#define condition frame->Xcondition
#define prev_is_word frame->Xprev_is_word
#ifdef SUPPORT_UCP
#define prop_type frame->Xprop_type
#define prop_value frame->Xprop_value
#define prop_fail_result frame->Xprop_fail_result
#define oclength frame->Xoclength
#define occhars frame->Xocchars
#endif
#define ctype frame->Xctype
#define fc frame->Xfc
#define fi frame->Xfi
#define length frame->Xlength
#define max frame->Xmax
#define min frame->Xmin
#define number frame->Xnumber
#define offset frame->Xoffset
#define op frame->Xop
#define save_capture_last frame->Xsave_capture_last
#define save_offset1 frame->Xsave_offset1
#define save_offset2 frame->Xsave_offset2
#define save_offset3 frame->Xsave_offset3
#define stacksave frame->Xstacksave
#define newptrb frame->Xnewptrb
/* When recursion is being used, local variables are allocated on the stack and
get preserved during recursion in the normal way. In this environment, fi and
i, and fc and c, can be the same variables. */
#else /* NO_RECURSE not defined */
#define fi i
#define fc c
/* Many of the following variables are used only in small blocks of the code.
My normal style of coding would have declared them within each of those blocks.
However, in order to accommodate the version of this code that uses an external
"stack" implemented on the heap, it is easier to declare them all here, so the
declarations can be cut out in a block. The only declarations within blocks
below are for variables that do not have to be preserved over a recursive call
to RMATCH(). */
#ifdef SUPPORT_UTF
const pcre_uchar *charptr;
#endif
const pcre_uchar *callpat;
const pcre_uchar *data;
const pcre_uchar *next;
PCRE_PUCHAR pp;
const pcre_uchar *prev;
PCRE_PUCHAR saved_eptr;
recursion_info new_recursive;
BOOL cur_is_word;
BOOL condition;
BOOL prev_is_word;
#ifdef SUPPORT_UCP
int prop_type;
unsigned int prop_value;
int prop_fail_result;
int oclength;
pcre_uchar occhars[6];
#endif
int codelink;
int ctype;
int length;
int max;
int min;
unsigned int number;
int offset;
unsigned int op;
pcre_int32 save_capture_last;
int save_offset1, save_offset2, save_offset3;
int stacksave[REC_STACK_SAVE_MAX];
eptrblock newptrb;
/* There is a special fudge for calling match() in a way that causes it to
measure the size of its basic stack frame when the stack is being used for
recursion. The second argument (ecode) being NULL triggers this behaviour. It
cannot normally ever be NULL. The return is the negated value of the frame
size. */
if (ecode == NULL)
{
if (rdepth == 0)
return match((PCRE_PUCHAR)&rdepth, NULL, NULL, 0, NULL, NULL, 1);
else
{
int len = (int)((char *)&rdepth - (char *)eptr);
return (len > 0)? -len : len;
}
}
#endif /* NO_RECURSE */
/* To save space on the stack and in the heap frame, I have doubled up on some
of the local variables that are used only in localised parts of the code, but
still need to be preserved over recursive calls of match(). These macros define
the alternative names that are used. */
#define allow_zero cur_is_word
#define cbegroup condition
#define code_offset codelink
#define condassert condition
#define matched_once prev_is_word
#define foc number
#define save_mark data
/* These statements are here to stop the compiler complaining about unitialized
variables. */
#ifdef SUPPORT_UCP
prop_value = 0;
prop_fail_result = 0;
#endif
/* This label is used for tail recursion, which is used in a few cases even
when NO_RECURSE is not defined, in order to reduce the amount of stack that is
used. Thanks to Ian Taylor for noticing this possibility and sending the
original patch. */
TAIL_RECURSE:
/* OK, now we can get on with the real code of the function. Recursive calls
are specified by the macro RMATCH and RRETURN is used to return. When
NO_RECURSE is *not* defined, these just turn into a recursive call to match()
and a "return", respectively (possibly with some debugging if PCRE_DEBUG is
defined). However, RMATCH isn't like a function call because it's quite a
complicated macro. It has to be used in one particular way. This shouldn't,
however, impact performance when true recursion is being used. */
#ifdef SUPPORT_UTF
utf = md->utf; /* Local copy of the flag */
#else
utf = FALSE;
#endif
/* First check that we haven't called match() too many times, or that we
haven't exceeded the recursive call limit. */
if (md->match_call_count++ >= md->match_limit) RRETURN(PCRE_ERROR_MATCHLIMIT);
if (rdepth >= md->match_limit_recursion) RRETURN(PCRE_ERROR_RECURSIONLIMIT);
/* At the start of a group with an unlimited repeat that may match an empty
string, the variable md->match_function_type is set to MATCH_CBEGROUP. It is
done this way to save having to use another function argument, which would take
up space on the stack. See also MATCH_CONDASSERT below.
