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Exporter.t (and question)
[perl5.git] / regcomp.c
1 /*    regcomp.c
2  */
3
4 /*
5  * "A fair jaw-cracker dwarf-language must be."  --Samwise Gamgee
6  */
7
8 /* NOTE: this is derived from Henry Spencer's regexp code, and should not
9  * confused with the original package (see point 3 below).  Thanks, Henry!
10  */
11
12 /* Additional note: this code is very heavily munged from Henry's version
13  * in places.  In some spots I've traded clarity for efficiency, so don't
14  * blame Henry for some of the lack of readability.
15  */
16
17 /* The names of the functions have been changed from regcomp and
18  * regexec to  pregcomp and pregexec in order to avoid conflicts
19  * with the POSIX routines of the same names.
20 */
21
22 #ifdef PERL_EXT_RE_BUILD
23 /* need to replace pregcomp et al, so enable that */
24 #  ifndef PERL_IN_XSUB_RE
25 #    define PERL_IN_XSUB_RE
26 #  endif
27 /* need access to debugger hooks */
28 #  if defined(PERL_EXT_RE_DEBUG) && !defined(DEBUGGING)
29 #    define DEBUGGING
30 #  endif
31 #endif
32
33 #ifdef PERL_IN_XSUB_RE
34 /* We *really* need to overwrite these symbols: */
35 #  define Perl_pregcomp my_regcomp
36 #  define Perl_regdump my_regdump
37 #  define Perl_regprop my_regprop
38 #  define Perl_pregfree my_regfree
39 #  define Perl_re_intuit_string my_re_intuit_string
40 /* *These* symbols are masked to allow static link. */
41 #  define Perl_regnext my_regnext
42 #  define Perl_save_re_context my_save_re_context
43 #  define Perl_reginitcolors my_reginitcolors
44
45 #  define PERL_NO_GET_CONTEXT
46 #endif
47
48 /*SUPPRESS 112*/
49 /*
50  * pregcomp and pregexec -- regsub and regerror are not used in perl
51  *
52  *      Copyright (c) 1986 by University of Toronto.
53  *      Written by Henry Spencer.  Not derived from licensed software.
54  *
55  *      Permission is granted to anyone to use this software for any
56  *      purpose on any computer system, and to redistribute it freely,
57  *      subject to the following restrictions:
58  *
59  *      1. The author is not responsible for the consequences of use of
60  *              this software, no matter how awful, even if they arise
61  *              from defects in it.
62  *
63  *      2. The origin of this software must not be misrepresented, either
64  *              by explicit claim or by omission.
65  *
66  *      3. Altered versions must be plainly marked as such, and must not
67  *              be misrepresented as being the original software.
68  *
69  *
70  ****    Alterations to Henry's code are...
71  ****
72  ****    Copyright (c) 1991-2001, Larry Wall
73  ****
74  ****    You may distribute under the terms of either the GNU General Public
75  ****    License or the Artistic License, as specified in the README file.
76
77  *
78  * Beware that some of this code is subtly aware of the way operator
79  * precedence is structured in regular expressions.  Serious changes in
80  * regular-expression syntax might require a total rethink.
81  */
82 #include "EXTERN.h"
83 #define PERL_IN_REGCOMP_C
84 #include "perl.h"
85
86 #ifndef PERL_IN_XSUB_RE
87 #  include "INTERN.h"
88 #endif
89
90 #define REG_COMP_C
91 #include "regcomp.h"
92
93 #ifdef op
94 #undef op
95 #endif /* op */
96
97 #ifdef MSDOS
98 # if defined(BUGGY_MSC6)
99  /* MSC 6.00A breaks on op/regexp.t test 85 unless we turn this off */
100  # pragma optimize("a",off)
101  /* But MSC 6.00A is happy with 'w', for aliases only across function calls*/
102  # pragma optimize("w",on )
103 # endif /* BUGGY_MSC6 */
104 #endif /* MSDOS */
105
106 #ifndef STATIC
107 #define STATIC  static
108 #endif
109
110 typedef struct RExC_state_t {
111     U16         flags16;                /* are we folding, multilining? */
112     char        *precomp;               /* uncompiled string. */
113     regexp      *rx;
114     char        *start;                 /* Start of input for compile */
115     char        *end;                   /* End of input for compile */
116     char        *parse;                 /* Input-scan pointer. */
117     I32         whilem_seen;            /* number of WHILEM in this expr */
118     regnode     *emit_start;            /* Start of emitted-code area */
119     regnode     *emit;                  /* Code-emit pointer; &regdummy = don't = compiling */
120     I32         naughty;                /* How bad is this pattern? */
121     I32         sawback;                /* Did we see \1, ...? */
122     U32         seen;
123     I32         size;                   /* Code size. */
124     I32         npar;                   /* () count. */
125     I32         extralen;
126     I32         seen_zerolen;
127     I32         seen_evals;
128     I32         utf8;
129 #if ADD_TO_REGEXEC
130     char        *starttry;              /* -Dr: where regtry was called. */
131 #define RExC_starttry   (pRExC_state->starttry)
132 #endif
133 } RExC_state_t;
134
135 #define RExC_flags16    (pRExC_state->flags16)
136 #define RExC_precomp    (pRExC_state->precomp)
137 #define RExC_rx         (pRExC_state->rx)
138 #define RExC_start      (pRExC_state->start)
139 #define RExC_end        (pRExC_state->end)
140 #define RExC_parse      (pRExC_state->parse)
141 #define RExC_whilem_seen        (pRExC_state->whilem_seen)
142 #define RExC_offsets    (pRExC_state->rx->offsets) /* I am not like the others */
143 #define RExC_emit       (pRExC_state->emit)
144 #define RExC_emit_start (pRExC_state->emit_start)
145 #define RExC_naughty    (pRExC_state->naughty)
146 #define RExC_sawback    (pRExC_state->sawback)
147 #define RExC_seen       (pRExC_state->seen)
148 #define RExC_size       (pRExC_state->size)
149 #define RExC_npar       (pRExC_state->npar)
150 #define RExC_extralen   (pRExC_state->extralen)
151 #define RExC_seen_zerolen       (pRExC_state->seen_zerolen)
152 #define RExC_seen_evals (pRExC_state->seen_evals)
153 #define RExC_utf8       (pRExC_state->utf8)
154
155 #define ISMULT1(c)      ((c) == '*' || (c) == '+' || (c) == '?')
156 #define ISMULT2(s)      ((*s) == '*' || (*s) == '+' || (*s) == '?' || \
157         ((*s) == '{' && regcurly(s)))
158
159 #ifdef SPSTART
160 #undef SPSTART          /* dratted cpp namespace... */
161 #endif
162 /*
163  * Flags to be passed up and down.
164  */
165 #define WORST           0       /* Worst case. */
166 #define HASWIDTH        0x1     /* Known to match non-null strings. */
167 #define SIMPLE          0x2     /* Simple enough to be STAR/PLUS operand. */
168 #define SPSTART         0x4     /* Starts with * or +. */
169 #define TRYAGAIN        0x8     /* Weeded out a declaration. */
170
171 /* Length of a variant. */
172
173 typedef struct scan_data_t {
174     I32 len_min;
175     I32 len_delta;
176     I32 pos_min;
177     I32 pos_delta;
178     SV *last_found;
179     I32 last_end;                       /* min value, <0 unless valid. */
180     I32 last_start_min;
181     I32 last_start_max;
182     SV **longest;                       /* Either &l_fixed, or &l_float. */
183     SV *longest_fixed;
184     I32 offset_fixed;
185     SV *longest_float;
186     I32 offset_float_min;
187     I32 offset_float_max;
188     I32 flags;
189     I32 whilem_c;
190     I32 *last_closep;
191     struct regnode_charclass_class *start_class;
192 } scan_data_t;
193
194 /*
195  * Forward declarations for pregcomp()'s friends.
196  */
197
198 static scan_data_t zero_scan_data = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
199                                       0, 0, 0, 0, 0, 0};
200
201 #define SF_BEFORE_EOL           (SF_BEFORE_SEOL|SF_BEFORE_MEOL)
202 #define SF_BEFORE_SEOL          0x1
203 #define SF_BEFORE_MEOL          0x2
204 #define SF_FIX_BEFORE_EOL       (SF_FIX_BEFORE_SEOL|SF_FIX_BEFORE_MEOL)
205 #define SF_FL_BEFORE_EOL        (SF_FL_BEFORE_SEOL|SF_FL_BEFORE_MEOL)
206
207 #ifdef NO_UNARY_PLUS
208 #  define SF_FIX_SHIFT_EOL      (0+2)
209 #  define SF_FL_SHIFT_EOL               (0+4)
210 #else
211 #  define SF_FIX_SHIFT_EOL      (+2)
212 #  define SF_FL_SHIFT_EOL               (+4)
213 #endif
214
215 #define SF_FIX_BEFORE_SEOL      (SF_BEFORE_SEOL << SF_FIX_SHIFT_EOL)
216 #define SF_FIX_BEFORE_MEOL      (SF_BEFORE_MEOL << SF_FIX_SHIFT_EOL)
217
218 #define SF_FL_BEFORE_SEOL       (SF_BEFORE_SEOL << SF_FL_SHIFT_EOL)
219 #define SF_FL_BEFORE_MEOL       (SF_BEFORE_MEOL << SF_FL_SHIFT_EOL) /* 0x20 */
220 #define SF_IS_INF               0x40
221 #define SF_HAS_PAR              0x80
222 #define SF_IN_PAR               0x100
223 #define SF_HAS_EVAL             0x200
224 #define SCF_DO_SUBSTR           0x400
225 #define SCF_DO_STCLASS_AND      0x0800
226 #define SCF_DO_STCLASS_OR       0x1000
227 #define SCF_DO_STCLASS          (SCF_DO_STCLASS_AND|SCF_DO_STCLASS_OR)
228 #define SCF_WHILEM_VISITED_POS  0x2000
229
230 #define UTF RExC_utf8
231 #define LOC (RExC_flags16 & PMf_LOCALE)
232 #define FOLD (RExC_flags16 & PMf_FOLD)
233
234 #define OOB_UNICODE             12345678
235 #define OOB_NAMEDCLASS          -1
236
237 #define CHR_SVLEN(sv) (UTF ? sv_len_utf8(sv) : SvCUR(sv))
238 #define CHR_DIST(a,b) (UTF ? utf8_distance(a,b) : a - b)
239
240
241 /* length of regex to show in messages that don't mark a position within */
242 #define RegexLengthToShowInErrorMessages 127
243
244 /*
245  * If MARKER[12] are adjusted, be sure to adjust the constants at the top
246  * of t/op/regmesg.t, the tests in t/op/re_tests, and those in
247  * op/pragma/warn/regcomp.
248  */
249 #define MARKER1 "<-- HERE"    /* marker as it appears in the description */
250 #define MARKER2 " <-- HERE "  /* marker as it appears within the regex */
251
252 #define REPORT_LOCATION " in regex; marked by " MARKER1 " in m/%.*s" MARKER2 "%s/"
253
254 /*
255  * Calls SAVEDESTRUCTOR_X if needed, then calls Perl_croak with the given
256  * arg. Show regex, up to a maximum length. If it's too long, chop and add
257  * "...".
258  */
259 #define FAIL(msg)                                                             \
260     STMT_START {                                                             \
261         char *ellipses = "";                                                 \
262         IV len = RExC_end - RExC_precomp;                                \
263                                                                              \
264         if (!SIZE_ONLY)                                                      \
265             SAVEDESTRUCTOR_X(clear_re,(void*)RExC_rx);                 \
266                                                                              \
267         if (len > RegexLengthToShowInErrorMessages) {                        \
268             /* chop 10 shorter than the max, to ensure meaning of "..." */   \
269             len = RegexLengthToShowInErrorMessages - 10;                     \
270             ellipses = "...";                                                \
271         }                                                                    \
272         Perl_croak(aTHX_ "%s in regex m/%.*s%s/",                            \
273                    msg, (int)len, RExC_precomp, ellipses);                  \
274     } STMT_END
275
276 /*
277  * Calls SAVEDESTRUCTOR_X if needed, then calls Perl_croak with the given
278  * args. Show regex, up to a maximum length. If it's too long, chop and add
279  * "...".
280  */
281 #define FAIL2(pat,msg)                                                        \
282     STMT_START {                                                             \
283         char *ellipses = "";                                                 \
284         IV len = RExC_end - RExC_precomp;                                \
285                                                                              \
286         if (!SIZE_ONLY)                                                      \
287             SAVEDESTRUCTOR_X(clear_re,(void*)RExC_rx);                 \
288                                                                              \
289         if (len > RegexLengthToShowInErrorMessages) {                        \
290             /* chop 10 shorter than the max, to ensure meaning of "..." */   \
291             len = RegexLengthToShowInErrorMessages - 10;                     \
292             ellipses = "...";                                                \
293         }                                                                    \
294         S_re_croak2(aTHX_ pat, " in regex m/%.*s%s/",                        \
295                     msg, (int)len, RExC_precomp, ellipses);                \
296     } STMT_END
297
298
299 /*
300  * Simple_vFAIL -- like FAIL, but marks the current location in the scan
301  */
302 #define Simple_vFAIL(m)                                                      \
303     STMT_START {                                                             \
304       IV offset = RExC_parse - RExC_precomp; \
305                                                                              \
306       Perl_croak(aTHX_ "%s" REPORT_LOCATION,               \
307                  m, (int)offset, RExC_precomp, RExC_precomp + offset);     \
308     } STMT_END
309
310 /*
311  * Calls SAVEDESTRUCTOR_X if needed, then Simple_vFAIL()
312  */
313 #define vFAIL(m)                                                             \
314     STMT_START {                                                             \
315       if (!SIZE_ONLY)                                                        \
316             SAVEDESTRUCTOR_X(clear_re,(void*)RExC_rx);                 \
317       Simple_vFAIL(m);                                                       \
318     } STMT_END
319
320 /*
321  * Like Simple_vFAIL(), but accepts two arguments.
322  */
323 #define Simple_vFAIL2(m,a1)                                                  \
324     STMT_START {                                                             \
325       IV offset = RExC_parse - RExC_precomp; \
326                                                                              \
327       S_re_croak2(aTHX_ m, REPORT_LOCATION, a1,       \
328                   (int)offset, RExC_precomp, RExC_precomp + offset);       \
329     } STMT_END
330
331 /*
332  * Calls SAVEDESTRUCTOR_X if needed, then Simple_vFAIL2().
333  */
334 #define vFAIL2(m,a1)                                                         \
335     STMT_START {                                                             \
336       if (!SIZE_ONLY)                                                        \
337             SAVEDESTRUCTOR_X(clear_re,(void*)RExC_rx);                 \
338       Simple_vFAIL2(m, a1);                                                  \
339     } STMT_END
340
341
342 /*
343  * Like Simple_vFAIL(), but accepts three arguments.
344  */
345 #define Simple_vFAIL3(m, a1, a2)                                             \
346     STMT_START {                                                             \
347       IV offset = RExC_parse - RExC_precomp; \
348                                                                              \
349       S_re_croak2(aTHX_ m, REPORT_LOCATION, a1, a2,   \
350                   (int)offset, RExC_precomp, RExC_precomp + offset);       \
351     } STMT_END
352
353 /*
354  * Calls SAVEDESTRUCTOR_X if needed, then Simple_vFAIL3().
355  */
356 #define vFAIL3(m,a1,a2)                                                      \
357     STMT_START {                                                             \
358       if (!SIZE_ONLY)                                                        \
359             SAVEDESTRUCTOR_X(clear_re,(void*)RExC_rx);                 \
360       Simple_vFAIL3(m, a1, a2);                                              \
361     } STMT_END
362
363 /*
364  * Like Simple_vFAIL(), but accepts four arguments.
365  */
366 #define Simple_vFAIL4(m, a1, a2, a3)                                         \
367     STMT_START {                                                             \
368       IV offset = RExC_parse - RExC_precomp; \
369                                                                              \
370       S_re_croak2(aTHX_ m, REPORT_LOCATION, a1, a2, a3,\
371                   (int)offset, RExC_precomp, RExC_precomp + offset);       \
372     } STMT_END
373
374 /*
375  * Like Simple_vFAIL(), but accepts five arguments.
376  */
377 #define Simple_vFAIL5(m, a1, a2, a3, a4)                                     \
378     STMT_START {                                                             \
379       IV offset = RExC_parse - RExC_precomp; \
380       S_re_croak2(aTHX_ m, REPORT_LOCATION, a1, a2, a3, a4,\
381                   (int)offset, RExC_precomp, RExC_precomp + offset);       \
382     } STMT_END
383
384
385 #define vWARN(loc,m)                                                         \
386     STMT_START {                                                             \
387         IV offset = loc - RExC_precomp;          \
388         Perl_warner(aTHX_ WARN_REGEXP, "%s" REPORT_LOCATION,\
389                  m, (int)offset, RExC_precomp, RExC_precomp + offset);          \
390     } STMT_END                                                               \
391
392 #define vWARNdep(loc,m)                                                         \
393     STMT_START {                                                             \
394         IV offset = loc - RExC_precomp;          \
395         int warn_cat = ckWARN(WARN_REGEXP) ? WARN_REGEXP : WARN_DEPRECATED;  \
396         Perl_warner(aTHX_ warn_cat, "%s" REPORT_LOCATION,\
397                  m, (int)offset, RExC_precomp, RExC_precomp + offset);          \
398     } STMT_END                                                               \
399
400
401 #define vWARN2(loc, m, a1)                                                   \
402     STMT_START {                                                             \
403         IV offset = loc - RExC_precomp;          \
404         Perl_warner(aTHX_ WARN_REGEXP, m REPORT_LOCATION,\
405                  a1,                                                         \
406                  (int)offset, RExC_precomp, RExC_precomp + offset);        \
407     } STMT_END
408
409 #define vWARN3(loc, m, a1, a2)                                               \
410     STMT_START {                                                             \
411       IV offset = loc - RExC_precomp;        \
412         Perl_warner(aTHX_ WARN_REGEXP, m REPORT_LOCATION,                    \
413                  a1, a2,                                                     \
414                  (int)offset, RExC_precomp, RExC_precomp + offset);        \
415     } STMT_END
416
417 #define vWARN4(loc, m, a1, a2, a3)                                           \
418     STMT_START {                                                             \
419       IV offset = loc - RExC_precomp;            \
420         Perl_warner(aTHX_ WARN_REGEXP, m REPORT_LOCATION,\
421                  a1, a2, a3,                                                 \
422                  (int)offset, RExC_precomp, RExC_precomp + offset);        \
423     } STMT_END
424
425 /* used for the parse_flags section for (?c) -- japhy */
426 #define vWARN5(loc, m, a1, a2, a3, a4)                                       \
427   STMT_START {                                                   \
428       IV offset = loc - RExC_precomp;   \
429         Perl_warner(aTHX_ WARN_REGEXP, m REPORT_LOCATION,      \
430                  a1, a2, a3, a4,                                 \
431                  (int)offset, RExC_precomp, RExC_precomp + offset);  \
432     } STMT_END
433
434
435 /* Allow for side effects in s */
436 #define REGC(c,s) STMT_START { if (!SIZE_ONLY) *(s) = (c); else (void)(s);} STMT_END
437
438 /* Macros for recording node offsets.   20001227 mjd@plover.com 
439  * Nodes are numbered 1, 2, 3, 4.  Node #n's position is recorded in
440  * element 2*n-1 of the array.  Element #2n holds the byte length node #n.
441  * Element 0 holds the number n.
442  */
443
444 #define MJD_OFFSET_DEBUG(x)
445 /* #define MJD_OFFSET_DEBUG(x) fprintf x */
446
447
448 #  define Set_Node_Offset_To_R(node,byte)                           \
449    STMT_START {                                        \
450      if (! SIZE_ONLY) {                                  \
451        if((node) < 0) {                   \
452          Perl_croak(aTHX_ "value of node is %d in Offset macro", node); \
453        } else {                                                        \
454          RExC_offsets[2*(node)-1] = (byte);                               \
455        }                                                               \
456      }                                                                 \
457    } STMT_END
458
459 #  define Set_Node_Offset(node,byte) Set_Node_Offset_To_R((node)-RExC_emit_start, (byte)-RExC_start)
460 #  define Set_Cur_Node_Offset Set_Node_Offset(RExC_emit, RExC_parse)
461
462 #  define Set_Node_Length_To_R(node,len)                            \
463    STMT_START {                                        \
464      if (! SIZE_ONLY) {                                  \
465        MJD_OFFSET_DEBUG((stderr, "** (%d) size of node %d is %d.\n", __LINE__, (node), (len))); \
466        if((node) < 0) {                   \
467          Perl_croak(aTHX_ "value of node is %d in Length macro", node); \
468        } else {                                                        \
469          RExC_offsets[2*(node)] = (len);                               \
470        }                                                               \
471      }                                                                 \
472    } STMT_END
473
474 #  define Set_Node_Length(node,len) Set_Node_Length_To_R((node)-RExC_emit_start, len)
475 #  define Set_Cur_Node_Length(len)  Set_Node_Length(RExC_emit, len)
476 #  define Set_Node_Cur_Length(node)   Set_Node_Length(node, RExC_parse - parse_start)
477
478 /* Get offsets and lengths */
479 #define Node_Offset(n) (RExC_offsets[2*((n)-RExC_emit_start)-1])
480 #define Node_Length(n) (RExC_offsets[2*((n)-RExC_emit_start)])
481
482 static void clear_re(pTHX_ void *r);
483
484 /* Mark that we cannot extend a found fixed substring at this point.
