src/regex/regguts.h

   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  * $Id$
  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 #       ifndef NDEBUG
  52 #               define  NDEBUG                                  /* no assertions */
  53 #       endif
  54 #endif
  55 #include <assert.h>
  56 #endif
  57
  58 /* voids */
  59 #ifndef DISCARD
  60 #define DISCARD void                    /* for throwing values away */
  61 #endif
  62 #ifndef VS
  63 #define VS(x)   ((void *)(x))   /* cast something to generic ptr */
  64 #endif
  65
  66 /* function-pointer declarator */
  67 #ifndef FUNCPTR
  68 #define FUNCPTR(name, args) (*name) args
  69 #endif
  70
  71 /* memory allocation */
  72 #ifndef MALLOC
  73 #define MALLOC(n)       malloc(n)
  74 #endif
  75 #ifndef REALLOC
  76 #define REALLOC(p, n)   realloc(VS(p), n)
  77 #endif
  78 #ifndef FREE
  79 #define FREE(p)         free(VS(p))
  80 #endif
  81
  82 /* want size of a char in bits, and max value in bounded quantifiers */
  83 #ifndef CHAR_BIT
  84 #include <limits.h>
  85 #endif
  86 #ifndef _POSIX2_RE_DUP_MAX
  87 #define _POSIX2_RE_DUP_MAX      255 /* normally from <limits.h> */
  88 #endif
  89
  90
  91
  92 /*
  93  * misc
  94  */
  95
  96 #define NOTREACHED      0
  97 #define xxx             1
  98
  99 #define DUPMAX  _POSIX2_RE_DUP_MAX
 100 #define INFINITY        (DUPMAX+1)
 101
 102 #define REMAGIC 0xfed7                  /* magic number for main struct */
 103
 104
 105
 106 /*
 107  * debugging facilities
 108  */
 109 #ifdef REG_DEBUG
 110 /* FDEBUG does finite-state tracing */
 111 #define FDEBUG(arglist) { if (v->eflags&REG_FTRACE) printf arglist; }
 112 /* MDEBUG does higher-level tracing */
 113 #define MDEBUG(arglist) { if (v->eflags&REG_MTRACE) printf arglist; }
 114 #else
 115 #define FDEBUG(arglist) {}
 116 #define MDEBUG(arglist) {}
 117 #endif
 118
 119
 120
 121 /*
 122  * bitmap manipulation
 123  */
 124 #define UBITS   (CHAR_BIT * sizeof(unsigned))
 125 #define BSET(uv, sn)    ((uv)[(sn)/UBITS] |= (unsigned)1 << ((sn)%UBITS))
 126 #define ISBSET(uv, sn)  ((uv)[(sn)/UBITS] & ((unsigned)1 << ((sn)%UBITS)))
 127
 128
 129
 130 /*
 131  * We dissect a chr into byts for colormap table indexing.      Here we define
 132  * a byt, which will be the same as a byte on most machines...  The exact
 133  * size of a byt is not critical, but about 8 bits is good, and extraction
 134  * of 8-bit chunks is sometimes especially fast.
 135  */
 136 #ifndef BYTBITS
 137 #define BYTBITS 8                               /* bits in a byt */
 138 #endif
 139 #define BYTTAB  (1<<BYTBITS)    /* size of table with one entry per byt
 140                                                                  * value */
 141 #define BYTMASK (BYTTAB-1)              /* bit mask for byt */
 142 #define NBYTS   ((CHRBITS+BYTBITS-1)/BYTBITS)
 143 /* the definition of GETCOLOR(), below, assumes NBYTS <= 4 */
 144
 145
 146
 147 /*
 148  * As soon as possible, we map chrs into equivalence classes -- "colors" --
 149  * which are of much more manageable number.
 150  */
 151 typedef short color;                    /* colors of characters */
 152 typedef int pcolor;                             /* what color promotes to */
 153
 154 #define COLORLESS       (-1)            /* impossible color */
 155 #define WHITE           0                       /* default color, parent of all others */
 156
 157
 158
 159 /*
 160  * A colormap is a tree -- more precisely, a DAG -- indexed at each level
 161  * by a byt of the chr, to map the chr to a color efficiently.  Because
 162  * lower sections of the tree can be shared, it can exploit the usual
 163  * sparseness of such a mapping table.  The tree is always NBYTS levels
 164  * deep (in the past it was shallower during construction but was "filled"
 165  * to full depth at the end of that); areas that are unaltered as yet point
 166  * to "fill blocks" which are entirely WHITE in color.
