1 /*    regexp.h
2  *
3  *    Copyright (C) 1993, 1994, 1996, 1997, 1999, 2000, 2001, 2003,
4  *    2005, 2006, 2007, 2008 by Larry Wall and others
5  *
6  *    You may distribute under the terms of either the GNU General Public
7  *    License or the Artistic License, as specified in the README file.
8  *
9  */
10 
11 /*
12  * Definitions etc. for regexp(3) routines.
13  *
14  * Caveat:  this is V8 regexp(3) [actually, a reimplementation thereof],
15  * not the System V one.
16  */
17 #ifndef PLUGGABLE_RE_EXTENSION
18 /* we don't want to include this stuff if we are inside of
19    an external regex engine based on the core one - like re 'debug'*/
20 
21 #  include "utf8.h"
22 
23 typedef SSize_t regnode_offset;
24 
25 struct regnode {
26     U8	flags;
27     U8  type;
28     U16 next_off;
29 };
30 
31 typedef struct regnode regnode;
32 
33 struct reg_substr_data;
34 
35 struct reg_data;
36 
37 struct regexp_engine;
38 struct regexp;
39 
40 struct reg_substr_datum {
41     SSize_t min_offset; /* min pos (in chars) that substr must appear */
42     SSize_t max_offset  /* max pos (in chars) that substr must appear */;
43     SV *substr;		/* non-utf8 variant */
44     SV *utf8_substr;	/* utf8 variant */
45     SSize_t end_shift;  /* how many fixed chars must end the string */
46 };
47 struct reg_substr_data {
48     U8      check_ix;   /* index into data[] of check substr */
49     struct reg_substr_datum data[3];	/* Actual array */
50 };
51 
52 #  ifdef PERL_ANY_COW
53 #    define SV_SAVED_COPY   SV *saved_copy; /* If non-NULL, SV which is COW from original */
54 #  else
55 #    define SV_SAVED_COPY
56 #  endif
57 
58 /* offsets within a string of a particular /(.)/ capture */
59 
60 typedef struct regexp_paren_pair {
61     SSize_t start;
62     SSize_t end;
63     /* 'start_tmp' records a new opening position before the matching end
64      * has been found, so that the old start and end values are still
65      * valid, e.g.
66      *	  "abc" =~ /(.(?{print "[$1]"}))+/
67      *outputs [][a][b]
68      * This field is not part of the API.  */
69     SSize_t start_tmp;
70 } regexp_paren_pair;
71 
72 #  if defined(PERL_IN_REGCOMP_C) || defined(PERL_IN_UTF8_C)
73 #    define _invlist_union(a, b, output) _invlist_union_maybe_complement_2nd(a, b, FALSE, output)
74 #    define _invlist_intersection(a, b, output) _invlist_intersection_maybe_complement_2nd(a, b, FALSE, output)
75 
76 /* Subtracting b from a leaves in a everything that was there that isn't in b,
77  * that is the intersection of a with b's complement */
78 #    define _invlist_subtract(a, b, output) _invlist_intersection_maybe_complement_2nd(a, b, TRUE, output)
79 #  endif
80 
81 /* record the position of a (?{...}) within a pattern */
82 
83 struct reg_code_block {
84     STRLEN start;
85     STRLEN end;
86     OP     *block;
87     REGEXP *src_regex;
88 };
89 
90 /* array of reg_code_block's plus header info */
91 
92 struct reg_code_blocks {
93     int refcnt; /* we may be pointed to from a regex and from the savestack */
94     int  count;    /* how many code blocks */
95     struct reg_code_block *cb; /* array of reg_code_block's */
96 };
97 
98 
99 /*
100 = for apidoc AyT||regexp
101   The regexp/REGEXP struct, see L<perlreapi> for further documentation
102   on the individual fields. The struct is ordered so that the most
103   commonly used fields are placed at the start.
104 
105   Any patch that adds items to this struct will need to include
106   changes to F<sv.c> (C<Perl_re_dup()>) and F<regcomp.c>
107   (C<pregfree()>). This involves freeing or cloning items in the
108   regexp's data array based on the data item's type.
109 */
110 
111 typedef struct regexp {
112     _XPV_HEAD;
113     const struct regexp_engine* engine; /* what engine created this regexp? */
114     REGEXP *mother_re; /* what re is this a lightweight copy of? */
115     HV *paren_names;   /* Optional hash of paren names */
116 
117     /*----------------------------------------------------------------------
118      * Information about the match that the perl core uses to manage things
119      */
120 
121     U32 extflags;      /* Flags used both externally and internally */
122     U32 nparens;       /* number of capture buffers */
123     SSize_t minlen;    /* minimum possible number of chars in string to match */
124     SSize_t minlenret; /* mininum possible number of chars in $& */
125     STRLEN gofs;       /* chars left of pos that we search from */
126                        /* substring data about strings that must appear in
127                         * the final match, used for optimisations */
128     struct reg_substr_data *substrs;
129 
130     /* private engine specific data */
131 
132     void *pprivate;    /* Data private to the regex engine which
133                         * created this object. */
134     U32 intflags;      /* Engine Specific Internal flags */
135 
136     /*----------------------------------------------------------------------
137      * Data about the last/current match. These are modified during matching
138      */
139 
140     U32 lastparen;           /* highest close paren matched ($+) */
141     regexp_paren_pair *offs; /* Array of offsets for (@-) and (@+) */
142     char **recurse_locinput; /* used to detect infinite recursion, XXX: move to internal */
143     U32 lastcloseparen;      /* last close paren matched ($^N) */
144 
145     /*---------------------------------------------------------------------- */
146 
147     /* offset from wrapped to the start of precomp */
148     PERL_BITFIELD32 pre_prefix:4;
149 
150     /* original flags used to compile the pattern, may differ from
151      * extflags in various ways */
152     PERL_BITFIELD32 compflags:9;
153 
154     /*---------------------------------------------------------------------- */
155 
156     char *subbeg;       /* saved or original string so \digit works forever. */
157     SV_SAVED_COPY       /* If non-NULL, SV which is COW from original */
158     SSize_t sublen;     /* Length of string pointed by subbeg */
159     SSize_t suboffset;  /* byte offset of subbeg from logical start of str */
160     SSize_t subcoffset; /* suboffset equiv, but in chars (for @-/@+) */
161     SSize_t maxlen;  /* minimum possible number of chars in string to match */
162 
163     /*---------------------------------------------------------------------- */
164 
165 
166     CV *qr_anoncv;      /* the anon sub wrapped round qr/(?{..})/ */
167 } regexp;
168 
169 
170 #  define RXp_PAREN_NAMES(rx)	((rx)->paren_names)
171 
172 /* used for high speed searches */
173 typedef struct re_scream_pos_data_s
174 {
175     char **scream_olds;		/* match pos */
176     SSize_t *scream_pos;	/* Internal iterator of scream. */
177 } re_scream_pos_data;
178 
179 /* regexp_engine structure. This is the dispatch table for regexes.