When MATCH_CBEGROUP is set, add the current subject pointer to the chain of
such remembered pointers, to be checked when we hit the closing ket, in order
to break infinite loops that match no characters. When match() is called in
other circumstances, don't add to the chain. The MATCH_CBEGROUP feature must
NOT be used with tail recursion, because the memory block that is used is on
the stack, so a new one may be required for each match(). */
if (md->match_function_type == MATCH_CBEGROUP)
{
newptrb.epb_saved_eptr = eptr;
newptrb.epb_prev = eptrb;
eptrb = &newptrb;
md->match_function_type = 0;
}
/* Now start processing the opcodes. */
for (;;)
{
minimize = possessive = FALSE;
op = *ecode;
switch(op)
{
case OP_MARK:
md->nomatch_mark = ecode + 2;
md->mark = NULL; /* In case previously set by assertion */
RMATCH(eptr, ecode + PRIV(OP_lengths)[*ecode] + ecode[1], offset_top, md,
eptrb, RM55);
if ((rrc == MATCH_MATCH || rrc == MATCH_ACCEPT || rrc == MATCH_KETRPOS) &&
md->mark == NULL) md->mark = ecode + 2;
/* A return of MATCH_SKIP_ARG means that matching failed at SKIP with an
argument, and we must check whether that argument matches this MARK's
argument. It is passed back in md->start_match_ptr (an overloading of that
variable). If it does match, we reset that variable to the current subject
position and return MATCH_SKIP. Otherwise, pass back the return code
unaltered. */
else if (rrc == MATCH_SKIP_ARG &&
STRCMP_UC_UC_TEST(ecode + 2, md->start_match_ptr) == 0)
{
md->start_match_ptr = eptr;
RRETURN(MATCH_SKIP);
}
RRETURN(rrc);
case OP_FAIL:
RRETURN(MATCH_NOMATCH);
case OP_COMMIT:
RMATCH(eptr, ecode + PRIV(OP_lengths)[*ecode], offset_top, md,
eptrb, RM52);
if (rrc != MATCH_NOMATCH) RRETURN(rrc);
RRETURN(MATCH_COMMIT);
case OP_PRUNE:
RMATCH(eptr, ecode + PRIV(OP_lengths)[*ecode], offset_top, md,
eptrb, RM51);
if (rrc != MATCH_NOMATCH) RRETURN(rrc);
RRETURN(MATCH_PRUNE);
case OP_PRUNE_ARG:
md->nomatch_mark = ecode + 2;
md->mark = NULL; /* In case previously set by assertion */
RMATCH(eptr, ecode + PRIV(OP_lengths)[*ecode] + ecode[1], offset_top, md,
eptrb, RM56);
if ((rrc == MATCH_MATCH || rrc == MATCH_ACCEPT) &&
md->mark == NULL) md->mark = ecode + 2;
if (rrc != MATCH_NOMATCH) RRETURN(rrc);
RRETURN(MATCH_PRUNE);
case OP_SKIP:
RMATCH(eptr, ecode + PRIV(OP_lengths)[*ecode], offset_top, md,
eptrb, RM53);
if (rrc != MATCH_NOMATCH) RRETURN(rrc);
md->start_match_ptr = eptr; /* Pass back current position */
RRETURN(MATCH_SKIP);
/* Note that, for Perl compatibility, SKIP with an argument does NOT set
nomatch_mark. When a pattern match ends with a SKIP_ARG for which there was
not a matching mark, we have to re-run the match, ignoring the SKIP_ARG
that failed and any that precede it (either they also failed, or were not
triggered). To do this, we maintain a count of executed SKIP_ARGs. If a
SKIP_ARG gets to top level, the match is re-run with md->ignore_skip_arg
set to the count of the one that failed. */
case OP_SKIP_ARG:
md->skip_arg_count++;
if (md->skip_arg_count <= md->ignore_skip_arg)
