forked from schacon/perl
-
Notifications
You must be signed in to change notification settings - Fork 1
/
regexec.c
1295 lines (1219 loc) · 28.3 KB
/
regexec.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
/* regexec.c
*/
/*
* "One Ring to rule them all, One Ring to find them..."
*/
/* NOTE: this is derived from Henry Spencer's regexp code, and should not
* confused with the original package (see point 3 below). Thanks, Henry!
*/
/* Additional note: this code is very heavily munged from Henry's version
* in places. In some spots I've traded clarity for efficiency, so don't
* blame Henry for some of the lack of readability.
*/
/* The names of the functions have been changed from regcomp and
* regexec to pregcomp and pregexec in order to avoid conflicts
* with the POSIX routines of the same names.
*/
/*SUPPRESS 112*/
/*
* pregcomp and pregexec -- regsub and regerror are not used in perl
*
* Copyright (c) 1986 by University of Toronto.
* Written by Henry Spencer. Not derived from licensed software.
*
* Permission is granted to anyone to use this software for any
* purpose on any computer system, and to redistribute it freely,
* subject to the following restrictions:
*
* 1. The author is not responsible for the consequences of use of
* this software, no matter how awful, even if they arise
* from defects in it.
*
* 2. The origin of this software must not be misrepresented, either
* by explicit claim or by omission.
*
* 3. Altered versions must be plainly marked as such, and must not
* be misrepresented as being the original software.
*
**** Alterations to Henry's code are...
****
**** Copyright (c) 1991-1994, Larry Wall
****
**** You may distribute under the terms of either the GNU General Public
**** License or the Artistic License, as specified in the README file.
*
* Beware that some of this code is subtly aware of the way operator
* precedence is structured in regular expressions. Serious changes in
* regular-expression syntax might require a total rethink.
*/
#include "EXTERN.h"
#include "perl.h"
#include "regcomp.h"
#ifndef STATIC
#define STATIC static
#endif
#ifdef DEBUGGING
static I32 regnarrate = 0;
static char* regprogram = 0;
#endif
/* Current curly descriptor */
typedef struct curcur CURCUR;
struct curcur {
int parenfloor; /* how far back to strip paren data */
int cur; /* how many instances of scan we've matched */
int min; /* the minimal number of scans to match */
int max; /* the maximal number of scans to match */
int minmod; /* whether to work our way up or down */
char * scan; /* the thing to match */
char * next; /* what has to match after it */
char * lastloc; /* where we started matching this scan */
CURCUR * oldcc; /* current curly before we started this one */
};
static CURCUR* regcc;
typedef I32 CHECKPOINT;
static CHECKPOINT regcppush _((I32 parenfloor));
static char * regcppop _((void));
static CHECKPOINT
regcppush(parenfloor)
I32 parenfloor;
{
int retval = savestack_ix;
int i = (regsize - parenfloor) * 3;
int p;
SSCHECK(i + 5);
for (p = regsize; p > parenfloor; p--) {
SSPUSHPTR(regendp[p]);
SSPUSHPTR(regstartp[p]);
SSPUSHINT(p);
}
SSPUSHINT(regsize);
SSPUSHINT(*reglastparen);
SSPUSHPTR(reginput);
SSPUSHINT(i + 3);
SSPUSHINT(SAVEt_REGCONTEXT);
return retval;
}
static char *
regcppop()
{
I32 i = SSPOPINT;
U32 paren = 0;
char *input;
char *tmps;
assert(i == SAVEt_REGCONTEXT);
i = SSPOPINT;
input = (char *) SSPOPPTR;
*reglastparen = SSPOPINT;
regsize = SSPOPINT;
for (i -= 3; i > 0; i -= 3) {
paren = (U32)SSPOPINT;
regstartp[paren] = (char *) SSPOPPTR;
tmps = (char*)SSPOPPTR;
if (paren <= *reglastparen)
regendp[paren] = tmps;
}
for (paren = *reglastparen + 1; paren <= regnpar; paren++) {
if (paren > regsize)
regstartp[paren] = Nullch;
regendp[paren] = Nullch;
}
return input;
}
#define regcpblow(cp) leave_scope(cp)
/*
* pregexec and friends
*/
/*
* Forwards.