180  * Any regex engine implementation must be able to build one of these.
181  */
182 typedef struct regexp_engine {
183     REGEXP* (*comp) (pTHX_ SV * const pattern, U32 flags);
184     I32     (*exec) (pTHX_ REGEXP * const rx, char* stringarg, char* strend,
185                      char* strbeg, SSize_t minend, SV* sv,
186                      void* data, U32 flags);
187     char*   (*intuit) (pTHX_
188                         REGEXP * const rx,
189                         SV *sv,
190                         const char * const strbeg,
191                         char *strpos,
192                         char *strend,
193                         const U32 flags,
194                        re_scream_pos_data *data);
195     SV*     (*checkstr) (pTHX_ REGEXP * const rx);
196     void    (*rxfree) (pTHX_ REGEXP * const rx);
197     void    (*numbered_buff_FETCH) (pTHX_ REGEXP * const rx, const I32 paren,
198                                     SV * const sv);
199     void    (*numbered_buff_STORE) (pTHX_ REGEXP * const rx, const I32 paren,
200                                    SV const * const value);
201     I32     (*numbered_buff_LENGTH) (pTHX_ REGEXP * const rx, const SV * const sv,
202                                     const I32 paren);
203     SV*     (*named_buff) (pTHX_ REGEXP * const rx, SV * const key,
204                            SV * const value, const U32 flags);
205     SV*     (*named_buff_iter) (pTHX_ REGEXP * const rx, const SV * const lastkey,
206                                 const U32 flags);
207     SV*     (*qr_package)(pTHX_ REGEXP * const rx);
208 #  ifdef USE_ITHREADS
209     void*   (*dupe) (pTHX_ REGEXP * const rx, CLONE_PARAMS *param);
210 #  endif
211     REGEXP* (*op_comp) (pTHX_ SV ** const patternp, int pat_count,
212 		    OP *expr, const struct regexp_engine* eng,
213 		    REGEXP *old_re,
214 		    bool *is_bare_re, U32 orig_rx_flags, U32 pm_flags);
215 } regexp_engine;
216 
217 /*
218   These are passed to the numbered capture variable callbacks as the
219   paren name. >= 1 is reserved for actual numbered captures, i.e. $1,
220   $2 etc.
221 */
222 #  define RX_BUFF_IDX_CARET_PREMATCH  -5 /* ${^PREMATCH}  */
223 #  define RX_BUFF_IDX_CARET_POSTMATCH -4 /* ${^POSTMATCH} */
224 #  define RX_BUFF_IDX_CARET_FULLMATCH -3 /* ${^MATCH}     */
225 #  define RX_BUFF_IDX_PREMATCH        -2 /* $` */
226 #  define RX_BUFF_IDX_POSTMATCH       -1 /* $' */
227 #  define RX_BUFF_IDX_FULLMATCH        0 /* $& */
228 
229 /*
230   Flags that are passed to the named_buff and named_buff_iter
231   callbacks above. Those routines are called from universal.c via the
232   Tie::Hash::NamedCapture interface for %+ and %- and the re::
233   functions in the same file.
234 */
235 
236 /* The Tie::Hash::NamedCapture operation this is part of, if any */
237 #  define RXapif_FETCH     0x0001
238 #  define RXapif_STORE     0x0002
239 #  define RXapif_DELETE    0x0004
240 #  define RXapif_CLEAR     0x0008
241 #  define RXapif_EXISTS    0x0010
242 #  define RXapif_SCALAR    0x0020
243 #  define RXapif_FIRSTKEY  0x0040
244 #  define RXapif_NEXTKEY   0x0080
245 
246 /* Whether %+ or %- is being operated on */
247 #  define RXapif_ONE       0x0100 /* %+ */
248 #  define RXapif_ALL       0x0200 /* %- */
249 
250 /* Whether this is being called from a re:: function */
251 #  define RXapif_REGNAME         0x0400
252 #  define RXapif_REGNAMES        0x0800
253 #  define RXapif_REGNAMES_COUNT  0x1000
254 
255 /*
256 =for apidoc Am|REGEXP *|SvRX|SV *sv
257 
258 Convenience macro to get the REGEXP from a SV.  This is approximately
259 equivalent to the following snippet:
260 
261     if (SvMAGICAL(sv))
262         mg_get(sv);
263     if (SvROK(sv))
264         sv = MUTABLE_SV(SvRV(sv));
265     if (SvTYPE(sv) == SVt_REGEXP)
266         return (REGEXP*) sv;
267 
268 C<NULL> will be returned if a REGEXP* is not found.
269 
270 =for apidoc Am|bool|SvRXOK|SV* sv
271 
272 Returns a boolean indicating whether the SV (or the one it references)
273 is a REGEXP.
274 
275 If you want to do something with the REGEXP* later use SvRX instead
276 and check for NULL.
277 
278 =cut
279 */
280 
281 #  define SvRX(sv)   (Perl_get_re_arg(aTHX_ sv))
282 #  define SvRXOK(sv) cBOOL(Perl_get_re_arg(aTHX_ sv))
283 
284 
285 /* Flags stored in regexp->extflags
286  * These are used by code external to the regexp engine
287  *
288  * Note that the flags whose names start with RXf_PMf_ are defined in
289  * op_reg_common.h, being copied from the parallel flags of op_pmflags
290  *
291  * NOTE: if you modify any RXf flags you should run regen.pl or
292  * regen/regcomp.pl so that regnodes.h is updated with the changes.
