xref: /openbsd/gnu/usr.bin/perl/regexp.h (revision cecf84d4)
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 struct regnode {
24     U8	flags;
25     U8  type;
26     U16 next_off;
27 };
28 
29 typedef struct regnode regnode;
30 
31 struct reg_substr_data;
32 
33 struct reg_data;
34 
35 struct regexp_engine;
36 struct regexp;
37 
38 struct reg_substr_datum {
39     SSize_t min_offset; /* min pos (in chars) that substr must appear */
40     SSize_t max_offset  /* max pos (in chars) that substr must appear */;
41     SV *substr;		/* non-utf8 variant */
42     SV *utf8_substr;	/* utf8 variant */
43     SSize_t end_shift;  /* how many fixed chars must end the string */
44 };
45 struct reg_substr_data {
46     U8      check_ix;   /* index into data[] of check substr */
47     struct reg_substr_datum data[3];	/* Actual array */
48 };
49 
50 #ifdef PERL_ANY_COW
51 #define SV_SAVED_COPY   SV *saved_copy; /* If non-NULL, SV which is COW from original */
52 #else
53 #define SV_SAVED_COPY
54 #endif
55 
56 /* offsets within a string of a particular /(.)/ capture */
57 
58 typedef struct regexp_paren_pair {
59     SSize_t start;
60     SSize_t end;
61     /* 'start_tmp' records a new opening position before the matching end
62      * has been found, so that the old start and end values are still
63      * valid, e.g.
64      *	  "abc" =~ /(.(?{print "[$1]"}))+/
65      *outputs [][a][b]
66      * This field is not part of the API.  */
67     SSize_t start_tmp;
68 } regexp_paren_pair;
69 
70 #if defined(PERL_IN_REGCOMP_C) || defined(PERL_IN_UTF8_C)
71 #define _invlist_union(a, b, output) _invlist_union_maybe_complement_2nd(a, b, FALSE, output)
72 #define _invlist_intersection(a, b, output) _invlist_intersection_maybe_complement_2nd(a, b, FALSE, output)
73 
74 /* Subtracting b from a leaves in a everything that was there that isn't in b,
75  * that is the intersection of a with b's complement */
76 #define _invlist_subtract(a, b, output) _invlist_intersection_maybe_complement_2nd(a, b, TRUE, output)
77 #endif
78 
79 /* record the position of a (?{...}) within a pattern */
80 
81 struct reg_code_block {
82     STRLEN start;
83     STRLEN end;
84     OP     *block;
85     REGEXP *src_regex;
86 };
87 
88 
89 /*
90   The regexp/REGEXP struct, see L<perlreapi> for further documentation
91   on the individual fields. The struct is ordered so that the most
92   commonly used fields are placed at the start.
93 
94   Any patch that adds items to this struct will need to include
95   changes to F<sv.c> (C<Perl_re_dup()>) and F<regcomp.c>
96   (C<pregfree()>). This involves freeing or cloning items in the
97   regexp's data array based on the data item's type.
98 */
99 
100 #define _REGEXP_COMMON							\
101         /* what engine created this regexp? */				\
102 	const struct regexp_engine* engine; 				\
103 	REGEXP *mother_re; /* what re is this a lightweight copy of? */	\
104 	HV *paren_names;   /* Optional hash of paren names */		\
105 	/* Information about the match that the perl core uses to */	\
106 	/* manage things */						\
107 	U32 extflags;	/* Flags used both externally and internally */	\
108 	SSize_t minlen;	/* mininum possible number of chars in string to match */\
109 	SSize_t minlenret; /* mininum possible number of chars in $& */		\
110 	STRLEN gofs;	/* chars left of pos that we search from */	\
111 	/* substring data about strings that must appear in the */	\
112 	/* final match, used for optimisations */			\
113 	struct reg_substr_data *substrs;				\
114 	U32 nparens;	/* number of capture buffers */			\
115 	/* private engine specific data */				\
116 	U32 intflags;	/* Engine Specific Internal flags */		\
117 	void *pprivate;	/* Data private to the regex engine which */	\
118 			/* created this object. */			\
119 	/* Data about the last/current match. These are modified */	\
120 	/* during matching */						\
121 	U32 lastparen;			/* last open paren matched */	\
122 	U32 lastcloseparen;		/* last close paren matched */	\
123 	/* Array of offsets for (@-) and (@+) */			\
124 	regexp_paren_pair *offs;					\
125 	/* saved or original string so \digit works forever. */		\
126 	char *subbeg;							\
127 	SV_SAVED_COPY	/* If non-NULL, SV which is COW from original */\
128 	SSize_t sublen;	/* Length of string pointed by subbeg */	\
129 	SSize_t suboffset; /* byte offset of subbeg from logical start of str */ \
130 	SSize_t subcoffset; /* suboffset equiv, but in chars (for @-/@+) */ \
131 	/* Information about the match that isn't often used */		\
132         SSize_t maxlen;        /* mininum possible number of chars in string to match */\
133 	/* offset from wrapped to the start of precomp */		\
134 	PERL_BITFIELD32 pre_prefix:4;					\
135         /* original flags used to compile the pattern, may differ */    \
136         /* from extflags in various ways */                             \
137         PERL_BITFIELD32 compflags:9;                                    \
138 	CV *qr_anoncv	/* the anon sub wrapped round qr/(?{..})/ */
139 
140 typedef struct regexp {
141 	_XPV_HEAD;
142 	_REGEXP_COMMON;
143 } regexp;
144 
145 #define RXp_PAREN_NAMES(rx)	((rx)->paren_names)
146 
147 /* used for high speed searches */
148 typedef struct re_scream_pos_data_s
149 {
150     char **scream_olds;		/* match pos */
151     SSize_t *scream_pos;	/* Internal iterator of scream. */
152 } re_scream_pos_data;
153 
154 /* regexp_engine structure. This is the dispatch table for regexes.