*/
static I32 regmatch _((char *prog));
static I32 regrepeat _((char *p, I32 max));
static I32 regtry _((regexp *prog, char *startpos));
static bool reginclass _((char *p, I32 c));
static bool regtainted; /* tainted information used? */
/*
- pregexec - match a regexp against a string
*/
I32
pregexec(prog, stringarg, strend, strbeg, minend, screamer, safebase)
register regexp *prog;
char *stringarg;
register char *strend; /* pointer to null at end of string */
char *strbeg; /* real beginning of string */
I32 minend; /* end of match must be at least minend after stringarg */
SV *screamer;
I32 safebase; /* no need to remember string in subbase */
{
register char *s;
register char *c;
register char *startpos = stringarg;
register I32 tmp;
I32 minlen = 0; /* must match at least this many chars */
I32 dontbother = 0; /* how many characters not to try at end */
CURCUR cc;
cc.cur = 0;
cc.oldcc = 0;
regcc = &cc;
#ifdef DEBUGGING
regnarrate = debug & 512;
regprogram = prog->program;
#endif
/* Be paranoid... */
if (prog == NULL || startpos == NULL) {
croak("NULL regexp parameter");
return 0;
}
if (startpos == strbeg) /* is ^ valid at stringarg? */
regprev = '\n';
else {
regprev = stringarg[-1];
if (!multiline && regprev == '\n')
regprev = '\0'; /* force ^ to NOT match */
}
regprecomp = prog->precomp;
/* Check validity of program. */
if (UCHARAT(prog->program) != MAGIC) {
FAIL("corrupted regexp program");
}
regnpar = prog->nparens;
regtainted = FALSE;
/* If there is a "must appear" string, look for it. */
s = startpos;
if (prog->regmust != Nullsv &&
(!(prog->reganch & ROPT_ANCH)
|| (multiline && prog->regback >= 0)) )
{
if (stringarg == strbeg && screamer) {
if (screamfirst[BmRARE(prog->regmust)] >= 0)
s = screaminstr(screamer,prog->regmust);
else
s = Nullch;
}
else
s = fbm_instr((unsigned char*)s, (unsigned char*)strend,
prog->regmust);
if (!s) {
++BmUSEFUL(prog->regmust); /* hooray */
goto phooey; /* not present */
}
else if (prog->regback >= 0) {
s -= prog->regback;
if (s < startpos)
s = startpos;
minlen = prog->regback + SvCUR(prog->regmust);
}
else if (!prog->naughty && --BmUSEFUL(prog->regmust) < 0) { /* boo */
SvREFCNT_dec(prog->regmust);
prog->regmust = Nullsv; /* disable regmust */
s = startpos;
}
else {
s = startpos;
minlen = SvCUR(prog->regmust);
}
}
/* Mark beginning of line for ^ . */
regbol = startpos;
/* Mark end of line for $ (and such) */
regeol = strend;
/* see how far we have to get to not match where we matched before */
regtill = startpos+minend;
/* Simplest case: anchored match need be tried only once. */
/* [unless multiline is set] */
if (prog->reganch & ROPT_ANCH) {
if (regtry(prog, startpos))
goto got_it;
else if (multiline || (prog->reganch & ROPT_IMPLICIT)) {
if (minlen)
dontbother = minlen - 1;
strend -= dontbother;
/* for multiline we only have to try after newlines */
if (s > startpos)
s--;
while (s < strend) {
if (*s++ == '\n') {
if (s < strend && regtry(prog, s))
goto got_it;
}
}
}
goto phooey;
}
/* Messy cases: unanchored match. */
if (prog->regstart) {
if (prog->reganch & ROPT_SKIP) { /* we have /x+whatever/ */
/* it must be a one character string */
char ch = SvPVX(prog->regstart)[0];
while (s < strend) {
if (*s == ch) {
if (regtry(prog, s))
goto got_it;
s++;