293  *
294  */
295 
296 #  include "op_reg_common.h"
297 
298 #  define RXf_PMf_STD_PMMOD	(RXf_PMf_MULTILINE|RXf_PMf_SINGLELINE|RXf_PMf_FOLD|RXf_PMf_EXTENDED|RXf_PMf_EXTENDED_MORE|RXf_PMf_NOCAPTURE)
299 
300 #  define CASE_STD_PMMOD_FLAGS_PARSE_SET(pmfl, x_count)                       \
301     case IGNORE_PAT_MOD:    *(pmfl) |= RXf_PMf_FOLD;       break;           \
302     case MULTILINE_PAT_MOD: *(pmfl) |= RXf_PMf_MULTILINE;  break;           \
303     case SINGLE_PAT_MOD:    *(pmfl) |= RXf_PMf_SINGLELINE; break;           \
304     case XTENDED_PAT_MOD:   if (x_count == 0) {                             \
305                                 *(pmfl) |= RXf_PMf_EXTENDED;                \
306                                 *(pmfl) &= ~RXf_PMf_EXTENDED_MORE;          \
307                             }                                               \
308                             else {                                          \
309                                 *(pmfl) |= RXf_PMf_EXTENDED                 \
310                                           |RXf_PMf_EXTENDED_MORE;           \
311                             }                                               \
312                             (x_count)++; break;                             \
313     case NOCAPTURE_PAT_MOD: *(pmfl) |= RXf_PMf_NOCAPTURE; break;
314 
315 /* Note, includes charset ones, assumes 0 is the default for them */
316 #  define STD_PMMOD_FLAGS_CLEAR(pmfl)                        \
317     *(pmfl) &= ~(RXf_PMf_FOLD|RXf_PMf_MULTILINE|RXf_PMf_SINGLELINE|RXf_PMf_EXTENDED|RXf_PMf_EXTENDED_MORE|RXf_PMf_CHARSET|RXf_PMf_NOCAPTURE)
318 
319 /* chars and strings used as regex pattern modifiers
320  * Singular is a 'c'har, plural is a "string"
321  *
322  * NOTE, KEEPCOPY was originally 'k', but was changed to 'p' for preserve
323  * for compatibility reasons with Regexp::Common which highjacked (?k:...)
324  * for its own uses. So 'k' is out as well.
325  */
326 #  define DEFAULT_PAT_MOD      '^'    /* Short for all the default modifiers */
327 #  define EXEC_PAT_MOD         'e'
328 #  define KEEPCOPY_PAT_MOD     'p'
329 #  define NOCAPTURE_PAT_MOD    'n'
330 #  define ONCE_PAT_MOD         'o'
331 #  define GLOBAL_PAT_MOD       'g'
332 #  define CONTINUE_PAT_MOD     'c'
333 #  define MULTILINE_PAT_MOD    'm'
334 #  define SINGLE_PAT_MOD       's'
335 #  define IGNORE_PAT_MOD       'i'
336 #  define XTENDED_PAT_MOD      'x'
337 #  define NONDESTRUCT_PAT_MOD  'r'
338 #  define LOCALE_PAT_MOD       'l'
339 #  define UNICODE_PAT_MOD      'u'
340 #  define DEPENDS_PAT_MOD      'd'
341 #  define ASCII_RESTRICT_PAT_MOD 'a'
342 
343 #  define ONCE_PAT_MODS        "o"
344 #  define KEEPCOPY_PAT_MODS    "p"
345 #  define NOCAPTURE_PAT_MODS   "n"
346 #  define EXEC_PAT_MODS        "e"
347 #  define LOOP_PAT_MODS        "gc"
348 #  define NONDESTRUCT_PAT_MODS "r"
349 #  define LOCALE_PAT_MODS      "l"
350 #  define UNICODE_PAT_MODS     "u"
351 #  define DEPENDS_PAT_MODS     "d"
352 #  define ASCII_RESTRICT_PAT_MODS "a"
353 #  define ASCII_MORE_RESTRICT_PAT_MODS "aa"
354 
355 /* This string is expected by regcomp.c to be ordered so that the first
356  * character is the flag in bit RXf_PMf_STD_PMMOD_SHIFT of extflags; the next
357  * character is bit +1, etc. */
358 #  define STD_PAT_MODS        "msixxn"
359 
360 #  define CHARSET_PAT_MODS    ASCII_RESTRICT_PAT_MODS DEPENDS_PAT_MODS LOCALE_PAT_MODS UNICODE_PAT_MODS
361 
362 /* This string is expected by XS_re_regexp_pattern() in universal.c to be ordered
363  * so that the first character is the flag in bit RXf_PMf_STD_PMMOD_SHIFT of
364  * extflags; the next character is in bit +1, etc. */
365 #  define INT_PAT_MODS    STD_PAT_MODS    KEEPCOPY_PAT_MODS
366 
367 #  define EXT_PAT_MODS    ONCE_PAT_MODS   KEEPCOPY_PAT_MODS  NOCAPTURE_PAT_MODS
368 #  define QR_PAT_MODS     STD_PAT_MODS    EXT_PAT_MODS	   CHARSET_PAT_MODS
369 #  define M_PAT_MODS      QR_PAT_MODS     LOOP_PAT_MODS
370 #  define S_PAT_MODS      M_PAT_MODS      EXEC_PAT_MODS      NONDESTRUCT_PAT_MODS
371 
372 /*
373  * NOTE: if you modify any RXf flags you should run regen.pl or
374  * regen/regcomp.pl so that regnodes.h is updated with the changes.