485    Updata the longest found anchored substring and the longest found
486    floating substrings if needed. */
487
488 STATIC void
489 S_scan_commit(pTHX_ RExC_state_t *pRExC_state, scan_data_t *data)
490 {
491     STRLEN l = CHR_SVLEN(data->last_found);
492     STRLEN old_l = CHR_SVLEN(*data->longest);
493
494     if ((l >= old_l) && ((l > old_l) || (data->flags & SF_BEFORE_EOL))) {
495         sv_setsv(*data->longest, data->last_found);
496         if (*data->longest == data->longest_fixed) {
497             data->offset_fixed = l ? data->last_start_min : data->pos_min;
498             if (data->flags & SF_BEFORE_EOL)
499                 data->flags
500                     |= ((data->flags & SF_BEFORE_EOL) << SF_FIX_SHIFT_EOL);
501             else
502                 data->flags &= ~SF_FIX_BEFORE_EOL;
503         }
504         else {
505             data->offset_float_min = l ? data->last_start_min : data->pos_min;
506             data->offset_float_max = (l
507                                       ? data->last_start_max
508                                       : data->pos_min + data->pos_delta);
509             if (data->flags & SF_BEFORE_EOL)
510                 data->flags
511                     |= ((data->flags & SF_BEFORE_EOL) << SF_FL_SHIFT_EOL);
512             else
513                 data->flags &= ~SF_FL_BEFORE_EOL;
514         }
515     }
516     SvCUR_set(data->last_found, 0);
517     data->last_end = -1;
518     data->flags &= ~SF_BEFORE_EOL;
519 }
520
521 /* Can match anything (initialization) */
522 STATIC void
523 S_cl_anything(pTHX_ RExC_state_t *pRExC_state, struct regnode_charclass_class *cl)
524 {
525     ANYOF_CLASS_ZERO(cl);
526     ANYOF_BITMAP_SETALL(cl);
527     cl->flags = ANYOF_EOS|ANYOF_UNICODE_ALL;
528     if (LOC)
529         cl->flags |= ANYOF_LOCALE;
530 }
531
532 /* Can match anything (initialization) */
533 STATIC int
534 S_cl_is_anything(pTHX_ struct regnode_charclass_class *cl)
535 {
536     int value;
537
538     for (value = 0; value <= ANYOF_MAX; value += 2)
539         if (ANYOF_CLASS_TEST(cl, value) && ANYOF_CLASS_TEST(cl, value + 1))
540             return 1;
541     if (!(cl->flags & ANYOF_UNICODE_ALL))
542         return 0;
543     if (!ANYOF_BITMAP_TESTALLSET(cl))
544         return 0;
545     return 1;
546 }
547
548 /* Can match anything (initialization) */
549 STATIC void
550 S_cl_init(pTHX_ RExC_state_t *pRExC_state, struct regnode_charclass_class *cl)
551 {
552     Zero(cl, 1, struct regnode_charclass_class);
553     cl->type = ANYOF;
554     cl_anything(pRExC_state, cl);
555 }
556
557 STATIC void
558 S_cl_init_zero(pTHX_ RExC_state_t *pRExC_state, struct regnode_charclass_class *cl)
559 {
560     Zero(cl, 1, struct regnode_charclass_class);
561     cl->type = ANYOF;
562     cl_anything(pRExC_state, cl);
563     if (LOC)
564         cl->flags |= ANYOF_LOCALE;
565 }
566
567 /* 'And' a given class with another one.  Can create false positives */
568 /* We assume that cl is not inverted */
569 STATIC void
570 S_cl_and(pTHX_ struct regnode_charclass_class *cl,
571          struct regnode_charclass_class *and_with)
572 {
573     if (!(and_with->flags & ANYOF_CLASS)
574         && !(cl->flags & ANYOF_CLASS)
575         && (and_with->flags & ANYOF_LOCALE) == (cl->flags & ANYOF_LOCALE)
576         && !(and_with->flags & ANYOF_FOLD)
577         && !(cl->flags & ANYOF_FOLD)) {
578         int i;
579
580         if (and_with->flags & ANYOF_INVERT)
581             for (i = 0; i < ANYOF_BITMAP_SIZE; i++)
582                 cl->bitmap[i] &= ~and_with->bitmap[i];
583         else
584             for (i = 0; i < ANYOF_BITMAP_SIZE; i++)
585                 cl->bitmap[i] &= and_with->bitmap[i];
586     } /* XXXX: logic is complicated otherwise, leave it along for a moment. */
587     if (!(and_with->flags & ANYOF_EOS))
588         cl->flags &= ~ANYOF_EOS;
589
590     if (cl->flags & ANYOF_UNICODE_ALL && and_with->flags & ANYOF_UNICODE) {
591         cl->flags &= ~ANYOF_UNICODE_ALL;
592         cl->flags |= ANYOF_UNICODE;
593         ARG_SET(cl, ARG(and_with));
594     }
595     if (!(and_with->flags & ANYOF_UNICODE_ALL))
596         cl->flags &= ~ANYOF_UNICODE_ALL;
597     if (!(and_with->flags & (ANYOF_UNICODE|ANYOF_UNICODE_ALL)))
598         cl->flags &= ~ANYOF_UNICODE;
599 }
600
601 /* 'OR' a given class with another one.  Can create false positives */
602 /* We assume that cl is not inverted */
603 STATIC void
604 S_cl_or(pTHX_ RExC_state_t *pRExC_state, struct regnode_charclass_class *cl, struct regnode_charclass_class *or_with)
605 {
606     if (or_with->flags & ANYOF_INVERT) {
607         /* We do not use
608          * (B1 | CL1) | (!B2 & !CL2) = (B1 | !B2 & !CL2) | (CL1 | (!B2 & !CL2))
609          *   <= (B1 | !B2) | (CL1 | !CL2)
610          * which is wasteful if CL2 is small, but we ignore CL2:
611          *   (B1 | CL1) | (!B2 & !CL2) <= (B1 | CL1) | !B2 = (B1 | !B2) | CL1
612          * XXXX Can we handle case-fold?  Unclear:
613          *   (OK1(i) | OK1(i')) | !(OK1(i) | OK1(i')) =
614          *   (OK1(i) | OK1(i')) | (!OK1(i) & !OK1(i'))
615          */
616         if ( (or_with->flags & ANYOF_LOCALE) == (cl->flags & ANYOF_LOCALE)
617              && !(or_with->flags & ANYOF_FOLD)
618              && !(cl->flags & ANYOF_FOLD) ) {
619             int i;
620
621             for (i = 0; i < ANYOF_BITMAP_SIZE; i++)
622                 cl->bitmap[i] |= ~or_with->bitmap[i];
623         } /* XXXX: logic is complicated otherwise */
624         else {
625             cl_anything(pRExC_state, cl);
626         }
627     } else {
628         /* (B1 | CL1) | (B2 | CL2) = (B1 | B2) | (CL1 | CL2)) */
629         if ( (or_with->flags & ANYOF_LOCALE) == (cl->flags & ANYOF_LOCALE)
630              && (!(or_with->flags & ANYOF_FOLD)
631                  || (cl->flags & ANYOF_FOLD)) ) {
632             int i;
633
634             /* OR char bitmap and class bitmap separately */
635             for (i = 0; i < ANYOF_BITMAP_SIZE; i++)
636                 cl->bitmap[i] |= or_with->bitmap[i];
637             if (or_with->flags & ANYOF_CLASS) {
638                 for (i = 0; i < ANYOF_CLASSBITMAP_SIZE; i++)
639                     cl->classflags[i] |= or_with->classflags[i];
640                 cl->flags |= ANYOF_CLASS;
641             }
642         }
643         else { /* XXXX: logic is complicated, leave it along for a moment. */
644             cl_anything(pRExC_state, cl);
645         }
646     }
647     if (or_with->flags & ANYOF_EOS)
648         cl->flags |= ANYOF_EOS;
649
650     if (cl->flags & ANYOF_UNICODE && or_with->flags & ANYOF_UNICODE &&
651         ARG(cl) != ARG(or_with)) {
652         cl->flags |= ANYOF_UNICODE_ALL;
653         cl->flags &= ~ANYOF_UNICODE;
654     }
655     if (or_with->flags & ANYOF_UNICODE_ALL) {
656         cl->flags |= ANYOF_UNICODE_ALL;
657         cl->flags &= ~ANYOF_UNICODE;
658     }
659 }
660
661 /*
662  * There are strange code-generation bugs caused on sparc64 by gcc-2.95.2.
663  * These need to be revisited when a newer toolchain becomes available.
664  */
665 #if defined(__sparc64__) && defined(__GNUC__)
666 #   if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 96)
667 #       undef  SPARC64_GCC_WORKAROUND
668 #       define SPARC64_GCC_WORKAROUND 1
669 #   endif
670 #endif
671
672 /* REx optimizer.  Converts nodes into quickier variants "in place".
673    Finds fixed substrings.  */
674
675 /* Stops at toplevel WHILEM as well as at `last'. At end *scanp is set
676    to the position after last scanned or to NULL. */
677
678 STATIC I32
679 S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp, I32 *deltap, regnode *last, scan_data_t *data, U32 flags)
680                         /* scanp: Start here (read-write). */
681                         /* deltap: Write maxlen-minlen here. */
682                         /* last: Stop before this one. */
683 {
684     I32 min = 0, pars = 0, code;
685     regnode *scan = *scanp, *next;
686     I32 delta = 0;
687     int is_inf = (flags & SCF_DO_SUBSTR) && (data->flags & SF_IS_INF);
688     int is_inf_internal = 0;            /* The studied chunk is infinite */
689     I32 is_par = OP(scan) == OPEN ? ARG(scan) : 0;
690     scan_data_t data_fake;
691     struct regnode_charclass_class and_with; /* Valid if flags & SCF_DO_STCLASS_OR */
692
693     while (scan && OP(scan) != END && scan < last) {
694         /* Peephole optimizer: */
695
696         if (PL_regkind[(U8)OP(scan)] == EXACT) {
697             /* Merge several consecutive EXACTish nodes into one. */
698             regnode *n = regnext(scan);
699             U32 stringok = 1;
700 #ifdef DEBUGGING
701             regnode *stop = scan;
702 #endif
703
704             next = scan + NODE_SZ_STR(scan);
705             /* Skip NOTHING, merge EXACT*. */
706             while (n &&
707                    ( PL_regkind[(U8)OP(n)] == NOTHING ||
708                      (stringok && (OP(n) == OP(scan))))
709                    && NEXT_OFF(n)
710                    && NEXT_OFF(scan) + NEXT_OFF(n) < I16_MAX) {
711                 if (OP(n) == TAIL || n > next)
712                     stringok = 0;
713                 if (PL_regkind[(U8)OP(n)] == NOTHING) {
714                     NEXT_OFF(scan) += NEXT_OFF(n);
715                     next = n + NODE_STEP_REGNODE;
716 #ifdef DEBUGGING
717                     if (stringok)
718                         stop = n;
719 #endif
720                     n = regnext(n);
721                 }
722                 else if (stringok) {
723                     int oldl = STR_LEN(scan);
724                     regnode *nnext = regnext(n);
725
726                     if (oldl + STR_LEN(n) > U8_MAX)
727                         break;
728                     NEXT_OFF(scan) += NEXT_OFF(n);
729                     STR_LEN(scan) += STR_LEN(n);
730                     next = n + NODE_SZ_STR(n);
731                     /* Now we can overwrite *n : */
732                     Move(STRING(n), STRING(scan) + oldl, STR_LEN(n), char);
733 #ifdef DEBUGGING
734                     stop = next - 1;
735 #endif
736                     n = nnext;
737                 }
738             }
739 #ifdef DEBUGGING
740             /* Allow dumping */
741             n = scan + NODE_SZ_STR(scan);
742             while (n <= stop) {
743                 if (PL_regkind[(U8)OP(n)] != NOTHING || OP(n) == NOTHING) {
744                     OP(n) = OPTIMIZED;
745                     NEXT_OFF(n) = 0;
746                 }
747                 n++;
748             }
749 #endif
750         }
751         /* Follow the next-chain of the current node and optimize
752            away all the NOTHINGs from it.  */
753         if (OP(scan) != CURLYX) {
754             int max = (reg_off_by_arg[OP(scan)]
755                        ? I32_MAX
756                        /* I32 may be smaller than U16 on CRAYs! */
757                        : (I32_MAX < U16_MAX ? I32_MAX : U16_MAX));
758             int off = (reg_off_by_arg[OP(scan)] ? ARG(scan) : NEXT_OFF(scan));
759             int noff;
760             regnode *n = scan;
761         
762             /* Skip NOTHING and LONGJMP. */
763             while ((n = regnext(n))
764                    && ((PL_regkind[(U8)OP(n)] == NOTHING && (noff = NEXT_OFF(n)))
765                        || ((OP(n) == LONGJMP) && (noff = ARG(n))))
766                    && off + noff < max)
767                 off += noff;
768             if (reg_off_by_arg[OP(scan)])
769                 ARG(scan) = off;
770             else
771                 NEXT_OFF(scan) = off;
772         }
773         /* The principal pseudo-switch.  Cannot be a switch, since we
774            look into several different things.  */
775         if (OP(scan) == BRANCH || OP(scan) == BRANCHJ
776                    || OP(scan) == IFTHEN || OP(scan) == SUSPEND) {
777             next = regnext(scan);
778             code = OP(scan);
779         
780             if (OP(next) == code || code == IFTHEN || code == SUSPEND) {
781                 I32 max1 = 0, min1 = I32_MAX, num = 0;
782                 struct regnode_charclass_class accum;
783                 
784                 if (flags & SCF_DO_SUBSTR) /* XXXX Add !SUSPEND? */
785                     scan_commit(pRExC_state, data); /* Cannot merge strings after this. */
786                 if (flags & SCF_DO_STCLASS)
787                     cl_init_zero(pRExC_state, &accum);
788                 while (OP(scan) == code) {
789                     I32 deltanext, minnext, f = 0, fake;
790                     struct regnode_charclass_class this_class;
791
792                     num++;
793                     data_fake.flags = 0;
794                     if (data) {         
795                         data_fake.whilem_c = data->whilem_c;
796                         data_fake.last_closep = data->last_closep;
797                     }
798                     else
799                         data_fake.last_closep = &fake;
800                     next = regnext(scan);
801                     scan = NEXTOPER(scan);
802                     if (code != BRANCH)
803                         scan = NEXTOPER(scan);
804                     if (flags & SCF_DO_STCLASS) {
805                         cl_init(pRExC_state, &this_class);
806                         data_fake.start_class = &this_class;
807                         f = SCF_DO_STCLASS_AND;
808                     }           
809                     if (flags & SCF_WHILEM_VISITED_POS)
810                         f |= SCF_WHILEM_VISITED_POS;
811                     /* we suppose the run is continuous, last=next...*/
812                     minnext = study_chunk(pRExC_state, &scan, &deltanext,
813                                           next, &data_fake, f);
814                     if (min1 > minnext)
815                         min1 = minnext;
816                     if (max1 < minnext + deltanext)
817                         max1 = minnext + deltanext;
818                     if (deltanext == I32_MAX)
819                         is_inf = is_inf_internal = 1;
820                     scan = next;
821                     if (data_fake.flags & (SF_HAS_PAR|SF_IN_PAR))
822                         pars++;
823                     if (data && (data_fake.flags & SF_HAS_EVAL))
824                         data->flags |= SF_HAS_EVAL;
825                     if (data)
826                         data->whilem_c = data_fake.whilem_c;
827                     if (flags & SCF_DO_STCLASS)
828                         cl_or(pRExC_state, &accum, &this_class);
829                     if (code == SUSPEND)
830                         break;
831                 }
832                 if (code == IFTHEN && num < 2) /* Empty ELSE branch */
833                     min1 = 0;
834                 if (flags & SCF_DO_SUBSTR) {
835                     data->pos_min += min1;
836                     data->pos_delta += max1 - min1;
837                     if (max1 != min1 || is_inf)
838                         data->longest = &(data->longest_float);
839                 }
840                 min += min1;
841                 delta += max1 - min1;
842                 if (flags & SCF_DO_STCLASS_OR) {
843                     cl_or(pRExC_state, data->start_class, &accum);
844                     if (min1) {
845                         cl_and(data->start_class, &and_with);
846                         flags &= ~SCF_DO_STCLASS;
847                     }
848                 }
849                 else if (flags & SCF_DO_STCLASS_AND) {
850                     if (min1) {
851                         cl_and(data->start_class, &accum);
852                         flags &= ~SCF_DO_STCLASS;
853                     }
854                     else {
855                         /* Switch to OR mode: cache the old value of
856                          * data->start_class */
857                         StructCopy(data->start_class, &and_with,
858                                    struct regnode_charclass_class);
859                         flags &= ~SCF_DO_STCLASS_AND;
860                         StructCopy(&accum, data->start_class,
861                                    struct regnode_charclass_class);
862                         flags |= SCF_DO_STCLASS_OR;
863                         data->start_class->flags |= ANYOF_EOS;
864                     }
865                 }
866             }
867             else if (code == BRANCHJ)   /* single branch is optimized. */
868                 scan = NEXTOPER(NEXTOPER(scan));
869             else                        /* single branch is optimized. */
870                 scan = NEXTOPER(scan);
871             continue;
872         }
873         else if (OP(scan) == EXACT) {
874             I32 l = STR_LEN(scan);
875             UV uc = *((U8*)STRING(scan));
876             if (UTF) {
877                 U8 *s = (U8*)STRING(scan);
878                 l = utf8_length(s, s + l);
879                 uc = utf8_to_uvchr(s, NULL);
880             }
881             min += l;
882             if (flags & SCF_DO_SUBSTR) { /* Update longest substr. */
883                 /* The code below prefers earlier match for fixed
884                    offset, later match for variable offset.  */
885                 if (data->last_end == -1) { /* Update the start info. */
886                     data->last_start_min = data->pos_min;
887                     data->last_start_max = is_inf
888                         ? I32_MAX : data->pos_min + data->pos_delta;
889                 }
890                 sv_catpvn(data->last_found, STRING(scan), STR_LEN(scan));
891                 data->last_end = data->pos_min + l;
892                 data->pos_min += l; /* As in the first entry. */
893                 data->flags &= ~SF_BEFORE_EOL;
894             }
895             if (flags & SCF_DO_STCLASS_AND) {
896                 /* Check whether it is compatible with what we know already! */
897                 int compat = 1;
898
899                 if (uc >= 0x100 ||
900                     (!(data->start_class->flags & (ANYOF_CLASS | ANYOF_LOCALE))
901                     && !ANYOF_BITMAP_TEST(data->start_class, uc)
902                     && (!(data->start_class->flags & ANYOF_FOLD)
903                         || !ANYOF_BITMAP_TEST(data->start_class, PL_fold[uc])))
904                     )
905                     compat = 0;
906                 ANYOF_CLASS_ZERO(data->start_class);
907                 ANYOF_BITMAP_ZERO(data->start_class);
908                 if (compat)
909                     ANYOF_BITMAP_SET(data->start_class, uc);
910                 data->start_class->flags &= ~ANYOF_EOS;
911                 if (uc < 0x100)
912                   data->start_class->flags &= ~ANYOF_UNICODE_ALL;
913             }
914             else if (flags & SCF_DO_STCLASS_OR) {
915                 /* false positive possible if the class is case-folded */
916                 if (uc < 0x100)
917                     ANYOF_BITMAP_SET(data->start_class, uc);
918                 else
919                     data->start_class->flags |= ANYOF_UNICODE_ALL;
920                 data->start_class->flags &= ~ANYOF_EOS;
921                 cl_and(data->start_class, &and_with);
922             }
923             flags &= ~SCF_DO_STCLASS;
924         }
925         else if (PL_regkind[(U8)OP(scan)] == EXACT) { /* But OP != EXACT! */
926             I32 l = STR_LEN(scan);
927             UV uc = *((U8*)STRING(scan));
928
929             /* Search for fixed substrings supports EXACT only. */
930             if (flags & SCF_DO_SUBSTR)
931                 scan_commit(pRExC_state, data);
932             if (UTF) {
933                 U8 *s = (U8 *)STRING(scan);
934                 l = utf8_length(s, s + l);
935                 uc = utf8_to_uvchr(s, NULL);
936             }
937             min += l;
938             if (data && (flags & SCF_DO_SUBSTR))
939                 data->pos_min += l;
940             if (flags & SCF_DO_STCLASS_AND) {
941                 /* Check whether it is compatible with what we know already! */
942                 int compat = 1;
943
944                 if (uc >= 0x100 ||
945                     (!(data->start_class->flags & (ANYOF_CLASS | ANYOF_LOCALE))
946                     && !ANYOF_BITMAP_TEST(data->start_class, uc)
947                      && !ANYOF_BITMAP_TEST(data->start_class, PL_fold[uc])))
948                     compat = 0;
949                 ANYOF_CLASS_ZERO(data->start_class);
950                 ANYOF_BITMAP_ZERO(data->start_class);
951                 if (compat) {
952                     ANYOF_BITMAP_SET(data->start_class, uc);
953                     data->start_class->flags &= ~ANYOF_EOS;
954                     data->start_class->flags |= ANYOF_FOLD;
955                     if (OP(scan) == EXACTFL)
956                         data->start_class->flags |= ANYOF_LOCALE;
957                 }
958             }
959             else if (flags & SCF_DO_STCLASS_OR) {
960                 if (data->start_class->flags & ANYOF_FOLD) {
961                     /* false positive possible if the class is case-folded.
962                        Assume that the locale settings are the same... */
963                     if (uc < 0x100)
964                         ANYOF_BITMAP_SET(data->start_class, uc);
965                     data->start_class->flags &= ~ANYOF_EOS;
966                 }
967                 cl_and(data->start_class, &and_with);
968             }
969             flags &= ~SCF_DO_STCLASS;
970         }
971         else if (strchr((char*)PL_varies,OP(scan))) {
972             I32 mincount, maxcount, minnext, deltanext, fl = 0;
973             I32 f = flags, pos_before = 0;
974             regnode *oscan = scan;
975             struct regnode_charclass_class this_class;
976             struct regnode_charclass_class *oclass = NULL;
977             I32 next_is_eval = 0;
978
979             switch (PL_regkind[(U8)OP(scan)]) {
980             case WHILEM:                /* End of (?:...)* . */
981                 scan = NEXTOPER(scan);
982                 goto finish;
983             case PLUS:
984                 if (flags & (SCF_DO_SUBSTR | SCF_DO_STCLASS)) {
985                     next = NEXTOPER(scan);
986                     if (OP(next) == EXACT || (flags & SCF_DO_STCLASS)) {
987                         mincount = 1;
988                         maxcount = REG_INFTY;
989                         next = regnext(scan);
990                         scan = NEXTOPER(scan);
991                         goto do_curly;
992                     }
993                 }
994                 if (flags & SCF_DO_SUBSTR)
995                     data->pos_min++;
996                 min++;
997                 /* Fall through. */
998             case STAR:
999                 if (flags & SCF_DO_STCLASS) {
1000                     mincount = 0;
1001                     maxcount = REG_INFTY;
1002                     next = regnext(scan);
1003                     scan = NEXTOPER(scan);
1004                     goto do_curly;
1005                 }
1006                 is_inf = is_inf_internal = 1;
1007                 scan = regnext(scan);
1008                 if (flags & SCF_DO_SUBSTR) {
1009                     scan_commit(pRExC_state, data); /* Cannot extend fixed substrings */
1010                     data->longest = &(data->longest_float);
1011                 }
1012                 goto optimize_curly_tail;
1013             case CURLY:
1014                 mincount = ARG1(scan);
1015                 maxcount = ARG2(scan);
1016                 next = regnext(scan);
1017                 if (OP(scan) == CURLYX) {
1018                     I32 lp = (data ? *(data->last_closep) : 0);
1019
1020                     scan->flags = ((lp <= U8_MAX) ? lp : U8_MAX);
1021                 }
1022                 scan = NEXTOPER(scan) + EXTRA_STEP_2ARGS;
1023                 next_is_eval = (OP(scan) == EVAL);
1024               do_curly:
1025                 if (flags & SCF_DO_SUBSTR) {
1026                     if (mincount == 0) scan_commit(pRExC_state,data); /* Cannot extend fixed substrings */
1027                     pos_before = data->pos_min;
1028                 }
1029                 if (data) {
1030                     fl = data->flags;
1031                     data->flags &= ~(SF_HAS_PAR|SF_IN_PAR|SF_HAS_EVAL);
1032                     if (is_inf)
1033                         data->flags |= SF_IS_INF;
1034                 }
1035                 if (flags & SCF_DO_STCLASS) {
1036                     cl_init(pRExC_state, &this_class);
1037                     oclass = data->start_class;
1038                     data->start_class = &this_class;
1039                     f |= SCF_DO_STCLASS_AND;
1040                     f &= ~SCF_DO_STCLASS_OR;
1041                 }
1042                 /* These are the cases when once a subexpression
1043                    fails at a particular position, it cannot succeed
1044                    even after backtracking at the enclosing scope.
1045                 
1046                    XXXX what if minimal match and we are at the
1047                         initial run of {n,m}? */
1048                 if ((mincount != maxcount - 1) && (maxcount != REG_INFTY))
1049                     f &= ~SCF_WHILEM_VISITED_POS;
1050
1051                 /* This will finish on WHILEM, setting scan, or on NULL: */
1052                 minnext = study_chunk(pRExC_state, &scan, &deltanext, last, data,
1053                                       mincount == 0
1054                                         ? (f & ~SCF_DO_SUBSTR) : f);
1055
1056                 if (flags & SCF_DO_STCLASS)
1057                     data->start_class = oclass;
1058                 if (mincount == 0 || minnext == 0) {
1059                     if (flags & SCF_DO_STCLASS_OR) {
1060                         cl_or(pRExC_state, data->start_class, &this_class);
1061                     }
1062                     else if (flags & SCF_DO_STCLASS_AND) {
1063                         /* Switch to OR mode: cache the old value of
1064                          * data->start_class */
1065                         StructCopy(data->start_class, &and_with,
1066                                    struct regnode_charclass_class);
1067                         flags &= ~SCF_DO_STCLASS_AND;
1068                         StructCopy(&this_class, data->start_class,
1069                                    struct regnode_charclass_class);
1070                         flags |= SCF_DO_STCLASS_OR;
1071                         data->start_class->flags |= ANYOF_EOS;
1072                     }
1073                 } else {                /* Non-zero len */
1074                     if (flags & SCF_DO_STCLASS_OR) {
1075                         cl_or(pRExC_state, data->start_class, &this_class);
1076                         cl_and(data->start_class, &and_with);
1077                     }
1078                     else if (flags & SCF_DO_STCLASS_AND)
1079                         cl_and(data->start_class, &this_class);
1080                     flags &= ~SCF_DO_STCLASS;
1081                 }
1082                 if (!scan)              /* It was not CURLYX, but CURLY. */
1083                     scan = next;
1084                 if (ckWARN(WARN_REGEXP)
1085                        /* ? quantifier ok, except for (?{ ... }) */
1086                     && (next_is_eval || !(mincount == 0 && maxcount == 1))
1087                     && (minnext == 0) && (deltanext == 0)
1088                     && data && !(data->flags & (SF_HAS_PAR|SF_IN_PAR))
1089                     && maxcount <= REG_INFTY/3) /* Complement check for big count */
1090                 {
1091                     vWARN(RExC_parse,
1092                           "Quantifier unexpected on zero-length expression");
1093                 }
1094
1095                 min += minnext * mincount;
1096                 is_inf_internal |= ((maxcount == REG_INFTY
1097                                      && (minnext + deltanext) > 0)
1098                                     || deltanext == I32_MAX);
1099                 is_inf |= is_inf_internal;
1100                 delta += (minnext + deltanext) * maxcount - minnext * mincount;
1101
1102                 /* Try powerful optimization CURLYX => CURLYN. */
1103                 if (  OP(oscan) == CURLYX && data
1104                       && data->flags & SF_IN_PAR
1105                       && !(data->flags & SF_HAS_EVAL)
1106                       && !deltanext && minnext == 1 ) {
1107                     /* Try to optimize to CURLYN.  */
1108                     regnode *nxt = NEXTOPER(oscan) + EXTRA_STEP_2ARGS;
1109                     regnode *nxt1 = nxt;
1110 #ifdef DEBUGGING
1111                     regnode *nxt2;
1112 #endif
1113
1114                     /* Skip open. */
1115                     nxt = regnext(nxt);
1116                     if (!strchr((char*)PL_simple,OP(nxt))
1117                         && !(PL_regkind[(U8)OP(nxt)] == EXACT
1118                              && STR_LEN(nxt) == 1))
1119                         goto nogo;
1120 #ifdef DEBUGGING
1121                     nxt2 = nxt;
1122 #endif
1123                     nxt = regnext(nxt);
1124                     if (OP(nxt) != CLOSE)
1125                         goto nogo;
1126                     /* Now we know that nxt2 is the only contents: */
1127                     oscan->flags = ARG(nxt);
1128                     OP(oscan) = CURLYN;
1129                     OP(nxt1) = NOTHING; /* was OPEN. */
1130 #ifdef DEBUGGING
1131                     OP(nxt1 + 1) = OPTIMIZED; /* was count. */
1132                     NEXT_OFF(nxt1+ 1) = 0; /* just for consistancy. */
1133                     NEXT_OFF(nxt2) = 0; /* just for consistancy with CURLY. */
1134                     OP(nxt) = OPTIMIZED;        /* was CLOSE. */
1135                     OP(nxt + 1) = OPTIMIZED; /* was count. */
1136                     NEXT_OFF(nxt+ 1) = 0; /* just for consistancy. */
1137 #endif
1138                 }
1139               nogo:
1140
1141                 /* Try optimization CURLYX => CURLYM. */
1142                 if (  OP(oscan) == CURLYX && data
1143                       && !(data->flags & SF_HAS_PAR)
1144                       && !(data->flags & SF_HAS_EVAL)
1145                       && !deltanext  ) {
1146                     /* XXXX How to optimize if data == 0? */
1147                     /* Optimize to a simpler form.  */
1148                     regnode *nxt = NEXTOPER(oscan) + EXTRA_STEP_2ARGS; /* OPEN */
1149                     regnode *nxt2;
1150
1151                     OP(oscan) = CURLYM;
1152                     while ( (nxt2 = regnext(nxt)) /* skip over embedded stuff*/
1153                             && (OP(nxt2) != WHILEM))
1154                         nxt = nxt2;
1155                     OP(nxt2)  = SUCCEED; /* Whas WHILEM */
1156                     /* Need to optimize away parenths. */
1157                     if (data->flags & SF_IN_PAR) {
1158                         /* Set the parenth number.  */
1159                         regnode *nxt1 = NEXTOPER(oscan) + EXTRA_STEP_2ARGS; /* OPEN*/
1160
1161                         if (OP(nxt) != CLOSE)
1162                             FAIL("Panic opt close");
1163                         oscan->flags = ARG(nxt);
1164                         OP(nxt1) = OPTIMIZED;   /* was OPEN. */
1165                         OP(nxt) = OPTIMIZED;    /* was CLOSE. */
1166 #ifdef DEBUGGING
1167                         OP(nxt1 + 1) = OPTIMIZED; /* was count. */
1168                         OP(nxt + 1) = OPTIMIZED; /* was count. */
1169                         NEXT_OFF(nxt1 + 1) = 0; /* just for consistancy. */
1170                         NEXT_OFF(nxt + 1) = 0; /* just for consistancy. */
1171 #endif
1172 #if 0
1173                         while ( nxt1 && (OP(nxt1) != WHILEM)) {
1174                             regnode *nnxt = regnext(nxt1);
1175                         
1176                             if (nnxt == nxt) {
1177                                 if (reg_off_by_arg[OP(nxt1)])
1178                                     ARG_SET(nxt1, nxt2 - nxt1);
1179                                 else if (nxt2 - nxt1 < U16_MAX)
1180                                     NEXT_OFF(nxt1) = nxt2 - nxt1;
1181                                 else
1182                                     OP(nxt) = NOTHING;  /* Cannot beautify */
1183                             }
1184                             nxt1 = nnxt;
1185                         }
1186 #endif
1187                         /* Optimize again: */
1188                         study_chunk(pRExC_state, &nxt1, &deltanext, nxt,
1189                                     NULL, 0);
1190                     }
1191                     else
1192                         oscan->flags = 0;
1193                 }
1194                 else if ((OP(oscan) == CURLYX)
1195                          && (flags & SCF_WHILEM_VISITED_POS)
1196                          /* See the comment on a similar expression above.
