1/*
2 * Internal interface definitions, etc., for the reg package
3 *
4 * Copyright (c) 1998, 1999 Henry Spencer. All rights reserved.
5 *
6 * Development of this software was funded, in part, by Cray Research Inc.,
7 * UUNET Communications Services Inc., Sun Microsystems Inc., and Scriptics
8 * Corporation, none of whom are responsible for the results. The author
9 * thanks all of them.
10 *
11 * Redistribution and use in source and binary forms -- with or without
12 * modification -- are permitted for any purpose, provided that
13 * redistributions in source form retain this entire copyright notice and
14 * indicate the origin and nature of any modifications.
15 *
16 * I'd appreciate being given credit for this package in the documentation
17 * of software which uses it, but that is not a requirement.
18 *
19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
20 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
21 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
22 * HENRY SPENCER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
23 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
24 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
25 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
26 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
27 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
28 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 *
30 * src/include/regex/regguts.h
31 */
32
33
34
35/*
36 * Environmental customization. It should not (I hope) be necessary to
37 * alter the file you are now reading -- regcustom.h should handle it all,
38 * given care here and elsewhere.
39 */
40#include "regcustom.h"
41
42
43
44/*
45 * Things that regcustom.h might override.
46 */
47
48/* assertions */
49#ifndef assert
50#ifndef REG_DEBUG
51#define NDEBUG /* no assertions */
52#endif
53#include <assert.h>
54#endif
55
56/* voids */
57#ifndef DISCARD
58#define DISCARD void /* for throwing values away */
59#endif
60#ifndef VS
61#define VS(x) ((void *)(x)) /* cast something to generic ptr */
62#endif
63
64/* function-pointer declarator */
65#ifndef FUNCPTR
66#define FUNCPTR(name, args) (*(name)) args
67#endif
68
69/* memory allocation */
70#ifndef MALLOC
71#define MALLOC(n) malloc(n)
72#endif
73#ifndef REALLOC
74#define REALLOC(p, n) realloc(VS(p), n)
75#endif
76#ifndef FREE
77#define FREE(p) free(VS(p))
78#endif
79
80/* want size of a char in bits, and max value in bounded quantifiers */
81#ifndef _POSIX2_RE_DUP_MAX
82#define _POSIX2_RE_DUP_MAX 255 /* normally from <limits.h> */
83#endif
84
85
86
87/*
88 * misc
89 */
90
91#define NOTREACHED 0
92
93#define DUPMAX _POSIX2_RE_DUP_MAX
94#define DUPINF (DUPMAX+1)
95
96#define REMAGIC 0xfed7 /* magic number for main struct */
97
98/* Type codes for lookaround constraints */
99#define LATYPE_AHEAD_POS 03 /* positive lookahead */
100#define LATYPE_AHEAD_NEG 02 /* negative lookahead */
101#define LATYPE_BEHIND_POS 01 /* positive lookbehind */
102#define LATYPE_BEHIND_NEG 00 /* negative lookbehind */
103#define LATYPE_IS_POS(la) ((la) & 01)
104#define LATYPE_IS_AHEAD(la) ((la) & 02)
105
106
107/*
108 * debugging facilities
109 */
110#ifdef REG_DEBUG
111/* FDEBUG does finite-state tracing */
112#define FDEBUG(arglist) { if (v->eflags&REG_FTRACE) printf arglist; }
113/* MDEBUG does higher-level tracing */
114#define MDEBUG(arglist) { if (v->eflags&REG_MTRACE) printf arglist; }
115#else
116#define FDEBUG(arglist) {}
117#define MDEBUG(arglist) {}
118#endif
119
120
121
122/*
123 * bitmap manipulation
124 */
125#define UBITS (CHAR_BIT * sizeof(unsigned))
126#define BSET(uv, sn) ((uv)[(sn)/UBITS] |= (unsigned)1 << ((sn)%UBITS))
127#define ISBSET(uv, sn) ((uv)[(sn)/UBITS] & ((unsigned)1 << ((sn)%UBITS)))
128
129
130/*
131 * As soon as possible, we map chrs into equivalence classes -- "colors" --
132 * which are of much more manageable number.
133 */
134typedef short color; /* colors of characters */
135
136#define MAX_COLOR 32767 /* max color (must fit in 'color' datatype) */
137#define COLORLESS (-1) /* impossible color */
138#define WHITE 0 /* default color, parent of all others */
139/* Note: various places in the code know that WHITE is zero */
140
141
142/*
143 * Per-color data structure for the compile-time color machinery
144 *
145 * If "sub" is not NOSUB then it is the number of the color's current
146 * subcolor, i.e. we are in process of dividing this color (character
147 * equivalence class) into two colors. See src/backend/regex/README for
148 * discussion of subcolors.
