text: /*-
   * 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
   */
  
  /*
   * 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	0xf8000000L
  #define	OPDMASK	0x07ffffffL
  #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	(1L<<OPSHIFT)	/* endmarker	-			*/
  #define	OCHAR	(2L<<OPSHIFT)	/* character	unsigned char		*/
  #define	OBOL	(3L<<OPSHIFT)	/* left anchor	-			*/
  #define	OEOL	(4L<<OPSHIFT)	/* right anchor	-			*/
  #define	OANY	(5L<<OPSHIFT)	/* .		-			*/
  #define	OANYOF	(6L<<OPSHIFT)	/* [...]	set number		*/
  #define	OBACK_	(7L<<OPSHIFT)	/* begin \d	paren number		*/
  #define	O_BACK	(8L<<OPSHIFT)	/* end \d	paren number		*/
  #define	OPLUS_	(9L<<OPSHIFT)	/* + prefix	fwd to suffix		*/
  #define	O_PLUS	(10L<<OPSHIFT)	/* + suffix	back to prefix		*/
  #define	OQUEST_	(11L<<OPSHIFT)	/* ? prefix	fwd to suffix		*/
  #define	O_QUEST	(12L<<OPSHIFT)	/* ? suffix	back to prefix		*/
  #define	OLPAREN	(13L<<OPSHIFT)	/* (		fwd to )		*/
  #define	ORPAREN	(14L<<OPSHIFT)	/* )		back to (		*/
  #define	OCH_	(15L<<OPSHIFT)	/* begin choice	fwd to OOR2		*/
  #define	OOR1	(16L<<OPSHIFT)	/* | pt. 1	back to OOR1 or OCH_	*/
  #define	OOR2	(17L<<OPSHIFT)	/* | pt. 2	fwd to OOR2 or O_CH	*/
  #define	O_CH	(18L<<OPSHIFT)	/* end choice	back to OOR1		*/
  #define	OBOW	(19L<<OPSHIFT)	/* begin word	-			*/
  #define	OEOW	(20L<<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 */
  	short hash;             /* hash code */
  	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 */
  #define CHadd(cs, c)    ((cs)->ptr[(uch)(c)] |= (cs)->mask, (cs)->hash += (uch)(c))
  #define CHsub(cs, c)    ((cs)->ptr[(uch)(c)] &= ~(cs)->mask, (cs)->hash -= (uch)(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((uch)(c)) || (c) == '_')
  