1197                             However, this time it not a subexpression
1198                             we care about, but the expression itself. */
1199                          && (maxcount == REG_INFTY)
1200                          && data && ++data->whilem_c < 16) {
1201                     /* This stays as CURLYX, we can put the count/of pair. */
1202                     /* Find WHILEM (as in regexec.c) */
1203                     regnode *nxt = oscan + NEXT_OFF(oscan);
1204
1205                     if (OP(PREVOPER(nxt)) == NOTHING) /* LONGJMP */
1206                         nxt += ARG(nxt);
1207                     PREVOPER(nxt)->flags = data->whilem_c
1208                         | (RExC_whilem_seen << 4); /* On WHILEM */
1209                 }
1210                 if (data && fl & (SF_HAS_PAR|SF_IN_PAR))
1211                     pars++;
1212                 if (flags & SCF_DO_SUBSTR) {
1213                     SV *last_str = Nullsv;
1214                     int counted = mincount != 0;
1215
1216                     if (data->last_end > 0 && mincount != 0) { /* Ends with a string. */
1217 #if defined(SPARC64_GCC_WORKAROUND)
1218                         I32 b = 0;
1219                         STRLEN l = 0;
1220                         char *s = NULL;
1221                         I32 old = 0;
1222
1223                         if (pos_before >= data->last_start_min)
1224                             b = pos_before;
1225                         else
1226                             b = data->last_start_min;
1227
1228                         l = 0;
1229                         s = SvPV(data->last_found, l);
1230                         old = b - data->last_start_min;
1231
1232 #else
1233                         I32 b = pos_before >= data->last_start_min
1234                             ? pos_before : data->last_start_min;
1235                         STRLEN l;
1236                         char *s = SvPV(data->last_found, l);
1237                         I32 old = b - data->last_start_min;
1238 #endif
1239
1240                         if (UTF)
1241                             old = utf8_hop((U8*)s, old) - (U8*)s;
1242                         
1243                         l -= old;
1244                         /* Get the added string: */
1245                         last_str = newSVpvn(s  + old, l);
1246                         if (deltanext == 0 && pos_before == b) {
1247                             /* What was added is a constant string */
1248                             if (mincount > 1) {
1249                                 SvGROW(last_str, (mincount * l) + 1);
1250                                 repeatcpy(SvPVX(last_str) + l,
1251                                           SvPVX(last_str), l, mincount - 1);
1252                                 SvCUR(last_str) *= mincount;
1253                                 /* Add additional parts. */
1254                                 SvCUR_set(data->last_found,
1255                                           SvCUR(data->last_found) - l);
1256                                 sv_catsv(data->last_found, last_str);
1257                                 data->last_end += l * (mincount - 1);
1258                             }
1259                         } else {
1260                             /* start offset must point into the last copy */
1261                             data->last_start_min += minnext * (mincount - 1);
1262                             data->last_start_max += is_inf ? 0 : (maxcount - 1)
1263                                 * (minnext + data->pos_delta);
1264                         }
1265                     }
1266                     /* It is counted once already... */
1267                     data->pos_min += minnext * (mincount - counted);
1268                     data->pos_delta += - counted * deltanext +
1269                         (minnext + deltanext) * maxcount - minnext * mincount;
1270                     if (mincount != maxcount) {
1271                          /* Cannot extend fixed substrings found inside
1272                             the group.  */
1273                         scan_commit(pRExC_state,data);
1274                         if (mincount && last_str) {
1275                             sv_setsv(data->last_found, last_str);
1276                             data->last_end = data->pos_min;
1277                             data->last_start_min =
1278                                 data->pos_min - CHR_SVLEN(last_str);
1279                             data->last_start_max = is_inf
1280                                 ? I32_MAX
1281                                 : data->pos_min + data->pos_delta
1282                                 - CHR_SVLEN(last_str);
1283                         }
1284                         data->longest = &(data->longest_float);
1285                     }
1286                     SvREFCNT_dec(last_str);
1287                 }
1288                 if (data && (fl & SF_HAS_EVAL))
1289                     data->flags |= SF_HAS_EVAL;
1290               optimize_curly_tail:
1291                 if (OP(oscan) != CURLYX) {
1292                     while (PL_regkind[(U8)OP(next = regnext(oscan))] == NOTHING
1293                            && NEXT_OFF(next))
1294                         NEXT_OFF(oscan) += NEXT_OFF(next);
1295                 }
1296                 continue;
1297             default:                    /* REF and CLUMP only? */
1298                 if (flags & SCF_DO_SUBSTR) {
1299                     scan_commit(pRExC_state,data);      /* Cannot expect anything... */
1300                     data->longest = &(data->longest_float);
1301                 }
1302                 is_inf = is_inf_internal = 1;
1303                 if (flags & SCF_DO_STCLASS_OR)
1304                     cl_anything(pRExC_state, data->start_class);
1305                 flags &= ~SCF_DO_STCLASS;
1306                 break;
1307             }
1308         }
1309         else if (strchr((char*)PL_simple,OP(scan))) {
1310             int value = 0;
1311
1312             if (flags & SCF_DO_SUBSTR) {
1313                 scan_commit(pRExC_state,data);
1314                 data->pos_min++;
1315             }
1316             min++;
1317             if (flags & SCF_DO_STCLASS) {
1318                 data->start_class->flags &= ~ANYOF_EOS; /* No match on empty */
1319
1320                 /* Some of the logic below assumes that switching
1321                    locale on will only add false positives. */
1322                 switch (PL_regkind[(U8)OP(scan)]) {
1323                 case SANY:
1324                 default:
1325                   do_default:
1326                     /* Perl_croak(aTHX_ "panic: unexpected simple REx opcode %d", OP(scan)); */
1327                     if (flags & SCF_DO_STCLASS_OR) /* Allow everything */
1328                         cl_anything(pRExC_state, data->start_class);
1329                     break;
1330                 case REG_ANY:
1331                     if (OP(scan) == SANY)
1332                         goto do_default;
1333                     if (flags & SCF_DO_STCLASS_OR) { /* Everything but \n */
1334                         value = (ANYOF_BITMAP_TEST(data->start_class,'\n')
1335                                  || (data->start_class->flags & ANYOF_CLASS));
1336                         cl_anything(pRExC_state, data->start_class);
1337                     }
1338                     if (flags & SCF_DO_STCLASS_AND || !value)
1339                         ANYOF_BITMAP_CLEAR(data->start_class,'\n');
1340                     break;
1341                 case ANYOF:
1342                     if (flags & SCF_DO_STCLASS_AND)
1343                         cl_and(data->start_class,
1344                                (struct regnode_charclass_class*)scan);
1345                     else
1346                         cl_or(pRExC_state, data->start_class,
1347                               (struct regnode_charclass_class*)scan);
1348                     break;
1349                 case ALNUM:
1350                     if (flags & SCF_DO_STCLASS_AND) {
1351                         if (!(data->start_class->flags & ANYOF_LOCALE)) {
1352                             ANYOF_CLASS_CLEAR(data->start_class,ANYOF_NALNUM);
1353                             for (value = 0; value < 256; value++)
1354                                 if (!isALNUM(value))
1355                                     ANYOF_BITMAP_CLEAR(data->start_class, value);
1356                         }
1357                     }
1358                     else {
1359                         if (data->start_class->flags & ANYOF_LOCALE)
1360                             ANYOF_CLASS_SET(data->start_class,ANYOF_ALNUM);
1361                         else {
1362                             for (value = 0; value < 256; value++)
1363                                 if (isALNUM(value))
1364                                     ANYOF_BITMAP_SET(data->start_class, value);                 
1365                         }
1366                     }
1367                     break;
1368                 case ALNUML:
1369                     if (flags & SCF_DO_STCLASS_AND) {
1370                         if (data->start_class->flags & ANYOF_LOCALE)
1371                             ANYOF_CLASS_CLEAR(data->start_class,ANYOF_NALNUM);
1372                     }
1373                     else {
1374                         ANYOF_CLASS_SET(data->start_class,ANYOF_ALNUM);
1375                         data->start_class->flags |= ANYOF_LOCALE;
1376                     }
1377                     break;
1378                 case NALNUM:
1379                     if (flags & SCF_DO_STCLASS_AND) {
1380                         if (!(data->start_class->flags & ANYOF_LOCALE)) {
1381                             ANYOF_CLASS_CLEAR(data->start_class,ANYOF_ALNUM);
1382                             for (value = 0; value < 256; value++)
1383                                 if (isALNUM(value))
1384                                     ANYOF_BITMAP_CLEAR(data->start_class, value);
1385                         }
1386                     }
1387                     else {
1388                         if (data->start_class->flags & ANYOF_LOCALE)
1389                             ANYOF_CLASS_SET(data->start_class,ANYOF_NALNUM);
1390                         else {
1391                             for (value = 0; value < 256; value++)
1392                                 if (!isALNUM(value))
1393                                     ANYOF_BITMAP_SET(data->start_class, value);                 
1394                         }
1395                     }
1396                     break;
1397                 case NALNUML:
1398                     if (flags & SCF_DO_STCLASS_AND) {
1399                         if (data->start_class->flags & ANYOF_LOCALE)
1400                             ANYOF_CLASS_CLEAR(data->start_class,ANYOF_ALNUM);
1401                     }
1402                     else {
1403                         data->start_class->flags |= ANYOF_LOCALE;
1404                         ANYOF_CLASS_SET(data->start_class,ANYOF_NALNUM);
1405                     }
1406                     break;
1407                 case SPACE:
1408                     if (flags & SCF_DO_STCLASS_AND) {
1409                         if (!(data->start_class->flags & ANYOF_LOCALE)) {
1410                             ANYOF_CLASS_CLEAR(data->start_class,ANYOF_NSPACE);
1411                             for (value = 0; value < 256; value++)
1412                                 if (!isSPACE(value))
1413                                     ANYOF_BITMAP_CLEAR(data->start_class, value);
1414                         }
1415                     }
1416                     else {
1417                         if (data->start_class->flags & ANYOF_LOCALE)
1418                             ANYOF_CLASS_SET(data->start_class,ANYOF_SPACE);
1419                         else {
1420                             for (value = 0; value < 256; value++)
1421                                 if (isSPACE(value))
1422                                     ANYOF_BITMAP_SET(data->start_class, value);                 
1423                         }
1424                     }
1425                     break;
1426                 case SPACEL:
1427                     if (flags & SCF_DO_STCLASS_AND) {
1428                         if (data->start_class->flags & ANYOF_LOCALE)
1429                             ANYOF_CLASS_CLEAR(data->start_class,ANYOF_NSPACE);
1430                     }
1431                     else {
1432                         data->start_class->flags |= ANYOF_LOCALE;
1433                         ANYOF_CLASS_SET(data->start_class,ANYOF_SPACE);
1434                     }
1435                     break;
1436                 case NSPACE:
1437                     if (flags & SCF_DO_STCLASS_AND) {
1438                         if (!(data->start_class->flags & ANYOF_LOCALE)) {
1439                             ANYOF_CLASS_CLEAR(data->start_class,ANYOF_SPACE);
1440                             for (value = 0; value < 256; value++)
1441                                 if (isSPACE(value))
1442                                     ANYOF_BITMAP_CLEAR(data->start_class, value);
1443                         }
1444                     }
1445                     else {
1446                         if (data->start_class->flags & ANYOF_LOCALE)
1447                             ANYOF_CLASS_SET(data->start_class,ANYOF_NSPACE);
1448                         else {
1449                             for (value = 0; value < 256; value++)
1450                                 if (!isSPACE(value))
1451                                     ANYOF_BITMAP_SET(data->start_class, value);                 
1452                         }
1453                     }
1454                     break;
1455                 case NSPACEL:
1456                     if (flags & SCF_DO_STCLASS_AND) {
1457                         if (data->start_class->flags & ANYOF_LOCALE) {
1458                             ANYOF_CLASS_CLEAR(data->start_class,ANYOF_SPACE);
1459                             for (value = 0; value < 256; value++)
1460                                 if (!isSPACE(value))
1461                                     ANYOF_BITMAP_CLEAR(data->start_class, value);
1462                         }
1463                     }
1464                     else {
1465                         data->start_class->flags |= ANYOF_LOCALE;
1466                         ANYOF_CLASS_SET(data->start_class,ANYOF_NSPACE);
1467                     }
1468                     break;
1469                 case DIGIT:
1470                     if (flags & SCF_DO_STCLASS_AND) {
1471                         ANYOF_CLASS_CLEAR(data->start_class,ANYOF_NDIGIT);
1472                         for (value = 0; value < 256; value++)
1473                             if (!isDIGIT(value))
1474                                 ANYOF_BITMAP_CLEAR(data->start_class, value);
1475                     }
1476                     else {
1477                         if (data->start_class->flags & ANYOF_LOCALE)
1478                             ANYOF_CLASS_SET(data->start_class,ANYOF_DIGIT);
1479                         else {
1480                             for (value = 0; value < 256; value++)
1481                                 if (isDIGIT(value))
1482                                     ANYOF_BITMAP_SET(data->start_class, value);                 
1483                         }
1484                     }
1485                     break;
1486                 case NDIGIT:
1487                     if (flags & SCF_DO_STCLASS_AND) {
1488                         ANYOF_CLASS_CLEAR(data->start_class,ANYOF_DIGIT);
1489                         for (value = 0; value < 256; value++)
1490                             if (isDIGIT(value))
1491                                 ANYOF_BITMAP_CLEAR(data->start_class, value);
1492                     }
1493                     else {
1494                         if (data->start_class->flags & ANYOF_LOCALE)
1495                             ANYOF_CLASS_SET(data->start_class,ANYOF_NDIGIT);
1496                         else {
1497                             for (value = 0; value < 256; value++)
1498                                 if (!isDIGIT(value))
1499                                     ANYOF_BITMAP_SET(data->start_class, value);                 
1500                         }
1501                     }
1502                     break;
1503                 }
1504                 if (flags & SCF_DO_STCLASS_OR)
1505                     cl_and(data->start_class, &and_with);
1506                 flags &= ~SCF_DO_STCLASS;
1507             }
1508         }
1509         else if (PL_regkind[(U8)OP(scan)] == EOL && flags & SCF_DO_SUBSTR) {
1510             data->flags |= (OP(scan) == MEOL
1511                             ? SF_BEFORE_MEOL
1512                             : SF_BEFORE_SEOL);
1513         }
1514         else if (  PL_regkind[(U8)OP(scan)] == BRANCHJ
1515                  /* Lookbehind, or need to calculate parens/evals/stclass: */
1516                    && (scan->flags || data || (flags & SCF_DO_STCLASS))
1517                    && (OP(scan) == IFMATCH || OP(scan) == UNLESSM)) {
1518             /* Lookahead/lookbehind */
1519             I32 deltanext, minnext, fake = 0;
1520             regnode *nscan;
1521             struct regnode_charclass_class intrnl;
1522             int f = 0;
1523
1524             data_fake.flags = 0;
1525             if (data) {         
1526                 data_fake.whilem_c = data->whilem_c;
1527                 data_fake.last_closep = data->last_closep;
1528             }
1529             else
1530                 data_fake.last_closep = &fake;
1531             if ( flags & SCF_DO_STCLASS && !scan->flags
1532                  && OP(scan) == IFMATCH ) { /* Lookahead */
1533                 cl_init(pRExC_state, &intrnl);
1534                 data_fake.start_class = &intrnl;
1535                 f |= SCF_DO_STCLASS_AND;
1536             }
1537             if (flags & SCF_WHILEM_VISITED_POS)
1538                 f |= SCF_WHILEM_VISITED_POS;
1539             next = regnext(scan);
1540             nscan = NEXTOPER(NEXTOPER(scan));
1541             minnext = study_chunk(pRExC_state, &nscan, &deltanext, last, &data_fake, f);
1542             if (scan->flags) {
1543                 if (deltanext) {
1544                     vFAIL("Variable length lookbehind not implemented");
1545                 }
1546                 else if (minnext > U8_MAX) {
1547                     vFAIL2("Lookbehind longer than %"UVuf" not implemented", (UV)U8_MAX);
1548                 }
1549                 scan->flags = minnext;
1550             }
1551             if (data && data_fake.flags & (SF_HAS_PAR|SF_IN_PAR))
1552                 pars++;
1553             if (data && (data_fake.flags & SF_HAS_EVAL))
1554                 data->flags |= SF_HAS_EVAL;
1555             if (data)
1556                 data->whilem_c = data_fake.whilem_c;
1557             if (f & SCF_DO_STCLASS_AND) {
1558                 int was = (data->start_class->flags & ANYOF_EOS);
1559
1560                 cl_and(data->start_class, &intrnl);
1561                 if (was)
1562                     data->start_class->flags |= ANYOF_EOS;
1563             }
1564         }
1565         else if (OP(scan) == OPEN) {
1566             pars++;
1567         }
1568         else if (OP(scan) == CLOSE) {
1569             if (ARG(scan) == is_par) {
1570                 next = regnext(scan);
1571
1572                 if ( next && (OP(next) != WHILEM) && next < last)
1573                     is_par = 0;         /* Disable optimization */
1574             }
1575             if (data)
1576                 *(data->last_closep) = ARG(scan);
1577         }
1578         else if (OP(scan) == EVAL) {
1579                 if (data)
1580                     data->flags |= SF_HAS_EVAL;
1581         }
1582         else if (OP(scan) == LOGICAL && scan->flags == 2) { /* Embedded follows */
1583                 if (flags & SCF_DO_SUBSTR) {
1584                     scan_commit(pRExC_state,data);
1585                     data->longest = &(data->longest_float);
1586                 }
1587                 is_inf = is_inf_internal = 1;
1588                 if (flags & SCF_DO_STCLASS_OR) /* Allow everything */
1589                     cl_anything(pRExC_state, data->start_class);
1590                 flags &= ~SCF_DO_STCLASS;
1591         }
1592         /* Else: zero-length, ignore. */
1593         scan = regnext(scan);
1594     }
1595
1596   finish:
1597     *scanp = scan;
1598     *deltap = is_inf_internal ? I32_MAX : delta;
1599     if (flags & SCF_DO_SUBSTR && is_inf)
1600         data->pos_delta = I32_MAX - data->pos_min;
1601     if (is_par > U8_MAX)
1602         is_par = 0;
1603     if (is_par && pars==1 && data) {
1604         data->flags |= SF_IN_PAR;
1605         data->flags &= ~SF_HAS_PAR;
1606     }
1607     else if (pars && data) {
1608         data->flags |= SF_HAS_PAR;
1609         data->flags &= ~SF_IN_PAR;
1610     }
1611     if (flags & SCF_DO_STCLASS_OR)
1612         cl_and(data->start_class, &and_with);
1613     return min;
1614 }
1615
1616 STATIC I32
1617 S_add_data(pTHX_ RExC_state_t *pRExC_state, I32 n, char *s)
1618 {
1619     if (RExC_rx->data) {
1620         Renewc(RExC_rx->data,
1621                sizeof(*RExC_rx->data) + sizeof(void*) * (RExC_rx->data->count + n - 1),
1622                char, struct reg_data);
1623         Renew(RExC_rx->data->what, RExC_rx->data->count + n, U8);
1624         RExC_rx->data->count += n;
1625     }
1626     else {
1627         Newc(1207, RExC_rx->data, sizeof(*RExC_rx->data) + sizeof(void*) * (n - 1),
1628              char, struct reg_data);
1629         New(1208, RExC_rx->data->what, n, U8);
1630         RExC_rx->data->count = n;
1631     }
1632     Copy(s, RExC_rx->data->what + RExC_rx->data->count - n, n, U8);
1633     return RExC_rx->data->count - n;
1634 }
1635
1636 void
1637 Perl_reginitcolors(pTHX)
1638 {
1639     int i = 0;
1640     char *s = PerlEnv_getenv("PERL_RE_COLORS");
1641         
1642     if (s) {
1643         PL_colors[0] = s = savepv(s);
1644         while (++i < 6) {
1645             s = strchr(s, '\t');
1646             if (s) {
1647                 *s = '\0';
1648                 PL_colors[i] = ++s;
1649             }
1650             else
1651                 PL_colors[i] = s = "";
1652         }
1653     } else {
1654         while (i < 6)
1655             PL_colors[i++] = "";
1656     }
1657     PL_colorset = 1;
1658 }
1659
1660
1661 /*
1662  - pregcomp - compile a regular expression into internal code
1663  *
1664  * We can't allocate space until we know how big the compiled form will be,
1665  * but we can't compile it (and thus know how big it is) until we've got a
1666  * place to put the code.  So we cheat:  we compile it twice, once with code
1667  * generation turned off and size counting turned on, and once "for real".
1668  * This also means that we don't allocate space until we are sure that the
1669  * thing really will compile successfully, and we never have to move the
1670  * code and thus invalidate pointers into it.  (Note that it has to be in
1671  * one piece because free() must be able to free it all.) [NB: not true in perl]
1672  *
1673  * Beware that the optimization-preparation code in here knows about some
1674  * of the structure of the compiled regexp.  [I'll say.]
1675  */
1676 regexp *
1677 Perl_pregcomp(pTHX_ char *exp, char *xend, PMOP *pm)
1678 {
1679     register regexp *r;
1680     regnode *scan;
1681     regnode *first;
1682     I32 flags;
1683     I32 minlen = 0;
1684     I32 sawplus = 0;
1685     I32 sawopen = 0;
1686     scan_data_t data;
1687     RExC_state_t RExC_state;
1688     RExC_state_t *pRExC_state = &RExC_state;
1689
1690     if (exp == NULL)
1691         FAIL("NULL regexp argument");
1692
1693     /* XXXX This looks very suspicious... */
1694     if (pm->op_pmdynflags & PMdf_CMP_UTF8)
1695         RExC_utf8 = 1;
1696     else
1697         RExC_utf8 = 0;
1698
1699     RExC_precomp = exp;
1700     DEBUG_r(if (!PL_colorset) reginitcolors());
1701     DEBUG_r(PerlIO_printf(Perl_debug_log, "%sCompiling REx%s `%s%*s%s'\n",
1702                       PL_colors[4],PL_colors[5],PL_colors[0],
1703                       (int)(xend - exp), RExC_precomp, PL_colors[1]));
1704     RExC_flags16 = pm->op_pmflags;
1705     RExC_sawback = 0;
1706
1707     RExC_seen = 0;
1708     RExC_seen_zerolen = *exp == '^' ? -1 : 0;
1709     RExC_seen_evals = 0;
1710     RExC_extralen = 0;
1711
1712     /* First pass: determine size, legality. */
1713     RExC_parse = exp;
1714     RExC_start = exp;
1715     RExC_end = xend;
1716     RExC_naughty = 0;
1717     RExC_npar = 1;
1718     RExC_size = 0L;
1719     RExC_emit = &PL_regdummy;
1720     RExC_whilem_seen = 0;
1721 #if 0 /* REGC() is (currently) a NOP at the first pass.
