/*

 * 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

#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)	((PVOID)(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 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.

 * Multi-character collating elements (MCCEs) cause most of the trouble.

 */

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 */

	int nmcces;		/* number of MCCEs */

	int mccespace;		/* number of MCCEs possible */

	int nmccechrs;		/* number of chrs used for MCCEs */

	chr *mcces[1];		/* pointers to 0-terminated MCCEs */

				/* and both batches of chrs are on the end */

};

/* caution:  this value cannot be changed easily */

#define	MAXMCCE	2		/* length of longest MCCE */

/*

 * definitions for 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 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 */

	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)

/*

 * 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 */

};