375  *
376  */
377 
378 /*
379   Set in Perl_pmruntime for a split. Will be used by regex engines to
380   check whether they should set RXf_SKIPWHITE
381 */
382 #  define RXf_SPLIT   RXf_PMf_SPLIT
383 
384 /* Currently the regex flags occupy a single 32-bit word.  Not all bits are
385  * currently used.  The lower bits are shared with their corresponding PMf flag
386  * bits, up to but not including _RXf_PMf_SHIFT_NEXT.  The unused bits
387  * immediately follow; finally the used RXf-only (unshared) bits, so that the
388  * highest bit in the word is used.  This gathers all the unused bits as a pool
389  * in the middle, like so: 11111111111111110000001111111111
390  * where the '1's represent used bits, and the '0's unused.  This design allows
391  * us to allocate off one end of the pool if we need to add a shared bit, and
392  * off the other end if we need a non-shared bit, without disturbing the other
393  * bits.  This maximizes the likelihood of being able to change things without
394  * breaking binary compatibility.
395  *
396  * To add shared bits, do so in op_reg_common.h.  This should change
397  * _RXf_PMf_SHIFT_NEXT so that things won't compile.  Then come to regexp.h and
398  * op.h and adjust the constant adders in the definitions of RXf_BASE_SHIFT and
399  * Pmf_BASE_SHIFT down by the number of shared bits you added.  That's it.
400  * Things should be binary compatible.  But if either of these gets to having
401  * to subtract rather than add, leave at 0 and instead adjust all the entries
402  * that are in terms of it.  But if the first one of those is already
403  * RXf_BASE_SHIFT+0, there are no bits left, and a redesign is in order.
404  *
405  * To remove unshared bits, just delete its entry.  If you're where breaking
406  * binary compatibility is ok to do, you might want to adjust things to move
407  * the newly opened space so that it gets absorbed into the common pool.
408  *
409  * To add unshared bits, first use up any gaps in the middle.  Otherwise,
410  * allocate off the low end until you get to RXf_BASE_SHIFT+0.  If that isn't
411  * enough, move RXf_BASE_SHIFT down (if possible) and add the new bit at the
412  * other end instead; this preserves binary compatibility.
413  *
414  * For the regexp bits, PL_reg_extflags_name[] in regnodes.h has a comment
415  * giving which bits are used/unused */
416 
417 #  define RXf_BASE_SHIFT (_RXf_PMf_SHIFT_NEXT + 2)
418 
419 /* What we have seen */
420 #  define RXf_NO_INPLACE_SUBST  (1U<<(RXf_BASE_SHIFT+2))
421 #  define RXf_EVAL_SEEN   	(1U<<(RXf_BASE_SHIFT+3))
422 
423 /* Special */
424 #  define RXf_UNBOUNDED_QUANTIFIER_SEEN   (1U<<(RXf_BASE_SHIFT+4))
425 #  define RXf_CHECK_ALL   	(1U<<(RXf_BASE_SHIFT+5))
426 
427 /* UTF8 related */
428 #  define RXf_MATCH_UTF8  	(1U<<(RXf_BASE_SHIFT+6)) /* $1 etc are utf8 */
429 
430 /* Intuit related */
431 #  define RXf_USE_INTUIT_NOML	(1U<<(RXf_BASE_SHIFT+7))
432 #  define RXf_USE_INTUIT_ML	(1U<<(RXf_BASE_SHIFT+8))
433 #  define RXf_INTUIT_TAIL 	(1U<<(RXf_BASE_SHIFT+9))
434 #  define RXf_USE_INTUIT        (RXf_USE_INTUIT_NOML|RXf_USE_INTUIT_ML)
435 
436 /* Do we have some sort of anchor? */
437 #  define RXf_IS_ANCHORED       (1U<<(RXf_BASE_SHIFT+10))
438 
439 /* Copy and tainted info */
440 #  define RXf_COPY_DONE   	(1U<<(RXf_BASE_SHIFT+11))
441 
442 /* post-execution: $1 et al are tainted */
443 #  define RXf_TAINTED_SEEN	(1U<<(RXf_BASE_SHIFT+12))
444 /* this pattern was tainted during compilation */
445 #  define RXf_TAINTED		(1U<<(RXf_BASE_SHIFT+13))
446 
447 /* Flags indicating special patterns */
448 #  define RXf_START_ONLY        (1U<<(RXf_BASE_SHIFT+14)) /* Pattern is /^/ */
449 #  define RXf_SKIPWHITE         (1U<<(RXf_BASE_SHIFT+15)) /* Pattern is for a */
450                                                           /* split " " */
451 #  define RXf_WHITE		(1U<<(RXf_BASE_SHIFT+16)) /* Pattern is /\s+/ */
452 #  define RXf_NULL		(1U<<(RXf_BASE_SHIFT+17)) /* Pattern is // */
453 
454 /* See comments at the beginning of these defines about adding bits.  The
455  * highest bit position should be used, so that if RXf_BASE_SHIFT gets
456  * increased, the #error below will be triggered so that you will be reminded
457  * to adjust things at the other end to keep the bit positions unchanged */
458 #  if RXf_BASE_SHIFT+17 > 31
459 #     error Too many RXf_PMf bits used.  See comments at beginning of these for what to do
460 #  endif
461 
462 /*
463  * NOTE: if you modify any RXf flags you should run regen.pl or
464  * regen/regcomp.pl so that regnodes.h is updated with the changes.
