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regguts.h

/*
 * Internal interface definitions, etc., for the reg package
 *
 * Copyright (c) 1998, 1999 Henry Spencer.  All rights reserved.
 *
 * Development of this software was funded, in part, by Cray Research Inc.,
 * UUNET Communications Services Inc., Sun Microsystems Inc., and Scriptics
 * Corporation, none of whom are responsible for the results.  The author
 * thanks all of them.
 *
 * Redistribution and use in source and binary forms -- with or without
 * modification -- are permitted for any purpose, provided that
 * redistributions in source form retain this entire copyright notice and
 * indicate the origin and nature of any modifications.
 *
 * I'd appreciate being given credit for this package in the documentation of
 * software which uses it, but that is not a requirement.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
 * HENRY SPENCER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Environmental customization. It should not (I hope) be necessary to alter
 * the file you are now reading -- regcustom.h should handle it all, given
 * care here and elsewhere.
 */
#include "regcustom.h"

/*
 * Things that regcustom.h might override.
 */

/* standard header files (NULL is a reasonable indicator for them) */
#ifndef NULL
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <limits.h>
#include <string.h>
#endif

/* assertions */
#ifndef assert
#ifndef REG_DEBUG
#ifndef NDEBUG
#define     NDEBUG            /* no assertions */
#endif
#endif /* !REG_DEBUG */
#include <assert.h>
#endif

/* voids */
#ifndef VOID
#define     VOID  void        /* for function return values */
#endif
#ifndef DISCARD
#define     DISCARD     void        /* for throwing values away */
#endif
#ifndef PVOID
#define     PVOID void *            /* generic pointer */
#endif
#ifndef VS
#define     VS(x) ((void*)(x))      /* cast something to generic ptr */
#endif
#ifndef NOPARMS
#define     NOPARMS     void        /* for empty parm lists */
#endif

/* const */
#ifndef CONST
#define     CONST const       /* for old compilers, might be empty */
#endif

/* function-pointer declarator */
#ifndef FUNCPTR
#if __STDC__ >= 1
#define     FUNCPTR(name, args)     (*name)args
#else
#define     FUNCPTR(name, args)     (*name)()
#endif
#endif

/* memory allocation */
#ifndef MALLOC
#define     MALLOC(n)   malloc(n)
#endif
#ifndef REALLOC
#define     REALLOC(p, n)     realloc(VS(p), n)
#endif
#ifndef FREE
#define     FREE(p)           free(VS(p))
#endif

/* want size of a char in bits, and max value in bounded quantifiers */
#ifndef CHAR_BIT
#include <limits.h>
#endif
#ifndef _POSIX2_RE_DUP_MAX
#define     _POSIX2_RE_DUP_MAX 255  /* normally from <limits.h> */
#endif

/*
 * misc
 */

#define     NOTREACHED  0
#define     xxx         1

#define     DUPMAX      _POSIX2_RE_DUP_MAX
#define     INFINITY    (DUPMAX+1)

#define     REMAGIC     0xfed7            /* magic number for main struct */

/*
 * debugging facilities
 */
#ifdef REG_DEBUG
/* FDEBUG does finite-state tracing */
#define     FDEBUG(arglist)   { if (v->eflags&REG_FTRACE) printf arglist; }
/* MDEBUG does higher-level tracing */
#define     MDEBUG(arglist)   { if (v->eflags&REG_MTRACE) printf arglist; }
#else
#define     FDEBUG(arglist)   {}
#define     MDEBUG(arglist)   {}
#endif

/*
 * bitmap manipulation
 */
#define     UBITS (CHAR_BIT * sizeof(unsigned))
#define     BSET(uv, sn)      ((uv)[(sn)/UBITS] |= (unsigned)1 << ((sn)%UBITS))
#define     ISBSET(uv, sn)    ((uv)[(sn)/UBITS] & ((unsigned)1 << ((sn)%UBITS)))

/*
 * We dissect a chr into byts for colormap table indexing. Here we define a
 * byt, which will be the same as a byte on most machines... The exact size of
 * a byt is not critical, but about 8 bits is good, and extraction of 8-bit
 * chunks is sometimes especially fast.
 */

#ifndef BYTBITS
#define     BYTBITS     8           /* bits in a byt */
#endif
#define     BYTTAB      (1<<BYTBITS)      /* size of table with one entry per byt value */
#define     BYTMASK     (BYTTAB-1)  /* bit mask for byt */
#define     NBYTS ((CHRBITS+BYTBITS-1)/BYTBITS)
/* the definition of GETCOLOR(), below, assumes NBYTS <= 4 */

/*
 * As soon as possible, we map chrs into equivalence classes -- "colors" --
 * which are of much more manageable number.
 */

typedef short color;          /* colors of characters */
typedef int pcolor;           /* what color promotes to */
#define     COLORLESS   (-1)  /* impossible color */
#define     WHITE       0     /* default color, parent of all others */

