/*-
 * Copyright (c) 1992, 1993, 1994 Henry Spencer.
 * Copyright (c) 1992, 1993, 1994
 *		The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Henry Spencer.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *	  notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *	  notice, this list of conditions and the following disclaimer in the
 *	  documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *	  must display the following acknowledgement:
 *		This product includes software developed by the University of
 *		California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *	  may be used to endorse or promote products derived from this software
 *	  without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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.
 *
 *		@(#)regex2.h	8.4 (Berkeley) 3/20/94
 */

#include "postgres.h"

/*
 * 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	((size_t)1<<OPSHIFT)	/* endmarker	-						*/
#define OCHAR	((size_t)2<<OPSHIFT)	/* character	unsigned char			*/
#define OBOL	((size_t)3<<OPSHIFT)	/* left anchor	-						*/
#define OEOL	((size_t)4<<OPSHIFT)	/* right anchor -						*/
#define OANY	((size_t)5<<OPSHIFT)	/* .			-						*/
#define OANYOF	((size_t)6<<OPSHIFT)	/* [...]		set number				*/
#define OBACK_	((size_t)7<<OPSHIFT)	/* begin \d		paren number			*/
#define O_BACK	((size_t)8<<OPSHIFT)	/* end \d		paren number			*/
#define OPLUS_	((size_t)9<<OPSHIFT)	/* + prefix		fwd to suffix			*/
#define O_PLUS	((size_t)10<<OPSHIFT)	/* + suffix		back to prefix			*/
#define OQUEST_ ((size_t)11<<OPSHIFT)	/* ? prefix		fwd to suffix			*/
#define O_QUEST ((size_t)12<<OPSHIFT)	/* ? suffix		back to prefix			*/
#define OLPAREN ((size_t)13<<OPSHIFT)	/* (			fwd to )				*/
#define ORPAREN ((size_t)14<<OPSHIFT)	/* )			back to (				*/
#define OCH_	((size_t)15<<OPSHIFT)	/* begin choice fwd to OOR2				*/
#define OOR1	((size_t)16<<OPSHIFT)	/* | pt. 1		back to OOR1 or
										 * OCH_    */
#define OOR2	((size_t)17<<OPSHIFT)	/* | pt. 2		fwd to OOR2 or
										 * O_CH		*/
#define O_CH	((size_t)18<<OPSHIFT)	/* end choice	back to OOR1			*/
#define OBOW	((size_t)19<<OPSHIFT)	/* begin word	-						*/
#define OEOW	((size_t)20<<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
{
	uch		   *ptr;			/* -> uch [csetsize] */
	uch			mask;			/* bit within array */
#ifdef MULTIBYTE
	pg_wchar	hash;			/* hash code */
	unsigned int lc;			/* leading character (character-set) */
#else
	uch			hash;			/* hash code */
#endif
	size_t		smultis;
	char	   *multis;			/* -> char[smulti]	ab\0cd\0ef\0\0 */
} cset;

/* note that CHadd and CHsub are unsafe, and CHIN doesn't yield 0/1 */
#ifdef MULTIBYTE
#define CHlc(c) (((unsigned)(c)&0xff0000)>>16)
#define CHadd(cs, c)	((cs)->ptr[(unsigned)(c)&0xffff] |= (cs)->mask, (cs)->hash += (unsigned)(c)&0xffff,\
			 (cs)->lc = CHlc(c))
#define CHsub(cs, c)	((cs)->ptr[(unsigned)(c)&0xffff] &= ~(cs)->mask, (cs)->hash -= (unsigned)(c)&0xffff)
#define CHIN(cs, c) ((cs)->ptr[(unsigned)(c)&0xffff] & (cs)->mask && \
			 ((cs)->lc == CHlc(c)))
#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)
#else
#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)
#endif

/* 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] */
	pg_wchar   *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 */
#ifdef MULTIBYTE
#define OUT		  (16777216+1)	/* 16777216 == 2^24 == 3 bytes */
#else
#define OUT		  (CHAR_MAX+1)	/* a non-character value */
#endif

#ifdef MULTIBYTE
#define ISWORD(c)	((c >= 0 && c <= UCHAR_MAX) && \
			 (isalnum(c) || (c) == '_'))
#else
#define ISWORD(c)	(isalnum(c) || (c) == '_')
#endif