{
ecode += PRIV(OP_lengths)[*ecode] + ecode[1];
break;
}
RMATCH(eptr, ecode + PRIV(OP_lengths)[*ecode] + ecode[1], offset_top, md,
eptrb, RM57);
if (rrc != MATCH_NOMATCH) RRETURN(rrc);
/* Pass back the current skip name by overloading md->start_match_ptr and
returning the special MATCH_SKIP_ARG return code. This will either be
caught by a matching MARK, or get to the top, where it causes a rematch
with md->ignore_skip_arg set to the value of md->skip_arg_count. */
md->start_match_ptr = ecode + 2;
RRETURN(MATCH_SKIP_ARG);
/* For THEN (and THEN_ARG) we pass back the address of the opcode, so that
the branch in which it occurs can be determined. Overload the start of
match pointer to do this. */
case OP_THEN:
RMATCH(eptr, ecode + PRIV(OP_lengths)[*ecode], offset_top, md,
eptrb, RM54);
if (rrc != MATCH_NOMATCH) RRETURN(rrc);
md->start_match_ptr = ecode;
RRETURN(MATCH_THEN);
case OP_THEN_ARG:
md->nomatch_mark = ecode + 2;
md->mark = NULL; /* In case previously set by assertion */
RMATCH(eptr, ecode + PRIV(OP_lengths)[*ecode] + ecode[1], offset_top,
md, eptrb, RM58);
if ((rrc == MATCH_MATCH || rrc == MATCH_ACCEPT) &&
md->mark == NULL) md->mark = ecode + 2;
if (rrc != MATCH_NOMATCH) RRETURN(rrc);
md->start_match_ptr = ecode;
RRETURN(MATCH_THEN);
/* Handle an atomic group that does not contain any capturing parentheses.
This can be handled like an assertion. Prior to 8.13, all atomic groups
were handled this way. In 8.13, the code was changed as below for ONCE, so
that backups pass through the group and thereby reset captured values.
However, this uses a lot more stack, so in 8.20, atomic groups that do not
contain any captures generate OP_ONCE_NC, which can be handled in the old,
less stack intensive way.
Check the alternative branches in turn - the matching won't pass the KET
for this kind of subpattern. If any one branch matches, we carry on as at
the end of a normal bracket, leaving the subject pointer, but resetting
the start-of-match value in case it was changed by \K. */
case OP_ONCE_NC:
prev = ecode;
saved_eptr = eptr;
save_mark = md->mark;
do
{
RMATCH(eptr, ecode + 1 + LINK_SIZE, offset_top, md, eptrb, RM64);
if (rrc == MATCH_MATCH) /* Note: _not_ MATCH_ACCEPT */
{
mstart = md->start_match_ptr;
break;
}
if (rrc == MATCH_THEN)
{
next = ecode + GET(ecode,1);
if (md->start_match_ptr < next &&
(*ecode == OP_ALT || *next == OP_ALT))
rrc = MATCH_NOMATCH;
}
if (rrc != MATCH_NOMATCH) RRETURN(rrc);
ecode += GET(ecode,1);
md->mark = save_mark;
}
while (*ecode == OP_ALT);
/* If hit the end of the group (which could be repeated), fail */
if (*ecode != OP_ONCE_NC && *ecode != OP_ALT) RRETURN(MATCH_NOMATCH);
/* Continue as from after the group, updating the offsets high water
mark, since extracts may have been taken. */
do ecode += GET(ecode, 1); while (*ecode == OP_ALT);
offset_top = md->end_offset_top;
eptr = md->end_match_ptr;
/* For a non-repeating ket, just continue at this level. This also
happens for a repeating ket if no characters were matched in the group.
