/*_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
*                                                                          *
* regular.h..                                                              *
*                                                                          *
* Function:..Routine for TWEB                                              *
*                                                                          *
*                                                                          *
*                                                                          *
* Authors:...Dr. Kurt Spanier & Bernhard Winkler,                          *
*            Zentrum fuer Datenverarbeitung, Bereich Entwicklung           *
*            neuer Dienste, Universitaet Tuebingen, GERMANY                *
*                                                                          *
*                                       ZZZZZ  DDD    V   V                *
*            Creation date:                Z   D  D   V   V                *
*            January 20 1998              Z    D   D   V V                 *
*            Last modification:          Z     D  D    V V                 *
*            December 31 1998           ZZZZZ  DDD      V                  *
*                                                                          *
_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_*/
/*
 * $Id: regular.h,v 1.6 1999/09/10 15:01:19 zrnsk01 Exp $
 *
 */

#ifndef _REGULAR_
#define _REGULAR_


/* definition	number	opnd?	meaning */
#define	END	0	/* no	End of program. */
#define	BOL	1	/* no	Match "" at beginning of line. */
#define	EOL	2	/* no	Match "" at end of line. */
#define	ANY	3	/* no	Match any one character. */
#define	ANYOF	4	/* str	Match any character in this string. */
#define	ANYBUT	5	/* str	Match any character not in this string. */
#define	BRANCH	6	/* node	Match this alternative, or the next... */
#define	BACK	7	/* no	Match "", "next" ptr points backward. */
#define	EXACTLY	8	/* str	Match this string. */
#define	NOTHING	9	/* no	Match empty string. */
#define	STAR	10	/* node	Match this (simple) thing 0 or more times. */
#define	PLUS	11	/* node	Match this (simple) thing 1 or more times. */
#define	OPEN	20	/* no	Mark this point in input as start of #n. */
			/*	OPEN+1 is number 1, etc. */
#define	CLOSE	((OPEN)+(NSUBEXP)+1) 	/* no	Analogous to OPEN. */

/*
 * Opcode notes:
 *
 * BRANCH	The set of branches constituting a single choice are hooked
 *		together with their "next" pointers, since precedence prevents
 *		anything being concatenated to any individual branch.  The
 *		"next" pointer of the last BRANCH in a choice points to the
 *		thing following the whole choice.  This is also where the
 *		final "next" pointer of each individual branch points; each
 *		branch starts with the operand node of a BRANCH node.
 *
 * BACK		Normal "next" pointers all implicitly point forward; BACK
 *		exists to make loop structures possible.
 *
 * STAR,PLUS	'?', and complex '*' and '+', are implemented as circular
 *		BRANCH structures using BACK.  Simple cases (one character
 *		per match) are implemented with STAR and PLUS for speed
 *		and to minimize recursive plunges.
 *
 * OPEN,CLOSE	...are numbered at compile time.
 */

/*
 * A node is one char of opcode followed by two chars of "next" pointer.
 * "Next" pointers are stored as two 8-bit pieces, high order first.  The
 * value is a positive offset from the opcode of the node containing it.
 * An operand, if any, simply follows the node.  (Note that much of the
 * code generation knows about this implicit relationship.)
 *
 * Using two bytes for the "next" pointer is vast overkill for most things,
 * but allows patterns to get big without disasters.
 */
#define	OP(p)	(*(p))
#define	NEXT(p)	(((*((p)+1)&0377)<<8) + (*((p)+2)&0377))
#define	OPERAND(p)	((p) + 3)

/*
 * See regmagic.h for one further detail of program structure.
 */


/*
 * Utility definitions.
 */
#ifndef CHARBITS
#define	UCHARAT(p)	((int)*(unsigned char *)(p))
#else
#define	UCHARAT(p)	((int)*(p)&CHARBITS)
#endif

#define	FAIL(m)	{ tweb_regerror(m); return(NULL); }
#define	ISMULT(c)	((c) == '*' || (c) == '+' || (c) == '?')
#define	META	"^$.[()|?+*\\"

/*
 * Flags to be passed up and down.
 */
#define	HASWIDTH	01	/* Known never to match null string. */
#define	SIMPLE		02	/* Simple enough to be STAR/PLUS operand. */
#define	SPSTART		04	/* Starts with * or +. */
#define	WORST		0	/* Worst case. */

/*
 * Global work variables for regcomp().
 */
PRIVATE char *regparse;		/* Input-scan pointer. */
PRIVATE int regnpar;		/* () count. */
PRIVATE char regdummy;
PRIVATE char *regcode;		/* Code-emit pointer; &regdummy = don't. */
PRIVATE long regsize;		/* Code size. */

/*
 * Forward declarations for regcomp()'s friends.
 */
#ifndef STATIC
#define	STATIC	static
#endif
PRIVATE char *tweb_reg();
PRIVATE char *tweb_regbranch();
PRIVATE char *tweb_regpiece();
PRIVATE char *tweb_regatom();
PRIVATE char *tweb_regnode();
PRIVATE char *tweb_regnext();
PRIVATE void tweb_regc();
PRIVATE void tweb_reginsert();
PRIVATE void tweb_regtail();
PRIVATE void tweb_regoptail();
#ifdef STRCSPN
STATIC int tweb_strcspn();
#endif

#endif /* _REGULAR_ */