149 *
150 * Currently-unused colors have the FREECOL bit set and are linked into a
151 * freelist using their "sub" fields, but only if their color numbers are
152 * less than colormap.max. Any array entries beyond "max" are just garbage.
153 */
154struct colordesc
155{
156 int nschrs; /* number of simple chars of this color */
157 int nuchrs; /* number of upper map entries of this color */
158 color sub; /* open subcolor, if any; or free-chain ptr */
159#define NOSUB COLORLESS /* value of "sub" when no open subcolor */
160 struct arc *arcs; /* chain of all arcs of this color */
161 chr firstchr; /* simple char first assigned to this color */
162 int flags; /* bit values defined next */
163#define FREECOL 01 /* currently free */
164#define PSEUDO 02 /* pseudocolor, no real chars */
165#define UNUSEDCOLOR(cd) ((cd)->flags & FREECOL)
166};
167
168/*
169 * The color map itself
170 *
171 * This struct holds both data used only at compile time, and the chr to
172 * color mapping information, used at both compile and run time. The latter
173 * is the bulk of the space, so it's not really worth separating out the
174 * compile-only portion.
175 *
176 * Ideally, the mapping data would just be an array of colors indexed by
177 * chr codes; but for large character sets that's impractical. Fortunately,
178 * common characters have smaller codes, so we can use a simple array for chr
179 * codes up to MAX_SIMPLE_CHR, and do something more complex for codes above
180 * that, without much loss of performance. The "something more complex" is a
181 * 2-D array of color entries, where row indexes correspond to individual chrs
182 * or chr ranges that have been mentioned in the regex (with row zero
183 * representing all other chrs), and column indexes correspond to different
184 * sets of locale-dependent character classes such as "isalpha". The
185 * classbits[k] entry is zero if we do not care about the k'th character class
186 * in this regex, and otherwise it is the bit to be OR'd into the column index
187 * if the character in question is a member of that class. We find the color
188 * of a high-valued chr by identifying which colormaprange it is in to get
189 * the row index (use row zero if it's in none of them), identifying which of
190 * the interesting cclasses it's in to get the column index, and then indexing
191 * into the 2-D hicolormap array.
192 *
193 * The colormapranges are required to be nonempty, nonoverlapping, and to
194 * appear in increasing chr-value order.
195 */
196
197#define NUM_CCLASSES 13 /* must match data in regc_locale.c */
198
199typedef struct colormaprange
200{
201 chr cmin; /* range represents cmin..cmax inclusive */
202 chr cmax;
203 int rownum; /* row index in hicolormap array (>= 1) */
204} colormaprange;
205
206struct colormap
207{
208 int magic;
209#define CMMAGIC 0x876
210 struct vars *v; /* for compile error reporting */
211 size_t ncds; /* allocated length of colordescs array */
212 size_t max; /* highest color number currently in use */
213 color free; /* beginning of free chain (if non-0) */
214 struct colordesc *cd; /* pointer to array of colordescs */
215#define CDEND(cm) (&(cm)->cd[(cm)->max + 1])
216
217 /* mapping data for chrs <= MAX_SIMPLE_CHR: */
218 color *locolormap; /* simple array indexed by chr code */
219
220 /* mapping data for chrs > MAX_SIMPLE_CHR: */
221 int classbits[NUM_CCLASSES]; /* see comment above */
222 int numcmranges; /* number of colormapranges */
223 colormaprange *cmranges; /* ranges of high chrs */
224 color *hicolormap; /* 2-D array of color entries */
225 int maxarrayrows; /* number of array rows allocated */
226 int hiarrayrows; /* number of array rows in use */
227 int hiarraycols; /* number of array columns (2^N) */
228
229 /* If we need up to NINLINECDS, we store them here to save a malloc */
230#define NINLINECDS ((size_t) 10)
231 struct colordesc cdspace[NINLINECDS];
232};
233
234/* fetch color for chr; beware of multiple evaluation of c argument */
235#define GETCOLOR(cm, c) \
236 ((c) <= MAX_SIMPLE_CHR ? (cm)->locolormap[(c) - CHR_MIN] : pg_reg_getcolor(cm, c))
237
238
239/*
240 * Interface definitions for locale-interface functions in regc_locale.c.
241 */
242
243/*
244 * Representation of a set of characters. chrs[] represents individual
245 * code points, ranges[] represents ranges in the form min..max inclusive.
246 *
247 * If the cvec represents a locale-specific character class, eg [[:alpha:]],
248 * then the chrs[] and ranges[] arrays contain only members of that class
249 * up to MAX_SIMPLE_CHR (inclusive). cclasscode is set to regc_locale.c's
250 * code for the class, rather than being -1 as it is in an ordinary cvec.