1722        * Clever compilers notice this and complain. --jhi */
1723     REGC((U8)REG_MAGIC, (char*)RExC_emit);
1724 #endif
1725     if (reg(pRExC_state, 0, &flags) == NULL) {
1726         RExC_precomp = Nullch;
1727         return(NULL);
1728     }
1729     DEBUG_r(PerlIO_printf(Perl_debug_log, "size %"IVdf" ", (IV)RExC_size));
1730
1731     /* Small enough for pointer-storage convention?
1732        If extralen==0, this means that we will not need long jumps. */
1733     if (RExC_size >= 0x10000L && RExC_extralen)
1734         RExC_size += RExC_extralen;
1735     else
1736         RExC_extralen = 0;
1737     if (RExC_whilem_seen > 15)
1738         RExC_whilem_seen = 15;
1739
1740     /* Allocate space and initialize. */
1741     Newc(1001, r, sizeof(regexp) + (unsigned)RExC_size * sizeof(regnode),
1742          char, regexp);
1743     if (r == NULL)
1744         FAIL("Regexp out of space");
1745
1746 #ifdef DEBUGGING
1747     /* avoid reading uninitialized memory in DEBUGGING code in study_chunk() */
1748     Zero(r, sizeof(regexp) + (unsigned)RExC_size * sizeof(regnode), char);
1749 #endif
1750     r->refcnt = 1;
1751     r->prelen = xend - exp;
1752     r->precomp = savepvn(RExC_precomp, r->prelen);
1753     r->subbeg = NULL;
1754     r->reganch = pm->op_pmflags & PMf_COMPILETIME;
1755     r->nparens = RExC_npar - 1; /* set early to validate backrefs */
1756
1757     r->substrs = 0;                     /* Useful during FAIL. */
1758     r->startp = 0;                      /* Useful during FAIL. */
1759     r->endp = 0;                        /* Useful during FAIL. */
1760
1761     Newz(1304, r->offsets, 2*RExC_size+1, U32); /* MJD 20001228 */
1762     if (r->offsets) {
1763       r->offsets[0] = RExC_size; 
1764     }
1765     DEBUG_r(PerlIO_printf(Perl_debug_log, 
1766                           "%s %"UVuf" bytes for offset annotations.\n", 
1767                           r->offsets ? "Got" : "Couldn't get", 
1768                           (UV)((2*RExC_size+1) * sizeof(U32))));
1769
1770     RExC_rx = r;
1771
1772     /* Second pass: emit code. */
1773     RExC_flags16 = pm->op_pmflags;      /* don't let top level (?i) bleed */
1774     RExC_parse = exp;
1775     RExC_end = xend;
1776     RExC_naughty = 0;
1777     RExC_npar = 1;
1778     RExC_emit_start = r->program;
1779     RExC_emit = r->program;
1780     /* Store the count of eval-groups for security checks: */
1781     RExC_emit->next_off = ((RExC_seen_evals > U16_MAX) ? U16_MAX : RExC_seen_evals);
1782     REGC((U8)REG_MAGIC, (char*) RExC_emit++);
1783     r->data = 0;
1784     if (reg(pRExC_state, 0, &flags) == NULL)
1785         return(NULL);
1786
1787     /* Dig out information for optimizations. */
1788     r->reganch = pm->op_pmflags & PMf_COMPILETIME; /* Again? */
1789     pm->op_pmflags = RExC_flags16;
1790     if (UTF)
1791         r->reganch |= ROPT_UTF8;        /* Unicode in it? */
1792     r->regstclass = NULL;
1793     if (RExC_naughty >= 10)     /* Probably an expensive pattern. */
1794         r->reganch |= ROPT_NAUGHTY;
1795     scan = r->program + 1;              /* First BRANCH. */
1796
1797     /* XXXX To minimize changes to RE engine we always allocate
1798        3-units-long substrs field. */
1799     Newz(1004, r->substrs, 1, struct reg_substr_data);
1800
1801     StructCopy(&zero_scan_data, &data, scan_data_t);
1802     /* XXXX Should not we check for something else?  Usually it is OPEN1... */
1803     if (OP(scan) != BRANCH) {   /* Only one top-level choice. */
1804         I32 fake;
1805         STRLEN longest_float_length, longest_fixed_length;
1806         struct regnode_charclass_class ch_class;
1807         int stclass_flag;
1808         I32 last_close = 0;
1809
1810         first = scan;
1811         /* Skip introductions and multiplicators >= 1. */
1812         while ((OP(first) == OPEN && (sawopen = 1)) ||
1813                /* An OR of *one* alternative - should not happen now. */
1814             (OP(first) == BRANCH && OP(regnext(first)) != BRANCH) ||
1815             (OP(first) == PLUS) ||
1816             (OP(first) == MINMOD) ||
1817                /* An {n,m} with n>0 */
1818             (PL_regkind[(U8)OP(first)] == CURLY && ARG1(first) > 0) ) {
1819                 if (OP(first) == PLUS)
1820                     sawplus = 1;
1821                 else
1822                     first += regarglen[(U8)OP(first)];
1823                 first = NEXTOPER(first);
1824         }
1825
1826         /* Starting-point info. */
1827       again:
1828         if (PL_regkind[(U8)OP(first)] == EXACT) {
1829             if (OP(first) == EXACT)
1830                 ;       /* Empty, get anchored substr later. */
1831             else if ((OP(first) == EXACTF || OP(first) == EXACTFL))
1832                 r->regstclass = first;
1833         }
1834         else if (strchr((char*)PL_simple,OP(first)))
1835             r->regstclass = first;
1836         else if (PL_regkind[(U8)OP(first)] == BOUND ||
1837                  PL_regkind[(U8)OP(first)] == NBOUND)
1838             r->regstclass = first;
1839         else if (PL_regkind[(U8)OP(first)] == BOL) {
1840             r->reganch |= (OP(first) == MBOL
1841                            ? ROPT_ANCH_MBOL
1842                            : (OP(first) == SBOL
1843                               ? ROPT_ANCH_SBOL
1844                               : ROPT_ANCH_BOL));
1845             first = NEXTOPER(first);
1846             goto again;
1847         }
1848         else if (OP(first) == GPOS) {
1849             r->reganch |= ROPT_ANCH_GPOS;
1850             first = NEXTOPER(first);
1851             goto again;
1852         }
1853         else if ((OP(first) == STAR &&
1854             PL_regkind[(U8)OP(NEXTOPER(first))] == REG_ANY) &&
1855             !(r->reganch & ROPT_ANCH) )
1856         {
1857             /* turn .* into ^.* with an implied $*=1 */
1858             int type = OP(NEXTOPER(first));
1859
1860             if (type == REG_ANY)
1861                 type = ROPT_ANCH_MBOL;
1862             else
1863                 type = ROPT_ANCH_SBOL;
1864
1865             r->reganch |= type | ROPT_IMPLICIT;
1866             first = NEXTOPER(first);
1867             goto again;
1868         }
1869         if (sawplus && (!sawopen || !RExC_sawback)
1870             && !(RExC_seen & REG_SEEN_EVAL)) /* May examine pos and $& */
1871             /* x+ must match at the 1st pos of run of x's */
1872             r->reganch |= ROPT_SKIP;
1873
1874         /* Scan is after the zeroth branch, first is atomic matcher. */
1875         DEBUG_r(PerlIO_printf(Perl_debug_log, "first at %"IVdf"\n",
1876                               (IV)(first - scan + 1)));
1877         /*
1878         * If there's something expensive in the r.e., find the
1879         * longest literal string that must appear and make it the
1880         * regmust.  Resolve ties in favor of later strings, since
1881         * the regstart check works with the beginning of the r.e.
1882         * and avoiding duplication strengthens checking.  Not a
1883         * strong reason, but sufficient in the absence of others.
1884         * [Now we resolve ties in favor of the earlier string if
1885         * it happens that c_offset_min has been invalidated, since the
1886         * earlier string may buy us something the later one won't.]
1887         */
1888         minlen = 0;
1889
1890         data.longest_fixed = newSVpvn("",0);
1891         data.longest_float = newSVpvn("",0);
1892         data.last_found = newSVpvn("",0);
1893         data.longest = &(data.longest_fixed);
1894         first = scan;
1895         if (!r->regstclass) {
1896             cl_init(pRExC_state, &ch_class);
1897             data.start_class = &ch_class;
1898             stclass_flag = SCF_DO_STCLASS_AND;
1899         } else                          /* XXXX Check for BOUND? */
1900             stclass_flag = 0;
1901         data.last_closep = &last_close;
1902
1903         minlen = study_chunk(pRExC_state, &first, &fake, scan + RExC_size, /* Up to end */
1904                              &data, SCF_DO_SUBSTR | SCF_WHILEM_VISITED_POS | stclass_flag);
1905         if ( RExC_npar == 1 && data.longest == &(data.longest_fixed)
1906              && data.last_start_min == 0 && data.last_end > 0
1907              && !RExC_seen_zerolen
1908              && (!(RExC_seen & REG_SEEN_GPOS) || (r->reganch & ROPT_ANCH_GPOS)))
1909             r->reganch |= ROPT_CHECK_ALL;
1910         scan_commit(pRExC_state, &data);
1911         SvREFCNT_dec(data.last_found);
1912
1913         longest_float_length = CHR_SVLEN(data.longest_float);
1914         if (longest_float_length
1915             || (data.flags & SF_FL_BEFORE_EOL
1916                 && (!(data.flags & SF_FL_BEFORE_MEOL)
1917                     || (RExC_flags16 & PMf_MULTILINE)))) {
1918             int t;
1919
1920             if (SvCUR(data.longest_fixed)                       /* ok to leave SvCUR */
1921                 && data.offset_fixed == data.offset_float_min
1922                 && SvCUR(data.longest_fixed) == SvCUR(data.longest_float))
1923                     goto remove_float;          /* As in (a)+. */
1924
1925             r->float_substr = data.longest_float;
1926             r->float_min_offset = data.offset_float_min;
1927             r->float_max_offset = data.offset_float_max;
1928             t = (data.flags & SF_FL_BEFORE_EOL /* Can't have SEOL and MULTI */
1929                        && (!(data.flags & SF_FL_BEFORE_MEOL)
1930                            || (RExC_flags16 & PMf_MULTILINE)));
1931             fbm_compile(r->float_substr, t ? FBMcf_TAIL : 0);
1932         }
1933         else {
1934           remove_float:
1935             r->float_substr = Nullsv;
1936             SvREFCNT_dec(data.longest_float);
1937             longest_float_length = 0;
1938         }
1939
1940         longest_fixed_length = CHR_SVLEN(data.longest_fixed);
1941         if (longest_fixed_length
1942             || (data.flags & SF_FIX_BEFORE_EOL /* Cannot have SEOL and MULTI */
1943                 && (!(data.flags & SF_FIX_BEFORE_MEOL)
1944                     || (RExC_flags16 & PMf_MULTILINE)))) {
1945             int t;
1946
1947             r->anchored_substr = data.longest_fixed;
1948             r->anchored_offset = data.offset_fixed;
1949             t = (data.flags & SF_FIX_BEFORE_EOL /* Can't have SEOL and MULTI */
1950                  && (!(data.flags & SF_FIX_BEFORE_MEOL)
1951                      || (RExC_flags16 & PMf_MULTILINE)));
1952             fbm_compile(r->anchored_substr, t ? FBMcf_TAIL : 0);
1953         }
1954         else {
1955             r->anchored_substr = Nullsv;
1956             SvREFCNT_dec(data.longest_fixed);
1957             longest_fixed_length = 0;
1958         }
1959         if (r->regstclass
1960             && (OP(r->regstclass) == REG_ANY || OP(r->regstclass) == SANY))
1961             r->regstclass = NULL;
1962         if ((!r->anchored_substr || r->anchored_offset) && stclass_flag
1963             && !(data.start_class->flags & ANYOF_EOS)
1964             && !cl_is_anything(data.start_class)) {
1965             I32 n = add_data(pRExC_state, 1, "f");
1966
1967             New(1006, RExC_rx->data->data[n], 1,
1968                 struct regnode_charclass_class);
1969             StructCopy(data.start_class,
1970                        (struct regnode_charclass_class*)RExC_rx->data->data[n],
1971                        struct regnode_charclass_class);
1972             r->regstclass = (regnode*)RExC_rx->data->data[n];
1973             r->reganch &= ~ROPT_SKIP;   /* Used in find_byclass(). */
1974             PL_regdata = r->data; /* for regprop() */
1975             DEBUG_r({ SV *sv = sv_newmortal();
1976                       regprop(sv, (regnode*)data.start_class);
1977                       PerlIO_printf(Perl_debug_log,
1978                                     "synthetic stclass `%s'.\n",
1979                                     SvPVX(sv));});
1980         }
1981
1982         /* A temporary algorithm prefers floated substr to fixed one to dig more info. */
1983         if (longest_fixed_length > longest_float_length) {
1984             r->check_substr = r->anchored_substr;
1985             r->check_offset_min = r->check_offset_max = r->anchored_offset;
1986             if (r->reganch & ROPT_ANCH_SINGLE)
1987                 r->reganch |= ROPT_NOSCAN;
1988         }
1989         else {
1990             r->check_substr = r->float_substr;
1991             r->check_offset_min = data.offset_float_min;
1992             r->check_offset_max = data.offset_float_max;
1993         }
1994         /* XXXX Currently intuiting is not compatible with ANCH_GPOS.
1995            This should be changed ASAP!  */
1996         if (r->check_substr && !(r->reganch & ROPT_ANCH_GPOS)) {
1997             r->reganch |= RE_USE_INTUIT;
1998             if (SvTAIL(r->check_substr))
1999                 r->reganch |= RE_INTUIT_TAIL;
2000         }
2001     }
2002     else {
2003         /* Several toplevels. Best we can is to set minlen. */
2004         I32 fake;
2005         struct regnode_charclass_class ch_class;
2006         I32 last_close = 0;
2007         
2008         DEBUG_r(PerlIO_printf(Perl_debug_log, "\n"));
2009         scan = r->program + 1;
2010         cl_init(pRExC_state, &ch_class);
2011         data.start_class = &ch_class;
2012         data.last_closep = &last_close;
2013         minlen = study_chunk(pRExC_state, &scan, &fake, scan + RExC_size, &data, SCF_DO_STCLASS_AND|SCF_WHILEM_VISITED_POS);
2014         r->check_substr = r->anchored_substr = r->float_substr = Nullsv;
2015         if (!(data.start_class->flags & ANYOF_EOS)
2016             && !cl_is_anything(data.start_class)) {
2017             I32 n = add_data(pRExC_state, 1, "f");
2018
2019             New(1006, RExC_rx->data->data[n], 1,
2020                 struct regnode_charclass_class);
2021             StructCopy(data.start_class,
2022                        (struct regnode_charclass_class*)RExC_rx->data->data[n],
2023                        struct regnode_charclass_class);
2024             r->regstclass = (regnode*)RExC_rx->data->data[n];
2025             r->reganch &= ~ROPT_SKIP;   /* Used in find_byclass(). */
2026             DEBUG_r({ SV* sv = sv_newmortal();
2027                       regprop(sv, (regnode*)data.start_class);
2028                       PerlIO_printf(Perl_debug_log,
2029                                     "synthetic stclass `%s'.\n",
2030                                     SvPVX(sv));});
2031         }
2032     }
2033
2034     r->minlen = minlen;
2035     if (RExC_seen & REG_SEEN_GPOS)
2036         r->reganch |= ROPT_GPOS_SEEN;
2037     if (RExC_seen & REG_SEEN_LOOKBEHIND)
2038         r->reganch |= ROPT_LOOKBEHIND_SEEN;
2039     if (RExC_seen & REG_SEEN_EVAL)
2040         r->reganch |= ROPT_EVAL_SEEN;
2041     if (RExC_seen & REG_SEEN_CANY)
2042         r->reganch |= ROPT_CANY_SEEN;
2043     Newz(1002, r->startp, RExC_npar, I32);
2044     Newz(1002, r->endp, RExC_npar, I32);
2045     PL_regdata = r->data; /* for regprop() */
2046     DEBUG_r(regdump(r));
2047     return(r);
2048 }
2049
2050 /*
2051  - reg - regular expression, i.e. main body or parenthesized thing
2052  *
2053  * Caller must absorb opening parenthesis.
2054  *
2055  * Combining parenthesis handling with the base level of regular expression
2056  * is a trifle forced, but the need to tie the tails of the branches to what
2057  * follows makes it hard to avoid.
2058  */
2059 STATIC regnode *
2060 S_reg(pTHX_ RExC_state_t *pRExC_state, I32 paren, I32 *flagp)
2061     /* paren: Parenthesized? 0=top, 1=(, inside: changed to letter. */
2062 {
2063     register regnode *ret;              /* Will be the head of the group. */
2064     register regnode *br;
2065     register regnode *lastbr;
2066     register regnode *ender = 0;
2067     register I32 parno = 0;
2068     I32 flags, oregflags = RExC_flags16, have_branch = 0, open = 0;
2069
2070     /* for (?g), (?gc), and (?o) warnings; warning
2071        about (?c) will warn about (?g) -- japhy    */
2072
2073     I32 wastedflags = 0x00,
2074         wasted_o    = 0x01,
2075         wasted_g    = 0x02,
2076         wasted_gc   = 0x02 | 0x04,
2077         wasted_c    = 0x04;
2078
2079     char * parse_start = RExC_parse; /* MJD */
2080     char *oregcomp_parse = RExC_parse;
2081     char c;
2082
2083     *flagp = 0;                         /* Tentatively. */
2084
2085
2086     /* Make an OPEN node, if parenthesized. */
2087     if (paren) {
2088         if (*RExC_parse == '?') { /* (?...) */
2089             U16 posflags = 0, negflags = 0;
2090             U16 *flagsp = &posflags;
2091             int logical = 0;
2092             char *seqstart = RExC_parse;
2093
2094             RExC_parse++;
2095             paren = *RExC_parse++;
2096             ret = NULL;                 /* For look-ahead/behind. */
2097             switch (paren) {
2098             case '<':           /* (?<...) */
2099                 RExC_seen |= REG_SEEN_LOOKBEHIND;
2100                 if (*RExC_parse == '!')
2101                     paren = ',';
2102                 if (*RExC_parse != '=' && *RExC_parse != '!')
2103                     goto unknown;
2104                 RExC_parse++;
2105             case '=':           /* (?=...) */
2106             case '!':           /* (?!...) */
2107                 RExC_seen_zerolen++;
2108             case ':':           /* (?:...) */
2109             case '>':           /* (?>...) */
2110                 break;
2111             case '$':           /* (?$...) */
2112             case '@':           /* (?@...) */
2113                 vFAIL2("Sequence (?%c...) not implemented", (int)paren);
2114                 break;
2115             case '#':           /* (?#...) */
2116                 while (*RExC_parse && *RExC_parse != ')')
2117                     RExC_parse++;
2118                 if (*RExC_parse != ')')
2119                     FAIL("Sequence (?#... not terminated");
2120                 nextchar(pRExC_state);
2121                 *flagp = TRYAGAIN;
2122                 return NULL;
2123             case 'p':           /* (?p...) */
2124                 if (SIZE_ONLY && ckWARN2(WARN_DEPRECATED, WARN_REGEXP))
2125                     vWARNdep(RExC_parse, "(?p{}) is deprecated - use (??{})");
2126                 /* FALL THROUGH*/
2127             case '?':           /* (??...) */
2128                 logical = 1;
2129                 paren = *RExC_parse++;
2130                 /* FALL THROUGH */
2131             case '{':           /* (?{...}) */
2132             {
2133                 I32 count = 1, n = 0;
2134                 char c;
2135                 char *s = RExC_parse;
2136                 SV *sv;
2137                 OP_4tree *sop, *rop;
2138
2139                 RExC_seen_zerolen++;
2140                 RExC_seen |= REG_SEEN_EVAL;
2141                 while (count && (c = *RExC_parse)) {
2142                     if (c == '\\' && RExC_parse[1])
2143                         RExC_parse++;
2144                     else if (c == '{')
2145                         count++;
2146                     else if (c == '}')
2147                         count--;
2148                     RExC_parse++;
2149                 }
2150                 if (*RExC_parse != ')')
2151                 {
2152                     RExC_parse = s;             
2153                     vFAIL("Sequence (?{...}) not terminated or not {}-balanced");
2154                 }
2155                 if (!SIZE_ONLY) {
2156                     AV *av;
2157                 
2158                     if (RExC_parse - 1 - s)
2159                         sv = newSVpvn(s, RExC_parse - 1 - s);
2160                     else
2161                         sv = newSVpvn("", 0);
2162
2163                     ENTER;
2164                     Perl_save_re_context(aTHX);
2165                     rop = sv_compile_2op(sv, &sop, "re", &av);
2166                     sop->op_private |= OPpREFCOUNTED;
2167                     /* re_dup will OpREFCNT_inc */
2168                     OpREFCNT_set(sop, 1);
2169                     LEAVE;
2170
2171                     n = add_data(pRExC_state, 3, "nop");
2172                     RExC_rx->data->data[n] = (void*)rop;
2173                     RExC_rx->data->data[n+1] = (void*)sop;
2174                     RExC_rx->data->data[n+2] = (void*)av;
2175                     SvREFCNT_dec(sv);
2176                 }
2177                 else {                                          /* First pass */
2178                     if (PL_reginterp_cnt < ++RExC_seen_evals
2179                         && PL_curcop != &PL_compiling)
2180                         /* No compiled RE interpolated, has runtime
2181                            components ===> unsafe.  */
2182                         FAIL("Eval-group not allowed at runtime, use re 'eval'");
2183                     if (PL_tainting && PL_tainted)
2184                         FAIL("Eval-group in insecure regular expression");
2185                 }
2186                 
2187                 nextchar(pRExC_state);
2188                 if (logical) {
2189                     ret = reg_node(pRExC_state, LOGICAL);
2190                     if (!SIZE_ONLY)
2191                         ret->flags = 2;
2192                     regtail(pRExC_state, ret, reganode(pRExC_state, EVAL, n));
2193                     /* deal with the length of this later - MJD */
2194                     return ret;
2195                 }
2196                 return reganode(pRExC_state, EVAL, n);
2197             }
2198             case '(':           /* (?(?{...})...) and (?(?=...)...) */
2199             {
2200                 if (RExC_parse[0] == '?') {        /* (?(?...)) */
2201                     if (RExC_parse[1] == '=' || RExC_parse[1] == '!'