155  * Any regex engine implementation must be able to build one of these.
156  */
157 typedef struct regexp_engine {
158     REGEXP* (*comp) (pTHX_ SV * const pattern, U32 flags);
159     I32     (*exec) (pTHX_ REGEXP * const rx, char* stringarg, char* strend,
160                      char* strbeg, SSize_t minend, SV* sv,
161                      void* data, U32 flags);
162     char*   (*intuit) (pTHX_
163                         REGEXP * const rx,
164                         SV *sv,
165                         const char * const strbeg,
166                         char *strpos,
167                         char *strend,
168                         const U32 flags,
169                        re_scream_pos_data *data);
170     SV*     (*checkstr) (pTHX_ REGEXP * const rx);
171     void    (*free) (pTHX_ REGEXP * const rx);
172     void    (*numbered_buff_FETCH) (pTHX_ REGEXP * const rx, const I32 paren,
173                                     SV * const sv);
174     void    (*numbered_buff_STORE) (pTHX_ REGEXP * const rx, const I32 paren,
175                                    SV const * const value);
176     I32     (*numbered_buff_LENGTH) (pTHX_ REGEXP * const rx, const SV * const sv,
177                                     const I32 paren);
178     SV*     (*named_buff) (pTHX_ REGEXP * const rx, SV * const key,
179                            SV * const value, const U32 flags);
180     SV*     (*named_buff_iter) (pTHX_ REGEXP * const rx, const SV * const lastkey,
181                                 const U32 flags);
182     SV*     (*qr_package)(pTHX_ REGEXP * const rx);
183 #ifdef USE_ITHREADS
184     void*   (*dupe) (pTHX_ REGEXP * const rx, CLONE_PARAMS *param);
185 #endif
186     REGEXP* (*op_comp) (pTHX_ SV ** const patternp, int pat_count,
187 		    OP *expr, const struct regexp_engine* eng,
188 		    REGEXP *VOL old_re,
189 		    bool *is_bare_re, U32 orig_rx_flags, U32 pm_flags);
190 } regexp_engine;
191 
192 /*
193   These are passed to the numbered capture variable callbacks as the
194   paren name. >= 1 is reserved for actual numbered captures, i.e. $1,
195   $2 etc.
196 */
197 #define RX_BUFF_IDX_CARET_PREMATCH  -5 /* ${^PREMATCH}  */
198 #define RX_BUFF_IDX_CARET_POSTMATCH -4 /* ${^POSTMATCH} */
199 #define RX_BUFF_IDX_CARET_FULLMATCH -3 /* ${^MATCH}     */
200 #define RX_BUFF_IDX_PREMATCH        -2 /* $` */
201 #define RX_BUFF_IDX_POSTMATCH       -1 /* $' */
202 #define RX_BUFF_IDX_FULLMATCH        0 /* $& */
203 
204 /*
205   Flags that are passed to the named_buff and named_buff_iter
206   callbacks above. Those routines are called from universal.c via the
207   Tie::Hash::NamedCapture interface for %+ and %- and the re::
208   functions in the same file.
209 */
210 
211 /* The Tie::Hash::NamedCapture operation this is part of, if any */
212 #define RXapif_FETCH     0x0001
213 #define RXapif_STORE     0x0002
214 #define RXapif_DELETE    0x0004
215 #define RXapif_CLEAR     0x0008
216 #define RXapif_EXISTS    0x0010
217 #define RXapif_SCALAR    0x0020
218 #define RXapif_FIRSTKEY  0x0040
219 #define RXapif_NEXTKEY   0x0080
220 
221 /* Whether %+ or %- is being operated on */
222 #define RXapif_ONE       0x0100 /* %+ */
223 #define RXapif_ALL       0x0200 /* %- */
224 
225 /* Whether this is being called from a re:: function */
226 #define RXapif_REGNAME         0x0400
227 #define RXapif_REGNAMES        0x0800
228 #define RXapif_REGNAMES_COUNT  0x1000
229 
230 /*
231 =head1 REGEXP Functions
232 
233 =for apidoc Am|REGEXP *|SvRX|SV *sv
234 
235 Convenience macro to get the REGEXP from a SV.  This is approximately
236 equivalent to the following snippet:
237 
238     if (SvMAGICAL(sv))
239         mg_get(sv);
240     if (SvROK(sv))
241         sv = MUTABLE_SV(SvRV(sv));
242     if (SvTYPE(sv) == SVt_REGEXP)
243         return (REGEXP*) sv;
244 
245 NULL will be returned if a REGEXP* is not found.
246 
247 =for apidoc Am|bool|SvRXOK|SV* sv
248 
249 Returns a boolean indicating whether the SV (or the one it references)
250 is a REGEXP.
251 
252 If you want to do something with the REGEXP* later use SvRX instead
253 and check for NULL.