while (s < strend && *s == ch)
s++;
}
s++;
}
}
else if (SvPOK(prog->regstart) == 3) {
/* We know what string it must start with. */
while ((s = fbm_instr((unsigned char*)s,
(unsigned char*)strend, prog->regstart)) != NULL)
{
if (regtry(prog, s))
goto got_it;
s++;
}
}
else {
c = SvPVX(prog->regstart);
while ((s = ninstr(s, strend, c, c + SvCUR(prog->regstart))) != NULL)
{
if (regtry(prog, s))
goto got_it;
s++;
}
}
goto phooey;
}
/*SUPPRESS 560*/
if (c = prog->regstclass) {
I32 doevery = (prog->reganch & ROPT_SKIP) == 0;
if (minlen)
dontbother = minlen - 1;
strend -= dontbother; /* don't bother with what can't match */
tmp = 1;
/* We know what class it must start with. */
switch (OP(c)) {
case ANYOF:
c = OPERAND(c);
while (s < strend) {
if (reginclass(c, *s)) {
if (tmp && regtry(prog, s))
goto got_it;
else
tmp = doevery;
}
else
tmp = 1;
s++;
}
break;
case BOUNDL:
regtainted = TRUE;
/* FALL THROUGH */
case BOUND:
if (minlen)
dontbother++,strend--;
tmp = (s != startpos) ? UCHARAT(s - 1) : regprev;
tmp = ((OP(c) == BOUND ? isALNUM(tmp) : isALNUM_LC(tmp)) != 0);
while (s < strend) {
if (tmp == !(OP(c) == BOUND ? isALNUM(*s) : isALNUM_LC(*s))) {
tmp = !tmp;
if (regtry(prog, s))
goto got_it;
}
s++;
}
if ((minlen || tmp) && regtry(prog,s))
goto got_it;
break;
case NBOUNDL:
regtainted = TRUE;
/* FALL THROUGH */
case NBOUND:
if (minlen)
dontbother++,strend--;
tmp = (s != startpos) ? UCHARAT(s - 1) : regprev;
tmp = ((OP(c) == NBOUND ? isALNUM(tmp) : isALNUM_LC(tmp)) != 0);
while (s < strend) {
if (tmp == !(OP(c) == NBOUND ? isALNUM(*s) : isALNUM_LC(*s)))
tmp = !tmp;
else if (regtry(prog, s))
goto got_it;
s++;
}
if ((minlen || !tmp) && regtry(prog,s))
goto got_it;
break;
case ALNUM:
while (s < strend) {
if (isALNUM(*s)) {
if (tmp && regtry(prog, s))
goto got_it;
else
tmp = doevery;
}
else
tmp = 1;
s++;
}
break;
case ALNUML:
regtainted = TRUE;
while (s < strend) {
if (isALNUM_LC(*s)) {
if (tmp && regtry(prog, s))
goto got_it;
else
tmp = doevery;
}
else
tmp = 1;
s++;
}
break;
case NALNUM:
while (s < strend) {
if (!isALNUM(*s)) {
if (tmp && regtry(prog, s))
goto got_it;
else
tmp = doevery;
}
else
tmp = 1;
s++;
}
break;
case NALNUML:
regtainted = TRUE;
while (s < strend) {
if (!isALNUM_LC(*s)) {
if (tmp && regtry(prog, s))
goto got_it;
else
tmp = doevery;
}
else
tmp = 1;
s++;
}
break;
case SPACE:
while (s < strend) {
if (isSPACE(*s)) {
if (tmp && regtry(prog, s))
goto got_it;
else
tmp = doevery;
}
else
tmp = 1;
s++;
}
break;
case SPACEL:
regtainted = TRUE;
while (s < strend) {
if (isSPACE_LC(*s)) {
if (tmp && regtry(prog, s))
goto got_it;
else
tmp = doevery;
}
else
tmp = 1;
s++;
}
break;
case NSPACE:
while (s < strend) {
if (!isSPACE(*s)) {
if (tmp && regtry(prog, s))
goto got_it;
else
tmp = doevery;
}
else
tmp = 1;
s++;
}
break;
case NSPACEL:
regtainted = TRUE;
while (s < strend) {
if (!isSPACE_LC(*s)) {
if (tmp && regtry(prog, s))
goto got_it;
else
tmp = doevery;
}
else
tmp = 1;
s++;
}
break;
case DIGIT:
while (s < strend) {
if (isDIGIT(*s)) {
if (tmp && regtry(prog, s))
goto got_it;
else
tmp = doevery;
}
else
tmp = 1;
s++;
}
break;
case NDIGIT:
while (s < strend) {
if (!isDIGIT(*s)) {
if (tmp && regtry(prog, s))
goto got_it;
else
tmp = doevery;
}
else
tmp = 1;
s++;
}
break;
}
}
else {
if (minlen)