2202                         || RExC_parse[1] == '<'
2203                         || RExC_parse[1] == '{') { /* Lookahead or eval. */
2204                         I32 flag;
2205                         
2206                         ret = reg_node(pRExC_state, LOGICAL);
2207                         if (!SIZE_ONLY)
2208                             ret->flags = 1;
2209                         regtail(pRExC_state, ret, reg(pRExC_state, 1, &flag));
2210                         goto insert_if;
2211                     }
2212                 }
2213                 else if (RExC_parse[0] >= '1' && RExC_parse[0] <= '9' ) {
2214                     /* (?(1)...) */
2215                     parno = atoi(RExC_parse++);
2216
2217                     while (isDIGIT(*RExC_parse))
2218                         RExC_parse++;
2219                     ret = reganode(pRExC_state, GROUPP, parno);
2220                     
2221                     if ((c = *nextchar(pRExC_state)) != ')')
2222                         vFAIL("Switch condition not recognized");
2223                   insert_if:
2224                     regtail(pRExC_state, ret, reganode(pRExC_state, IFTHEN, 0));
2225                     br = regbranch(pRExC_state, &flags, 1);
2226                     if (br == NULL)
2227                         br = reganode(pRExC_state, LONGJMP, 0);
2228                     else
2229                         regtail(pRExC_state, br, reganode(pRExC_state, LONGJMP, 0));
2230                     c = *nextchar(pRExC_state);
2231                     if (flags&HASWIDTH)
2232                         *flagp |= HASWIDTH;
2233                     if (c == '|') {
2234                         lastbr = reganode(pRExC_state, IFTHEN, 0); /* Fake one for optimizer. */
2235                         regbranch(pRExC_state, &flags, 1);
2236                         regtail(pRExC_state, ret, lastbr);
2237                         if (flags&HASWIDTH)
2238                             *flagp |= HASWIDTH;
2239                         c = *nextchar(pRExC_state);
2240                     }
2241                     else
2242                         lastbr = NULL;
2243                     if (c != ')')
2244                         vFAIL("Switch (?(condition)... contains too many branches");
2245                     ender = reg_node(pRExC_state, TAIL);
2246                     regtail(pRExC_state, br, ender);
2247                     if (lastbr) {
2248                         regtail(pRExC_state, lastbr, ender);
2249                         regtail(pRExC_state, NEXTOPER(NEXTOPER(lastbr)), ender);
2250                     }
2251                     else
2252                         regtail(pRExC_state, ret, ender);
2253                     return ret;
2254                 }
2255                 else {
2256                     vFAIL2("Unknown switch condition (?(%.2s", RExC_parse);
2257                 }
2258             }
2259             case 0:
2260                 RExC_parse--; /* for vFAIL to print correctly */
2261                 vFAIL("Sequence (? incomplete");
2262                 break;
2263             default:
2264                 --RExC_parse;
2265               parse_flags:      /* (?i) */
2266                 while (*RExC_parse && strchr("iogcmsx", *RExC_parse)) {
2267                     /* (?g), (?gc) and (?o) are useless here
2268                        and must be globally applied -- japhy */
2269
2270                     if (*RExC_parse == 'o' || *RExC_parse == 'g') {
2271                         if (SIZE_ONLY && ckWARN(WARN_REGEXP)) {
2272                             I32 wflagbit = *RExC_parse == 'o' ? wasted_o : wasted_g;
2273                             if (! (wastedflags & wflagbit) ) {
2274                                 wastedflags |= wflagbit;
2275                                 vWARN5(
2276                                     RExC_parse + 1,
2277                                     "Useless (%s%c) - %suse /%c modifier",
2278                                     flagsp == &negflags ? "?-" : "?",
2279                                     *RExC_parse,
2280                                     flagsp == &negflags ? "don't " : "",
2281                                     *RExC_parse
2282                                 );
2283                             }
2284                         }
2285                     }
2286                     else if (*RExC_parse == 'c') {
2287                         if (SIZE_ONLY && ckWARN(WARN_REGEXP)) {
2288                             if (! (wastedflags & wasted_c) ) {
2289                                 wastedflags |= wasted_gc;
2290                                 vWARN3(
2291                                     RExC_parse + 1,
2292                                     "Useless (%sc) - %suse /gc modifier",
2293                                     flagsp == &negflags ? "?-" : "?",
2294                                     flagsp == &negflags ? "don't " : ""
2295                                 );
2296                             }
2297                         }
2298                     }
2299                     else { pmflag(flagsp, *RExC_parse); }
2300
2301                     ++RExC_parse;
2302                 }
2303                 if (*RExC_parse == '-') {
2304                     flagsp = &negflags;
2305                     wastedflags = 0;  /* reset so (?g-c) warns twice */
2306                     ++RExC_parse;
2307                     goto parse_flags;
2308                 }
2309                 RExC_flags16 |= posflags;
2310                 RExC_flags16 &= ~negflags;
2311                 if (*RExC_parse == ':') {
2312                     RExC_parse++;
2313                     paren = ':';
2314                     break;
2315                 }               
2316               unknown:
2317                 if (*RExC_parse != ')') {
2318                     RExC_parse++;
2319                     vFAIL3("Sequence (%.*s...) not recognized", RExC_parse-seqstart, seqstart);
2320                 }
2321                 nextchar(pRExC_state);
2322                 *flagp = TRYAGAIN;
2323                 return NULL;
2324             }
2325         }
2326         else {                  /* (...) */
2327             parno = RExC_npar;
2328             RExC_npar++;
2329             ret = reganode(pRExC_state, OPEN, parno);
2330             Set_Node_Length(ret, 1); /* MJD */
2331             Set_Node_Offset(ret, RExC_parse); /* MJD */
2332             open = 1;
2333         }
2334     }
2335     else                        /* ! paren */
2336         ret = NULL;
2337
2338     /* Pick up the branches, linking them together. */
2339     parse_start = RExC_parse;   /* MJD */
2340     br = regbranch(pRExC_state, &flags, 1);
2341     /*     branch_len = (paren != 0); */
2342     
2343     if (br == NULL)
2344         return(NULL);
2345     if (*RExC_parse == '|') {
2346         if (!SIZE_ONLY && RExC_extralen) {
2347             reginsert(pRExC_state, BRANCHJ, br);
2348         }
2349         else {                  /* MJD */
2350             reginsert(pRExC_state, BRANCH, br);
2351             Set_Node_Length(br, paren != 0);
2352             Set_Node_Offset_To_R(br-RExC_emit_start, parse_start-RExC_start);
2353         }
2354         have_branch = 1;
2355         if (SIZE_ONLY)
2356             RExC_extralen += 1;         /* For BRANCHJ-BRANCH. */
2357     }
2358     else if (paren == ':') {
2359         *flagp |= flags&SIMPLE;
2360     }
2361     if (open) {                         /* Starts with OPEN. */
2362         regtail(pRExC_state, ret, br);          /* OPEN -> first. */
2363     }
2364     else if (paren != '?')              /* Not Conditional */
2365         ret = br;
2366     if (flags&HASWIDTH)
2367         *flagp |= HASWIDTH;
2368     *flagp |= flags&SPSTART;
2369     lastbr = br;
2370     while (*RExC_parse == '|') {
2371         if (!SIZE_ONLY && RExC_extralen) {
2372             ender = reganode(pRExC_state, LONGJMP,0);
2373             regtail(pRExC_state, NEXTOPER(NEXTOPER(lastbr)), ender); /* Append to the previous. */
2374         }
2375         if (SIZE_ONLY)
2376             RExC_extralen += 2;         /* Account for LONGJMP. */
2377         nextchar(pRExC_state);
2378         br = regbranch(pRExC_state, &flags, 0);
2379         
2380         if (br == NULL)
2381             return(NULL);
2382         regtail(pRExC_state, lastbr, br);               /* BRANCH -> BRANCH. */
2383         lastbr = br;
2384         if (flags&HASWIDTH)
2385             *flagp |= HASWIDTH;
2386         *flagp |= flags&SPSTART;
2387     }
2388
2389     if (have_branch || paren != ':') {
2390         /* Make a closing node, and hook it on the end. */
2391         switch (paren) {
2392         case ':':
2393             ender = reg_node(pRExC_state, TAIL);
2394             break;
2395         case 1:
2396             ender = reganode(pRExC_state, CLOSE, parno);
2397             Set_Node_Offset(ender,RExC_parse+1); /* MJD */
2398             Set_Node_Length(ender,1); /* MJD */
2399             break;
2400         case '<':
2401         case ',':
2402         case '=':
2403         case '!':
2404             *flagp &= ~HASWIDTH;
2405             /* FALL THROUGH */
2406         case '>':
2407             ender = reg_node(pRExC_state, SUCCEED);
2408             break;
2409         case 0:
2410             ender = reg_node(pRExC_state, END);
2411             break;
2412         }
2413         regtail(pRExC_state, lastbr, ender);
2414
2415         if (have_branch) {
2416             /* Hook the tails of the branches to the closing node. */
2417             for (br = ret; br != NULL; br = regnext(br)) {
2418                 regoptail(pRExC_state, br, ender);
2419             }
2420         }
2421     }
2422
2423     {
2424         char *p;
2425         static char parens[] = "=!<,>";
2426
2427         if (paren && (p = strchr(parens, paren))) {
2428             int node = ((p - parens) % 2) ? UNLESSM : IFMATCH;
2429             int flag = (p - parens) > 1;
2430
2431             if (paren == '>')
2432                 node = SUSPEND, flag = 0;
2433             reginsert(pRExC_state, node,ret);
2434             ret->flags = flag;
2435             regtail(pRExC_state, ret, reg_node(pRExC_state, TAIL));
2436         }
2437     }
2438
2439     /* Check for proper termination. */
2440     if (paren) {
2441         RExC_flags16 = oregflags;
2442         if (RExC_parse >= RExC_end || *nextchar(pRExC_state) != ')') {
2443             RExC_parse = oregcomp_parse;
2444             vFAIL("Unmatched (");
2445         }
2446     }
2447     else if (!paren && RExC_parse < RExC_end) {
2448         if (*RExC_parse == ')') {
2449             RExC_parse++;
2450             vFAIL("Unmatched )");
2451         }
2452         else
2453             FAIL("Junk on end of regexp");      /* "Can't happen". */
2454         /* NOTREACHED */
2455     }
2456
2457     return(ret);
2458 }
2459
2460 /*
2461  - regbranch - one alternative of an | operator
2462  *
2463  * Implements the concatenation operator.
2464  */
2465 STATIC regnode *
2466 S_regbranch(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, I32 first)
2467 {
2468     register regnode *ret;
2469     register regnode *chain = NULL;
2470     register regnode *latest;
2471     I32 flags = 0, c = 0;
2472
2473     if (first)
2474         ret = NULL;
2475     else {
2476         if (!SIZE_ONLY && RExC_extralen)
2477             ret = reganode(pRExC_state, BRANCHJ,0);
2478         else {
2479             ret = reg_node(pRExC_state, BRANCH);
2480             Set_Node_Length(ret, 1);
2481         }
2482     }
2483         
2484     if (!first && SIZE_ONLY)
2485         RExC_extralen += 1;                     /* BRANCHJ */
2486
2487     *flagp = WORST;                     /* Tentatively. */
2488
2489     RExC_parse--;
2490     nextchar(pRExC_state);
2491     while (RExC_parse < RExC_end && *RExC_parse != '|' && *RExC_parse != ')') {
2492         flags &= ~TRYAGAIN;
2493         latest = regpiece(pRExC_state, &flags);
2494         if (latest == NULL) {
2495             if (flags & TRYAGAIN)
2496                 continue;
2497             return(NULL);
2498         }
2499         else if (ret == NULL)
2500             ret = latest;
2501         *flagp |= flags&HASWIDTH;
2502         if (chain == NULL)      /* First piece. */
2503             *flagp |= flags&SPSTART;
2504         else {
2505             RExC_naughty++;
2506             regtail(pRExC_state, chain, latest);
2507         }
2508         chain = latest;
2509         c++;
2510     }
2511     if (chain == NULL) {        /* Loop ran zero times. */
2512         chain = reg_node(pRExC_state, NOTHING);
2513         if (ret == NULL)
2514             ret = chain;
2515     }
2516     if (c == 1) {
2517         *flagp |= flags&SIMPLE;
2518     }
2519
2520     return(ret);
2521 }
2522
2523 /*
2524  - regpiece - something followed by possible [*+?]
2525  *
2526  * Note that the branching code sequences used for ? and the general cases
2527  * of * and + are somewhat optimized:  they use the same NOTHING node as
2528  * both the endmarker for their branch list and the body of the last branch.
2529  * It might seem that this node could be dispensed with entirely, but the
2530  * endmarker role is not redundant.
2531  */
2532 STATIC regnode *
2533 S_regpiece(pTHX_ RExC_state_t *pRExC_state, I32 *flagp)
2534 {
2535     register regnode *ret;
2536     register char op;
2537     register char *next;
2538     I32 flags;
2539     char *origparse = RExC_parse;
2540     char *maxpos;
2541     I32 min;
2542     I32 max = REG_INFTY;
2543     char *parse_start;
2544
2545     ret = regatom(pRExC_state, &flags);
2546     if (ret == NULL) {
2547         if (flags & TRYAGAIN)
2548             *flagp |= TRYAGAIN;
2549         return(NULL);
2550     }
2551
2552     op = *RExC_parse;
2553
2554     if (op == '{' && regcurly(RExC_parse)) {
2555         parse_start = RExC_parse; /* MJD */
2556         next = RExC_parse + 1;
2557         maxpos = Nullch;
2558         while (isDIGIT(*next) || *next == ',') {
2559             if (*next == ',') {
2560                 if (maxpos)
2561                     break;
2562                 else
2563                     maxpos = next;
2564             }
2565             next++;
2566         }
2567         if (*next == '}') {             /* got one */
2568             if (!maxpos)
2569                 maxpos = next;
2570             RExC_parse++;
2571             min = atoi(RExC_parse);
2572             if (*maxpos == ',')
2573                 maxpos++;
2574             else
2575                 maxpos = RExC_parse;
2576             max = atoi(maxpos);
2577             if (!max && *maxpos != '0')
2578                 max = REG_INFTY;                /* meaning "infinity" */
2579             else if (max >= REG_INFTY)
2580                 vFAIL2("Quantifier in {,} bigger than %d", REG_INFTY - 1);
2581             RExC_parse = next;
2582             nextchar(pRExC_state);
2583
2584         do_curly:
2585             if ((flags&SIMPLE)) {
2586                 RExC_naughty += 2 + RExC_naughty / 2;
2587                 reginsert(pRExC_state, CURLY, ret);
2588                 Set_Node_Offset(ret, parse_start+1); /* MJD */
2589                 Set_Node_Cur_Length(ret);
2590             }
2591             else {
2592                 regnode *w = reg_node(pRExC_state, WHILEM);
2593
2594                 w->flags = 0;
2595                 regtail(pRExC_state, ret, w);
2596                 if (!SIZE_ONLY && RExC_extralen) {
2597                     reginsert(pRExC_state, LONGJMP,ret);
2598                     reginsert(pRExC_state, NOTHING,ret);
2599                     NEXT_OFF(ret) = 3;  /* Go over LONGJMP. */
2600                 }
2601                 reginsert(pRExC_state, CURLYX,ret);
2602                                 /* MJD hk */
2603                 Set_Node_Offset(ret, parse_start+1);
2604                 Set_Node_Length(ret, 
2605                                 op == '{' ? (RExC_parse - parse_start) : 1);
2606                 
2607                 if (!SIZE_ONLY && RExC_extralen)
2608                     NEXT_OFF(ret) = 3;  /* Go over NOTHING to LONGJMP. */
2609                 regtail(pRExC_state, ret, reg_node(pRExC_state, NOTHING));
2610                 if (SIZE_ONLY)
2611                     RExC_whilem_seen++, RExC_extralen += 3;
2612                 RExC_naughty += 4 + RExC_naughty;       /* compound interest */
2613             }
2614             ret->flags = 0;
2615
2616             if (min > 0)
2617                 *flagp = WORST;
2618             if (max > 0)
2619                 *flagp |= HASWIDTH;
2620             if (max && max < min)
2621                 vFAIL("Can't do {n,m} with n > m");
2622             if (!SIZE_ONLY) {
2623                 ARG1_SET(ret, min);
2624                 ARG2_SET(ret, max);
2625             }
2626
2627             goto nest_check;
2628         }
2629     }
2630
2631     if (!ISMULT1(op)) {
2632         *flagp = flags;
2633         return(ret);
2634     }
2635
2636 #if 0                           /* Now runtime fix should be reliable. */
2637
2638     /* if this is reinstated, don't forget to put this back into perldiag:
2639
2640             =item Regexp *+ operand could be empty at {#} in regex m/%s/
2641
2642            (F) The part of the regexp subject to either the * or + quantifier
2643            could match an empty string. The {#} shows in the regular
2644            expression about where the problem was discovered.
2645
2646     */
2647
2648     if (!(flags&HASWIDTH) && op != '?')
2649       vFAIL("Regexp *+ operand could be empty");
2650 #endif
2651
2652     parse_start = RExC_parse;
2653     nextchar(pRExC_state);
2654
2655     *flagp = (op != '+') ? (WORST|SPSTART|HASWIDTH) : (WORST|HASWIDTH);
2656
2657     if (op == '*' && (flags&SIMPLE)) {
2658         reginsert(pRExC_state, STAR, ret);
2659         ret->flags = 0;
2660         RExC_naughty += 4;
2661     }
2662     else if (op == '*') {
2663         min = 0;
2664         goto do_curly;
2665     }
2666     else if (op == '+' && (flags&SIMPLE)) {
2667         reginsert(pRExC_state, PLUS, ret);
2668         ret->flags = 0;
2669         RExC_naughty += 3;
2670     }
2671     else if (op == '+') {
2672         min = 1;
2673         goto do_curly;
2674     }
2675     else if (op == '?') {
2676         min = 0; max = 1;
2677         goto do_curly;
2678     }
2679   nest_check:
2680     if (ckWARN(WARN_REGEXP) && !SIZE_ONLY && !(flags&HASWIDTH) && max > REG_INFTY/3) {
2681         vWARN3(RExC_parse,
2682                "%.*s matches null string many times",
2683                RExC_parse - origparse,
2684                origparse);
2685     }
2686
2687     if (*RExC_parse == '?') {
2688         nextchar(pRExC_state);
2689         reginsert(pRExC_state, MINMOD, ret);
2690         regtail(pRExC_state, ret, ret + NODE_STEP_REGNODE);
2691     }
2692     if (ISMULT2(RExC_parse)) {
2693         RExC_parse++;
2694         vFAIL("Nested quantifiers");
2695     }
2696
2697     return(ret);
2698 }
2699
2700 /*
2701  - regatom - the lowest level
2702  *
2703  * Optimization:  gobbles an entire sequence of ordinary characters so that
2704  * it can turn them into a single node, which is smaller to store and
2705  * faster to run.  Backslashed characters are exceptions, each becoming a
2706  * separate node; the code is simpler that way and it's not worth fixing.
2707  *
2708  * [Yes, it is worth fixing, some scripts can run twice the speed.] */
2709 STATIC regnode *
2710 S_regatom(pTHX_ RExC_state_t *pRExC_state, I32 *flagp)
2711 {
2712     register regnode *ret = 0;
2713     I32 flags;
2714     char *parse_start = 0;
2715
2716     *flagp = WORST;             /* Tentatively. */
2717
2718 tryagain:
2719     switch (*RExC_parse) {
2720     case '^':
2721         RExC_seen_zerolen++;
2722         nextchar(pRExC_state);
2723         if (RExC_flags16 & PMf_MULTILINE)
2724             ret = reg_node(pRExC_state, MBOL);
2725         else if (RExC_flags16 & PMf_SINGLELINE)
2726             ret = reg_node(pRExC_state, SBOL);
2727         else
2728             ret = reg_node(pRExC_state, BOL);
2729         Set_Node_Length(ret, 1); /* MJD */
2730         break;
2731     case '$':
2732         nextchar(pRExC_state);
2733         if (*RExC_parse)
2734             RExC_seen_zerolen++;
2735         if (RExC_flags16 & PMf_MULTILINE)
2736             ret = reg_node(pRExC_state, MEOL);
2737         else if (RExC_flags16 & PMf_SINGLELINE)
2738             ret = reg_node(pRExC_state, SEOL);
2739         else
2740             ret = reg_node(pRExC_state, EOL);
2741         Set_Node_Length(ret, 1); /* MJD */
2742         break;
2743     case '.':
2744         nextchar(pRExC_state);
2745         if (RExC_flags16 & PMf_SINGLELINE)
2746             ret = reg_node(pRExC_state, SANY);
2747         else
2748             ret = reg_node(pRExC_state, REG_ANY);
2749         *flagp |= HASWIDTH|SIMPLE;
2750         RExC_naughty++;
2751         Set_Node_Length(ret, 1); /* MJD */
2752         break;
2753     case '[':
2754     {
2755         char *oregcomp_parse = ++RExC_parse;
2756         ret = regclass(pRExC_state);
2757         if (*RExC_parse != ']') {
2758             RExC_parse = oregcomp_parse;
2759             vFAIL("Unmatched [");
2760         }
2761         nextchar(pRExC_state);
2762         *flagp |= HASWIDTH|SIMPLE;
2763         Set_Node_Length(ret, RExC_parse - oregcomp_parse + 1); /* MJD */
2764         break;
2765     }
2766     case '(':
2767         nextchar(pRExC_state);
2768         ret = reg(pRExC_state, 1, &flags);
2769         if (ret == NULL) {
2770                 if (flags & TRYAGAIN) {
2771                     if (RExC_parse == RExC_end) {
2772                          /* Make parent create an empty node if needed. */
2773                         *flagp |= TRYAGAIN;
2774                         return(NULL);
2775                     }
2776                     goto tryagain;
2777                 }
2778                 return(NULL);
2779         }
2780         *flagp |= flags&(HASWIDTH|SPSTART|SIMPLE);
2781         break;
2782     case '|':
2783     case ')':
2784         if (flags & TRYAGAIN) {
2785             *flagp |= TRYAGAIN;
2786             return NULL;
2787         }
2788         vFAIL("Internal urp");
2789                                 /* Supposed to be caught earlier. */
2790         break;
2791     case '{':
2792         if (!regcurly(RExC_parse)) {
2793             RExC_parse++;
2794             goto defchar;
2795         }
2796         /* FALL THROUGH */
2797     case '?':
2798     case '+':
2799     case '*':
2800         RExC_parse++;
2801         vFAIL("Quantifier follows nothing");
2802         break;
2803     case '\\':
2804         switch (*++RExC_parse) {
2805         case 'A':
2806             RExC_seen_zerolen++;
2807             ret = reg_node(pRExC_state, SBOL);
2808             *flagp |= SIMPLE;
2809             nextchar(pRExC_state);
2810             Set_Node_Length(ret, 2); /* MJD */
2811             break;
2812         case 'G':
2813             ret = reg_node(pRExC_state, GPOS);
2814             RExC_seen |= REG_SEEN_GPOS;
2815             *flagp |= SIMPLE;
2816             nextchar(pRExC_state);
2817             Set_Node_Length(ret, 2); /* MJD */
2818             break;
2819         case 'Z':
2820             ret = reg_node(pRExC_state, SEOL);
2821             *flagp |= SIMPLE;
2822             RExC_seen_zerolen++;                /* Do not optimize RE away */
2823             nextchar(pRExC_state);
2824             break;
2825         case 'z':
2826             ret = reg_node(pRExC_state, EOS);
2827             *flagp |= SIMPLE;
2828             RExC_seen_zerolen++;                /* Do not optimize RE away */
2829             nextchar(pRExC_state);
2830             Set_Node_Length(ret, 2); /* MJD */
2831             break;
2832         case 'C':
2833             ret = reg_node(pRExC_state, CANY);
2834             RExC_seen |= REG_SEEN_CANY;
2835             *flagp |= HASWIDTH|SIMPLE;
2836             nextchar(pRExC_state);
2837             Set_Node_Length(ret, 2); /* MJD */
2838             break;
2839         case 'X':
2840             ret = reg_node(pRExC_state, CLUMP);
2841             *flagp |= HASWIDTH;
2842             nextchar(pRExC_state);
2843             Set_Node_Length(ret, 2); /* MJD */
2844             break;
2845         case 'w':
2846             ret = reg_node(pRExC_state, LOC ? ALNUML     : ALNUM);
2847             *flagp |= HASWIDTH|SIMPLE;
2848             nextchar(pRExC_state);
2849             Set_Node_Length(ret, 2); /* MJD */
2850             break;
2851         case 'W':
2852             ret = reg_node(pRExC_state, LOC ? NALNUML     : NALNUM);
2853             *flagp |= HASWIDTH|SIMPLE;
2854             nextchar(pRExC_state);
2855             Set_Node_Length(ret, 2); /* MJD */
2856             break;
2857         case 'b':
2858             RExC_seen_zerolen++;
2859             RExC_seen |= REG_SEEN_LOOKBEHIND;
2860             ret = reg_node(pRExC_state, LOC ? BOUNDL     : BOUND);
2861             *flagp |= SIMPLE;
2862             nextchar(pRExC_state);
2863             Set_Node_Length(ret, 2); /* MJD */
2864             break;
2865         case 'B':
2866             RExC_seen_zerolen++;
2867             RExC_seen |= REG_SEEN_LOOKBEHIND;
2868             ret = reg_node(pRExC_state, LOC ? NBOUNDL     : NBOUND);
2869             *flagp |= SIMPLE;
2870             nextchar(pRExC_state);
2871             Set_Node_Length(ret, 2); /* MJD */
2872             break;
2873         case 's':
2874             ret = reg_node(pRExC_state, LOC ? SPACEL     : SPACE);
2875             *flagp |= HASWIDTH|SIMPLE;
2876             nextchar(pRExC_state);
2877             Set_Node_Length(ret, 2); /* MJD */
2878             break;
2879         case 'S':
2880             ret = reg_node(pRExC_state, LOC ? NSPACEL     : NSPACE);
2881             *flagp |= HASWIDTH|SIMPLE;
2882             nextchar(pRExC_state);
2883             Set_Node_Length(ret, 2); /* MJD */
2884             break;
2885         case 'd':
2886             ret = reg_node(pRExC_state, DIGIT);
2887             *flagp |= HASWIDTH|SIMPLE;
2888             nextchar(pRExC_state);
2889             Set_Node_Length(ret, 2); /* MJD */
2890             break;
2891         case 'D':
2892             ret = reg_node(pRExC_state, NDIGIT);
2893             *flagp |= HASWIDTH|SIMPLE;
2894             nextchar(pRExC_state);
2895             Set_Node_Length(ret, 2); /* MJD */
2896             break;
2897         case 'p':
2898         case 'P':
2899             {   
2900                 char* oldregxend = RExC_end;
2901                 char* parse_start = RExC_parse;
2902
2903                 if (RExC_parse[1] == '{') {
2904                   /* a lovely hack--pretend we saw [\pX] instead */
2905                     RExC_end = strchr(RExC_parse, '}');
2906                     if (!RExC_end) {
2907                         U8 c = (U8)*RExC_parse;
2908                         RExC_parse += 2;
2909                         RExC_end = oldregxend;
2910                         vFAIL2("Missing right brace on \\%c{}", c);
2911                     }
2912                     RExC_end++;
2913                 }
2914                 else
2915                     RExC_end = RExC_parse + 2;
2916                 RExC_parse--;
2917
2918                 ret = regclass(pRExC_state);
2919
2920                 RExC_end = oldregxend;
2921                 RExC_parse--;
2922                 Set_Node_Cur_Length(ret); /* MJD */
2923                 nextchar(pRExC_state);
2924                 *flagp |= HASWIDTH|SIMPLE;
2925             }
2926             break;
2927         case 'n':
2928         case 'r':
2929         case 't':