254 
255 =cut
256 */
257 
258 #define SvRX(sv)   (Perl_get_re_arg(aTHX_ sv))
259 #define SvRXOK(sv) (Perl_get_re_arg(aTHX_ sv) ? TRUE : FALSE)
260 
261 
262 /* Flags stored in regexp->extflags
263  * These are used by code external to the regexp engine
264  *
265  * Note that the flags whose names start with RXf_PMf_ are defined in
266  * op_reg_common.h, being copied from the parallel flags of op_pmflags
267  *
268  * NOTE: if you modify any RXf flags you should run regen.pl or
269  * regen/regcomp.pl so that regnodes.h is updated with the changes.
270  *
271  */
272 
273 #include "op_reg_common.h"
274 
275 #define RXf_PMf_STD_PMMOD	(RXf_PMf_MULTILINE|RXf_PMf_SINGLELINE|RXf_PMf_FOLD|RXf_PMf_EXTENDED)
276 
277 #define CASE_STD_PMMOD_FLAGS_PARSE_SET(pmfl)                        \
278     case IGNORE_PAT_MOD:    *(pmfl) |= RXf_PMf_FOLD;       break;   \
279     case MULTILINE_PAT_MOD: *(pmfl) |= RXf_PMf_MULTILINE;  break;   \
280     case SINGLE_PAT_MOD:    *(pmfl) |= RXf_PMf_SINGLELINE; break;   \
281     case XTENDED_PAT_MOD:   *(pmfl) |= RXf_PMf_EXTENDED;   break
282 
283 /* Note, includes charset ones, assumes 0 is the default for them */
284 #define STD_PMMOD_FLAGS_CLEAR(pmfl)                        \
285     *(pmfl) &= ~(RXf_PMf_FOLD|RXf_PMf_MULTILINE|RXf_PMf_SINGLELINE|RXf_PMf_EXTENDED|RXf_PMf_CHARSET)
286 
287 /* chars and strings used as regex pattern modifiers
288  * Singular is a 'c'har, plural is a "string"
289  *
290  * NOTE, KEEPCOPY was originally 'k', but was changed to 'p' for preserve
291  * for compatibility reasons with Regexp::Common which highjacked (?k:...)
292  * for its own uses. So 'k' is out as well.
293  */
294 #define DEFAULT_PAT_MOD      '^'    /* Short for all the default modifiers */
295 #define EXEC_PAT_MOD         'e'
296 #define KEEPCOPY_PAT_MOD     'p'
297 #define ONCE_PAT_MOD         'o'
298 #define GLOBAL_PAT_MOD       'g'
299 #define CONTINUE_PAT_MOD     'c'
300 #define MULTILINE_PAT_MOD    'm'
301 #define SINGLE_PAT_MOD       's'
302 #define IGNORE_PAT_MOD       'i'
303 #define XTENDED_PAT_MOD      'x'
304 #define NONDESTRUCT_PAT_MOD  'r'
305 #define LOCALE_PAT_MOD       'l'
306 #define UNICODE_PAT_MOD      'u'
307 #define DEPENDS_PAT_MOD      'd'
308 #define ASCII_RESTRICT_PAT_MOD 'a'
309 
310 #define ONCE_PAT_MODS        "o"
311 #define KEEPCOPY_PAT_MODS    "p"
312 #define EXEC_PAT_MODS        "e"
313 #define LOOP_PAT_MODS        "gc"
314 #define NONDESTRUCT_PAT_MODS "r"
315 #define LOCALE_PAT_MODS      "l"
316 #define UNICODE_PAT_MODS     "u"
317 #define DEPENDS_PAT_MODS     "d"
318 #define ASCII_RESTRICT_PAT_MODS "a"
319 #define ASCII_MORE_RESTRICT_PAT_MODS "aa"
320 
321 /* This string is expected by regcomp.c to be ordered so that the first
322  * character is the flag in bit RXf_PMf_STD_PMMOD_SHIFT of extflags; the next
323  * character is bit +1, etc. */
324 #define STD_PAT_MODS        "msix"
325 
326 #define CHARSET_PAT_MODS    ASCII_RESTRICT_PAT_MODS DEPENDS_PAT_MODS LOCALE_PAT_MODS UNICODE_PAT_MODS
327 
328 /* This string is expected by XS_re_regexp_pattern() in universal.c to be ordered
329  * so that the first character is the flag in bit RXf_PMf_STD_PMMOD_SHIFT of
330  * extflags; the next character is in bit +1, etc. */
331 #define INT_PAT_MODS    STD_PAT_MODS    KEEPCOPY_PAT_MODS
332 
333 #define EXT_PAT_MODS    ONCE_PAT_MODS   KEEPCOPY_PAT_MODS
334 #define QR_PAT_MODS     STD_PAT_MODS    EXT_PAT_MODS	   CHARSET_PAT_MODS
335 #define M_PAT_MODS      QR_PAT_MODS     LOOP_PAT_MODS
336 #define S_PAT_MODS      M_PAT_MODS      EXEC_PAT_MODS      NONDESTRUCT_PAT_MODS
337 
338 /*
339  * NOTE: if you modify any RXf flags you should run regen.pl or
340  * regen/regcomp.pl so that regnodes.h is updated with the changes.