 167  */
 168
 169 /* the tree itself */
 170 struct colors
 171 {
 172         color           ccolor[BYTTAB];
 173 };
 174 struct ptrs
 175 {
 176         union tree *pptr[BYTTAB];
 177 };
 178 union tree
 179 {
 180         struct colors colors;
 181         struct ptrs ptrs;
 182 };
 183
 184 #define tcolor  colors.ccolor
 185 #define tptr    ptrs.pptr
 186
 187 /* internal per-color structure for the color machinery */
 188 struct colordesc
 189 {
 190         uchr            nchrs;                  /* number of chars of this color */
 191         color           sub;                    /* open subcolor (if any); free chain ptr */
 192 #define  NOSUB   COLORLESS
 193         struct arc *arcs;                       /* color chain */
 194         int                     flags;
 195 #define  FREECOL 01                             /* currently free */
 196 #define  PSEUDO  02                             /* pseudocolor, no real chars */
 197 #define  UNUSEDCOLOR(cd) ((cd)->flags&FREECOL)
 198         union tree *block;                      /* block of solid color, if any */
 199 };
 200
 201 /* the color map itself */
 202 struct colormap
 203 {
 204         int                     magic;
 205 #define  CMMAGIC 0x876
 206         struct vars *v;                         /* for compile error reporting */
 207         size_t          ncds;                   /* number of colordescs */
 208         size_t          max;                    /* highest in use */
 209         color           free;                   /* beginning of free chain (if non-0) */
 210         struct colordesc *cd;
 211 #define  CDEND(cm)       (&(cm)->cd[(cm)->max + 1])
 212 #define  NINLINECDS  ((size_t)10)
 213         struct colordesc cdspace[NINLINECDS];
 214         union tree      tree[NBYTS];    /* tree top, plus fill blocks */
 215 };
 216
 217 /* optimization magic to do fast chr->color mapping */
 218 #define B0(c)   ((c) & BYTMASK)
 219 #define B1(c)   (((c)>>BYTBITS) & BYTMASK)
 220 #define B2(c)   (((c)>>(2*BYTBITS)) & BYTMASK)
 221 #define B3(c)   (((c)>>(3*BYTBITS)) & BYTMASK)
 222 #if NBYTS == 1
 223 #define GETCOLOR(cm, c) ((cm)->tree->tcolor[B0(c)])
 224 #endif
 225 /* beware, for NBYTS>1, GETCOLOR() is unsafe -- 2nd arg used repeatedly */
 226 #if NBYTS == 2
 227 #define GETCOLOR(cm, c) ((cm)->tree->tptr[B1(c)]->tcolor[B0(c)])
 228 #endif
 229 #if NBYTS == 4
 230 #define GETCOLOR(cm, c) ((cm)->tree->tptr[B3(c)]->tptr[B2(c)]->tptr[B1(c)]->tcolor[B0(c)])
 231 #endif
 232
 233
 234
 235 /*
 236  * Interface definitions for locale-interface functions in locale.c.
 237  * Multi-character collating elements (MCCEs) cause most of the trouble.
 238  */
 239 struct cvec
 240 {
 241         int                     nchrs;                  /* number of chrs */
 242         int                     chrspace;               /* number of chrs possible */
 243         chr                *chrs;                       /* pointer to vector of chrs */
 244         int                     nranges;                /* number of ranges (chr pairs) */
 245         int                     rangespace;             /* number of chrs possible */
 246         chr                *ranges;                     /* pointer to vector of chr pairs */
 247         int                     nmcces;                 /* number of MCCEs */
 248         int                     mccespace;              /* number of MCCEs possible */
 249         int                     nmccechrs;              /* number of chrs used for MCCEs */
 250         chr                *mcces[1];           /* pointers to 0-terminated MCCEs */
 251         /* and both batches of chrs are on the end */
 252 };
 253
 254 /* caution:  this value cannot be changed easily */
 255 #define MAXMCCE 2                               /* length of longest MCCE */
 256
 257
 258
 259 /*
 260  * definitions for NFA internal representation
 261  *
 262  * Having a "from" pointer within each arc may seem redundant, but it
 263  * saves a lot of hassle.