465  *
466  */
467 
468 #  ifdef NO_TAINT_SUPPORT
469 #    define RX_ISTAINTED(rx_sv)           0
470 #    define RXp_ISTAINTED(prog)           0
471 #    define RX_TAINT_on(rx_sv)            NOOP
472 #    define RXp_MATCH_TAINTED(prog)       0
473 #    define RX_MATCH_TAINTED(rx_sv)       0
474 #    define RXp_MATCH_TAINTED_on(prog)    NOOP
475 #    define RX_MATCH_TAINTED_on(rx_sv)    NOOP
476 #    define RXp_MATCH_TAINTED_off(prog)   NOOP
477 #    define RX_MATCH_TAINTED_off(rx_sv)   NOOP
478 #  else
479 #    define RX_ISTAINTED(rx_sv)           (RX_EXTFLAGS(rx_sv) & RXf_TAINTED)
480 #    define RXp_ISTAINTED(prog)           (RXp_EXTFLAGS(prog) & RXf_TAINTED)
481 #    define RX_TAINT_on(rx_sv)            (RX_EXTFLAGS(rx_sv) |= RXf_TAINTED)
482 #    define RXp_MATCH_TAINTED(prog)       (RXp_EXTFLAGS(prog) & RXf_TAINTED_SEEN)
483 #    define RX_MATCH_TAINTED(rx_sv)       (RX_EXTFLAGS(rx_sv) & RXf_TAINTED_SEEN)
484 #    define RXp_MATCH_TAINTED_on(prog)    (RXp_EXTFLAGS(prog) |= RXf_TAINTED_SEEN)
485 #    define RX_MATCH_TAINTED_on(rx_sv)    (RX_EXTFLAGS(rx_sv) |= RXf_TAINTED_SEEN)
486 #    define RXp_MATCH_TAINTED_off(prog)   (RXp_EXTFLAGS(prog) &= ~RXf_TAINTED_SEEN)
487 #    define RX_MATCH_TAINTED_off(rx_sv)   (RX_EXTFLAGS(rx_sv) &= ~RXf_TAINTED_SEEN)
488 #  endif
489 
490 #  define RXp_HAS_CUTGROUP(prog)          ((prog)->intflags & PREGf_CUTGROUP_SEEN)
491 
492 #  define RX_MATCH_TAINTED_set(rx_sv, t)  ((t) \
493                                         ? RX_MATCH_TAINTED_on(rx_sv) \
494                                         : RX_MATCH_TAINTED_off(rx_sv))
495 
496 #  define RXp_MATCH_COPIED(prog)          (RXp_EXTFLAGS(prog) & RXf_COPY_DONE)
497 #  define RX_MATCH_COPIED(rx_sv)          (RX_EXTFLAGS(rx_sv) & RXf_COPY_DONE)
498 #  define RXp_MATCH_COPIED_on(prog)       (RXp_EXTFLAGS(prog) |= RXf_COPY_DONE)
499 #  define RX_MATCH_COPIED_on(rx_sv)       (RX_EXTFLAGS(rx_sv) |= RXf_COPY_DONE)
500 #  define RXp_MATCH_COPIED_off(prog)      (RXp_EXTFLAGS(prog) &= ~RXf_COPY_DONE)
501 #  define RX_MATCH_COPIED_off(rx_sv)      (RX_EXTFLAGS(rx_sv) &= ~RXf_COPY_DONE)
502 #  define RX_MATCH_COPIED_set(rx_sv,t)    ((t) \
503                                          ? RX_MATCH_COPIED_on(rx_sv) \
504                                          : RX_MATCH_COPIED_off(rx_sv))
505 
506 #  define RXp_EXTFLAGS(rx)                ((rx)->extflags)
507 #  define RXp_COMPFLAGS(rx)               ((rx)->compflags)
508 
509 /* For source compatibility. We used to store these explicitly.  */
510 #  define RX_PRECOMP(rx_sv)              (RX_WRAPPED(rx_sv) \
511                                             + ReANY(rx_sv)->pre_prefix)
512 #  define RX_PRECOMP_const(rx_sv)        (RX_WRAPPED_const(rx_sv) \
513                                             + ReANY(rx_sv)->pre_prefix)
514 /* FIXME? Are we hardcoding too much here and constraining plugin extension
515    writers? Specifically, the value 1 assumes that the wrapped version always
516    has exactly one character at the end, a ')'. Will that always be true?  */
517 #  define RX_PRELEN(rx_sv)                (RX_WRAPLEN(rx_sv) \
518                                             - ReANY(rx_sv)->pre_prefix - 1)
519 
520 #  define RX_WRAPPED(rx_sv)               SvPVX(rx_sv)
521 #  define RX_WRAPPED_const(rx_sv)         SvPVX_const(rx_sv)
522 #  define RX_WRAPLEN(rx_sv)               SvCUR(rx_sv)
523 #  define RX_CHECK_SUBSTR(rx_sv)          (ReANY(rx_sv)->check_substr)
524 #  define RX_REFCNT(rx_sv)                SvREFCNT(rx_sv)
525 #  define RX_EXTFLAGS(rx_sv)              RXp_EXTFLAGS(ReANY(rx_sv))
526 #  define RX_COMPFLAGS(rx_sv)             RXp_COMPFLAGS(ReANY(rx_sv))
527 #  define RXp_ENGINE(prog)                ((prog)->engine)
528 #  define RX_ENGINE(rx_sv)                (RXp_ENGINE(ReANY(rx_sv)))
529 #  define RXp_SUBBEG(prog)                (prog->subbeg)
530 #  define RX_SUBBEG(rx_sv)                (RXp_SUBBEG(ReANY(rx_sv)))
531 #  define RXp_SUBOFFSET(prog)             (prog->suboffset)
532 #  define RX_SUBOFFSET(rx_sv)             (RXp_SUBOFFSET(ReANY(rx_sv)))
533 #  define RX_SUBCOFFSET(rx_sv)            (ReANY(rx_sv)->subcoffset)
534 #  define RXp_OFFS(prog)                  (prog->offs)
535 #  define RX_OFFS(rx_sv)                  (RXp_OFFS(ReANY(rx_sv)))
536 #  define RXp_NPARENS(prog)               (prog->nparens)
537 #  define RX_NPARENS(rx_sv)               (RXp_NPARENS(ReANY(rx_sv)))
538 #  define RX_SUBLEN(rx_sv)                (ReANY(rx_sv)->sublen)
539 #  define RXp_MINLEN(prog)                (prog->minlen)
540 #  define RX_MINLEN(rx_sv)                (RXp_MINLEN(ReANY(rx_sv)))
541 #  define RXp_MINLENRET(prog)             (prog->minlenret)
542 #  define RX_MINLENRET(rx_sv)             (RXp_MINLENRET(ReANY(rx_sv)))
543 #  define RXp_GOFS(prog)                  (prog->gofs)
544 #  define RX_GOFS(rx_sv)                  (RXp_GOFS(ReANY(rx_sv)))
545 #  define RX_LASTPAREN(rx_sv)             (ReANY(rx_sv)->lastparen)
546 #  define RX_LASTCLOSEPAREN(rx_sv)        (ReANY(rx_sv)->lastcloseparen)
547 #  define RXp_SAVED_COPY(prog)            (prog->saved_copy)
548 #  define RX_SAVED_COPY(rx_sv)            (RXp_SAVED_COPY(ReANY(rx_sv)))
549 /* last match was zero-length */
550 #  define RXp_ZERO_LEN(prog) \
551         (RXp_OFFS(prog)[0].start + (SSize_t)RXp_GOFS(prog) \
552           == RXp_OFFS(prog)[0].end)
553 #  define RX_ZERO_LEN(rx_sv)              (RXp_ZERO_LEN(ReANY(rx_sv)))