341  *
342  */
343 
344 /* Leave some space, so future bit allocations can go either in the shared or
345  * unshared area without affecting binary compatibility */
346 #define RXf_BASE_SHIFT (_RXf_PMf_SHIFT_NEXT)
347 
348 /*
349   Set in Perl_pmruntime if op_flags & OPf_SPECIAL, i.e. split. Will
350   be used by regex engines to check whether they should set
351   RXf_SKIPWHITE
352 */
353 #define RXf_SPLIT                (1<<(RXf_BASE_SHIFT-1))
354 #if RXf_SPLIT != RXf_PMf_SPLIT
355 #   error "RXf_SPLIT does not match RXf_PMf_SPLIT"
356 #endif
357 
358 /* Manually decorate this function with gcc-style attributes just to
359  * avoid having to restructure the header files and their called order,
360  * as proto.h would have to be included before this file, and isn't */
361 
362 PERL_STATIC_INLINE const char *
363 get_regex_charset_name(const U32 flags, STRLEN* const lenp)
364     __attribute__warn_unused_result__;
365 
366 #define MAX_CHARSET_NAME_LENGTH 2
367 
368 PERL_STATIC_INLINE const char *
369 get_regex_charset_name(const U32 flags, STRLEN* const lenp)
370 {
371     /* Returns a string that corresponds to the name of the regex character set
372      * given by 'flags', and *lenp is set the length of that string, which
373      * cannot exceed MAX_CHARSET_NAME_LENGTH characters */
374 
375     *lenp = 1;
376     switch (get_regex_charset(flags)) {
377         case REGEX_DEPENDS_CHARSET: return DEPENDS_PAT_MODS;
378         case REGEX_LOCALE_CHARSET:  return LOCALE_PAT_MODS;
379         case REGEX_UNICODE_CHARSET: return UNICODE_PAT_MODS;
380 	case REGEX_ASCII_RESTRICTED_CHARSET: return ASCII_RESTRICT_PAT_MODS;
381 	case REGEX_ASCII_MORE_RESTRICTED_CHARSET:
382 	    *lenp = 2;
383 	    return ASCII_MORE_RESTRICT_PAT_MODS;
384         default:
385 	    return "?";	    /* Unknown */
386     }
387 }
388 
389 /* Do we have some sort of anchor? */
390 #define RXf_IS_ANCHORED         (1<<(RXf_BASE_SHIFT+0))
391 #define RXf_UNUSED1             (1<<(RXf_BASE_SHIFT+1))
392 #define RXf_UNUSED2             (1<<(RXf_BASE_SHIFT+2))
393 #define RXf_UNUSED3             (1<<(RXf_BASE_SHIFT+3))
394 #define RXf_UNUSED4             (1<<(RXf_BASE_SHIFT+4))
395 #define RXf_UNUSED5             (1<<(RXf_BASE_SHIFT+5))
396 
397 /* What we have seen */
398 #define RXf_NO_INPLACE_SUBST    (1<<(RXf_BASE_SHIFT+6))
399 #define RXf_EVAL_SEEN   	(1<<(RXf_BASE_SHIFT+7))
400 #define RXf_UNUSED8             (1<<(RXf_BASE_SHIFT+8))
401 
402 /* Special */
403 #define RXf_UNBOUNDED_QUANTIFIER_SEEN   (1<<(RXf_BASE_SHIFT+9))
404 #define RXf_CHECK_ALL   	(1<<(RXf_BASE_SHIFT+10))
405 
406 /* UTF8 related */
407 #define RXf_MATCH_UTF8  	(1<<(RXf_BASE_SHIFT+11)) /* $1 etc are utf8 */
408 
409 /* Intuit related */
410 #define RXf_USE_INTUIT_NOML	(1<<(RXf_BASE_SHIFT+12))
411 #define RXf_USE_INTUIT_ML	(1<<(RXf_BASE_SHIFT+13))
412 #define RXf_INTUIT_TAIL 	(1<<(RXf_BASE_SHIFT+14))
413 #define RXf_USE_INTUIT		(RXf_USE_INTUIT_NOML|RXf_USE_INTUIT_ML)
414 
415 /* Copy and tainted info */
416 #define RXf_COPY_DONE   	(1<<(RXf_BASE_SHIFT+16))
417 
418 /* post-execution: $1 et al are tainted */
419 #define RXf_TAINTED_SEEN	(1<<(RXf_BASE_SHIFT+17))
420 /* this pattern was tainted during compilation */
421 #define RXf_TAINTED		(1<<(RXf_BASE_SHIFT+18))
422 
423 /* Flags indicating special patterns */
424 #define RXf_START_ONLY		(1<<(RXf_BASE_SHIFT+19)) /* Pattern is /^/ */
425 #define RXf_SKIPWHITE                (1<<(RXf_BASE_SHIFT+20)) /* Pattern is for a split " " */
426 #define RXf_WHITE		(1<<(RXf_BASE_SHIFT+21)) /* Pattern is /\s+/ */
427 #define RXf_NULL		(1U<<(RXf_BASE_SHIFT+22)) /* Pattern is // */
428 #if RXf_BASE_SHIFT+22 > 31
429 #   error Too many RXf_PMf bits used.  See regnodes.h for any spare in middle
430 #endif
431 
432 /*
433  * NOTE: if you modify any RXf flags you should run regen.pl or
434  * regen/regcomp.pl so that regnodes.h is updated with the changes.