2930         case 'f':
2931         case 'e':
2932         case 'a':
2933         case 'x':
2934         case 'c':
2935         case '0':
2936             goto defchar;
2937         case '1': case '2': case '3': case '4':
2938         case '5': case '6': case '7': case '8': case '9':
2939             {
2940                 I32 num = atoi(RExC_parse);
2941
2942                 if (num > 9 && num >= RExC_npar)
2943                     goto defchar;
2944                 else {
2945                     char * parse_start = RExC_parse - 1; /* MJD */
2946                     while (isDIGIT(*RExC_parse))
2947                         RExC_parse++;
2948
2949                     if (!SIZE_ONLY && num > RExC_rx->nparens)
2950                         vFAIL("Reference to nonexistent group");
2951                     RExC_sawback = 1;
2952                     ret = reganode(pRExC_state, FOLD
2953                                    ? (LOC ? REFFL : REFF)
2954                                    : REF, num);
2955                     *flagp |= HASWIDTH;
2956                     
2957                     /* override incorrect value set in reganode MJD */
2958                     Set_Node_Offset(ret, parse_start+1); 
2959                     Set_Node_Cur_Length(ret); /* MJD */
2960                     RExC_parse--;
2961                     nextchar(pRExC_state);
2962                 }
2963             }
2964             break;
2965         case '\0':
2966             if (RExC_parse >= RExC_end)
2967                 FAIL("Trailing \\");
2968             /* FALL THROUGH */
2969         default:
2970             /* Do not generate `unrecognized' warnings here, we fall
2971                back into the quick-grab loop below */
2972             goto defchar;
2973         }
2974         break;
2975
2976     case '#':
2977         if (RExC_flags16 & PMf_EXTENDED) {
2978             while (RExC_parse < RExC_end && *RExC_parse != '\n') RExC_parse++;
2979             if (RExC_parse < RExC_end)
2980                 goto tryagain;
2981         }
2982         /* FALL THROUGH */
2983
2984     default: {
2985             register STRLEN len;
2986             register UV ender;
2987             register char *p;
2988             char *oldp, *s;
2989             STRLEN numlen;
2990             STRLEN ulen;
2991             U8 tmpbuf[UTF8_MAXLEN_UCLC+1];
2992
2993             parse_start = RExC_parse - 1;
2994
2995             RExC_parse++;
2996
2997         defchar:
2998             ret = reg_node(pRExC_state, FOLD
2999                           ? (LOC ? EXACTFL : EXACTF)
3000                           : EXACT);
3001             s = STRING(ret);
3002             for (len = 0, p = RExC_parse - 1;
3003               len < 127 && p < RExC_end;
3004               len++)
3005             {
3006                 oldp = p;
3007
3008                 if (RExC_flags16 & PMf_EXTENDED)
3009                     p = regwhite(p, RExC_end);
3010                 switch (*p) {
3011                 case '^':
3012                 case '$':
3013                 case '.':
3014                 case '[':
3015                 case '(':
3016                 case ')':
3017                 case '|':
3018                     goto loopdone;
3019                 case '\\':
3020                     switch (*++p) {
3021                     case 'A':
3022                     case 'G':
3023                     case 'Z':
3024                     case 'z':
3025                     case 'w':
3026                     case 'W':
3027                     case 'b':
3028                     case 'B':
3029                     case 's':
3030                     case 'S':
3031                     case 'd':
3032                     case 'D':
3033                     case 'p':
3034                     case 'P':
3035                         --p;
3036                         goto loopdone;
3037                     case 'n':
3038                         ender = '\n';
3039                         p++;
3040                         break;
3041                     case 'r':
3042                         ender = '\r';
3043                         p++;
3044                         break;
3045                     case 't':
3046                         ender = '\t';
3047                         p++;
3048                         break;
3049                     case 'f':
3050                         ender = '\f';
3051                         p++;
3052                         break;
3053                     case 'e':
3054                           ender = ASCII_TO_NATIVE('\033');
3055                         p++;
3056                         break;
3057                     case 'a':
3058                           ender = ASCII_TO_NATIVE('\007');
3059                         p++;
3060                         break;
3061                     case 'x':
3062                         if (*++p == '{') {
3063                             char* e = strchr(p, '}');
3064         
3065                             if (!e) {
3066                                 RExC_parse = p + 1;
3067                                 vFAIL("Missing right brace on \\x{}");
3068                             }
3069                             else {
3070                                 I32 flags = PERL_SCAN_ALLOW_UNDERSCORES
3071                                     | PERL_SCAN_DISALLOW_PREFIX;
3072                                 numlen = e - p - 1;
3073                                 ender = grok_hex(p + 1, &numlen, &flags, NULL);
3074                                 if (ender > 0xff)
3075                                     RExC_utf8 = 1;
3076                                 /* numlen is generous */
3077                                 if (numlen + len >= 127) {
3078                                     p--;
3079                                     goto loopdone;
3080                                 }
3081                                 p = e + 1;
3082                             }
3083                         }
3084                         else {
3085                             I32 flags = PERL_SCAN_DISALLOW_PREFIX;
3086                             numlen = 2;
3087                             ender = grok_hex(p, &numlen, &flags, NULL);
3088                             p += numlen;
3089                         }
3090                         break;
3091                     case 'c':
3092                         p++;
3093                         ender = UCHARAT(p++);
3094                         ender = toCTRL(ender);
3095                         break;
3096                     case '0': case '1': case '2': case '3':case '4':
3097                     case '5': case '6': case '7': case '8':case '9':
3098                         if (*p == '0' ||
3099                           (isDIGIT(p[1]) && atoi(p) >= RExC_npar) ) {
3100                             I32 flags = 0;
3101                             numlen = 3;
3102                             ender = grok_oct(p, &numlen, &flags, NULL);
3103                             p += numlen;
3104                         }
3105                         else {
3106                             --p;
3107                             goto loopdone;
3108                         }
3109                         break;
3110                     case '\0':
3111                         if (p >= RExC_end)
3112                             FAIL("Trailing \\");
3113                         /* FALL THROUGH */
3114                     default:
3115                         if (!SIZE_ONLY && ckWARN(WARN_REGEXP) && isALPHA(*p))
3116                             vWARN2(p + 1, "Unrecognized escape \\%c passed through", UCHARAT(p));
3117                         goto normal_default;
3118                     }
3119                     break;
3120                 default:
3121                   normal_default:
3122                     if (UTF8_IS_START(*p) && UTF) {
3123                         ender = utf8n_to_uvchr((U8*)p, RExC_end - p,
3124                                                &numlen, 0);
3125                         p += numlen;
3126                     }
3127                     else
3128                         ender = *p++;
3129                     break;
3130                 }
3131                 if (RExC_flags16 & PMf_EXTENDED)
3132                     p = regwhite(p, RExC_end);
3133                 if (UTF && FOLD) {
3134                     toLOWER_uni(ender, tmpbuf, &ulen);
3135                     ender = utf8_to_uvchr(tmpbuf, 0);
3136                 }
3137                 if (ISMULT2(p)) { /* Back off on ?+*. */
3138                     if (len)
3139                         p = oldp;
3140                     else if (!UNI_IS_INVARIANT(NATIVE_TO_UNI(ender)) && UTF) {
3141                         reguni(pRExC_state, ender, s, &numlen);
3142                         s += numlen;
3143                         len += numlen;
3144                     }
3145                     else {
3146                         len++;
3147                         REGC(ender, s++);
3148                     }
3149                     break;
3150                 }
3151                 if (!UNI_IS_INVARIANT(NATIVE_TO_UNI(ender)) && UTF) {
3152                     reguni(pRExC_state, ender, s, &numlen);
3153                     s += numlen;
3154                     len += numlen - 1;
3155                 }
3156                 else
3157                     REGC(ender, s++);
3158             }
3159         loopdone:
3160             RExC_parse = p - 1;
3161             Set_Node_Cur_Length(ret); /* MJD */
3162             nextchar(pRExC_state);
3163             {
3164                 /* len is STRLEN which is unsigned, need to copy to signed */
3165                 IV iv = len;
3166                 if (iv < 0)
3167                     vFAIL("Internal disaster");
3168             }
3169             if (len > 0)
3170                 *flagp |= HASWIDTH;
3171             if (len == 1)
3172                 *flagp |= SIMPLE;
3173             if (!SIZE_ONLY)
3174                 STR_LEN(ret) = len;
3175             if (SIZE_ONLY)
3176                 RExC_size += STR_SZ(len);
3177             else
3178                 RExC_emit += STR_SZ(len);
3179         }
3180         break;
3181     }
3182
3183     if (PL_encoding && PL_regkind[(U8)OP(ret)] == EXACT && !RExC_utf8) {
3184          STRLEN oldlen = STR_LEN(ret);
3185          SV *sv        = sv_2mortal(newSVpvn(STRING(ret), oldlen));
3186          char *s       = Perl_sv_recode_to_utf8(aTHX_ sv, PL_encoding);
3187          STRLEN newlen = SvCUR(sv);
3188          if (!SIZE_ONLY) {
3189               DEBUG_r(PerlIO_printf(Perl_debug_log, "recode %*s to %*s\n",
3190                                     (int)oldlen, STRING(ret), (int)newlen, s));
3191               Copy(s, STRING(ret), newlen, char);
3192               STR_LEN(ret) += newlen - oldlen;
3193               RExC_emit += STR_SZ(newlen) - STR_SZ(oldlen);
3194          } else
3195               RExC_size += STR_SZ(newlen) - STR_SZ(oldlen);
3196          RExC_utf8 = 1;
3197     }
3198
3199     return(ret);
3200 }
3201
3202 STATIC char *
3203 S_regwhite(pTHX_ char *p, char *e)
3204 {
3205     while (p < e) {
3206         if (isSPACE(*p))
3207             ++p;
3208         else if (*p == '#') {
3209             do {
3210                 p++;
3211             } while (p < e && *p != '\n');
3212         }
3213         else
3214             break;
3215     }
3216     return p;
3217 }
3218
3219 /* Parse POSIX character classes: [[:foo:]], [[=foo=]], [[.foo.]].
3220    Character classes ([:foo:]) can also be negated ([:^foo:]).
3221    Returns a named class id (ANYOF_XXX) if successful, -1 otherwise.
3222    Equivalence classes ([=foo=]) and composites ([.foo.]) are parsed,
3223    but trigger failures because they are currently unimplemented. */
3224
3225 #define POSIXCC_DONE(c)   ((c) == ':')
3226 #define POSIXCC_NOTYET(c) ((c) == '=' || (c) == '.')
3227 #define POSIXCC(c) (POSIXCC_DONE(c) || POSIXCC_NOTYET(c))
3228
3229 STATIC I32
3230 S_regpposixcc(pTHX_ RExC_state_t *pRExC_state, I32 value)
3231 {
3232     char *posixcc = 0;
3233     I32 namedclass = OOB_NAMEDCLASS;
3234
3235     if (value == '[' && RExC_parse + 1 < RExC_end &&
3236         /* I smell either [: or [= or [. -- POSIX has been here, right? */
3237         POSIXCC(UCHARAT(RExC_parse))) {
3238         char  c = UCHARAT(RExC_parse);
3239         char* s = RExC_parse++;
3240         
3241         while (RExC_parse < RExC_end && UCHARAT(RExC_parse) != c)
3242             RExC_parse++;
3243         if (RExC_parse == RExC_end)
3244             /* Grandfather lone [:, [=, [. */
3245             RExC_parse = s;
3246         else {
3247             char* t = RExC_parse++; /* skip over the c */
3248
3249             if (UCHARAT(RExC_parse) == ']') {
3250                 RExC_parse++; /* skip over the ending ] */
3251                 posixcc = s + 1;
3252                 if (*s == ':') {
3253                     I32 complement = *posixcc == '^' ? *posixcc++ : 0;
3254                     I32 skip = 5; /* the most common skip */
3255
3256                     switch (*posixcc) {
3257                     case 'a':
3258                         if (strnEQ(posixcc, "alnum", 5))
3259                             namedclass =
3260                                 complement ? ANYOF_NALNUMC : ANYOF_ALNUMC;
3261                         else if (strnEQ(posixcc, "alpha", 5))
3262                             namedclass =
3263                                 complement ? ANYOF_NALPHA : ANYOF_ALPHA;
3264                         else if (strnEQ(posixcc, "ascii", 5))
3265                             namedclass =
3266                                 complement ? ANYOF_NASCII : ANYOF_ASCII;
3267                         break;
3268                     case 'b':
3269                         if (strnEQ(posixcc, "blank", 5))
3270                             namedclass =
3271                                 complement ? ANYOF_NBLANK : ANYOF_BLANK;
3272                         break;
3273                     case 'c':
3274                         if (strnEQ(posixcc, "cntrl", 5))
3275                             namedclass =
3276                                 complement ? ANYOF_NCNTRL : ANYOF_CNTRL;
3277                         break;
3278                     case 'd':
3279                         if (strnEQ(posixcc, "digit", 5))
3280                             namedclass =
3281                                 complement ? ANYOF_NDIGIT : ANYOF_DIGIT;
3282                         break;
3283                     case 'g':
3284                         if (strnEQ(posixcc, "graph", 5))
3285                             namedclass =
3286                                 complement ? ANYOF_NGRAPH : ANYOF_GRAPH;
3287                         break;
3288                     case 'l':
3289                         if (strnEQ(posixcc, "lower", 5))
3290                             namedclass =
3291                                 complement ? ANYOF_NLOWER : ANYOF_LOWER;
3292                         break;
3293                     case 'p':
3294                         if (strnEQ(posixcc, "print", 5))
3295                             namedclass =
3296                                 complement ? ANYOF_NPRINT : ANYOF_PRINT;
3297                         else if (strnEQ(posixcc, "punct", 5))
3298                             namedclass =
3299                                 complement ? ANYOF_NPUNCT : ANYOF_PUNCT;
3300                         break;
3301                     case 's':
3302                         if (strnEQ(posixcc, "space", 5))
3303                             namedclass =
3304                                 complement ? ANYOF_NPSXSPC : ANYOF_PSXSPC;
3305                         break;
3306                     case 'u':
3307                         if (strnEQ(posixcc, "upper", 5))
3308                             namedclass =
3309                                 complement ? ANYOF_NUPPER : ANYOF_UPPER;
3310                         break;
3311                     case 'w': /* this is not POSIX, this is the Perl \w */
3312                         if (strnEQ(posixcc, "word", 4)) {
3313                             namedclass =
3314                                 complement ? ANYOF_NALNUM : ANYOF_ALNUM;
3315                             skip = 4;
3316                         }
3317                         break;
3318                     case 'x':
3319                         if (strnEQ(posixcc, "xdigit", 6)) {
3320                             namedclass =
3321                                 complement ? ANYOF_NXDIGIT : ANYOF_XDIGIT;
3322                             skip = 6;
3323                         }
3324                         break;
3325                     }
3326                     if (namedclass == OOB_NAMEDCLASS ||
3327                         posixcc[skip] != ':' ||
3328                         posixcc[skip+1] != ']')
3329                     {
3330                         Simple_vFAIL3("POSIX class [:%.*s:] unknown",
3331                                       t - s - 1, s + 1);
3332                     }
3333                 } else if (!SIZE_ONLY) {
3334                     /* [[=foo=]] and [[.foo.]] are still future. */
3335
3336                     /* adjust RExC_parse so the warning shows after
3337                        the class closes */
3338                     while (UCHARAT(RExC_parse) && UCHARAT(RExC_parse) != ']')
3339                         RExC_parse++;
3340                     Simple_vFAIL3("POSIX syntax [%c %c] is reserved for future extensions", c, c);
3341                 }
3342             } else {
3343                 /* Maternal grandfather:
3344                  * "[:" ending in ":" but not in ":]" */
3345                 RExC_parse = s;
3346             }
3347         }
3348     }
3349
3350     return namedclass;
3351 }
3352
3353 STATIC void
3354 S_checkposixcc(pTHX_ RExC_state_t *pRExC_state)
3355 {
3356     if (!SIZE_ONLY && ckWARN(WARN_REGEXP) &&
3357         POSIXCC(UCHARAT(RExC_parse))) {
3358         char *s = RExC_parse;
3359         char  c = *s++;
3360
3361         while(*s && isALNUM(*s))
3362             s++;
3363         if (*s && c == *s && s[1] == ']') {
3364             vWARN3(s+2, "POSIX syntax [%c %c] belongs inside character classes", c, c);
3365
3366             /* [[=foo=]] and [[.foo.]] are still future. */
3367             if (POSIXCC_NOTYET(c)) {
3368                 /* adjust RExC_parse so the error shows after
3369                    the class closes */
3370                 while (UCHARAT(RExC_parse) && UCHARAT(RExC_parse++) != ']')
3371                     ;
3372                 Simple_vFAIL3("POSIX syntax [%c %c] is reserved for future extensions", c, c);
3373             }
3374         }
3375     }
3376 }
3377
3378 STATIC regnode *
3379 S_regclass(pTHX_ RExC_state_t *pRExC_state)
3380 {
3381     register UV value;
3382     register UV nextvalue;
3383     register IV prevvalue = OOB_UNICODE;
3384     register IV range = 0;
3385     register regnode *ret;
3386     STRLEN numlen;
3387     IV namedclass;
3388     char *rangebegin = 0;
3389     bool need_class = 0;
3390     SV *listsv = Nullsv;
3391     register char *e;
3392     UV n;
3393     bool optimize_invert = TRUE;
3394
3395     ret = reganode(pRExC_state, ANYOF, 0);
3396
3397     if (!SIZE_ONLY)
3398         ANYOF_FLAGS(ret) = 0;
3399
3400     if (UCHARAT(RExC_parse) == '^') {   /* Complement of range. */
3401         RExC_naughty++;
3402         RExC_parse++;
3403         if (!SIZE_ONLY)
3404             ANYOF_FLAGS(ret) |= ANYOF_INVERT;
3405     }
3406
3407     if (SIZE_ONLY)
3408         RExC_size += ANYOF_SKIP;
3409     else {
3410         RExC_emit += ANYOF_SKIP;
3411         if (FOLD)
3412             ANYOF_FLAGS(ret) |= ANYOF_FOLD;
3413         if (LOC)
3414             ANYOF_FLAGS(ret) |= ANYOF_LOCALE;
3415         ANYOF_BITMAP_ZERO(ret);
3416         listsv = newSVpvn("# comment\n", 10);
3417     }
3418
3419     nextvalue = RExC_parse < RExC_end ? UCHARAT(RExC_parse) : 0;
3420
3421     if (!SIZE_ONLY && ckWARN(WARN_REGEXP) && POSIXCC(nextvalue))
3422         checkposixcc(pRExC_state);
3423
3424     if (UCHARAT(RExC_parse) == ']' || UCHARAT(RExC_parse) == '-')
3425         goto charclassloop;             /* allow 1st char to be ] or - */
3426
3427     while (RExC_parse < RExC_end && UCHARAT(RExC_parse) != ']') {
3428
3429     charclassloop:
3430
3431         namedclass = OOB_NAMEDCLASS; /* initialize as illegal */
3432
3433         if (!range)
3434             rangebegin = RExC_parse;
3435         if (UTF) {
3436             value = utf8n_to_uvchr((U8*)RExC_parse,
3437                                    RExC_end - RExC_parse,
3438                                    &numlen, 0);
3439             RExC_parse += numlen;
3440         }
3441         else
3442             value = UCHARAT(RExC_parse++);
3443         nextvalue = RExC_parse < RExC_end ? UCHARAT(RExC_parse) : 0;
3444         if (value == '[' && POSIXCC(nextvalue))
3445             namedclass = regpposixcc(pRExC_state, value);
3446         else if (value == '\\') {
3447             if (UTF) {
3448                 value = utf8n_to_uvchr((U8*)RExC_parse,
3449                                    RExC_end - RExC_parse,
3450                                    &numlen, 0);
3451                 RExC_parse += numlen;
3452             }
3453             else
3454                 value = UCHARAT(RExC_parse++);
3455             /* Some compilers cannot handle switching on 64-bit integer
3456              * values, therefore value cannot be an UV.  Yes, this will
3457              * be a problem later if we want switch on Unicode.
3458              * A similar issue a little bit later when switching on
3459              * namedclass. --jhi */
3460             switch ((I32)value) {
3461             case 'w':   namedclass = ANYOF_ALNUM;       break;
3462             case 'W':   namedclass = ANYOF_NALNUM;      break;
3463             case 's':   namedclass = ANYOF_SPACE;       break;
3464             case 'S':   namedclass = ANYOF_NSPACE;      break;
3465             case 'd':   namedclass = ANYOF_DIGIT;       break;
3466             case 'D':   namedclass = ANYOF_NDIGIT;      break;
3467             case 'p':
3468             case 'P':
3469                 if (*RExC_parse == '{') {
3470                     U8 c = (U8)value;
3471                     e = strchr(RExC_parse++, '}');
3472                     if (!e)
3473                         vFAIL2("Missing right brace on \\%c{}", c);
3474                     while (isSPACE(UCHARAT(RExC_parse)))
3475                         RExC_parse++;
3476                     if (e == RExC_parse)
3477                         vFAIL2("Empty \\%c{}", c);
3478                     n = e - RExC_parse;
3479                     while (isSPACE(UCHARAT(RExC_parse + n - 1)))
3480                         n--;
3481                 }
3482                 else {
3483                     e = RExC_parse;
3484                     n = 1;
3485                 }
3486                 if (!SIZE_ONLY) {
3487                     if (UCHARAT(RExC_parse) == '^') {
3488                          RExC_parse++;
3489                          n--;
3490                          value = value == 'p' ? 'P' : 'p'; /* toggle */
3491                          while (isSPACE(UCHARAT(RExC_parse))) {
3492                               RExC_parse++;
3493                               n--;
3494                          }
3495                     }
3496                     if (value == 'p')
3497                          Perl_sv_catpvf(aTHX_ listsv,
3498                                         "+utf8::%.*s\n", (int)n, RExC_parse);
3499                     else
3500                          Perl_sv_catpvf(aTHX_ listsv,
3501                                         "!utf8::%.*s\n", (int)n, RExC_parse);
3502                 }
3503                 RExC_parse = e + 1;
3504                 ANYOF_FLAGS(ret) |= ANYOF_UNICODE;
3505                 continue;
3506             case 'n':   value = '\n';                   break;
3507             case 'r':   value = '\r';                   break;
3508             case 't':   value = '\t';                   break;
3509             case 'f':   value = '\f';                   break;
3510             case 'b':   value = '\b';                   break;
3511             case 'e':   value = ASCII_TO_NATIVE('\033');break;
3512             case 'a':   value = ASCII_TO_NATIVE('\007');break;
3513             case 'x':
3514                 if (*RExC_parse == '{') {
3515                     I32 flags = PERL_SCAN_ALLOW_UNDERSCORES
3516                         | PERL_SCAN_DISALLOW_PREFIX;
3517                     e = strchr(RExC_parse++, '}');
3518                     if (!e)
3519                         vFAIL("Missing right brace on \\x{}");
3520
3521                     numlen = e - RExC_parse;
3522                     value = grok_hex(RExC_parse, &numlen, &flags, NULL);
3523                     RExC_parse = e + 1;
3524                 }
3525                 else {
3526                     I32 flags = PERL_SCAN_DISALLOW_PREFIX;
3527                     numlen = 2;
3528                     value = grok_hex(RExC_parse, &numlen, &flags, NULL);
3529                     RExC_parse += numlen;
3530                 }
3531                 break;
3532             case 'c':
3533                 value = UCHARAT(RExC_parse++);
3534                 value = toCTRL(value);
3535                 break;
3536             case '0': case '1': case '2': case '3': case '4':
3537             case '5': case '6': case '7': case '8': case '9':
3538             {
3539                 I32 flags = 0;
3540                 numlen = 3;
3541                 value = grok_oct(--RExC_parse, &numlen, &flags, NULL);
3542                 RExC_parse += numlen;
3543                 break;
3544             }
3545             default:
3546                 if (!SIZE_ONLY && ckWARN(WARN_REGEXP) && isALPHA(value))
3547                     vWARN2(RExC_parse,
3548                            "Unrecognized escape \\%c in character class passed through",
3549                            (int)value);
3550                 break;
3551             }
3552         } /* end of \blah */
3553
3554         if (namedclass > OOB_NAMEDCLASS) { /* this is a named class \blah */
3555
3556             if (!SIZE_ONLY && !need_class)
3557                 ANYOF_CLASS_ZERO(ret);
3558
3559             need_class = 1;
3560
3561             /* a bad range like a-\d, a-[:digit:] ? */
3562             if (range) {
3563                 if (!SIZE_ONLY) {
3564                     if (ckWARN(WARN_REGEXP))
3565                         vWARN4(RExC_parse,
3566                                "False [] range \"%*.*s\"",
3567                                RExC_parse - rangebegin,
3568                                RExC_parse - rangebegin,
3569                                rangebegin);
3570                     if (prevvalue < 256) {
3571                         ANYOF_BITMAP_SET(ret, prevvalue);
3572                         ANYOF_BITMAP_SET(ret, '-');
3573                     }
3574                     else {
3575                         ANYOF_FLAGS(ret) |= ANYOF_UNICODE;
3576                         Perl_sv_catpvf(aTHX_ listsv,
3577                                        "%04"UVxf"\n%04"UVxf"\n", (UV)prevvalue, (UV) '-');
3578                     }
3579                 }
3580
3581                 range = 0; /* this was not a true range */
3582             }
3583
3584             if (!SIZE_ONLY) {
3585                 if (namedclass > OOB_NAMEDCLASS)
3586                     optimize_invert = FALSE;
3587                 /* Possible truncation here but in some 64-bit environments
3588                  * the compiler gets heartburn about switch on 64-bit values.
