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WebSVN – planix.SVN – Blame – /os/branches/feature_posix/sys/src/ape/lib/regexp/regexec.c – Rev 2

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#include <stdlib.h>
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#include <stdio.h>
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#include "regexp.h"
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#include "regcomp.h"
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static Resublist sempty;		/* empty set of matches */
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/*
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 *  return	0 if no match
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 *		>0 if a match
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 *		<0 if we ran out of _relist space
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 */
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static int
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regexec1(Reprog *progp,	/* program to run */
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	char *bol,	/* string to run machine on */
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	Resub *mp,	/* subexpression elements */
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	int ms,		/* number of elements at mp */
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	char *starts,
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	char *eol,
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	wchar_t startchar)
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{
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	int flag=0;
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	Reinst *inst;
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	Relist *tlp;
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	char *s;
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	int i, checkstart;
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	wchar_t r, *rp, *ep;
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	int n;
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	Relist* tl;		/* This list, next list */
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	Relist* nl;
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	Relist* tle;		/* ends of this and next list */
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	Relist* nle;
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	int match;
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	match = 0;
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	checkstart = startchar;
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	sempty.m[0].s.sp = 0;
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	if(mp!=0)
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		for(i=0; i<ms; i++)
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			mp[i].s.sp = mp[i].e.ep = 0;
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	_relist[0][0].inst = _relist[1][0].inst = 0;
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	/* Execute machine once for each character, including terminal NUL */
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	s = starts;
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	do{
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		/* fast check for first char */
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		r = *(unsigned char*)s;
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		if(checkstart && r != startchar){
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			s++;
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			continue;
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		}
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		if(r < Runeself)
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			n = 1;
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		else {
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			n = mbtowc(&r, s, MB_CUR_MAX);
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			if (n <= 0)
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				n = 1;
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		}
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		/* switch run lists */
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		tl = _relist[flag];
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		tle = _reliste[flag];
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		nl = _relist[flag^=1];
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		nle = _reliste[flag];
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		nl->inst = 0;
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		/* Add first instruction to current list */
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		if(match == 0){
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			sempty.m[0].s.sp = s;
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			_renewthread(tl, progp->startinst, &sempty);
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		}
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		/* Execute machine until current list is empty */
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		for(tlp=tl; tlp->inst; tlp++){	/* assignment = */
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			if(s == eol)
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				break;
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			for(inst = tlp->inst; ; inst = inst->l.next){
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				switch(inst->type){
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				case RUNE:	/* regular character */
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					if(inst->r.r == r)
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						if(_renewthread(nl, inst->l.next, &tlp->se)==nle)
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							return -1;
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					break;
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				case LBRA:
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					tlp->se.m[inst->r.subid].s.sp = s;
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					continue;
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				case RBRA:
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					tlp->se.m[inst->r.subid].e.ep = s;
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					continue;
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				case ANY:
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					if(r != '\n')
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						if(_renewthread(nl, inst->l.next, &tlp->se)==nle)
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							return -1;
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					break;
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				case ANYNL:
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					if(_renewthread(nl, inst->l.next, &tlp->se)==nle)
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						return -1;
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					break;
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				case BOL:
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					if(s == bol || *(s-1) == '\n')
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						continue;
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					break;
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				case EOL:
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					if(r == 0 || r == '\n')
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						continue;
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					break;
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				case CCLASS:
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					ep = inst->r.cp->end;
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					for(rp = inst->r.cp->spans; rp < ep; rp += 2)
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						if(r >= rp[0] && r <= rp[1]){
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							if(_renewthread(nl, inst->l.next, &tlp->se)==nle)
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								return -1;
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							break;
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						}
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					break;
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				case NCCLASS:
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					ep = inst->r.cp->end;
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					for(rp = inst->r.cp->spans; rp < ep; rp += 2)
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						if(r >= rp[0] && r <= rp[1])
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							break;
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					if(rp == ep)
124 
						if(_renewthread(nl, inst->l.next, &tlp->se)==nle)
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							return -1;
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					break;
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				case OR:
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					/* evaluate right choice later */
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					if(_renewthread(tlp, inst->r.right, &tlp->se) == tle)
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						return -1;
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					/* efficiency: advance and re-evaluate */
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					continue;
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				case END:	/* Match! */
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					match = 1;
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					tlp->se.m[0].e.ep = s;
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					if(mp != 0)
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						_renewmatch(mp, ms, &tlp->se);
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					break;
139 
				}
140 
				break;
141 
			}
142 
		}
143 
		checkstart = startchar && nl->inst==0;
144 
		s += n;
145 
	}while(r);
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	return match;
147 
}
148 
 
149 
extern int
150 
regexec(Reprog *progp,	/* program to run */
151 
	char *bol,	/* string to run machine on */
152 
	Resub *mp,	/* subexpression elements */
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	int ms)		/* number of elements at mp */
154 
{
155 
	char *starts;	/* where to start match */
156 
	char *eol;	/* where to end match */
157 
	wchar_t startchar;
158 
	int rv;
159 
 
160 
	/*
161 
 	 *  use user-specified starting/ending location if specified
162 
	 */
163 
	starts = bol;
164 
	eol = 0;
165 
	if(mp && ms>0){
166 
		if(mp->s.sp)
167 
			starts = mp->s.sp;
168 
		if(mp->e.ep)
169 
			eol = mp->e.ep;
170 
	}
171 
	startchar = (progp->startinst->type == RUNE && progp->startinst->r.r < Runeself)
172 
		? progp->startinst->r.r : 0;
173 
 
174 
	/* keep trying till we have enough list space to terminate */
175 
	for(;;){
176 
		if(_relist[0] == 0){
177 
			_relist[0] = malloc(2*_relistsize*sizeof(Relist));
178 
			_relist[1] = _relist[0] + _relistsize;
179 
			_reliste[0] = _relist[0] + _relistsize - 1;
180 
			_reliste[1] = _relist[1] + _relistsize - 1;
181 
			if(_relist[0] == 0)
182 
				regerror("_relist overflow");
183 
		}
184 
		rv = regexec1(progp, bol, mp, ms, starts, eol, startchar);
185 
		if(rv >= 0)
186 
			return rv;
187 
		free(_relist[0]);
188 
		_relist[0] = 0;
189 
		_relistsize += LISTINCREMENT;
190 
	}
191 
}