435  *
436  */
437 
438 #ifdef NO_TAINT_SUPPORT
439 #   define RX_ISTAINTED(prog)    0
440 #   define RX_TAINT_on(prog)     NOOP
441 #   define RXp_MATCH_TAINTED(prog) 0
442 #   define RX_MATCH_TAINTED(prog)  0
443 #   define RXp_MATCH_TAINTED_on(prog) NOOP
444 #   define RX_MATCH_TAINTED_on(prog)  NOOP
445 #   define RX_MATCH_TAINTED_off(prog) NOOP
446 #else
447 #   define RX_ISTAINTED(prog)    (RX_EXTFLAGS(prog) & RXf_TAINTED)
448 #   define RX_TAINT_on(prog)     (RX_EXTFLAGS(prog) |= RXf_TAINTED)
449 #   define RXp_MATCH_TAINTED(prog)    (RXp_EXTFLAGS(prog) & RXf_TAINTED_SEEN)
450 #   define RX_MATCH_TAINTED(prog)     (RX_EXTFLAGS(prog)  & RXf_TAINTED_SEEN)
451 #   define RXp_MATCH_TAINTED_on(prog) (RXp_EXTFLAGS(prog) |= RXf_TAINTED_SEEN)
452 #   define RX_MATCH_TAINTED_on(prog)  (RX_EXTFLAGS(prog)  |= RXf_TAINTED_SEEN)
453 #   define RX_MATCH_TAINTED_off(prog) (RX_EXTFLAGS(prog)  &= ~RXf_TAINTED_SEEN)
454 #endif
455 
456 #define RX_HAS_CUTGROUP(prog) ((prog)->intflags & PREGf_CUTGROUP_SEEN)
457 #define RX_MATCH_TAINTED_set(prog, t) ((t) \
458 				       ? RX_MATCH_TAINTED_on(prog) \
459 				       : RX_MATCH_TAINTED_off(prog))
460 
461 #define RXp_MATCH_COPIED(prog)		(RXp_EXTFLAGS(prog) & RXf_COPY_DONE)
462 #define RX_MATCH_COPIED(prog)		(RX_EXTFLAGS(prog) & RXf_COPY_DONE)
463 #define RXp_MATCH_COPIED_on(prog)	(RXp_EXTFLAGS(prog) |= RXf_COPY_DONE)
464 #define RX_MATCH_COPIED_on(prog)	(RX_EXTFLAGS(prog) |= RXf_COPY_DONE)
465 #define RXp_MATCH_COPIED_off(prog)	(RXp_EXTFLAGS(prog) &= ~RXf_COPY_DONE)
466 #define RX_MATCH_COPIED_off(prog)	(RX_EXTFLAGS(prog) &= ~RXf_COPY_DONE)
467 #define RX_MATCH_COPIED_set(prog,t)	((t) \
468 					 ? RX_MATCH_COPIED_on(prog) \
469 					 : RX_MATCH_COPIED_off(prog))
470 
471 #define RXp_EXTFLAGS(rx)	((rx)->extflags)
472 #define RXp_COMPFLAGS(rx)        ((rx)->compflags)
473 
474 /* For source compatibility. We used to store these explicitly.  */
475 #define RX_PRECOMP(prog)	(RX_WRAPPED(prog) + ReANY(prog)->pre_prefix)
476 #define RX_PRECOMP_const(prog)	(RX_WRAPPED_const(prog) + ReANY(prog)->pre_prefix)
477 /* FIXME? Are we hardcoding too much here and constraining plugin extension
478    writers? Specifically, the value 1 assumes that the wrapped version always
479    has exactly one character at the end, a ')'. Will that always be true?  */
480 #define RX_PRELEN(prog)		(RX_WRAPLEN(prog) - ReANY(prog)->pre_prefix - 1)
481 #define RX_WRAPPED(prog)	ReANY(prog)->xpv_len_u.xpvlenu_pv
482 #define RX_WRAPPED_const(prog)	((const char *)RX_WRAPPED(prog))
483 #define RX_WRAPLEN(prog)	SvCUR(prog)
484 #define RX_CHECK_SUBSTR(prog)	(ReANY(prog)->check_substr)
485 #define RX_REFCNT(prog)		SvREFCNT(prog)
486 #define RX_EXTFLAGS(prog)	RXp_EXTFLAGS(ReANY(prog))
487 #define RX_COMPFLAGS(prog)        RXp_COMPFLAGS(ReANY(prog))
488 #define RX_ENGINE(prog)		(ReANY(prog)->engine)
489 #define RX_SUBBEG(prog)		(ReANY(prog)->subbeg)
490 #define RX_SUBOFFSET(prog)	(ReANY(prog)->suboffset)
491 #define RX_SUBCOFFSET(prog)	(ReANY(prog)->subcoffset)
492 #define RX_OFFS(prog)		(ReANY(prog)->offs)
493 #define RX_NPARENS(prog)	(ReANY(prog)->nparens)
494 #define RX_SUBLEN(prog)		(ReANY(prog)->sublen)
495 #define RX_MINLEN(prog)		(ReANY(prog)->minlen)
496 #define RX_MINLENRET(prog)	(ReANY(prog)->minlenret)
497 #define RX_GOFS(prog)		(ReANY(prog)->gofs)
498 #define RX_LASTPAREN(prog)	(ReANY(prog)->lastparen)
499 #define RX_LASTCLOSEPAREN(prog)	(ReANY(prog)->lastcloseparen)
500 #define RX_SAVED_COPY(prog)	(ReANY(prog)->saved_copy)
501 /* last match was zero-length */
502 #define RX_ZERO_LEN(prog) \
503         (RX_OFFS(prog)[0].start + (SSize_t)RX_GOFS(prog) \
504           == RX_OFFS(prog)[0].end)
505 
506 #endif /* PLUGGABLE_RE_EXTENSION */
507 
508 /* Stuff that needs to be included in the pluggable extension goes below here */
509 
510 #ifdef PERL_ANY_COW
511 #define RX_MATCH_COPY_FREE(rx) \
512 	STMT_START {if (RX_SAVED_COPY(rx)) { \
513 	    SV_CHECK_THINKFIRST_COW_DROP(RX_SAVED_COPY(rx)); \
514 	} \
515 	if (RX_MATCH_COPIED(rx)) { \
516 	    Safefree(RX_SUBBEG(rx)); \
517 	    RX_MATCH_COPIED_off(rx); \
518 	}} STMT_END
519 #else
520 #define RX_MATCH_COPY_FREE(rx) \
521 	STMT_START {if (RX_MATCH_COPIED(rx)) { \
522 	    Safefree(RX_SUBBEG(rx)); \
523 	    RX_MATCH_COPIED_off(rx); \
524 	}} STMT_END
525 #endif
526 
527 #define RXp_MATCH_UTF8(prog)		(RXp_EXTFLAGS(prog) & RXf_MATCH_UTF8)