/*
 * A colormap is a tree -- more precisely, a DAG -- indexed at each level by a
 * byt of the chr, to map the chr to a color efficiently. Because lower
 * sections of the tree can be shared, it can exploit the usual sparseness of
 * such a mapping table. The tree is always NBYTS levels deep (in the past it
 * was shallower during construction but was "filled" to full depth at the end
 * of that); areas that are unaltered as yet point to "fill blocks" which are
 * entirely WHITE in color.
 */

/* the tree itself */
struct colors {
    color ccolor[BYTTAB];
};
struct ptrs {
    union tree *pptr[BYTTAB];
};
union tree {
    struct colors colors;
    struct ptrs ptrs;
};
#define     tcolor      colors.ccolor
#define     tptr  ptrs.pptr

/* Internal per-color descriptor structure for the color machinery */
struct colordesc {
    uchr nchrs;               /* number of chars of this color */
    color sub;                /* open subcolor (if any); free chain ptr */
#define     NOSUB COLORLESS
    struct arc *arcs;         /* color chain */
    int flags;
#define     FREECOL     01          /* currently free */
#define     PSEUDO      02          /* pseudocolor, no real chars */
#define     UNUSEDCOLOR(cd)   ((cd)->flags&FREECOL)
    union tree *block;        /* block of solid color, if any */
};

/* the color map itself */
struct colormap {
    int magic;
#define     CMMAGIC     0x876
    struct vars *v;           /* for compile error reporting */
    size_t ncds;        /* number of colordescs */
    size_t max;               /* highest in use */
    color free;               /* beginning of free chain (if non-0) */
    struct colordesc *cd;
#define     CDEND(cm)   (&(cm)->cd[(cm)->max + 1])
#define     NINLINECDS  ((size_t)10)
    struct colordesc cdspace[NINLINECDS];
    union tree tree[NBYTS];   /* tree top, plus fill blocks */
};

/* optimization magic to do fast chr->color mapping */
#define     B0(c) ((c) & BYTMASK)
#define     B1(c) (((c)>>BYTBITS) & BYTMASK)
#define     B2(c) (((c)>>(2*BYTBITS)) & BYTMASK)
#define     B3(c) (((c)>>(3*BYTBITS)) & BYTMASK)
#if NBYTS == 1
#define     GETCOLOR(cm, c)   ((cm)->tree->tcolor[B0(c)])
#endif
/* beware, for NBYTS>1, GETCOLOR() is unsafe -- 2nd arg used repeatedly */
#if NBYTS == 2
#define     GETCOLOR(cm, c)   ((cm)->tree->tptr[B1(c)]->tcolor[B0(c)])
#endif
#if NBYTS == 4
#define     GETCOLOR(cm, c)   ((cm)->tree->tptr[B3(c)]->tptr[B2(c)]->tptr[B1(c)]->tcolor[B0(c)])
#endif

/*
 * Interface definitions for locale-interface functions in locale.c.
 */

/* Representation of a set of characters. */
struct cvec {
    int nchrs;                /* number of chrs */
    int chrspace;       /* number of chrs possible */
    chr *chrs;                /* pointer to vector of chrs */
    int nranges;        /* number of ranges (chr pairs) */
    int rangespace;           /* number of chrs possible */
    chr *ranges;        /* pointer to vector of chr pairs */
};

/*
 * definitions for non-deterministic finite autmaton (NFA) internal
 * representation
 *
 * Having a "from" pointer within each arc may seem redundant, but it saves a
 * lot of hassle.
 */

struct state;

struct arc {
    int type;
#define     ARCFREE     '\0'
    color co;
    struct state *from;       /* where it's from (and contained within) */
    struct state *to;         /* where it's to */
    struct arc *outchain;     /* *from's outs chain or free chain */
#define     freechain   outchain
    struct arc *inchain;      /* *to's ins chain */
    struct arc *colorchain;   /* color's arc chain */
    struct arc *colorchainRev;      /* back-link in color's arc chain */
};

struct arcbatch {       /* for bulk allocation of arcs */
    struct arcbatch *next;
#define     ABSIZE      10
    struct arc a[ABSIZE];
};

struct state {
    int no;
#define     FREESTATE   (-1)
    char flag;                /* marks special states */
    int nins;                 /* number of inarcs */
    struct arc *ins;          /* chain of inarcs */
    int nouts;                /* number of outarcs */
    struct arc *outs;         /* chain of outarcs */
    struct arc *free;         /* chain of free arcs */
    struct state *tmp;        /* temporary for traversal algorithms */
    struct state *next;       /* chain for traversing all */
    struct state *prev;       /* back chain */
    struct arcbatch oas;      /* first arcbatch, avoid malloc in easy case */
    int noas;                 /* number of arcs used in first arcbatch */
};