dontbother = minlen - 1;
strend -= dontbother;
/* We don't know much -- general case. */
do {
if (regtry(prog, s))
goto got_it;
} while (s++ < strend);
}
/* Failure. */
goto phooey;
got_it:
strend += dontbother; /* uncheat */
prog->subbeg = strbeg;
prog->subend = strend;
prog->exec_tainted = regtainted;
/* make sure $`, $&, $', and $digit will work later */
if (!safebase && (strbeg != prog->subbase)) {
I32 i = strend - startpos + (stringarg - strbeg);
s = savepvn(strbeg, i);
Safefree(prog->subbase);
prog->subbase = s;
prog->subbeg = prog->subbase;
prog->subend = prog->subbase + i;
s = prog->subbase + (stringarg - strbeg);
for (i = 0; i <= prog->nparens; i++) {
if (prog->endp[i]) {
prog->startp[i] = s + (prog->startp[i] - startpos);
prog->endp[i] = s + (prog->endp[i] - startpos);
}
}
}
return 1;
phooey:
return 0;
}
/*
- regtry - try match at specific point
*/
static I32 /* 0 failure, 1 success */
regtry(prog, startpos)
regexp *prog;
char *startpos;
{
register I32 i;
register char **sp;
register char **ep;
reginput = startpos;
regstartp = prog->startp;
regendp = prog->endp;
reglastparen = &prog->lastparen;
prog->lastparen = 0;
regsize = 0;
sp = prog->startp;
ep = prog->endp;
if (prog->nparens) {
for (i = prog->nparens; i >= 0; i--) {
*sp++ = NULL;
*ep++ = NULL;
}
}
if (regmatch(prog->program + 1) && reginput >= regtill) {
prog->startp[0] = startpos;
prog->endp[0] = reginput;
return 1;
}
else
return 0;
}
/*
- regmatch - main matching routine
*
* Conceptually the strategy is simple: check to see whether the current
* node matches, call self recursively to see whether the rest matches,
* and then act accordingly. In practice we make some effort to avoid
* recursion, in particular by going through "ordinary" nodes (that don't
* need to know whether the rest of the match failed) by a loop instead of
* by recursion.
*/
/* [lwall] I've hoisted the register declarations to the outer block in order to
* maybe save a little bit of pushing and popping on the stack. It also takes
* advantage of machines that use a register save mask on subroutine entry.
*/
static I32 /* 0 failure, 1 success */
regmatch(prog)
char *prog;
{
register char *scan; /* Current node. */
char *next; /* Next node. */
register I32 nextchar;
register I32 n; /* no or next */
register I32 ln; /* len or last */
register char *s; /* operand or save */
register char *locinput = reginput;
register I32 c1, c2; /* case fold search */
int minmod = 0;
#ifdef DEBUGGING
static int regindent = 0;
regindent++;
#endif
nextchar = UCHARAT(locinput);
scan = prog;
while (scan != NULL) {
#ifdef DEBUGGING
#define sayYES goto yes
#define sayNO goto no
#define saySAME(x) if (x) goto yes; else goto no
if (regnarrate) {
PerlIO_printf(Perl_debug_log, "%*s%2d%-8.8s\t<%.10s>\n", regindent*2, "",
scan - regprogram, regprop(scan), locinput);
}
#else
#define sayYES return 1
#define sayNO return 0
#define saySAME(x) return x
#endif
#ifdef REGALIGN
next = scan + NEXT(scan);
if (next == scan)
next = NULL;
#else
next = regnext(scan);
#endif
switch (OP(scan)) {
case BOL:
if (locinput == regbol
? regprev == '\n'
: ((nextchar || locinput < regeol) && locinput[-1] == '\n') )
{
/* regtill = regbol; */
break;
}
sayNO;
case MBOL:
if (locinput == regbol
? regprev == '\n'