554 
555 #endif /* PLUGGABLE_RE_EXTENSION */
556 
557 /* Stuff that needs to be included in the pluggable extension goes below here */
558 
559 #ifdef PERL_ANY_COW
560 #  define RXp_MATCH_COPY_FREE(prog) \
561 	STMT_START {if (RXp_SAVED_COPY(prog)) { \
562 	    SV_CHECK_THINKFIRST_COW_DROP(RXp_SAVED_COPY(prog)); \
563 	} \
564 	if (RXp_MATCH_COPIED(prog)) { \
565 	    Safefree(RXp_SUBBEG(prog)); \
566 	    RXp_MATCH_COPIED_off(prog); \
567 	}} STMT_END
568 #else
569 #  define RXp_MATCH_COPY_FREE(prog) \
570 	STMT_START {if (RXp_MATCH_COPIED(prog)) { \
571 	    Safefree(RXp_SUBBEG(prog)); \
572 	    RXp_MATCH_COPIED_off(prog); \
573 	}} STMT_END
574 #endif
575 #define RX_MATCH_COPY_FREE(rx_sv)       RXp_MATCH_COPY_FREE(ReANY(rx_sv))
576 
577 #define RXp_MATCH_UTF8(prog)            (RXp_EXTFLAGS(prog) & RXf_MATCH_UTF8)
578 #define RX_MATCH_UTF8(rx_sv)            (RX_EXTFLAGS(rx_sv) & RXf_MATCH_UTF8)
579 #define RXp_MATCH_UTF8_on(prog)         (RXp_EXTFLAGS(prog) |= RXf_MATCH_UTF8)
580 #define RX_MATCH_UTF8_on(rx_sv)         (RXp_MATCH_UTF8_on(ReANY(rx_sv)))
581 #define RXp_MATCH_UTF8_off(prog)        (RXp_EXTFLAGS(prog) &= ~RXf_MATCH_UTF8)
582 #define RX_MATCH_UTF8_off(rx_sv)        (RXp_MATCH_UTF8_off(ReANY(rx_sv))
583 #define RXp_MATCH_UTF8_set(prog, t)     ((t) \
584                                         ? RXp_MATCH_UTF8_on(prog) \
585                                         : RXp_MATCH_UTF8_off(prog))
586 #define RX_MATCH_UTF8_set(rx_sv, t)     (RXp_MATCH_UTF8_set(ReANY(rx_sv), t))
587 
588 /* Whether the pattern stored at RX_WRAPPED is in UTF-8  */
589 #define RX_UTF8(rx_sv)                  SvUTF8(rx_sv)
590 
591 
592 /* bits in flags arg of Perl_regexec_flags() */
593 
594 #define REXEC_COPY_STR  0x01    /* Need to copy the string for captures. */
595 #define REXEC_CHECKED   0x02    /* re_intuit_start() already called. */
596 #define REXEC_SCREAM    0x04    /* currently unused. */
597 #define REXEC_IGNOREPOS 0x08    /* use stringarg, not pos(), for \G match */
598 #define REXEC_NOT_FIRST 0x10    /* This is another iteration of //g:
599                                    no need to copy string again */
600 
601                                      /* under REXEC_COPY_STR, it's ok for the
602                                         engine (modulo PL_sawamperand etc)
603                                         to skip copying: ... */
604 #define REXEC_COPY_SKIP_PRE  0x20    /* ...the $` part of the string, or */
605 #define REXEC_COPY_SKIP_POST 0x40    /* ...the $' part of the string */
606 #define REXEC_FAIL_ON_UNDERFLOW 0x80 /* fail the match if $& would start before
607                                         the start pos (so s/.\G// would fail
608                                         on second iteration */
609 
610 #if defined(PERL_USE_GCC_BRACE_GROUPS)
611 #  define ReREFCNT_inc(re)						\
612     ({									\
613 	/* This is here to generate a casting warning if incorrect.  */	\
614 	REGEXP *const _rerefcnt_inc = (re);				\
615 	assert(SvTYPE(_rerefcnt_inc) == SVt_REGEXP);			\
616 	SvREFCNT_inc(_rerefcnt_inc);					\
617 	_rerefcnt_inc;							\
618     })
619 #  define ReREFCNT_dec(re)						\
620     ({									\
621 	/* This is here to generate a casting warning if incorrect.  */	\
622 	REGEXP *const _rerefcnt_dec = (re);				\
623 	SvREFCNT_dec(_rerefcnt_dec);					\
624     })
625 #else
626 #  define ReREFCNT_dec(re)	SvREFCNT_dec(re)
627 #  define ReREFCNT_inc(re)	((REGEXP *) SvREFCNT_inc(re))
628 #endif
629 #define ReANY(re)		Perl_ReANY((const REGEXP *)(re))
630 
631 /* FIXME for plugins. */
632 
633 #define FBMcf_TAIL_DOLLAR	1
634 #define FBMcf_TAIL_DOLLARM	2
635 #define FBMcf_TAIL_Z		4
636 #define FBMcf_TAIL_z		8
637 #define FBMcf_TAIL		(FBMcf_TAIL_DOLLAR|FBMcf_TAIL_DOLLARM|FBMcf_TAIL_Z|FBMcf_TAIL_z)
638 
639 #define FBMrf_MULTILINE	1
640 
641 struct regmatch_state;
642 struct regmatch_slab;
643 
644 /* like regmatch_info_aux, but contains extra fields only needed if the
645  * pattern contains (?{}). If used, is snuck into the second slot in the
646  * regmatch_state stack at the start of execution */
647 
648 typedef struct {
649     regexp *rex;
650     PMOP    *curpm;     /* saved PL_curpm */
651 #ifdef PERL_ANY_COW
652     SV      *saved_copy; /* saved saved_copy field from rex */
653 #endif
654     char    *subbeg;    /* saved subbeg     field from rex */
655     STRLEN  sublen;     /* saved sublen     field from rex */
656     STRLEN  suboffset;  /* saved suboffset  field from rex */
657     STRLEN  subcoffset; /* saved subcoffset field from rex */
658     SV      *sv;        /* $_  during (?{}) */
659     MAGIC   *pos_magic; /* pos() magic attached to $_ */
660     SSize_t pos;        /* the original value of pos() in pos_magic */
661     U8      pos_flags;  /* flags to be restored; currently only MGf_BYTES*/
662 } regmatch_info_aux_eval;
663 
664 
665 /* fields that logically  live in regmatch_info, but which need cleaning
666  * up on croak(), and so are instead are snuck into the first slot in
667  * the regmatch_state stack at the start of execution */
668 
669 typedef struct {
670     regmatch_info_aux_eval *info_aux_eval;
671     struct regmatch_state *old_regmatch_state; /* saved PL_regmatch_state */
672     struct regmatch_slab  *old_regmatch_slab;  /* saved PL_regmatch_slab */
673     char *poscache;	/* S-L cache of fail positions of WHILEMs */
674 } regmatch_info_aux;