struct nfa {
    struct state *pre;        /* pre-initial state */
    struct state *init;       /* initial state */
    struct state *final;      /* final state */
    struct state *post;       /* post-final state */
    int nstates;        /* for numbering states */
    struct state *states;     /* state-chain header */
    struct state *slast;      /* tail of the chain */
    struct state *free;       /* free list */
    struct colormap *cm;      /* the color map */
    color bos[2];       /* colors, if any, assigned to BOS and BOL */
    color eos[2];       /* colors, if any, assigned to EOS and EOL */
    size_t size;        /* Current NFA size; differs from nstates as
                         * it also counts the number of states created
                         * by children of this state. */
    struct vars *v;           /* simplifies compile error reporting */
    struct nfa *parent;       /* parent NFA, if any */
};

/*
 * definitions for compacted NFA
 */

struct carc {
    color co;                 /* COLORLESS is list terminator */
    int to;             /* state number */
};

struct cnfa {
    int nstates;        /* number of states */
    int ncolors;        /* number of colors */
    int flags;
#define     HASLACONS   01    /* uses lookahead constraints */
    int pre;                  /* setup state number */
    int post;                 /* teardown state number */
    color bos[2];       /* colors, if any, assigned to BOS and BOL */
    color eos[2];       /* colors, if any, assigned to EOS and EOL */
    struct carc **states;     /* vector of pointers to outarc lists */
    struct carc *arcs;        /* the area for the lists */
};
#define     ZAPCNFA(cnfa)     ((cnfa).nstates = 0)
#define     NULLCNFA(cnfa)    ((cnfa).nstates == 0)

/*
 * Used to limit the maximum NFA size to something sane. [Bug 1810264]
 */

#ifndef REG_MAX_STATES
#   define REG_MAX_STATES     100000
#endif

/*
 * subexpression tree
 */

struct subre {
    char op;                  /* '|', '.' (concat), 'b' (backref), '(',
                         * '=' */
    char flags;
#define     LONGER      01          /* prefers longer match */
#define     SHORTER     02          /* prefers shorter match */
#define     MIXED 04          /* mixed preference below */
#define     CAP   010         /* capturing parens below */
#define     BACKR 020         /* back reference below */
#define     INUSE 0100        /* in use in final tree */
#define     LOCAL 03          /* bits which may not propagate up */
#define     LMIX(f)     ((f)<<2)    /* LONGER -> MIXED */
#define     SMIX(f)     ((f)<<1)    /* SHORTER -> MIXED */
#define     UP(f) (((f)&~LOCAL) | (LMIX(f) & SMIX(f) & MIXED))
#define     MESSY(f)    ((f)&(MIXED|CAP|BACKR))
#define     PREF(f)     ((f)&LOCAL)
#define     PREF2(f1, f2)     ((PREF(f1) != 0) ? PREF(f1) : PREF(f2))
#define     COMBINE(f1, f2)   (UP((f1)|(f2)) | PREF2(f1, f2))
    short retry;        /* index into retry memory */
    int subno;                /* subexpression number (for 'b' and '(') */
    short min;                /* min repetitions, for backref only */
    short max;                /* max repetitions, for backref only */
    struct subre *left;       /* left child, if any (also freelist chain) */
    struct subre *right;      /* right child, if any */
    struct state *begin;      /* outarcs from here... */
    struct state *end;        /* ...ending in inarcs here */
    struct cnfa cnfa;         /* compacted NFA, if any */
    struct subre *chain;      /* for bookkeeping and error cleanup */
};

/*
 * table of function pointers for generic manipulation functions. A regex_t's
 * re_fns points to one of these.
 */

struct fns {
    VOID FUNCPTR(free, (regex_t *));
};

/*
 * the insides of a regex_t, hidden behind a void *
 */

struct guts {
    int magic;
#define     GUTSMAGIC   0xfed9
    int cflags;               /* copy of compile flags */
    long info;                /* copy of re_info */
    size_t nsub;        /* copy of re_nsub */
    struct subre *tree;
    struct cnfa search;       /* for fast preliminary search */
    int ntree;
    struct colormap cmap;
    int FUNCPTR(compare, (CONST chr *, CONST chr *, size_t));
    struct subre *lacons;     /* lookahead-constraint vector */
    int nlacons;        /* size of lacons */
};

/*
 * Magic for allocating a variable workspace. This default version is
 * stack-hungry.
 */

#ifndef AllocVars
#define AllocVars(vPtr) \
    struct vars var; \
    register struct vars *vPtr = &var
#endif
#ifndef FreeVars
#define FreeVars(vPtr) ((void) 0)
#endif

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */

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