: ((nextchar || locinput < regeol) && locinput[-1] == '\n') )
{
break;
}
sayNO;
case SBOL:
if (locinput == regbol && regprev == '\n')
break;
sayNO;
case GBOL:
if (locinput == regbol)
break;
sayNO;
case EOL:
if (multiline)
goto meol;
else
goto seol;
case MEOL:
meol:
if ((nextchar || locinput < regeol) && nextchar != '\n')
sayNO;
break;
case SEOL:
seol:
if ((nextchar || locinput < regeol) && nextchar != '\n')
sayNO;
if (regeol - locinput > 1)
sayNO;
break;
case SANY:
if (!nextchar && locinput >= regeol)
sayNO;
nextchar = UCHARAT(++locinput);
break;
case ANY:
if (!nextchar && locinput >= regeol || nextchar == '\n')
sayNO;
nextchar = UCHARAT(++locinput);
break;
case EXACT:
s = OPERAND(scan);
ln = *s++;
/* Inline the first character, for speed. */
if (UCHARAT(s) != nextchar)
sayNO;
if (regeol - locinput < ln)
sayNO;
if (ln > 1 && memNE(s, locinput, ln))
sayNO;
locinput += ln;
nextchar = UCHARAT(locinput);
break;
case EXACTFL:
regtainted = TRUE;
/* FALL THROUGH */
case EXACTF:
s = OPERAND(scan);
ln = *s++;
/* Inline the first character, for speed. */
if (UCHARAT(s) != nextchar &&
UCHARAT(s) != ((OP(scan) == EXACTF)
? fold : fold_locale)[nextchar])
sayNO;
if (regeol - locinput < ln)
sayNO;
if (ln > 1 && (OP(scan) == EXACTF
? ibcmp(s, locinput, ln)
: ibcmp_locale(s, locinput, ln)))
sayNO;
locinput += ln;
nextchar = UCHARAT(locinput);
break;
case ANYOF:
s = OPERAND(scan);
if (nextchar < 0)
nextchar = UCHARAT(locinput);
if (!reginclass(s, nextchar))
sayNO;
if (!nextchar && locinput >= regeol)
sayNO;
nextchar = UCHARAT(++locinput);
break;
case ALNUML:
regtainted = TRUE;
/* FALL THROUGH */
case ALNUM:
if (!nextchar)
sayNO;
if (!(OP(scan) == ALNUM
? isALNUM(nextchar) : isALNUM_LC(nextchar)))
sayNO;
nextchar = UCHARAT(++locinput);
break;
case NALNUML:
regtainted = TRUE;
/* FALL THROUGH */
case NALNUM:
if (!nextchar && locinput >= regeol)
sayNO;
if (OP(scan) == NALNUM
? isALNUM(nextchar) : isALNUM_LC(nextchar))
sayNO;
nextchar = UCHARAT(++locinput);
break;
case BOUNDL:
case NBOUNDL:
regtainted = TRUE;
/* FALL THROUGH */
case BOUND:
case NBOUND:
/* was last char in word? */
ln = (locinput != regbol) ? UCHARAT(locinput - 1) : regprev;
if (OP(scan) == BOUND || OP(scan) == NBOUND) {
ln = isALNUM(ln);
n = isALNUM(nextchar);
}
else {
ln = isALNUM_LC(ln);
n = isALNUM_LC(nextchar);
}
if (((!ln) == (!n)) == (OP(scan) == BOUND || OP(scan) == BOUNDL))
sayNO;
break;
case SPACEL:
regtainted = TRUE;
/* FALL THROUGH */
case SPACE:
if (!nextchar && locinput >= regeol)
sayNO;
if (!(OP(scan) == SPACE
? isSPACE(nextchar) : isSPACE_LC(nextchar)))
sayNO;
nextchar = UCHARAT(++locinput);
break;
case NSPACEL:
regtainted = TRUE;
/* FALL THROUGH */
case NSPACE:
if (!nextchar)
sayNO;
if (OP(scan) == SPACE
? isSPACE(nextchar) : isSPACE_LC(nextchar))
sayNO;
nextchar = UCHARAT(++locinput);
break;
case DIGIT:
if (!isDIGIT(nextchar))
sayNO;
nextchar = UCHARAT(++locinput);
break;
case NDIGIT:
if (!nextchar && locinput >= regeol)
sayNO;
if (isDIGIT(nextchar))
sayNO;
nextchar = UCHARAT(++locinput);
break;
case REF:
n = ARG1(scan); /* which paren pair */
s = regstartp[n];
if (!s)
sayNO;
if (!regendp[n])
sayNO;
if (s == regendp[n])
break;
/* Inline the first character, for speed. */
if (UCHARAT(s) != nextchar)
sayNO;
ln = regendp[n] - s;
if (locinput + ln > regeol)