This is the forcible breaking of infinite loops as implemented in Perl
5.005. */
if (*ecode == OP_KET || eptr == saved_eptr)
{
ecode += 1+LINK_SIZE;
break;
}
/* The repeating kets try the rest of the pattern or restart from the
preceding bracket, in the appropriate order. The second "call" of match()
uses tail recursion, to avoid using another stack frame. */
if (*ecode == OP_KETRMIN)
{
RMATCH(eptr, ecode + 1 + LINK_SIZE, offset_top, md, eptrb, RM65);
if (rrc != MATCH_NOMATCH) RRETURN(rrc);
ecode = prev;
goto TAIL_RECURSE;
}
else /* OP_KETRMAX */
{
RMATCH(eptr, prev, offset_top, md, eptrb, RM66);
if (rrc != MATCH_NOMATCH) RRETURN(rrc);
ecode += 1 + LINK_SIZE;
goto TAIL_RECURSE;
}
/* Control never gets here */
/* Handle a capturing bracket, other than those that are possessive with an
unlimited repeat. If there is space in the offset vector, save the current
subject position in the working slot at the top of the vector. We mustn't
change the current values of the data slot, because they may be set from a
previous iteration of this group, and be referred to by a reference inside
the group. A failure to match might occur after the group has succeeded,
if something later on doesn't match. For this reason, we need to restore
the working value and also the values of the final offsets, in case they
were set by a previous iteration of the same bracket.
If there isn't enough space in the offset vector, treat this as if it were
a non-capturing bracket. Don't worry about setting the flag for the error
case here; that is handled in the code for KET. */
case OP_CBRA:
case OP_SCBRA:
number = GET2(ecode, 1+LINK_SIZE);
offset = number << 1;
#ifdef PCRE_DEBUG
printf("start bracket %d\n", number);
printf("subject=");
pchars(eptr, 16, TRUE, md);
printf("\n");
#endif
if (offset < md->offset_max)
{
save_offset1 = md->offset_vector[offset];
save_offset2 = md->offset_vector[offset+1];
save_offset3 = md->offset_vector[md->offset_end - number];
save_capture_last = md->capture_last;
save_mark = md->mark;
DPRINTF(("saving %d %d %d\n", save_offset1, save_offset2, save_offset3));
md->offset_vector[md->offset_end - number] =
(int)(eptr - md->start_subject);
for (;;)
{
if (op >= OP_SBRA) md->match_function_type = MATCH_CBEGROUP;
RMATCH(eptr, ecode + PRIV(OP_lengths)[*ecode], offset_top, md,
eptrb, RM1);
if (rrc == MATCH_ONCE) break; /* Backing up through an atomic group */
/* If we backed up to a THEN, check whether it is within the current
branch by comparing the address of the THEN that is passed back with
the end of the branch. If it is within the current branch, and the
branch is one of two or more alternatives (it either starts or ends
with OP_ALT), we have reached the limit of THEN's action, so convert
the return code to NOMATCH, which will cause normal backtracking to
happen from now on. Otherwise, THEN is passed back to an outer
alternative. This implements Perl's treatment of parenthesized groups,
where a group not containing | does not affect the current alternative,
that is, (X) is NOT the same as (X|(*F)). */
if (rrc == MATCH_THEN)
{
next = ecode + GET(ecode,1);