3589                  * A similar issue a little earlier when switching on value.
3590                  * --jhi */
3591                 switch ((I32)namedclass) {
3592                 case ANYOF_ALNUM:
3593                     if (LOC)
3594                         ANYOF_CLASS_SET(ret, ANYOF_ALNUM);
3595                     else {
3596                         for (value = 0; value < 256; value++)
3597                             if (isALNUM(value))
3598                                 ANYOF_BITMAP_SET(ret, value);
3599                     }
3600                     Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsWord\n");    
3601                     break;
3602                 case ANYOF_NALNUM:
3603                     if (LOC)
3604                         ANYOF_CLASS_SET(ret, ANYOF_NALNUM);
3605                     else {
3606                         for (value = 0; value < 256; value++)
3607                             if (!isALNUM(value))
3608                                 ANYOF_BITMAP_SET(ret, value);
3609                     }
3610                     Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsWord\n");
3611                     break;
3612                 case ANYOF_ALNUMC:
3613                     if (LOC)
3614                         ANYOF_CLASS_SET(ret, ANYOF_ALNUMC);
3615                     else {
3616                         for (value = 0; value < 256; value++)
3617                             if (isALNUMC(value))
3618                                 ANYOF_BITMAP_SET(ret, value);
3619                     }
3620                     Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsAlnum\n");
3621                     break;
3622                 case ANYOF_NALNUMC:
3623                     if (LOC)
3624                         ANYOF_CLASS_SET(ret, ANYOF_NALNUMC);
3625                     else {
3626                         for (value = 0; value < 256; value++)
3627                             if (!isALNUMC(value))
3628                                 ANYOF_BITMAP_SET(ret, value);
3629                     }
3630                     Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsAlnum\n");
3631                     break;
3632                 case ANYOF_ALPHA:
3633                     if (LOC)
3634                         ANYOF_CLASS_SET(ret, ANYOF_ALPHA);
3635                     else {
3636                         for (value = 0; value < 256; value++)
3637                             if (isALPHA(value))
3638                                 ANYOF_BITMAP_SET(ret, value);
3639                     }
3640                     Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsAlpha\n");
3641                     break;
3642                 case ANYOF_NALPHA:
3643                     if (LOC)
3644                         ANYOF_CLASS_SET(ret, ANYOF_NALPHA);
3645                     else {
3646                         for (value = 0; value < 256; value++)
3647                             if (!isALPHA(value))
3648                                 ANYOF_BITMAP_SET(ret, value);
3649                     }
3650                     Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsAlpha\n");
3651                     break;
3652                 case ANYOF_ASCII:
3653                     if (LOC)
3654                         ANYOF_CLASS_SET(ret, ANYOF_ASCII);
3655                     else {
3656 #ifndef EBCDIC
3657                         for (value = 0; value < 128; value++)
3658                             ANYOF_BITMAP_SET(ret, value);
3659 #else  /* EBCDIC */
3660                         for (value = 0; value < 256; value++) {
3661                             if (isASCII(value))
3662                                 ANYOF_BITMAP_SET(ret, value);
3663                         }
3664 #endif /* EBCDIC */
3665                     }
3666                     Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsASCII\n");
3667                     break;
3668                 case ANYOF_NASCII:
3669                     if (LOC)
3670                         ANYOF_CLASS_SET(ret, ANYOF_NASCII);
3671                     else {
3672 #ifndef EBCDIC
3673                         for (value = 128; value < 256; value++)
3674                             ANYOF_BITMAP_SET(ret, value);
3675 #else  /* EBCDIC */
3676                         for (value = 0; value < 256; value++) {
3677                             if (!isASCII(value))
3678                                 ANYOF_BITMAP_SET(ret, value);
3679                         }
3680 #endif /* EBCDIC */
3681                     }
3682                     Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsASCII\n");
3683                     break;
3684                 case ANYOF_BLANK:
3685                     if (LOC)
3686                         ANYOF_CLASS_SET(ret, ANYOF_BLANK);
3687                     else {
3688                         for (value = 0; value < 256; value++)
3689                             if (isBLANK(value))
3690                                 ANYOF_BITMAP_SET(ret, value);
3691                     }
3692                     Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsBlank\n");
3693                     break;
3694                 case ANYOF_NBLANK:
3695                     if (LOC)
3696                         ANYOF_CLASS_SET(ret, ANYOF_NBLANK);
3697                     else {
3698                         for (value = 0; value < 256; value++)
3699                             if (!isBLANK(value))
3700                                 ANYOF_BITMAP_SET(ret, value);
3701                     }
3702                     Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsBlank\n");
3703                     break;
3704                 case ANYOF_CNTRL:
3705                     if (LOC)
3706                         ANYOF_CLASS_SET(ret, ANYOF_CNTRL);
3707                     else {
3708                         for (value = 0; value < 256; value++)
3709                             if (isCNTRL(value))
3710                                 ANYOF_BITMAP_SET(ret, value);
3711                     }
3712                     Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsCntrl\n");
3713                     break;
3714                 case ANYOF_NCNTRL:
3715                     if (LOC)
3716                         ANYOF_CLASS_SET(ret, ANYOF_NCNTRL);
3717                     else {
3718                         for (value = 0; value < 256; value++)
3719                             if (!isCNTRL(value))
3720                                 ANYOF_BITMAP_SET(ret, value);
3721                     }
3722                     Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsCntrl\n");
3723                     break;
3724                 case ANYOF_DIGIT:
3725                     if (LOC)
3726                         ANYOF_CLASS_SET(ret, ANYOF_DIGIT);
3727                     else {
3728                         /* consecutive digits assumed */
3729                         for (value = '0'; value <= '9'; value++)
3730                             ANYOF_BITMAP_SET(ret, value);
3731                     }
3732                     Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsDigit\n");
3733                     break;
3734                 case ANYOF_NDIGIT:
3735                     if (LOC)
3736                         ANYOF_CLASS_SET(ret, ANYOF_NDIGIT);
3737                     else {
3738                         /* consecutive digits assumed */
3739                         for (value = 0; value < '0'; value++)
3740                             ANYOF_BITMAP_SET(ret, value);
3741                         for (value = '9' + 1; value < 256; value++)
3742                             ANYOF_BITMAP_SET(ret, value);
3743                     }
3744                     Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsDigit\n");
3745                     break;
3746                 case ANYOF_GRAPH:
3747                     if (LOC)
3748                         ANYOF_CLASS_SET(ret, ANYOF_GRAPH);
3749                     else {
3750                         for (value = 0; value < 256; value++)
3751                             if (isGRAPH(value))
3752                                 ANYOF_BITMAP_SET(ret, value);
3753                     }
3754                     Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsGraph\n");
3755                     break;
3756                 case ANYOF_NGRAPH:
3757                     if (LOC)
3758                         ANYOF_CLASS_SET(ret, ANYOF_NGRAPH);
3759                     else {
3760                         for (value = 0; value < 256; value++)
3761                             if (!isGRAPH(value))
3762                                 ANYOF_BITMAP_SET(ret, value);
3763                     }
3764                     Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsGraph\n");
3765                     break;
3766                 case ANYOF_LOWER:
3767                     if (LOC)
3768                         ANYOF_CLASS_SET(ret, ANYOF_LOWER);
3769                     else {
3770                         for (value = 0; value < 256; value++)
3771                             if (isLOWER(value))
3772                                 ANYOF_BITMAP_SET(ret, value);
3773                     }
3774                     Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsLower\n");
3775                     break;
3776                 case ANYOF_NLOWER:
3777                     if (LOC)
3778                         ANYOF_CLASS_SET(ret, ANYOF_NLOWER);
3779                     else {
3780                         for (value = 0; value < 256; value++)
3781                             if (!isLOWER(value))
3782                                 ANYOF_BITMAP_SET(ret, value);
3783                     }
3784                     Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsLower\n");
3785                     break;
3786                 case ANYOF_PRINT:
3787                     if (LOC)
3788                         ANYOF_CLASS_SET(ret, ANYOF_PRINT);
3789                     else {
3790                         for (value = 0; value < 256; value++)
3791                             if (isPRINT(value))
3792                                 ANYOF_BITMAP_SET(ret, value);
3793                     }
3794                     Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsPrint\n");
3795                     break;
3796                 case ANYOF_NPRINT:
3797                     if (LOC)
3798                         ANYOF_CLASS_SET(ret, ANYOF_NPRINT);
3799                     else {
3800                         for (value = 0; value < 256; value++)
3801                             if (!isPRINT(value))
3802                                 ANYOF_BITMAP_SET(ret, value);
3803                     }
3804                     Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsPrint\n");
3805                     break;
3806                 case ANYOF_PSXSPC:
3807                     if (LOC)
3808                         ANYOF_CLASS_SET(ret, ANYOF_PSXSPC);
3809                     else {
3810                         for (value = 0; value < 256; value++)
3811                             if (isPSXSPC(value))
3812                                 ANYOF_BITMAP_SET(ret, value);
3813                     }
3814                     Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsSpace\n");
3815                     break;
3816                 case ANYOF_NPSXSPC:
3817                     if (LOC)
3818                         ANYOF_CLASS_SET(ret, ANYOF_NPSXSPC);
3819                     else {
3820                         for (value = 0; value < 256; value++)
3821                             if (!isPSXSPC(value))
3822                                 ANYOF_BITMAP_SET(ret, value);
3823                     }
3824                     Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsSpace\n");
3825                     break;
3826                 case ANYOF_PUNCT:
3827                     if (LOC)
3828                         ANYOF_CLASS_SET(ret, ANYOF_PUNCT);
3829                     else {
3830                         for (value = 0; value < 256; value++)
3831                             if (isPUNCT(value))
3832                                 ANYOF_BITMAP_SET(ret, value);
3833                     }
3834                     Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsPunct\n");
3835                     break;
3836                 case ANYOF_NPUNCT:
3837                     if (LOC)
3838                         ANYOF_CLASS_SET(ret, ANYOF_NPUNCT);
3839                     else {
3840                         for (value = 0; value < 256; value++)
3841                             if (!isPUNCT(value))
3842                                 ANYOF_BITMAP_SET(ret, value);
3843                     }
3844                     Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsPunct\n");
3845                     break;
3846                 case ANYOF_SPACE:
3847                     if (LOC)
3848                         ANYOF_CLASS_SET(ret, ANYOF_SPACE);
3849                     else {
3850                         for (value = 0; value < 256; value++)
3851                             if (isSPACE(value))
3852                                 ANYOF_BITMAP_SET(ret, value);
3853                     }
3854                     Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsSpacePerl\n");
3855                     break;
3856                 case ANYOF_NSPACE:
3857                     if (LOC)
3858                         ANYOF_CLASS_SET(ret, ANYOF_NSPACE);
3859                     else {
3860                         for (value = 0; value < 256; value++)
3861                             if (!isSPACE(value))
3862                                 ANYOF_BITMAP_SET(ret, value);
3863                     }
3864                     Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsSpacePerl\n");
3865                     break;
3866                 case ANYOF_UPPER:
3867                     if (LOC)
3868                         ANYOF_CLASS_SET(ret, ANYOF_UPPER);
3869                     else {
3870                         for (value = 0; value < 256; value++)
3871                             if (isUPPER(value))
3872                                 ANYOF_BITMAP_SET(ret, value);
3873                     }
3874                     Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsUpper\n");
3875                     break;
3876                 case ANYOF_NUPPER:
3877                     if (LOC)
3878                         ANYOF_CLASS_SET(ret, ANYOF_NUPPER);
3879                     else {
3880                         for (value = 0; value < 256; value++)
3881                             if (!isUPPER(value))
3882                                 ANYOF_BITMAP_SET(ret, value);
3883                     }
3884                     Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsUpper\n");
3885                     break;
3886                 case ANYOF_XDIGIT:
3887                     if (LOC)
3888                         ANYOF_CLASS_SET(ret, ANYOF_XDIGIT);
3889                     else {
3890                         for (value = 0; value < 256; value++)
3891                             if (isXDIGIT(value))
3892                                 ANYOF_BITMAP_SET(ret, value);
3893                     }
3894                     Perl_sv_catpvf(aTHX_ listsv, "+utf8::IsXDigit\n");
3895                     break;
3896                 case ANYOF_NXDIGIT:
3897                     if (LOC)
3898                         ANYOF_CLASS_SET(ret, ANYOF_NXDIGIT);
3899                     else {
3900                         for (value = 0; value < 256; value++)
3901                             if (!isXDIGIT(value))
3902                                 ANYOF_BITMAP_SET(ret, value);
3903                     }
3904                     Perl_sv_catpvf(aTHX_ listsv, "!utf8::IsXDigit\n");
3905                     break;
3906                 default:
3907                     vFAIL("Invalid [::] class");
3908                     break;
3909                 }
3910                 if (LOC)
3911                     ANYOF_FLAGS(ret) |= ANYOF_CLASS;
3912                 continue;
3913             }
3914         } /* end of namedclass \blah */
3915
3916         if (range) {
3917             if (prevvalue > value) /* b-a */ {
3918                 Simple_vFAIL4("Invalid [] range \"%*.*s\"",
3919                               RExC_parse - rangebegin,
3920                               RExC_parse - rangebegin,
3921                               rangebegin);
3922                 range = 0; /* not a valid range */
3923             }
3924         }
3925         else {
3926             prevvalue = value; /* save the beginning of the range */
3927             if (*RExC_parse == '-' && RExC_parse+1 < RExC_end &&
3928                 RExC_parse[1] != ']') {
3929                 RExC_parse++;
3930
3931                 /* a bad range like \w-, [:word:]- ? */
3932                 if (namedclass > OOB_NAMEDCLASS) {
3933                     if (ckWARN(WARN_REGEXP))
3934                         vWARN4(RExC_parse,
3935                                "False [] range \"%*.*s\"",
3936                                RExC_parse - rangebegin,
3937                                RExC_parse - rangebegin,
3938                                rangebegin);
3939                     if (!SIZE_ONLY)
3940                         ANYOF_BITMAP_SET(ret, '-');
3941                 } else
3942                     range = 1;  /* yeah, it's a range! */
3943                 continue;       /* but do it the next time */
3944             }
3945         }
3946
3947         /* now is the next time */
3948         if (!SIZE_ONLY) {
3949             IV i;
3950
3951             if (prevvalue < 256) {
3952                 IV ceilvalue = value < 256 ? value : 255;
3953
3954 #ifdef EBCDIC
3955                 if ((isLOWER(prevvalue) && isLOWER(ceilvalue)) ||
3956                     (isUPPER(prevvalue) && isUPPER(ceilvalue)))
3957                 {
3958                     if (isLOWER(prevvalue)) {
3959                         for (i = prevvalue; i <= ceilvalue; i++)
3960                             if (isLOWER(i))
3961                                 ANYOF_BITMAP_SET(ret, i);
3962                     } else {
3963                         for (i = prevvalue; i <= ceilvalue; i++)
3964                             if (isUPPER(i))
3965                                 ANYOF_BITMAP_SET(ret, i);
3966                     }
3967                 }
3968                 else
3969 #endif
3970                     for (i = prevvalue; i <= ceilvalue; i++)
3971                         ANYOF_BITMAP_SET(ret, i);
3972           }
3973           if (value > 255) {
3974                 ANYOF_FLAGS(ret) |= ANYOF_UNICODE;
3975                 if (prevvalue < value)
3976                     Perl_sv_catpvf(aTHX_ listsv, "%04"UVxf"\t%04"UVxf"\n",
3977                                    (UV)prevvalue, (UV)value);
3978                 else if (prevvalue == value)
3979                     Perl_sv_catpvf(aTHX_ listsv, "%04"UVxf"\n",
3980                                    (UV)value);
3981             }
3982         }
3983
3984         range = 0; /* this range (if it was one) is done now */
3985     }
3986
3987     if (need_class) {
3988         ANYOF_FLAGS(ret) |= ANYOF_LARGE;
3989         if (SIZE_ONLY)
3990             RExC_size += ANYOF_CLASS_ADD_SKIP;
3991         else
3992             RExC_emit += ANYOF_CLASS_ADD_SKIP;
3993     }
3994
3995     /* optimize case-insensitive simple patterns (e.g. /[a-z]/i) */
3996     if (!SIZE_ONLY &&
3997          /* If the only flag is folding (plus possibly inversion). */
3998         ((ANYOF_FLAGS(ret) & (ANYOF_FLAGS_ALL ^ ANYOF_INVERT)) == ANYOF_FOLD)
3999        ) {
4000         for (value = 0; value < 256; ++value) {
4001             if (ANYOF_BITMAP_TEST(ret, value)) {
4002                 IV fold = PL_fold[value];
4003
4004                 if (fold != value)
4005                     ANYOF_BITMAP_SET(ret, fold);
4006             }
4007         }
4008         ANYOF_FLAGS(ret) &= ~ANYOF_FOLD;
4009     }
4010
4011     /* optimize inverted simple patterns (e.g. [^a-z]) */
4012     if (!SIZE_ONLY && optimize_invert &&
4013         /* If the only flag is inversion. */
4014         (ANYOF_FLAGS(ret) & ANYOF_FLAGS_ALL) == ANYOF_INVERT) {
4015         for (value = 0; value < ANYOF_BITMAP_SIZE; ++value)
4016             ANYOF_BITMAP(ret)[value] ^= ANYOF_FLAGS_ALL;
4017         ANYOF_FLAGS(ret) = ANYOF_UNICODE_ALL;
4018     }
4019
4020     if (!SIZE_ONLY) {
4021         AV *av = newAV();
4022         SV *rv;
4023
4024         av_store(av, 0, listsv);
4025         av_store(av, 1, NULL);
4026         rv = newRV_noinc((SV*)av);
4027         n = add_data(pRExC_state, 1, "s");
4028         RExC_rx->data->data[n] = (void*)rv;
4029         ARG_SET(ret, n);
4030     }
4031
4032     return ret;
4033 }
4034
4035 STATIC char*
4036 S_nextchar(pTHX_ RExC_state_t *pRExC_state)
4037 {
4038     char* retval = RExC_parse++;
4039
4040     for (;;) {
4041         if (*RExC_parse == '(' && RExC_parse[1] == '?' &&
4042                 RExC_parse[2] == '#') {
4043             while (*RExC_parse && *RExC_parse != ')')
4044                 RExC_parse++;
4045             RExC_parse++;
4046             continue;
4047         }
4048         if (RExC_flags16 & PMf_EXTENDED) {
4049             if (isSPACE(*RExC_parse)) {
4050                 RExC_parse++;
4051                 continue;
4052             }
4053             else if (*RExC_parse == '#') {
4054                 while (*RExC_parse && *RExC_parse != '\n')
4055                     RExC_parse++;
4056                 RExC_parse++;
4057                 continue;
4058             }
4059         }
4060         return retval;
4061     }
4062 }
4063
4064 /*
4065 - reg_node - emit a node
4066 */
4067 STATIC regnode *                        /* Location. */
4068 S_reg_node(pTHX_ RExC_state_t *pRExC_state, U8 op)
4069 {
4070     register regnode *ret;
4071     register regnode *ptr;
4072
4073     ret = RExC_emit;
4074     if (SIZE_ONLY) {
4075         SIZE_ALIGN(RExC_size);
4076         RExC_size += 1;
4077         return(ret);
4078     }
4079
4080     NODE_ALIGN_FILL(ret);
4081     ptr = ret;
4082     FILL_ADVANCE_NODE(ptr, op);
4083     if (RExC_offsets) {         /* MJD */
4084       MJD_OFFSET_DEBUG((stderr, "%s:%u: (op %s) %s %u <- %u (len %u) (max %u).\n", 
4085               "reg_node", __LINE__, 
4086               reg_name[op],
4087               RExC_emit - RExC_emit_start > RExC_offsets[0] 
4088               ? "Overwriting end of array!\n" : "OK",
4089               RExC_emit - RExC_emit_start,
4090               RExC_parse - RExC_start,
4091               RExC_offsets[0])); 
4092       Set_Node_Offset(RExC_emit, RExC_parse + (op == END));
4093     }
4094             
4095     RExC_emit = ptr;
4096
4097     return(ret);
4098 }
4099
4100 /*
4101 - reganode - emit a node with an argument
4102 */
4103 STATIC regnode *                        /* Location. */
4104 S_reganode(pTHX_ RExC_state_t *pRExC_state, U8 op, U32 arg)
4105 {
4106     register regnode *ret;
4107     register regnode *ptr;
4108
4109     ret = RExC_emit;
4110     if (SIZE_ONLY) {
4111         SIZE_ALIGN(RExC_size);
4112         RExC_size += 2;
4113         return(ret);
4114     }
4115
4116     NODE_ALIGN_FILL(ret);
4117     ptr = ret;
4118     FILL_ADVANCE_NODE_ARG(ptr, op, arg);
4119     if (RExC_offsets) {         /* MJD */
4120       MJD_OFFSET_DEBUG((stderr, "%s: %s %u <- %u (max %u).\n", 
4121               "reganode",
4122               RExC_emit - RExC_emit_start > RExC_offsets[0] ? 
4123               "Overwriting end of array!\n" : "OK",
4124               RExC_emit - RExC_emit_start,
4125               RExC_parse - RExC_start,
4126               RExC_offsets[0])); 
4127       Set_Cur_Node_Offset;
4128     }
4129             
4130     RExC_emit = ptr;
4131
4132     return(ret);
4133 }
4134
4135 /*
4136 - reguni - emit (if appropriate) a Unicode character
4137 */
4138 STATIC void
4139 S_reguni(pTHX_ RExC_state_t *pRExC_state, UV uv, char* s, STRLEN* lenp)
4140 {
4141     *lenp = SIZE_ONLY ? UNISKIP(uv) : (uvchr_to_utf8((U8*)s, uv) - (U8*)s);
4142 }
4143
4144 /*
4145 - reginsert - insert an operator in front of already-emitted operand
4146 *
4147 * Means relocating the operand.
4148 */
4149 STATIC void
4150 S_reginsert(pTHX_ RExC_state_t *pRExC_state, U8 op, regnode *opnd)
4151 {
4152     register regnode *src;
4153     register regnode *dst;
4154     register regnode *place;
4155     register int offset = regarglen[(U8)op];
4156
4157 /* (PL_regkind[(U8)op] == CURLY ? EXTRA_STEP_2ARGS : 0); */
4158
4159     if (SIZE_ONLY) {
4160         RExC_size += NODE_STEP_REGNODE + offset;
4161         return;
4162     }
4163
4164     src = RExC_emit;
4165     RExC_emit += NODE_STEP_REGNODE + offset;
4166     dst = RExC_emit;
4167     while (src > opnd) {
4168         StructCopy(--src, --dst, regnode);
4169         if (RExC_offsets) {     /* MJD 20010112 */
4170           MJD_OFFSET_DEBUG((stderr, "%s: %s copy %u -> %u (max %u).\n", 
4171                   "reg_insert",
4172                   dst - RExC_emit_start > RExC_offsets[0] 
4173                   ? "Overwriting end of array!\n" : "OK",
4174                   src - RExC_emit_start,
4175                   dst - RExC_emit_start,
4176                   RExC_offsets[0])); 
4177           Set_Node_Offset_To_R(dst-RExC_emit_start, Node_Offset(src));
4178           Set_Node_Length_To_R(dst-RExC_emit_start, Node_Length(src));
4179         }
4180     }
4181     
4182
4183     place = opnd;               /* Op node, where operand used to be. */
4184     if (RExC_offsets) {         /* MJD */
4185       MJD_OFFSET_DEBUG((stderr, "%s: %s %u <- %u (max %u).\n", 
4186               "reginsert",
4187               place - RExC_emit_start > RExC_offsets[0] 
4188               ? "Overwriting end of array!\n" : "OK",
4189               place - RExC_emit_start,
4190               RExC_parse - RExC_start,
4191               RExC_offsets[0])); 
4192       Set_Node_Offset(place, RExC_parse);
4193     }
4194     src = NEXTOPER(place);
4195     FILL_ADVANCE_NODE(place, op);
4196     Zero(src, offset, regnode);
4197 }
4198
4199 /*
4200 - regtail - set the next-pointer at the end of a node chain of p to val.