sayNO;
if (ln > 1 && memNE(s, locinput, ln))
sayNO;
locinput += ln;
nextchar = UCHARAT(locinput);
break;
case NOTHING:
break;
case BACK:
break;
case OPEN:
n = ARG1(scan); /* which paren pair */
regstartp[n] = locinput;
if (n > regsize)
regsize = n;
break;
case CLOSE:
n = ARG1(scan); /* which paren pair */
regendp[n] = locinput;
if (n > *reglastparen)
*reglastparen = n;
break;
case CURLYX: {
CURCUR cc;
CHECKPOINT cp = savestack_ix;
cc.oldcc = regcc;
regcc = &cc;
cc.parenfloor = *reglastparen;
cc.cur = -1;
cc.min = ARG1(scan);
cc.max = ARG2(scan);
cc.scan = NEXTOPER(scan) + 4;
cc.next = next;
cc.minmod = minmod;
cc.lastloc = 0;
reginput = locinput;
n = regmatch(PREVOPER(next)); /* start on the WHILEM */
regcpblow(cp);
regcc = cc.oldcc;
saySAME(n);
}
/* NOT REACHED */
case WHILEM: {
/*
* This is really hard to understand, because after we match
* what we're trying to match, we must make sure the rest of
* the RE is going to match for sure, and to do that we have
* to go back UP the parse tree by recursing ever deeper. And
* if it fails, we have to reset our parent's current state
* that we can try again after backing off.
*/
CHECKPOINT cp;
CURCUR* cc = regcc;
n = cc->cur + 1; /* how many we know we matched */
reginput = locinput;
#ifdef DEBUGGING
if (regnarrate)
PerlIO_printf(Perl_debug_log, "%*s %d %lx\n", regindent*2, "",
n, (long)cc);
#endif
/* If degenerate scan matches "", assume scan done. */
if (locinput == cc->lastloc) {
regcc = cc->oldcc;
ln = regcc->cur;
if (regmatch(cc->next))
sayYES;
regcc->cur = ln;
regcc = cc;
sayNO;
}
/* First just match a string of min scans. */
if (n < cc->min) {
cc->cur = n;
cc->lastloc = locinput;
if (regmatch(cc->scan))
sayYES;
cc->cur = n - 1;
sayNO;
}
/* Prefer next over scan for minimal matching. */
if (cc->minmod) {
regcc = cc->oldcc;
ln = regcc->cur;
cp = regcppush(cc->parenfloor);
if (regmatch(cc->next)) {
regcpblow(cp);
sayYES; /* All done. */
}
regcppop();
regcc->cur = ln;
regcc = cc;
if (n >= cc->max) /* Maximum greed exceeded? */
sayNO;
/* Try scanning more and see if it helps. */
reginput = locinput;
cc->cur = n;
cc->lastloc = locinput;
cp = regcppush(cc->parenfloor);
if (regmatch(cc->scan)) {
regcpblow(cp);
sayYES;
}
regcppop();
cc->cur = n - 1;
sayNO;
}
/* Prefer scan over next for maximal matching. */
if (n < cc->max) { /* More greed allowed? */
cp = regcppush(cc->parenfloor);
cc->cur = n;
cc->lastloc = locinput;
if (regmatch(cc->scan)) {
regcpblow(cp);
sayYES;
}
regcppop(); /* Restore some previous $<digit>s? */
reginput = locinput;
}
/* Failed deeper matches of scan, so see if this one works. */
regcc = cc->oldcc;
ln = regcc->cur;
if (regmatch(cc->next))
sayYES;
regcc->cur = ln;
regcc = cc;
cc->cur = n - 1;
sayNO;
}
/* NOT REACHED */
case BRANCH: {
if (OP(next) != BRANCH) /* No choice. */
next = NEXTOPER(scan);/* Avoid recursion. */
else {
int lastparen = *reglastparen;
do {
reginput = locinput;
if (regmatch(NEXTOPER(scan)))
sayYES;
for (n = *reglastparen; n > lastparen; n--)
regendp[n] = 0;
*reglastparen = n;
#ifdef REGALIGN
/*SUPPRESS 560*/
if (n = NEXT(scan))
scan += n;
else
scan = NULL;
#else
scan = regnext(scan);
#endif
} while (scan != NULL && OP(scan) == BRANCH);
sayNO;
/* NOTREACHED */
}
}
break;
case MINMOD:
minmod = 1;