675 
676 
677 /*
678 =for apidoc Ay||regmatch_info
679 Some basic information about the current match that is created by
680 Perl_regexec_flags and then passed to regtry(), regmatch() etc.
681 It is allocated as a local var on the stack, so nothing should be
682 stored in it that needs preserving or clearing up on croak().
683 For that, see the aux_info and aux_info_eval members of the
684 regmatch_state union.
685 
686 =cut
687 */
688 
689 typedef struct {
690     REGEXP *prog;        /* the regex being executed */
691     const char * strbeg; /* real start of string */
692     char *strend;        /* one byte beyond last char of match string */
693     char *till;          /* matches shorter than this fail (see minlen arg) */
694     SV *sv;              /* the SV string currently being matched */
695     char *ganch;         /* position of \G anchor */
696     char *cutpoint;      /* (*COMMIT) position (if any) */
697     regmatch_info_aux      *info_aux; /* extra fields that need cleanup */
698     regmatch_info_aux_eval *info_aux_eval; /* extra saved state for (?{}) */
699     I32  poscache_maxiter; /* how many whilems todo before S-L cache kicks in */
700     I32  poscache_iter;    /* current countdown from _maxiter to zero */
701     STRLEN poscache_size;  /* size of regmatch_info_aux.poscache */
702     bool intuit;    /* re_intuit_start() is the top-level caller */
703     bool is_utf8_pat;    /* regex is utf8 */
704     bool is_utf8_target; /* string being matched is utf8 */
705     bool warned; /* we have issued a recursion warning; no need for more */
706 } regmatch_info;
707 
708 
709 /* structures for holding and saving the state maintained by regmatch() */
710 
711 #ifndef MAX_RECURSE_EVAL_NOCHANGE_DEPTH
712 #  define MAX_RECURSE_EVAL_NOCHANGE_DEPTH 10
713 #endif
714 
715 /* The +1 is because everything matches itself, which isn't included in
716  * MAX_FOLD_FROMS; the +2 is based on the current Unicode standards needs, and
717  * is unlikely to change.  An assertion should fail in regexec.c if it is too
718  * low.  It is needed for certain edge cases involving multi-character folds
719  * when the first component also participates in a fold individually. */
720 #define MAX_MATCHES (MAX_FOLD_FROMS + 1 + 2)
721 
722 struct next_matchable_info {
723     U8     first_byte_mask;
724     U8     first_byte_anded;
725     U32    mask32;
726     U32    anded32;
727     PERL_INT_FAST8_T count; /* Negative means not initialized */
728     PERL_UINT_FAST8_T min_length;
729     PERL_UINT_FAST8_T max_length;
730     PERL_UINT_FAST8_T initial_definitive;
731     PERL_UINT_FAST8_T initial_exact;
732     PERL_UINT_FAST8_T lengths[MAX_MATCHES];
733 
734     /* The size is from trial and error, and could change with new Unicode
735      * standards, in which case there is an assertion that should start
736      * failing.  This size could be calculated in one of the regen scripts
737      * dealing with Unicode, but khw thinks the likelihood of it changing is
738      * low enough that it isn't worth the effort. */
739     U8 matches[18];
740 };
741 
742 typedef I32 CHECKPOINT;
743 
744 typedef struct regmatch_state {
745     int resume_state;		/* where to jump to on return */
746     char *locinput;		/* where to backtrack in string on failure */
747     char *loceol;
748     U8 *sr0;                    /* position of start of script run, or NULL */
749 
750     union {
751 
752         /* the 'info_aux' and 'info_aux_eval' union members are cuckoos in
753          * the nest. They aren't saved backtrack state; rather they
754          * represent one or two extra chunks of data that need allocating
755          * at the start of a match. These fields would logically live in
756          * the regmatch_info struct, except that is allocated on the
757          * C stack, and these fields are all things that require cleanup
758          * after a croak(), when the stack is lost.
759          * As a convenience, we just use the first 1 or 2 regmatch_state
760          * slots to store this info, as we will be allocating a slab of
761          * these anyway. Otherwise we'd have to malloc and then free them,
762          * or allocate them on the save stack (where they will get
763          * realloced if the save stack grows).
764          * info_aux contains the extra fields that are always needed;
765          * info_aux_eval contains extra fields that only needed if
766          * the pattern contains code blocks
767          * We split them into two separate structs to avoid increasing
768          * the size of the union.