528 #define RX_MATCH_UTF8(prog)		(RX_EXTFLAGS(prog) & RXf_MATCH_UTF8)
529 #define RX_MATCH_UTF8_on(prog)		(RX_EXTFLAGS(prog) |= RXf_MATCH_UTF8)
530 #define RX_MATCH_UTF8_off(prog)		(RX_EXTFLAGS(prog) &= ~RXf_MATCH_UTF8)
531 #define RX_MATCH_UTF8_set(prog, t)	((t) \
532 			? RX_MATCH_UTF8_on(prog) \
533 			: RX_MATCH_UTF8_off(prog))
534 
535 /* Whether the pattern stored at RX_WRAPPED is in UTF-8  */
536 #define RX_UTF8(prog)			SvUTF8(prog)
537 
538 
539 /* bits in flags arg of Perl_regexec_flags() */
540 
541 #define REXEC_COPY_STR  0x01    /* Need to copy the string for captures. */
542 #define REXEC_CHECKED   0x02    /* re_intuit_start() already called. */
543 #define REXEC_SCREAM    0x04    /* currently unused. */
544 #define REXEC_IGNOREPOS 0x08    /* use stringarg, not pos(), for \G match */
545 #define REXEC_NOT_FIRST 0x10    /* This is another iteration of //g:
546                                    no need to copy string again */
547 
548                                      /* under REXEC_COPY_STR, it's ok for the
549                                         engine (modulo PL_sawamperand etc)
550                                         to skip copying: ... */
551 #define REXEC_COPY_SKIP_PRE  0x20    /* ...the $` part of the string, or */
552 #define REXEC_COPY_SKIP_POST 0x40    /* ...the $' part of the string */
553 #define REXEC_FAIL_ON_UNDERFLOW 0x80 /* fail the match if $& would start before
554                                         the start pos (so s/.\G// would fail
555                                         on second iteration */
556 
557 #if defined(__GNUC__) && !defined(PERL_GCC_BRACE_GROUPS_FORBIDDEN)
558 #  define ReREFCNT_inc(re)						\
559     ({									\
560 	/* This is here to generate a casting warning if incorrect.  */	\
561 	REGEXP *const _rerefcnt_inc = (re);				\
562 	assert(SvTYPE(_rerefcnt_inc) == SVt_REGEXP);			\
563 	SvREFCNT_inc(_rerefcnt_inc);					\
564 	_rerefcnt_inc;							\
565     })
566 #  define ReREFCNT_dec(re)						\
567     ({									\
568 	/* This is here to generate a casting warning if incorrect.  */	\
569 	REGEXP *const _rerefcnt_dec = (re);				\
570 	SvREFCNT_dec(_rerefcnt_dec);					\
571     })
572 #else
573 #  define ReREFCNT_dec(re)	SvREFCNT_dec(re)
574 #  define ReREFCNT_inc(re)	((REGEXP *) SvREFCNT_inc(re))
575 #endif
576 #define ReANY(re)		S_ReANY((const REGEXP *)(re))
577 
578 /* FIXME for plugins. */
579 
580 #define FBMcf_TAIL_DOLLAR	1
581 #define FBMcf_TAIL_DOLLARM	2
582 #define FBMcf_TAIL_Z		4
583 #define FBMcf_TAIL_z		8
584 #define FBMcf_TAIL		(FBMcf_TAIL_DOLLAR|FBMcf_TAIL_DOLLARM|FBMcf_TAIL_Z|FBMcf_TAIL_z)
585 
586 #define FBMrf_MULTILINE	1
587 
588 struct regmatch_state;
589 struct regmatch_slab;
590 
591 /* like regmatch_info_aux, but contains extra fields only needed if the
592  * pattern contains (?{}). If used, is snuck into the second slot in the
593  * regmatch_state stack at the start of execution */
594 
595 typedef struct {
596     regexp *rex;
597     PMOP    *curpm;     /* saved PL_curpm */
598 #ifdef PERL_ANY_COW
599     SV      *saved_copy; /* saved saved_copy field from rex */
600 #endif
601     char    *subbeg;    /* saved subbeg     field from rex */
602     STRLEN  sublen;     /* saved sublen     field from rex */
603     STRLEN  suboffset;  /* saved suboffset  field from rex */
604     STRLEN  subcoffset; /* saved subcoffset field from rex */
605     MAGIC   *pos_magic; /* pos() magic attached to $_ */
606     SSize_t pos;        /* the original value of pos() in pos_magic */
607     U8      pos_flags;  /* flags to be restored; currently only MGf_BYTES*/
608 } regmatch_info_aux_eval;
609 
610 
611 /* fields that logically  live in regmatch_info, but which need cleaning
612  * up on croak(), and so are instead are snuck into the first slot in
613  * the regmatch_state stack at the start of execution */
614 
615 typedef struct {
616     regmatch_info_aux_eval *info_aux_eval;
617     struct regmatch_state *old_regmatch_state; /* saved PL_regmatch_state */
618     struct regmatch_slab  *old_regmatch_slab;  /* saved PL_regmatch_slab */
619     char *poscache;	/* S-L cache of fail positions of WHILEMs */
620 } regmatch_info_aux;
621 
622 
623 /* some basic information about the current match that is created by
624  * Perl_regexec_flags and then passed to regtry(), regmatch() etc.
