/*
Copyright 1992, 1993, 1994, 1997 Henry Spencer.  All rights reserved.
This software is not subject to any license of the American Telephone
and Telegraph Company or of the Regents of the University of California.

Permission is granted to anyone to use this software for any purpose on
any computer system, and to alter it and redistribute it, subject
to the following restrictions:

1. The author is not responsible for the consequences of use of this
   software, no matter how awful, even if they arise from flaws in it.

2. The origin of this software must not be misrepresented, either by
   explicit claim or by omission.  Since few users ever read sources,
   credits must appear in the documentation.

3. Altered versions must be plainly marked as such, and must not be
   misrepresented as being the original software.  Since few users
   ever read sources, credits must appear in the documentation.

4. This notice may not be removed or altered.
*/

/*
 * First, the stuff that ends up in the outside-world include file
 = typedef off_t regoff_t;
 = typedef struct {
 = 	int re_magic;
 = 	size_t re_nsub;		// number of parenthesized subexpressions
 = 	const char *re_endp;	// end pointer for REG_PEND
 = 	struct re_guts *re_g;	// none of your business :-)
 = } regex_t;
 = typedef struct {
 = 	regoff_t rm_so;		// start of match
 = 	regoff_t rm_eo;		// end of match
 = } regmatch_t;
 */
/*
 * internals of regex_t
 */
#define	MAGIC1	((('r'^0200)<<8) | 'e')

/*
 * The internal representation is a *strip*, a sequence of
 * operators ending with an endmarker.  (Some terminology etc. is a
 * historical relic of earlier versions which used multiple strips.)
 * Certain oddities in the representation are there to permit running
 * the machinery backwards; in particular, any deviation from sequential
 * flow must be marked at both its source and its destination.  Some
 * fine points:
 *
 * - OPLUS_ and O_PLUS are *inside* the loop they create.
 * - OQUEST_ and O_QUEST are *outside* the bypass they create.
 * - OCH_ and O_CH are *outside* the multi-way branch they create, while
 *   OOR1 and OOR2 are respectively the end and the beginning of one of
 *   the branches.  Note that there is an implicit OOR2 following OCH_
 *   and an implicit OOR1 preceding O_CH.
 *
 * In state representations, an operator's bit is on to signify a state
 * immediately *preceding* "execution" of that operator.
 */
typedef unsigned long sop;	/* strip operator */
typedef long sopno;
#define	OPRMASK	0xf8000000
#define	OPDMASK	0x07ffffff
#define	OPSHIFT	((unsigned)27)
#define	OP(n)	((n)&OPRMASK)
#define	OPND(n)	((n)&OPDMASK)
#define	SOP(op, opnd)	((op)|(opnd))
/* operators			   meaning	operand			*/
/*						(back, fwd are offsets)	*/
#define	OEND	(1U<<OPSHIFT)	/* endmarker	-			*/
#define	OCHAR	(2U<<OPSHIFT)	/* character	unsigned char		*/
#define	OBOL	(3U<<OPSHIFT)	/* left anchor	-			*/
#define	OEOL	(4U<<OPSHIFT)	/* right anchor	-			*/
#define	OANY	(5U<<OPSHIFT)	/* .		-			*/
#define	OANYOF	(6U<<OPSHIFT)	/* [...]	set number		*/
#define	OBACK_	(7U<<OPSHIFT)	/* begin \d	paren number		*/
#define	O_BACK	(8U<<OPSHIFT)	/* end \d	paren number		*/
#define	OPLUS_	(9U<<OPSHIFT)	/* + prefix	fwd to suffix		*/
#define	O_PLUS	(10U<<OPSHIFT)	/* + suffix	back to prefix		*/
#define	OQUEST_	(11U<<OPSHIFT)	/* ? prefix	fwd to suffix		*/
#define	O_QUEST	(12U<<OPSHIFT)	/* ? suffix	back to prefix		*/
#define	OLPAREN	(13U<<OPSHIFT)	/* (		fwd to )		*/
#define	ORPAREN	(14U<<OPSHIFT)	/* )		back to (		*/
#define	OCH_	(15U<<OPSHIFT)	/* begin choice	fwd to OOR2		*/
#define	OOR1	(16U<<OPSHIFT)	/* | pt. 1	back to OOR1 or OCH_	*/
#define	OOR2	(17U<<OPSHIFT)	/* | pt. 2	fwd to OOR2 or O_CH	*/
#define	O_CH	(18U<<OPSHIFT)	/* end choice	back to OOR1		*/
#define	OBOW	(19U<<OPSHIFT)	/* begin word	-			*/
#define	OEOW	(20U<<OPSHIFT)	/* end word	-			*/

