/*  * This file is part of the UCB release of Plan 9. It is subject to the license * terms in the LICENSE file found in the top-level directory of this * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No * part of the UCB release of Plan 9, including this file, may be copied, * modified, propagated, or distributed except according to the terms contained * in the LICENSE file. */ #include <u.h>#include <libc.h>#include "regexp.h"#include "regcomp.h" /* *  return	0 if no match *		>0 if a match *		<0 if we ran out of _relist space */static intrregexec1(Reprog *progp,	/* program to run */	Rune *bol,		/* string to run machine on */	Resub *mp,		/* subexpression elements */	int ms,			/* number of elements at mp */	Reljunk *j){	int flag=0;	Reinst *inst;	Relist *tlp;	Rune *s;	int i, checkstart;	Rune r, *rp, *ep;	Relist* tl;		/* This list, next list */	Relist* nl;	Relist* tle;		/* ends of this and next list */	Relist* nle;	int match;	Rune *p; 	match = 0;	checkstart = j->startchar;	if(mp)		for(i=0; i<ms; i++) {			mp[i].rsp = 0;			mp[i].rep = 0;		}	j->relist[0][0].inst = 0;	j->relist[1][0].inst = 0; 	/* Execute machine once for each character, including terminal NUL */	s = j->rstarts;	do{		/* fast check for first char */		if(checkstart) {			switch(j->starttype) {			case RUNE:				p = runestrchr(s, j->startchar);				if(p == 0 || s == j->reol)					return match;				s = p;				break;			case BOL:				if(s == bol)					break;				p = runestrchr(s, '\n');				if(p == 0 || s == j->reol)					return match;				s = p+1;				break;			}		} 		r = *s; 		/* switch run lists */		tl = j->relist[flag];		tle = j->reliste[flag];		nl = j->relist[flag^=1];		nle = j->reliste[flag];		nl->inst = 0; 		/* Add first instruction to current list */		_rrenewemptythread(tl, progp->startinst, ms, s); 		/* Execute machine until current list is empty */		for(tlp=tl; tlp->inst; tlp++){			for(inst=tlp->inst; ; inst = inst->next){				switch(inst->type){				case RUNE:	/* regular character */					if(inst->r == r)						if(_renewthread(nl, inst->next, ms, &tlp->se)==nle)							return -1;					break;				case LBRA:					tlp->se.m[inst->subid].rsp = s;					continue;				case RBRA:					tlp->se.m[inst->subid].rep = s;					continue;				case ANY:					if(r != '\n')						if(_renewthread(nl, inst->next, ms, &tlp->se)==nle)							return -1;					break;				case ANYNL:					if(_renewthread(nl, inst->next, ms, &tlp->se)==nle)							return -1;					break;				case BOL:					if(s == bol || *(s-1) == '\n')						continue;					break;				case EOL:					if(s == j->reol || r == 0 || r == '\n')						continue;					break;				case CCLASS:					ep = inst->cp->end;					for(rp = inst->cp->spans; rp < ep; rp += 2)						if(r >= rp[0] && r <= rp[1]){							if(_renewthread(nl, inst->next, ms, &tlp->se)==nle)								return -1;							break;						}					break;				case NCCLASS:					ep = inst->cp->end;					for(rp = inst->cp->spans; rp < ep; rp += 2)						if(r >= rp[0] && r <= rp[1])							break;					if(rp == ep)						if(_renewthread(nl, inst->next, ms, &tlp->se)==nle)							return -1;					break;				case OR:					/* evaluate right choice later */					if(_renewthread(tlp, inst->right, ms, &tlp->se) == tle)						return -1;					/* efficiency: advance and re-evaluate */					continue;				case END:	/* Match! */					match = 1;					tlp->se.m[0].rep = s;					if(mp != 0)						_renewmatch(mp, ms, &tlp->se);					break;				}				break;			}		}		if(s == j->reol)			break;		checkstart = j->startchar && nl->inst==0;		s++;	}while(r);	return match;} static intrregexec2(Reprog *progp,	/* program to run */	Rune *bol,	/* string to run machine on */	Resub *mp,	/* subexpression elements */	int ms,		/* number of elements at mp */	Reljunk *j){	Relist relist0[5*LISTSIZE], relist1[5*LISTSIZE]; 	/* mark space */	j->relist[0] = relist0;	j->relist[1] = relist1;	j->reliste[0] = relist0 + nelem(relist0) - 2;	j->reliste[1] = relist1 + nelem(relist1) - 2; 	return rregexec1(progp, bol, mp, ms, j);} extern intrregexec(Reprog *progp,	/* program to run */	Rune *bol,	/* string to run machine on */	Resub *mp,	/* subexpression elements */	int ms)		/* number of elements at mp */{	Reljunk j;	Relist relist0[LISTSIZE], relist1[LISTSIZE];	int rv; 	/* 	 *  use user-specified starting/ending location if specified	 */	j.rstarts = bol;	j.reol = 0;	if(mp && ms>0){		if(mp->sp)			j.rstarts = mp->rsp;		if(mp->ep)			j.reol = mp->rep;	}	j.starttype = 0;	j.startchar = 0;	if(progp->startinst->type == RUNE && progp->startinst->r < Runeself) {		j.starttype = RUNE;		j.startchar = progp->startinst->r;	}	if(progp->startinst->type == BOL)		j.starttype = BOL; 	/* mark space */	j.relist[0] = relist0;	j.relist[1] = relist1;	j.reliste[0] = relist0 + nelem(relist0) - 2;	j.reliste[1] = relist1 + nelem(relist1) - 2; 	rv = rregexec1(progp, bol, mp, ms, &j);	if(rv >= 0)		return rv;	rv = rregexec2(progp, bol, mp, ms, &j);	if(rv >= 0)		return rv;	return -1;}