625  * It is allocated as a local var on the stack, so nothing should be
626  * stored in it that needs preserving or clearing up on croak().
627  * For that, see the aux_info and aux_info_eval members of the
628  * regmatch_state union. */
629 
630 typedef struct {
631     REGEXP *prog;        /* the regex being executed */
632     const char * strbeg; /* real start of string */
633     char *strend;        /* one byte beyond last char of match string */
634     char *till;          /* matches shorter than this fail (see minlen arg) */
635     SV *sv;              /* the SV string currently being matched */
636     char *ganch;         /* position of \G anchor */
637     char *cutpoint;      /* (*COMMIT) position (if any) */
638     regmatch_info_aux      *info_aux; /* extra fields that need cleanup */
639     regmatch_info_aux_eval *info_aux_eval; /* extra saved state for (?{}) */
640     I32  poscache_maxiter; /* how many whilems todo before S-L cache kicks in */
641     I32  poscache_iter;    /* current countdown from _maxiter to zero */
642     STRLEN poscache_size;  /* size of regmatch_info_aux.poscache */
643     bool intuit;    /* re_intuit_start() is the top-level caller */
644     bool is_utf8_pat;    /* regex is utf8 */
645     bool is_utf8_target; /* string being matched is utf8 */
646     bool warned; /* we have issued a recursion warning; no need for more */
647 } regmatch_info;
648 
649 
650 /* structures for holding and saving the state maintained by regmatch() */
651 
652 #ifndef MAX_RECURSE_EVAL_NOCHANGE_DEPTH
653 #define MAX_RECURSE_EVAL_NOCHANGE_DEPTH 1000
654 #endif
655 
656 typedef I32 CHECKPOINT;
657 
658 typedef struct regmatch_state {
659     int resume_state;		/* where to jump to on return */
660     char *locinput;		/* where to backtrack in string on failure */
661 
662     union {
663 
664         /* the 'info_aux' and 'info_aux_eval' union members are cuckoos in
665          * the nest. They aren't saved backtrack state; rather they
666          * represent one or two extra chunks of data that need allocating
667          * at the start of a match. These fields would logically live in
668          * the regmatch_info struct, except that is allocated on the
669          * C stack, and these fields are all things that require cleanup
670          * after a croak(), when the stack is lost.
671          * As a convenience, we just use the first 1 or 2 regmatch_state
672          * slots to store this info, as we will be allocating a slab of
673          * these anyway. Otherwise we'd have to malloc and then free them,
674          * or allocate them on the save stack (where they will get
675          * realloced if the save stack grows).
676          * info_aux contains the extra fields that are always needed;
677          * info_aux_eval contains extra fields that only needed if
678          * the pattern contains code blocks
679          * We split them into two separate structs to avoid increasing
680          * the size of the union.