/*
 * Structure for [] character-set representation.  Character sets are
 * done as bit vectors, grouped 8 to a byte vector for compactness.
 * The individual set therefore has both a pointer to the byte vector
 * and a mask to pick out the relevant bit of each byte.  A hash code
 * simplifies testing whether two sets could be identical.
 *
 * This will get trickier for multicharacter collating elements.  As
 * preliminary hooks for dealing with such things, we also carry along
 * a string of multi-character elements, and decide the size of the
 * vectors at run time.
 */
typedef struct {
	size_t smultis;
	char *multis;		/* -> char[smulti]  ab\0cd\0ef\0\0 */
	uch *ptr;		/* -> uch [csetsize] */
	uch mask;		/* bit within array */
	uch hash;		/* hash code */
} cset;
/* note that CHadd and CHsub are unsafe, and CHIN doesn't yield 0/1 */
#define	CHadd(cs, c)	((cs)->ptr[(uch)(c)] |= (cs)->mask, (cs)->hash += (c))
#define	CHsub(cs, c)	((cs)->ptr[(uch)(c)] &= ~(cs)->mask, (cs)->hash -= (c))
#define	CHIN(cs, c)	((cs)->ptr[(uch)(c)] & (cs)->mask)
#define	MCadd(p, cs, cp)	mcadd(p, cs, cp)	/* regcomp() internal fns */
#define	MCsub(p, cs, cp)	mcsub(p, cs, cp)
#define	MCin(p, cs, cp)	mcin(p, cs, cp)

/* stuff for character categories */
typedef unsigned char cat_t;

/*
 * main compiled-expression structure
 */
struct re_guts {
	int magic;
#		define	MAGIC2	((('R'^0200)<<8)|'E')
	sop *strip;		/* malloced area for strip */
	int csetsize;		/* number of bits in a cset vector */
	int ncsets;		/* number of csets in use */
	cset *sets;		/* -> cset [ncsets] */
	uch *setbits;		/* -> uch[csetsize][ncsets/CHAR_BIT] */
	int cflags;		/* copy of regcomp() cflags argument */
	sopno nstates;		/* = number of sops */
	sopno firststate;	/* the initial OEND (normally 0) */
	sopno laststate;	/* the final OEND */
	int iflags;		/* internal flags */
#		define	USEBOL	01	/* used ^ */
#		define	USEEOL	02	/* used $ */
#		define	BAD	04	/* something wrong */
	int nbol;		/* number of ^ used */
	int neol;		/* number of $ used */
	int ncategories;	/* how many character categories */
	cat_t *categories;	/* ->catspace[-CHAR_MIN] */
	char *must;		/* match must contain this string */
	int mlen;		/* length of must */
	size_t nsub;		/* copy of re_nsub */
	int backrefs;		/* does it use back references? */
	sopno nplus;		/* how deep does it nest +s? */
	/* catspace must be last */
	cat_t catspace[1];	/* actually [NC] */
};

/* misc utilities */
#define	OUT	(CHAR_MAX+1)	/* a non-character value */
#define	ISWORD(c)	(isalnum(c) || (c) == '_')

/* __SRCVERSION("regex2.h $Rev: 153052 $"); */