251 *
252 * Note that in cvecs gotten from newcvec() and intended to be freed by
253 * freecvec(), both arrays of chrs are after the end of the struct, not
254 * separately malloc'd; so chrspace and rangespace are effectively immutable.
255 */
256struct cvec
257{
258 int nchrs; /* number of chrs */
259 int chrspace; /* number of chrs allocated in chrs[] */
260 chr *chrs; /* pointer to vector of chrs */
261 int nranges; /* number of ranges (chr pairs) */
262 int rangespace; /* number of ranges allocated in ranges[] */
263 chr *ranges; /* pointer to vector of chr pairs */
264 int cclasscode; /* value of "enum classes", or -1 */
265};
266
267
268/*
269 * definitions for NFA internal representation
270 *
271 * Having a "from" pointer within each arc may seem redundant, but it
272 * saves a lot of hassle.
273 */
274struct state;
275
276struct arc
277{
278 int type; /* 0 if free, else an NFA arc type code */
279 color co;
280 struct state *from; /* where it's from (and contained within) */
281 struct state *to; /* where it's to */
282 struct arc *outchain; /* link in *from's outs chain or free chain */
283 struct arc *outchainRev; /* back-link in *from's outs chain */
284#define freechain outchain /* we do not maintain "freechainRev" */
285 struct arc *inchain; /* link in *to's ins chain */
286 struct arc *inchainRev; /* back-link in *to's ins chain */
287 struct arc *colorchain; /* link in color's arc chain */
288 struct arc *colorchainRev; /* back-link in color's arc chain */
289};
290
291struct arcbatch
292{ /* for bulk allocation of arcs */
293 struct arcbatch *next;
294#define ABSIZE 10
295 struct arc a[ABSIZE];
296};
297
298struct state
299{
300 int no;
301#define FREESTATE (-1)
302 char flag; /* marks special states */
303 int nins; /* number of inarcs */
304 struct arc *ins; /* chain of inarcs */
305 int nouts; /* number of outarcs */
306 struct arc *outs; /* chain of outarcs */
307 struct arc *free; /* chain of free arcs */
308 struct state *tmp; /* temporary for traversal algorithms */
309 struct state *next; /* chain for traversing all */
310 struct state *prev; /* back chain */
311 struct arcbatch oas; /* first arcbatch, avoid malloc in easy case */
312 int noas; /* number of arcs used in first arcbatch */
313};
314
315struct nfa
316{
317 struct state *pre; /* pre-initial state */
318 struct state *init; /* initial state */
319 struct state *final; /* final state */
320 struct state *post; /* post-final state */
321 int nstates; /* for numbering states */
322 struct state *states; /* state-chain header */
323 struct state *slast; /* tail of the chain */
324 struct state *free; /* free list */
325 struct colormap *cm; /* the color map */
326 color bos[2]; /* colors, if any, assigned to BOS and BOL */
327 color eos[2]; /* colors, if any, assigned to EOS and EOL */
328 struct vars *v; /* simplifies compile error reporting */
329 struct nfa *parent; /* parent NFA, if any */
330};
331
332
333
334/*
335 * definitions for compacted NFA
336 *
337 * The main space savings in a compacted NFA is from making the arcs as small
338 * as possible. We store only the transition color and next-state number for
339 * each arc. The list of out arcs for each state is an array beginning at
340 * cnfa.states[statenumber], and terminated by a dummy carc struct with
341 * co == COLORLESS.
342 *
343 * The non-dummy carc structs are of two types: plain arcs and LACON arcs.
344 * Plain arcs just store the transition color number as "co". LACON arcs
345 * store the lookaround constraint number plus cnfa.ncolors as "co". LACON
346 * arcs can be distinguished from plain by testing for co >= cnfa.ncolors.
347 */
348struct carc
349{
350 color co; /* COLORLESS is list terminator */
351 int to; /* next-state number */
352};
353
354struct cnfa
355{
356 int nstates; /* number of states */
357 int ncolors; /* number of colors (max color in use + 1) */
358 int flags;
359#define HASLACONS 01 /* uses lookaround constraints */
360 int pre; /* setup state number */
361 int post; /* teardown state number */
362 color bos[2]; /* colors, if any, assigned to BOS and BOL */
363 color eos[2]; /* colors, if any, assigned to EOS and EOL */
364 char *stflags; /* vector of per-state flags bytes */
365#define CNFA_NOPROGRESS 01 /* flag bit for a no-progress state */
366 struct carc **states; /* vector of pointers to outarc lists */
367 /* states[n] are pointers into a single malloc'd array of arcs */
368 struct carc *arcs; /* the area for the lists */
369};
370
371#define ZAPCNFA(cnfa) ((cnfa).nstates = 0)
372#define NULLCNFA(cnfa) ((cnfa).nstates == 0)
373
374/*
375 * This symbol limits the transient heap space used by the regex compiler,
376 * and thereby also the maximum complexity of NFAs that we'll deal with.