769          */
770 
771         regmatch_info_aux info_aux;
772 
773         regmatch_info_aux_eval info_aux_eval;
774 
775 	/* this is a fake union member that matches the first element
776 	 * of each member that needs to store positive backtrack
777 	 * information */
778 	struct {
779 	    struct regmatch_state *prev_yes_state;
780 	} yes;
781 
782         /* branchlike members */
783         /* this is a fake union member that matches the first elements
784          * of each member that needs to behave like a branch */
785         struct {
786 	    /* this first element must match u.yes */
787 	    struct regmatch_state *prev_yes_state;
788 	    U32 lastparen;
789 	    U32 lastcloseparen;
790 	    CHECKPOINT cp;
791 
792         } branchlike;
793 
794 	struct {
795 	    /* the first elements must match u.branchlike */
796 	    struct regmatch_state *prev_yes_state;
797 	    U32 lastparen;
798 	    U32 lastcloseparen;
799 	    CHECKPOINT cp;
800 
801 	    regnode *next_branch; /* next branch node */
802 	} branch;
803 
804 	struct {
805 	    /* the first elements must match u.branchlike */
806 	    struct regmatch_state *prev_yes_state;
807 	    U32 lastparen;
808 	    U32 lastcloseparen;
809 	    CHECKPOINT cp;
810 
811 	    U32		accepted; /* how many accepting states left */
812 	    bool	longfold;/* saw a fold with a 1->n char mapping */
813 	    U16         *jump;  /* positive offsets from me */
814 	    regnode	*me;	/* Which node am I - needed for jump tries*/
815 	    U8		*firstpos;/* pos in string of first trie match */
816 	    U32		firstchars;/* len in chars of firstpos from start */
817 	    U16		nextword;/* next word to try */
818 	    U16		topword; /* longest accepted word */
819 	} trie;
820 
821         /* special types - these members are used to store state for special
822            regops like eval, if/then, lookaround and the markpoint state */
823 	struct {
824 	    /* this first element must match u.yes */
825 	    struct regmatch_state *prev_yes_state;
826 	    struct regmatch_state *prev_curlyx;
827             struct regmatch_state *prev_eval;
828 	    REGEXP	*prev_rex;
829 	    CHECKPOINT	cp;	/* remember current savestack indexes */
830 	    CHECKPOINT	lastcp;
831             U32         close_paren; /* which close bracket is our end (+1) */
832 	    regnode	*B;	/* the node following us  */
833             char        *prev_recurse_locinput;
834 	} eval;
835 
836 	struct {
837 	    /* this first element must match u.yes */
838 	    struct regmatch_state *prev_yes_state;
839 	    I32 wanted;
840 	    I32 logical;	/* saved copy of 'logical' var */
841             U8  count;          /* number of beginning positions */
842             char *start;
843             char *end;
844 	    regnode  *me; /* the IFMATCH/SUSPEND/UNLESSM node  */
845 	} ifmatch; /* and SUSPEND/UNLESSM */
846 
847 	struct {
848 	    /* this first element must match u.yes */
849 	    struct regmatch_state *prev_yes_state;
850 	    struct regmatch_state *prev_mark;
851 	    SV* mark_name;
852 	    char *mark_loc;
853 	} mark;
854 
855 	struct {
856 	    int val;
857 	} keeper;
858 
859         /* quantifiers - these members are used for storing state for
860            the regops used to implement quantifiers */
861 	struct {
862 	    /* this first element must match u.yes */
863 	    struct regmatch_state *prev_yes_state;
864 	    struct regmatch_state *prev_curlyx; /* previous cur_curlyx */
865 	    regnode	*me;	/* the CURLYX node  */
866 	    regnode	*B;	/* the B node in /A*B/  */
867 	    CHECKPOINT	cp;	/* remember current savestack index */
868 	    bool	minmod;
869 	    int		parenfloor;/* how far back to strip paren data */
870 
871 	    /* these two are modified by WHILEM */
872 	    int		count;	/* how many instances of A we've matched */
873 	    char	*lastloc;/* where previous A matched (0-len detect) */
874 	} curlyx;
875 
876 	struct {
877 	    /* this first element must match u.yes */
878 	    struct regmatch_state *prev_yes_state;
879 	    struct regmatch_state *save_curlyx;
880 	    CHECKPOINT	cp;	/* remember current savestack indexes */
881 	    CHECKPOINT	lastcp;
882 	    char	*save_lastloc;	/* previous curlyx.lastloc */
883 	    I32		cache_offset;
884 	    I32		cache_mask;
885 	} whilem;
886 
887 	struct {
888 	    /* this first element must match u.yes */
889 	    struct regmatch_state *prev_yes_state;
890 	    CHECKPOINT cp;
891 	    U32 lastparen;
892 	    U32 lastcloseparen;
893 	    I32 alen;		/* length of first-matched A string */
894 	    I32 count;
895 	    bool minmod;
896 	    regnode *A, *B;	/* the nodes corresponding to /A*B/  */
897 	    regnode *me;	/* the curlym node */
898             struct next_matchable_info Binfo;
899 	} curlym;
900 
901 	struct {
902 	    U32 paren;
903 	    CHECKPOINT cp;
904 	    U32 lastparen;
905 	    U32 lastcloseparen;
906 	    char *maxpos;	/* highest possible point in string to match */
907 	    char *oldloc;	/* the previous locinput */
908 	    int count;
909 	    int min, max;	/* {m,n} */
910 	    regnode *A, *B;	/* the nodes corresponding to /A*B/  */
911             struct next_matchable_info Binfo;
912 	} curly; /* and CURLYN/PLUS/STAR */
913 
914     } u;
915 } regmatch_state;
916 
917 
918 
919 /* how many regmatch_state structs to allocate as a single slab.
920  * We do it in 4K blocks for efficiency. The "3" is 2 for the next/prev
921  * pointers, plus 1 for any mythical malloc overhead. */
922 
923 #define PERL_REGMATCH_SLAB_SLOTS \
924     ((4096 - 3 * sizeof (void*)) / sizeof(regmatch_state))
925 
926 typedef struct regmatch_slab {
927     regmatch_state states[PERL_REGMATCH_SLAB_SLOTS];
928     struct regmatch_slab *prev, *next;
929 } regmatch_slab;
930 
931 
932 
933 /*
934  * ex: set ts=8 sts=4 sw=4 et:
935  */
936