 264  */
 265 struct state;
 266
 267 struct arc
 268 {
 269         int                     type;
 270 #define  ARCFREE '\0'
 271         color           co;
 272         struct state *from;                     /* where it's from (and contained within) */
 273         struct state *to;                       /* where it's to */
 274         struct arc *outchain;           /* *from's outs chain or free chain */
 275 #define  freechain       outchain
 276         struct arc *inchain;            /* *to's ins chain */
 277         struct arc *colorchain;         /* color's arc chain */
 278 };
 279
 280 struct arcbatch
 281 {                                                               /* for bulk allocation of arcs */
 282         struct arcbatch *next;
 283 #define  ABSIZE  10
 284         struct arc      a[ABSIZE];
 285 };
 286
 287 struct state
 288 {
 289         int                     no;
 290 #define  FREESTATE       (-1)
 291         char            flag;                   /* marks special states */
 292         int                     nins;                   /* number of inarcs */
 293         struct arc *ins;                        /* chain of inarcs */
 294         int                     nouts;                  /* number of outarcs */
 295         struct arc *outs;                       /* chain of outarcs */
 296         struct arc *free;                       /* chain of free arcs */
 297         struct state *tmp;                      /* temporary for traversal algorithms */
 298         struct state *next;                     /* chain for traversing all */
 299         struct state *prev;                     /* back chain */
 300         struct arcbatch oas;            /* first arcbatch, avoid malloc in easy
 301                                                                  * case */
 302         int                     noas;                   /* number of arcs used in first arcbatch */
 303 };
 304
 305 struct nfa
 306 {
 307         struct state *pre;                      /* pre-initial state */
 308         struct state *init;                     /* initial state */
 309         struct state *final;            /* final state */
 310         struct state *post;                     /* post-final state */
 311         int                     nstates;                /* for numbering states */
 312         struct state *states;           /* state-chain header */
 313         struct state *slast;            /* tail of the chain */
 314         struct state *free;                     /* free list */
 315         struct colormap *cm;            /* the color map */
 316         color           bos[2];                 /* colors, if any, assigned to BOS and BOL */
 317         color           eos[2];                 /* colors, if any, assigned to EOS and EOL */
 318         struct vars *v;                         /* simplifies compile error reporting */
 319         struct nfa *parent;                     /* parent NFA, if any */
 320 };
 321
 322
 323
 324 /*
 325  * definitions for compacted NFA
 326  */
 327 struct carc
 328 {
 329         color           co;                             /* COLORLESS is list terminator */
 330         int                     to;                             /* state number */
 331 };
 332
 333 struct cnfa
 334 {
 335         int                     nstates;                /* number of states */
 336         int                     ncolors;                /* number of colors */
 337         int                     flags;
 338 #define  HASLACONS       01                     /* uses lookahead constraints */
 339         int                     pre;                    /* setup state number */
 340         int                     post;                   /* teardown state number */
 341         color           bos[2];                 /* colors, if any, assigned to BOS and BOL */
 342         color           eos[2];                 /* colors, if any, assigned to EOS and EOL */
 343         struct carc **states;           /* vector of pointers to outarc lists */
 344         struct carc *arcs;                      /* the area for the lists */
 345 };
 346
 347 #define ZAPCNFA(cnfa)   ((cnfa).nstates = 0)
 348 #define NULLCNFA(cnfa)  ((cnfa).nstates == 0)
 349
 350
 351
 352 /*
 353  * subexpression tree
 354  */
 355 struct subre
 356 {
 357         char            op;                             /* '|', '.' (concat), 'b' (backref), '(',
 358                                                                  * '=' */
 359         char            flags;
 360 #define  LONGER  01                             /* prefers longer match */
 361 #define  SHORTER 02                             /* prefers shorter match */
 362 #define  MIXED   04                             /* mixed preference below */
 363 #define  CAP 010                                /* capturing parens below */
 364 #define  BACKR   020                    /* back reference below */
 365 #define  INUSE   0100                   /* in use in final tree */
 366 #define  LOCAL   03                             /* bits which may not propagate up */
 367 #define  LMIX(f) ((f)<<2)               /* LONGER -> MIXED */
 368 #define  SMIX(f) ((f)<<1)               /* SHORTER -> MIXED */
 369 #define  UP(f)   (((f)&~LOCAL) | (LMIX(f) & SMIX(f) & MIXED))
 370 #define  MESSY(f)        ((f)&(MIXED|CAP|BACKR))
 371 #define  PREF(f) ((f)&LOCAL)
 372 #define  PREF2(f1, f2)   ((PREF(f1) != 0) ? PREF(f1) : PREF(f2))
 373 #define  COMBINE(f1, f2) (UP((f1)|(f2)) | PREF2(f1, f2))
 374         short           retry;                  /* index into retry memory */
 375         int                     subno;                  /* subexpression number (for 'b' and '(') */
 376         short           min;                    /* min repetitions, for backref only */
 377         short           max;                    /* max repetitions, for backref only */
 378         struct subre *left;                     /* left child, if any (also freelist
 379                                                                  * chain) */
 380         struct subre *right;            /* right child, if any */
 381         struct state *begin;            /* outarcs from here... */
 382         struct state *end;                      /* ...ending in inarcs here */
 383         struct cnfa cnfa;                       /* compacted NFA, if any */
 384         struct subre *chain;            /* for bookkeeping and error cleanup */
 385 };
 386
 387
 388
 389 /*
 390  * table of function pointers for generic manipulation functions
 391  * A regex_t's re_fns points to one of these.
 392  */
 393 struct fns
 394 {
 395         void            FUNCPTR(free, (regex_t *));
 396 };
 397
 398
 399
 400 /*
 401  * the insides of a regex_t, hidden behind a void *
 402  */
 403 struct guts
 404 {
 405         int                     magic;
 406 #define  GUTSMAGIC       0xfed9
 407         int                     cflags;                 /* copy of compile flags */
 408         long            info;                   /* copy of re_info */
 409         size_t          nsub;                   /* copy of re_nsub */
 410         struct subre *tree;
 411         struct cnfa search;                     /* for fast preliminary search */
 412         int                     ntree;
 413         struct colormap cmap;
 414         int                     FUNCPTR(compare, (const chr *, const chr *, size_t));
 415         struct subre *lacons;           /* lookahead-constraint vector */
 416         int                     nlacons;                /* size of lacons */
 417 };