681          */
682 
683         regmatch_info_aux info_aux;
684 
685         regmatch_info_aux_eval info_aux_eval;
686 
687 	/* this is a fake union member that matches the first element
688 	 * of each member that needs to store positive backtrack
689 	 * information */
690 	struct {
691 	    struct regmatch_state *prev_yes_state;
692 	} yes;
693 
694         /* branchlike members */
695         /* this is a fake union member that matches the first elements
696          * of each member that needs to behave like a branch */
697         struct {
698 	    /* this first element must match u.yes */
699 	    struct regmatch_state *prev_yes_state;
700 	    U32 lastparen;
701 	    U32 lastcloseparen;
702 	    CHECKPOINT cp;
703 
704         } branchlike;
705 
706 	struct {
707 	    /* the first elements must match u.branchlike */
708 	    struct regmatch_state *prev_yes_state;
709 	    U32 lastparen;
710 	    U32 lastcloseparen;
711 	    CHECKPOINT cp;
712 
713 	    regnode *next_branch; /* next branch node */
714 	} branch;
715 
716 	struct {
717 	    /* the first elements must match u.branchlike */
718 	    struct regmatch_state *prev_yes_state;
719 	    U32 lastparen;
720 	    U32 lastcloseparen;
721 	    CHECKPOINT cp;
722 
723 	    U32		accepted; /* how many accepting states left */
724 	    bool	longfold;/* saw a fold with a 1->n char mapping */
725 	    U16         *jump;  /* positive offsets from me */
726 	    regnode	*me;	/* Which node am I - needed for jump tries*/
727 	    U8		*firstpos;/* pos in string of first trie match */
728 	    U32		firstchars;/* len in chars of firstpos from start */
729 	    U16		nextword;/* next word to try */
730 	    U16		topword; /* longest accepted word */
731 	} trie;
732 
733         /* special types - these members are used to store state for special
734            regops like eval, if/then, lookaround and the markpoint state */
735 	struct {
736 	    /* this first element must match u.yes */
737 	    struct regmatch_state *prev_yes_state;
738 	    struct regmatch_state *prev_eval;
739 	    struct regmatch_state *prev_curlyx;
740 	    REGEXP	*prev_rex;
741 	    CHECKPOINT	cp;	/* remember current savestack indexes */
742 	    CHECKPOINT	lastcp;
743 	    U32        close_paren; /* which close bracket is our end */
744 	    regnode	*B;	/* the node following us  */
745 	} eval;
746 
747 	struct {
748 	    /* this first element must match u.yes */
749 	    struct regmatch_state *prev_yes_state;
750 	    I32 wanted;
751 	    I32 logical;	/* saved copy of 'logical' var */
752 	    regnode  *me; /* the IFMATCH/SUSPEND/UNLESSM node  */
753 	} ifmatch; /* and SUSPEND/UNLESSM */
754 
755 	struct {
756 	    /* this first element must match u.yes */
757 	    struct regmatch_state *prev_yes_state;
758 	    struct regmatch_state *prev_mark;
759 	    SV* mark_name;
760 	    char *mark_loc;
761 	} mark;
762 
763 	struct {
764 	    int val;
765 	} keeper;
766 
767         /* quantifiers - these members are used for storing state for
768            for the regops used to implement quantifiers */
769 	struct {
770 	    /* this first element must match u.yes */
771 	    struct regmatch_state *prev_yes_state;
772 	    struct regmatch_state *prev_curlyx; /* previous cur_curlyx */
773 	    regnode	*me;	/* the CURLYX node  */
774 	    regnode	*B;	/* the B node in /A*B/  */
775 	    CHECKPOINT	cp;	/* remember current savestack index */
776 	    bool	minmod;
777 	    int		parenfloor;/* how far back to strip paren data */
778 
779 	    /* these two are modified by WHILEM */
780 	    int		count;	/* how many instances of A we've matched */
781 	    char	*lastloc;/* where previous A matched (0-len detect) */
782 	} curlyx;
783 
784 	struct {
785 	    /* this first element must match u.yes */
786 	    struct regmatch_state *prev_yes_state;
787 	    struct regmatch_state *save_curlyx;
788 	    CHECKPOINT	cp;	/* remember current savestack indexes */
789 	    CHECKPOINT	lastcp;
790 	    char	*save_lastloc;	/* previous curlyx.lastloc */
791 	    I32		cache_offset;
792 	    I32		cache_mask;
793 	} whilem;
794 
795 	struct {
796 	    /* this first element must match u.yes */
797 	    struct regmatch_state *prev_yes_state;
798 	    int c1, c2;		/* case fold search */
799 	    CHECKPOINT cp;
800 	    U32 lastparen;
801 	    U32 lastcloseparen;
802 	    I32 alen;		/* length of first-matched A string */
803 	    I32 count;
804 	    bool minmod;
805 	    regnode *A, *B;	/* the nodes corresponding to /A*B/  */
806 	    regnode *me;	/* the curlym node */
807             U8 c1_utf8[UTF8_MAXBYTES+1];  /* */
808             U8 c2_utf8[UTF8_MAXBYTES+1];
809 	} curlym;
810 
811 	struct {
812 	    U32 paren;
813 	    CHECKPOINT cp;
814 	    U32 lastparen;
815 	    U32 lastcloseparen;
816 	    int c1, c2;		/* case fold search */
817 	    char *maxpos;	/* highest possible point in string to match */
818 	    char *oldloc;	/* the previous locinput */
819 	    int count;
820 	    int min, max;	/* {m,n} */
821 	    regnode *A, *B;	/* the nodes corresponding to /A*B/  */
822             U8 c1_utf8[UTF8_MAXBYTES+1];  /* */
823             U8 c2_utf8[UTF8_MAXBYTES+1];
824 	} curly; /* and CURLYN/PLUS/STAR */
825 
826     } u;
827 } regmatch_state;
828 
829 /* how many regmatch_state structs to allocate as a single slab.
830  * We do it in 4K blocks for efficiency. The "3" is 2 for the next/prev
831  * pointers, plus 1 for any mythical malloc overhead. */
832 
833 #define PERL_REGMATCH_SLAB_SLOTS \
834     ((4096 - 3 * sizeof (void*)) / sizeof(regmatch_state))
835 
836 typedef struct regmatch_slab {
837     regmatch_state states[PERL_REGMATCH_SLAB_SLOTS];
838     struct regmatch_slab *prev, *next;
839 } regmatch_slab;
840 
841 
842 
843 /*
844  * Local variables:
845  * c-indentation-style: bsd
846  * c-basic-offset: 4
847  * indent-tabs-mode: nil
848  * End:
849  *
850  * ex: set ts=8 sts=4 sw=4 et:
851  */
852