377 * Currently we only count NFA states and arcs against this; the other
378 * transient data is generally not large enough to notice compared to those.
379 * Note that we do not charge anything for the final output data structures
380 * (the compacted NFA and the colormap).
381 */
382#ifndef REG_MAX_COMPILE_SPACE
383#define REG_MAX_COMPILE_SPACE \
384 (100000 * sizeof(struct state) + 100000 * sizeof(struct arcbatch))
385#endif
386
387/*
388 * subexpression tree
389 *
390 * "op" is one of:
391 * '=' plain regex without interesting substructure (implemented as DFA)
392 * 'b' back-reference (has no substructure either)
393 * '(' capture node: captures the match of its single child
394 * '.' concatenation: matches a match for left, then a match for right
395 * '|' alternation: matches a match for left or a match for right
396 * '*' iteration: matches some number of matches of its single child
397 *
398 * Note: the right child of an alternation must be another alternation or
399 * NULL; hence, an N-way branch requires N alternation nodes, not N-1 as you
400 * might expect. This could stand to be changed. Actually I'd rather see
401 * a single alternation node with N children, but that will take revising
402 * the representation of struct subre.
403 *
404 * Note: when a backref is directly quantified, we stick the min/max counts
405 * into the backref rather than plastering an iteration node on top. This is
406 * for efficiency: there is no need to search for possible division points.
407 */
408struct subre
409{
410 char op; /* see type codes above */
411 char flags;
412#define LONGER 01 /* prefers longer match */
413#define SHORTER 02 /* prefers shorter match */
414#define MIXED 04 /* mixed preference below */
415#define CAP 010 /* capturing parens below */
416#define BACKR 020 /* back reference below */
417#define INUSE 0100 /* in use in final tree */
418#define NOPROP 03 /* bits which may not propagate up */
419#define LMIX(f) ((f)<<2) /* LONGER -> MIXED */
420#define SMIX(f) ((f)<<1) /* SHORTER -> MIXED */
421#define UP(f) (((f)&~NOPROP) | (LMIX(f) & SMIX(f) & MIXED))
422#define MESSY(f) ((f)&(MIXED|CAP|BACKR))
423#define PREF(f) ((f)&NOPROP)
424#define PREF2(f1, f2) ((PREF(f1) != 0) ? PREF(f1) : PREF(f2))
425#define COMBINE(f1, f2) (UP((f1)|(f2)) | PREF2(f1, f2))
426 short id; /* ID of subre (1..ntree-1) */
427 int subno; /* subexpression number for 'b' and '(', or
428 * LATYPE code for lookaround constraint */
429 short min; /* min repetitions for iteration or backref */
430 short max; /* max repetitions for iteration or backref */
431 struct subre *left; /* left child, if any (also freelist chain) */
432 struct subre *right; /* right child, if any */
433 struct state *begin; /* outarcs from here... */
434 struct state *end; /* ...ending in inarcs here */
435 struct cnfa cnfa; /* compacted NFA, if any */
436 struct subre *chain; /* for bookkeeping and error cleanup */
437};
438
439
440
441/*
442 * table of function pointers for generic manipulation functions
443 * A regex_t's re_fns points to one of these.
444 */
445struct fns
446{
447 void FUNCPTR(free, (regex_t *));
448 int FUNCPTR(cancel_requested, (void));
449 int FUNCPTR(stack_too_deep, (void));
450};
451
452#define CANCEL_REQUESTED(re) \
453 ((*((struct fns *) (re)->re_fns)->cancel_requested) ())
454
455#define STACK_TOO_DEEP(re) \
456 ((*((struct fns *) (re)->re_fns)->stack_too_deep) ())
457
458
459/*
460 * the insides of a regex_t, hidden behind a void *
461 */
462struct guts
463{
464 int magic;
465#define GUTSMAGIC 0xfed9
466 int cflags; /* copy of compile flags */
467 long info; /* copy of re_info */
468 size_t nsub; /* copy of re_nsub */
469 struct subre *tree;
470 struct cnfa search; /* for fast preliminary search */
471 int ntree; /* number of subre's, plus one */
472 struct colormap cmap;
473 int FUNCPTR(compare, (const chr *, const chr *, size_t));
474 struct subre *lacons; /* lookaround-constraint vector */
475 int nlacons; /* size of lacons[]; note that only slots
476 * numbered 1 .. nlacons-1 are used */
477};
478
479
480/* prototypes for functions that are exported from regcomp.c to regexec.c */
481extern void pg_set_regex_collation(Oid collation);
482extern color pg_reg_getcolor(struct colormap *cm, chr c);
483