4201 */
4202 STATIC void
4203 S_regtail(pTHX_ RExC_state_t *pRExC_state, regnode *p, regnode *val)
4204 {
4205     register regnode *scan;
4206     register regnode *temp;
4207
4208     if (SIZE_ONLY)
4209         return;
4210
4211     /* Find last node. */
4212     scan = p;
4213     for (;;) {
4214         temp = regnext(scan);
4215         if (temp == NULL)
4216             break;
4217         scan = temp;
4218     }
4219
4220     if (reg_off_by_arg[OP(scan)]) {
4221         ARG_SET(scan, val - scan);
4222     }
4223     else {
4224         NEXT_OFF(scan) = val - scan;
4225     }
4226 }
4227
4228 /*
4229 - regoptail - regtail on operand of first argument; nop if operandless
4230 */
4231 STATIC void
4232 S_regoptail(pTHX_ RExC_state_t *pRExC_state, regnode *p, regnode *val)
4233 {
4234     /* "Operandless" and "op != BRANCH" are synonymous in practice. */
4235     if (p == NULL || SIZE_ONLY)
4236         return;
4237     if (PL_regkind[(U8)OP(p)] == BRANCH) {
4238         regtail(pRExC_state, NEXTOPER(p), val);
4239     }
4240     else if ( PL_regkind[(U8)OP(p)] == BRANCHJ) {
4241         regtail(pRExC_state, NEXTOPER(NEXTOPER(p)), val);
4242     }
4243     else
4244         return;
4245 }
4246
4247 /*
4248  - regcurly - a little FSA that accepts {\d+,?\d*}
4249  */
4250 STATIC I32
4251 S_regcurly(pTHX_ register char *s)
4252 {
4253     if (*s++ != '{')
4254         return FALSE;
4255     if (!isDIGIT(*s))
4256         return FALSE;
4257     while (isDIGIT(*s))
4258         s++;
4259     if (*s == ',')
4260         s++;
4261     while (isDIGIT(*s))
4262         s++;
4263     if (*s != '}')
4264         return FALSE;
4265     return TRUE;
4266 }
4267
4268
4269 #ifdef DEBUGGING
4270
4271 STATIC regnode *
4272 S_dumpuntil(pTHX_ regnode *start, regnode *node, regnode *last, SV* sv, I32 l)
4273 {
4274     register U8 op = EXACT;     /* Arbitrary non-END op. */
4275     register regnode *next;
4276
4277     while (op != END && (!last || node < last)) {
4278         /* While that wasn't END last time... */
4279
4280         NODE_ALIGN(node);
4281         op = OP(node);
4282         if (op == CLOSE)
4283             l--;        
4284         next = regnext(node);
4285         /* Where, what. */
4286         if (OP(node) == OPTIMIZED)
4287             goto after_print;
4288         regprop(sv, node);
4289         PerlIO_printf(Perl_debug_log, "%4"IVdf":%*s%s", (IV)(node - start),
4290                       (int)(2*l + 1), "", SvPVX(sv));
4291         if (next == NULL)               /* Next ptr. */
4292             PerlIO_printf(Perl_debug_log, "(0)");
4293         else
4294             PerlIO_printf(Perl_debug_log, "(%"IVdf")", (IV)(next - start));
4295         (void)PerlIO_putc(Perl_debug_log, '\n');
4296       after_print:
4297         if (PL_regkind[(U8)op] == BRANCHJ) {
4298             register regnode *nnode = (OP(next) == LONGJMP
4299                                        ? regnext(next)
4300                                        : next);
4301             if (last && nnode > last)
4302                 nnode = last;
4303             node = dumpuntil(start, NEXTOPER(NEXTOPER(node)), nnode, sv, l + 1);
4304         }
4305         else if (PL_regkind[(U8)op] == BRANCH) {
4306             node = dumpuntil(start, NEXTOPER(node), next, sv, l + 1);
4307         }
4308         else if ( op == CURLY) {   /* `next' might be very big: optimizer */
4309             node = dumpuntil(start, NEXTOPER(node) + EXTRA_STEP_2ARGS,
4310                              NEXTOPER(node) + EXTRA_STEP_2ARGS + 1, sv, l + 1);
4311         }
4312         else if (PL_regkind[(U8)op] == CURLY && op != CURLYX) {
4313             node = dumpuntil(start, NEXTOPER(node) + EXTRA_STEP_2ARGS,
4314                              next, sv, l + 1);
4315         }
4316         else if ( op == PLUS || op == STAR) {
4317             node = dumpuntil(start, NEXTOPER(node), NEXTOPER(node) + 1, sv, l + 1);
4318         }
4319         else if (op == ANYOF) {
4320             /* arglen 1 + class block */
4321             node += 1 + ((ANYOF_FLAGS(node) & ANYOF_LARGE)
4322                     ? ANYOF_CLASS_SKIP : ANYOF_SKIP);
4323             node = NEXTOPER(node);
4324         }
4325         else if (PL_regkind[(U8)op] == EXACT) {
4326             /* Literal string, where present. */
4327             node += NODE_SZ_STR(node) - 1;
4328             node = NEXTOPER(node);
4329         }
4330         else {
4331             node = NEXTOPER(node);
4332             node += regarglen[(U8)op];
4333         }
4334         if (op == CURLYX || op == OPEN)
4335             l++;
4336         else if (op == WHILEM)
4337             l--;
4338     }
4339     return node;
4340 }
4341
4342 #endif  /* DEBUGGING */
4343
4344 /*
4345  - regdump - dump a regexp onto Perl_debug_log in vaguely comprehensible form
4346  */
4347 void
4348 Perl_regdump(pTHX_ regexp *r)
4349 {
4350 #ifdef DEBUGGING
4351     SV *sv = sv_newmortal();
4352
4353     (void)dumpuntil(r->program, r->program + 1, NULL, sv, 0);
4354
4355     /* Header fields of interest. */
4356     if (r->anchored_substr)
4357         PerlIO_printf(Perl_debug_log,
4358                       "anchored `%s%.*s%s'%s at %"IVdf" ",
4359                       PL_colors[0],
4360                       (int)(SvCUR(r->anchored_substr) - (SvTAIL(r->anchored_substr)!=0)),
4361                       SvPVX(r->anchored_substr),
4362                       PL_colors[1],
4363                       SvTAIL(r->anchored_substr) ? "$" : "",
4364                       (IV)r->anchored_offset);
4365     if (r->float_substr)
4366         PerlIO_printf(Perl_debug_log,
4367                       "floating `%s%.*s%s'%s at %"IVdf"..%"UVuf" ",
4368                       PL_colors[0],
4369                       (int)(SvCUR(r->float_substr) - (SvTAIL(r->float_substr)!=0)),
4370                       SvPVX(r->float_substr),
4371                       PL_colors[1],
4372                       SvTAIL(r->float_substr) ? "$" : "",
4373                       (IV)r->float_min_offset, (UV)r->float_max_offset);
4374     if (r->check_substr)
4375         PerlIO_printf(Perl_debug_log,
4376                       r->check_substr == r->float_substr
4377                       ? "(checking floating" : "(checking anchored");
4378     if (r->reganch & ROPT_NOSCAN)
4379         PerlIO_printf(Perl_debug_log, " noscan");
4380     if (r->reganch & ROPT_CHECK_ALL)
4381         PerlIO_printf(Perl_debug_log, " isall");
4382     if (r->check_substr)
4383         PerlIO_printf(Perl_debug_log, ") ");
4384
4385     if (r->regstclass) {
4386         regprop(sv, r->regstclass);
4387         PerlIO_printf(Perl_debug_log, "stclass `%s' ", SvPVX(sv));
4388     }
4389     if (r->reganch & ROPT_ANCH) {
4390         PerlIO_printf(Perl_debug_log, "anchored");
4391         if (r->reganch & ROPT_ANCH_BOL)
4392             PerlIO_printf(Perl_debug_log, "(BOL)");
4393         if (r->reganch & ROPT_ANCH_MBOL)
4394             PerlIO_printf(Perl_debug_log, "(MBOL)");
4395         if (r->reganch & ROPT_ANCH_SBOL)
4396             PerlIO_printf(Perl_debug_log, "(SBOL)");
4397         if (r->reganch & ROPT_ANCH_GPOS)
4398             PerlIO_printf(Perl_debug_log, "(GPOS)");
4399         PerlIO_putc(Perl_debug_log, ' ');
4400     }
4401     if (r->reganch & ROPT_GPOS_SEEN)
4402         PerlIO_printf(Perl_debug_log, "GPOS ");
4403     if (r->reganch & ROPT_SKIP)
4404         PerlIO_printf(Perl_debug_log, "plus ");
4405     if (r->reganch & ROPT_IMPLICIT)
4406         PerlIO_printf(Perl_debug_log, "implicit ");
4407     PerlIO_printf(Perl_debug_log, "minlen %ld ", (long) r->minlen);
4408     if (r->reganch & ROPT_EVAL_SEEN)
4409         PerlIO_printf(Perl_debug_log, "with eval ");
4410     PerlIO_printf(Perl_debug_log, "\n");
4411     if (r->offsets) {
4412       U32 i;
4413       U32 len = r->offsets[0];
4414       PerlIO_printf(Perl_debug_log, "Offsets: [%"UVuf"]\n\t", (UV)r->offsets[0]);
4415       for (i = 1; i <= len; i++)
4416         PerlIO_printf(Perl_debug_log, "%"UVuf"[%"UVuf"] ", 
4417                       (UV)r->offsets[i*2-1], 
4418                       (UV)r->offsets[i*2]);
4419       PerlIO_printf(Perl_debug_log, "\n");
4420     }
4421 #endif  /* DEBUGGING */
4422 }
4423
4424 #ifdef DEBUGGING
4425
4426 STATIC void
4427 S_put_byte(pTHX_ SV *sv, int c)
4428 {
4429     if (isCNTRL(c) || c == 255 || !isPRINT(c))
4430         Perl_sv_catpvf(aTHX_ sv, "\\%o", c);
4431     else if (c == '-' || c == ']' || c == '\\' || c == '^')
4432         Perl_sv_catpvf(aTHX_ sv, "\\%c", c);
4433     else
4434         Perl_sv_catpvf(aTHX_ sv, "%c", c);
4435 }
4436
4437 #endif  /* DEBUGGING */
4438
4439 /*
4440 - regprop - printable representation of opcode
4441 */
4442 void
4443 Perl_regprop(pTHX_ SV *sv, regnode *o)
4444 {
4445 #ifdef DEBUGGING
4446     register int k;
4447
4448     sv_setpvn(sv, "", 0);
4449     if (OP(o) >= reg_num)               /* regnode.type is unsigned */
4450         /* It would be nice to FAIL() here, but this may be called from
4451            regexec.c, and it would be hard to supply pRExC_state. */
4452         Perl_croak(aTHX_ "Corrupted regexp opcode");
4453     sv_catpv(sv, (char*)reg_name[OP(o)]); /* Take off const! */
4454
4455     k = PL_regkind[(U8)OP(o)];
4456
4457     if (k == EXACT) {
4458         SV *dsv = sv_2mortal(newSVpvn("", 0));
4459         bool do_utf8 = DO_UTF8(sv);
4460         char *s    = do_utf8 ?
4461           pv_uni_display(dsv, (U8*)STRING(o), STR_LEN(o), 60, 0) :
4462           STRING(o);
4463         int len = do_utf8 ?
4464           strlen(s) :
4465           STR_LEN(o);
4466         Perl_sv_catpvf(aTHX_ sv, " <%s%.*s%s>",
4467                        PL_colors[0],
4468                        len, s,
4469                        PL_colors[1]);
4470     }
4471     else if (k == CURLY) {
4472         if (OP(o) == CURLYM || OP(o) == CURLYN || OP(o) == CURLYX)
4473             Perl_sv_catpvf(aTHX_ sv, "[%d]", o->flags); /* Parenth number */
4474         Perl_sv_catpvf(aTHX_ sv, " {%d,%d}", ARG1(o), ARG2(o));
4475     }
4476     else if (k == WHILEM && o->flags)                   /* Ordinal/of */
4477         Perl_sv_catpvf(aTHX_ sv, "[%d/%d]", o->flags & 0xf, o->flags>>4);
4478     else if (k == REF || k == OPEN || k == CLOSE || k == GROUPP )
4479         Perl_sv_catpvf(aTHX_ sv, "%d", (int)ARG(o));    /* Parenth number */
4480     else if (k == LOGICAL)
4481         Perl_sv_catpvf(aTHX_ sv, "[%d]", o->flags);     /* 2: embedded, otherwise 1 */
4482     else if (k == ANYOF) {
4483         int i, rangestart = -1;
4484         U8 flags = ANYOF_FLAGS(o);
4485         const char * const anyofs[] = { /* Should be syncronized with
4486                                          * ANYOF_ #xdefines in regcomp.h */
4487             "\\w",
4488             "\\W",
4489             "\\s",
4490             "\\S",
4491             "\\d",
4492             "\\D",
4493             "[:alnum:]",
4494             "[:^alnum:]",
4495             "[:alpha:]",
4496             "[:^alpha:]",
4497             "[:ascii:]",
4498             "[:^ascii:]",
4499             "[:ctrl:]",
4500             "[:^ctrl:]",
4501             "[:graph:]",
4502             "[:^graph:]",
4503             "[:lower:]",
4504             "[:^lower:]",
4505             "[:print:]",
4506             "[:^print:]",
4507             "[:punct:]",
4508             "[:^punct:]",
4509             "[:upper:]",
4510             "[:^upper:]",
4511             "[:xdigit:]",
4512             "[:^xdigit:]",
4513             "[:space:]",
4514             "[:^space:]",
4515             "[:blank:]",
4516             "[:^blank:]"
4517         };
4518
4519         if (flags & ANYOF_LOCALE)
4520             sv_catpv(sv, "{loc}");
4521         if (flags & ANYOF_FOLD)
4522             sv_catpv(sv, "{i}");
4523         Perl_sv_catpvf(aTHX_ sv, "[%s", PL_colors[0]);
4524         if (flags & ANYOF_INVERT)
4525             sv_catpv(sv, "^");
4526         for (i = 0; i <= 256; i++) {
4527             if (i < 256 && ANYOF_BITMAP_TEST(o,i)) {
4528                 if (rangestart == -1)
4529                     rangestart = i;
4530             } else if (rangestart != -1) {
4531                 if (i <= rangestart + 3)
4532                     for (; rangestart < i; rangestart++)
4533                         put_byte(sv, rangestart);
4534                 else {
4535                     put_byte(sv, rangestart);
4536                     sv_catpv(sv, "-");
4537                     put_byte(sv, i - 1);
4538                 }
4539                 rangestart = -1;
4540             }
4541         }
4542
4543         if (o->flags & ANYOF_CLASS)
4544             for (i = 0; i < sizeof(anyofs)/sizeof(char*); i++)
4545                 if (ANYOF_CLASS_TEST(o,i))
4546                     sv_catpv(sv, anyofs[i]);
4547
4548         if (flags & ANYOF_UNICODE)
4549             sv_catpv(sv, "{unicode}");
4550         else if (flags & ANYOF_UNICODE_ALL)
4551             sv_catpv(sv, "{unicode_all}");
4552
4553         {
4554             SV *lv;
4555             SV *sw = regclass_swash(o, FALSE, &lv);
4556         
4557             if (lv) {
4558                 if (sw) {
4559                     UV i;
4560                     U8 s[UTF8_MAXLEN+1];
4561                 
4562                     for (i = 0; i <= 256; i++) { /* just the first 256 */
4563                         U8 *e = uvchr_to_utf8(s, i);
4564                         
4565                         if (i < 256 && swash_fetch(sw, s, TRUE)) {
4566                             if (rangestart == -1)
4567                                 rangestart = i;
4568                         } else if (rangestart != -1) {
4569                             U8 *p;
4570                         
4571                             if (i <= rangestart + 3)
4572                                 for (; rangestart < i; rangestart++) {
4573                                     for(e = uvchr_to_utf8(s, rangestart), p = s; p < e; p++)
4574                                         put_byte(sv, *p);
4575                                 }
4576                             else {
4577                                 for (e = uvchr_to_utf8(s, rangestart), p = s; p < e; p++)
4578                                     put_byte(sv, *p);
4579                                 sv_catpv(sv, "-");
4580                                     for (e = uvchr_to_utf8(s, i - 1), p = s; p < e; p++)
4581                                         put_byte(sv, *p);
4582                                 }
4583                                 rangestart = -1;
4584                             }
4585                         }
4586                         
4587                     sv_catpv(sv, "..."); /* et cetera */
4588                 }
4589
4590                 {
4591                     char *s = savepv(SvPVX(lv));
4592                     char *origs = s;
4593                 
4594                     while(*s && *s != '\n') s++;
4595                 
4596                     if (*s == '\n') {
4597                         char *t = ++s;
4598                         
4599                         while (*s) {
4600                             if (*s == '\n')
4601                                 *s = ' ';
4602                             s++;
4603                         }
4604                         if (s[-1] == ' ')
4605                             s[-1] = 0;
4606                         
4607                         sv_catpv(sv, t);
4608                     }
4609                 
4610                     Safefree(origs);
4611                 }
4612             }
4613         }
4614
4615         Perl_sv_catpvf(aTHX_ sv, "%s]", PL_colors[1]);
4616     }
4617     else if (k == BRANCHJ && (OP(o) == UNLESSM || OP(o) == IFMATCH))
4618         Perl_sv_catpvf(aTHX_ sv, "[-%d]", o->flags);
4619 #endif  /* DEBUGGING */
4620 }
4621
4622 SV *
4623 Perl_re_intuit_string(pTHX_ regexp *prog)
4624 {                               /* Assume that RE_INTUIT is set */
4625     DEBUG_r(
4626         {   STRLEN n_a;
4627             char *s = SvPV(prog->check_substr,n_a);
4628
4629             if (!PL_colorset) reginitcolors();
4630             PerlIO_printf(Perl_debug_log,
4631                       "%sUsing REx substr:%s `%s%.60s%s%s'\n",
4632                       PL_colors[4],PL_colors[5],PL_colors[0],
4633                       s,
4634                       PL_colors[1],
4635                       (strlen(s) > 60 ? "..." : ""));
4636         } );
4637
4638     return prog->check_substr;
4639 }
4640
4641 void
4642 Perl_pregfree(pTHX_ struct regexp *r)
4643 {
4644     DEBUG_r(if (!PL_colorset) reginitcolors());
4645
4646     if (!r || (--r->refcnt > 0))
4647         return;
4648     DEBUG_r(PerlIO_printf(Perl_debug_log,
4649                       "%sFreeing REx:%s `%s%.60s%s%s'\n",
4650                       PL_colors[4],PL_colors[5],PL_colors[0],
4651                       r->precomp,
4652                       PL_colors[1],
4653                       (strlen(r->precomp) > 60 ? "..." : "")));
4654
4655     if (r->precomp)
4656         Safefree(r->precomp);
4657     if (r->offsets)             /* 20010421 MJD */
4658         Safefree(r->offsets);
4659     if (RX_MATCH_COPIED(r))
4660         Safefree(r->subbeg);
4661     if (r->substrs) {
4662         if (r->anchored_substr)
4663             SvREFCNT_dec(r->anchored_substr);
4664         if (r->float_substr)
4665             SvREFCNT_dec(r->float_substr);
4666         Safefree(r->substrs);
4667     }
4668     if (r->data) {
4669         int n = r->data->count;
4670         AV* new_comppad = NULL;
4671         AV* old_comppad;
4672         SV** old_curpad;
4673
4674         while (--n >= 0) {
4675           /* If you add a ->what type here, update the comment in regcomp.h */
4676             switch (r->data->what[n]) {
4677             case 's':
4678                 SvREFCNT_dec((SV*)r->data->data[n]);
4679                 break;
4680             case 'f':
4681                 Safefree(r->data->data[n]);
4682                 break;
4683             case 'p':
4684                 new_comppad = (AV*)r->data->data[n];
4685                 break;
4686             case 'o':
4687                 if (new_comppad == NULL)
4688                     Perl_croak(aTHX_ "panic: pregfree comppad");
4689                 old_comppad = PL_comppad;
4690                 old_curpad = PL_curpad;
4691                 /* Watch out for global destruction's random ordering. */
4692                 if (SvTYPE(new_comppad) == SVt_PVAV) {
4693                     PL_comppad = new_comppad;
4694                     PL_curpad = AvARRAY(new_comppad);
4695                 }
4696                 else
4697                     PL_curpad = NULL;
4698
4699                 if (!OpREFCNT_dec((OP_4tree*)r->data->data[n])) {
4700                     op_free((OP_4tree*)r->data->data[n]);
4701                 }
4702
4703                 PL_comppad = old_comppad;
4704                 PL_curpad = old_curpad;
4705                 SvREFCNT_dec((SV*)new_comppad);
4706                 new_comppad = NULL;
4707                 break;
4708             case 'n':
4709                 break;
4710             default:
4711                 Perl_croak(aTHX_ "panic: regfree data code '%c'", r->data->what[n]);
4712             }
4713         }
4714         Safefree(r->data->what);
4715         Safefree(r->data);
4716     }
4717     Safefree(r->startp);
4718     Safefree(r->endp);
4719     Safefree(r);
4720 }
4721
4722 /*
4723  - regnext - dig the "next" pointer out of a node
4724  *
4725  * [Note, when REGALIGN is defined there are two places in regmatch()
4726  * that bypass this code for speed.]
4727  */
4728 regnode *
4729 Perl_regnext(pTHX_ register regnode *p)
4730 {
4731     register I32 offset;
4732
4733     if (p == &PL_regdummy)
4734         return(NULL);
4735
4736     offset = (reg_off_by_arg[OP(p)] ? ARG(p) : NEXT_OFF(p));
4737     if (offset == 0)
4738         return(NULL);
4739
4740     return(p+offset);
4741 }
4742
4743 STATIC void     
4744 S_re_croak2(pTHX_ const char* pat1,const char* pat2,...)
4745 {
4746     va_list args;
4747     STRLEN l1 = strlen(pat1);
4748     STRLEN l2 = strlen(pat2);
4749     char buf[512];
4750     SV *msv;
4751     char *message;
4752
4753     if (l1 > 510)
4754         l1 = 510;
4755     if (l1 + l2 > 510)
4756         l2 = 510 - l1;
4757     Copy(pat1, buf, l1 , char);
4758     Copy(pat2, buf + l1, l2 , char);
4759     buf[l1 + l2] = '\n';
4760     buf[l1 + l2 + 1] = '\0';
4761 #ifdef I_STDARG
4762     /* ANSI variant takes additional second argument */
4763     va_start(args, pat2);
4764 #else
4765     va_start(args);
4766 #endif
4767     msv = vmess(buf, &args);
4768     va_end(args);
4769     message = SvPV(msv,l1);
4770     if (l1 > 512)
4771         l1 = 512;
4772     Copy(message, buf, l1 , char);
4773     buf[l1] = '\0';                     /* Overwrite \n */
4774     Perl_croak(aTHX_ "%s", buf);
4775 }
4776
4777 /* XXX Here's a total kludge.  But we need to re-enter for swash routines. */
4778
4779 void
4780 Perl_save_re_context(pTHX)
4781 {
4782 #if 0
4783     SAVEPPTR(RExC_precomp);             /* uncompiled string. */
4784     SAVEI32(RExC_npar);         /* () count. */
4785     SAVEI32(RExC_size);         /* Code size. */
4786     SAVEI16(RExC_flags16);              /* are we folding, multilining? */
4787     SAVEVPTR(RExC_rx);          /* from regcomp.c */
4788     SAVEI32(RExC_seen);         /* from regcomp.c */
4789     SAVEI32(RExC_sawback);              /* Did we see \1, ...? */
4790     SAVEI32(RExC_naughty);              /* How bad is this pattern? */
4791     SAVEVPTR(RExC_emit);                /* Code-emit pointer; &regdummy = don't */
4792     SAVEPPTR(RExC_end);         /* End of input for compile */
4793     SAVEPPTR(RExC_parse);               /* Input-scan pointer. */
4794 #endif
4795
4796     SAVEI32(PL_reg_flags);              /* from regexec.c */
4797     SAVEPPTR(PL_bostr);
4798     SAVEPPTR(PL_reginput);              /* String-input pointer. */
4799     SAVEPPTR(PL_regbol);                /* Beginning of input, for ^ check. */
4800     SAVEPPTR(PL_regeol);                /* End of input, for $ check. */
4801     SAVEVPTR(PL_regstartp);             /* Pointer to startp array. */
4802     SAVEVPTR(PL_regendp);               /* Ditto for endp. */
4803     SAVEVPTR(PL_reglastparen);          /* Similarly for lastparen. */
4804     SAVEPPTR(PL_regtill);               /* How far we are required to go. */
4805     SAVEGENERICPV(PL_reg_start_tmp);            /* from regexec.c */
4806     PL_reg_start_tmp = 0;
4807     SAVEI32(PL_reg_start_tmpl);         /* from regexec.c */
4808     PL_reg_start_tmpl = 0;
4809     SAVEVPTR(PL_regdata);
4810     SAVEI32(PL_reg_eval_set);           /* from regexec.c */
4811     SAVEI32(PL_regnarrate);             /* from regexec.c */
4812     SAVEVPTR(PL_regprogram);            /* from regexec.c */
4813     SAVEINT(PL_regindent);              /* from regexec.c */
4814     SAVEVPTR(PL_regcc);                 /* from regexec.c */
4815     SAVEVPTR(PL_curcop);
4816     SAVEVPTR(PL_reg_call_cc);           /* from regexec.c */
4817     SAVEVPTR(PL_reg_re);                /* from regexec.c */
4818     SAVEPPTR(PL_reg_ganch);             /* from regexec.c */
4819     SAVESPTR(PL_reg_sv);                /* from regexec.c */
4820     SAVEI8(PL_reg_match_utf8);          /* from regexec.c */
4821     SAVEVPTR(PL_reg_magic);             /* from regexec.c */
4822     SAVEI32(PL_reg_oldpos);                     /* from regexec.c */
4823     SAVEVPTR(PL_reg_oldcurpm);          /* from regexec.c */
4824     SAVEVPTR(PL_reg_curpm);             /* from regexec.c */
4825     SAVEI32(PL_regnpar);                /* () count. */
4826     SAVEI32(PL_regsize);                /* from regexec.c */
4827 #ifdef DEBUGGING
4828     SAVEPPTR(PL_reg_starttry);          /* from regexec.c */
4829 #endif
4830 }
4831
4832 static void
4833 clear_re(pTHX_ void *r)
4834 {
4835     ReREFCNT_dec((regexp *)r);
4836 }
4837