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https://git.suckless.org/9base
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initial import
This commit is contained in:
garbeam@wmii.de
213
lib9/regex/rregexec.c
Normal file
213
lib9/regex/rregexec.c
Normal file
@@ -0,0 +1,213 @@
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#include "lib9.h"
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#include "regexp9.h"
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#include "regcomp.h"
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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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rregexec1(Reprog *progp, /* program to run */
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Rune *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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Reljunk *j)
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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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Rune *s;
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int i, checkstart;
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Rune r, *rp, *ep;
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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 = j->startchar;
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if(mp)
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for(i=0; i<ms; i++) {
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mp[i].s.rsp = 0;
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mp[i].e.rep = 0;
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}
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j->relist[0][0].inst = 0;
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j->relist[1][0].inst = 0;
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/* Execute machine once for each character, including terminal NUL */
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s = j->rstarts;
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do{
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/* fast check for first char */
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if(checkstart) {
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switch(j->starttype) {
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case RUNE:
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while(*s != j->startchar) {
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if(*s == 0 || s == j->reol)
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return match;
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s++;
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}
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break;
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case BOL:
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if(s == bol)
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break;
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while(*s != '\n') {
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if(*s == 0 || s == j->reol)
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return match;
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s++;
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}
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break;
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}
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}
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r = *s;
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/* switch run lists */
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tl = j->relist[flag];
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tle = j->reliste[flag];
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nl = j->relist[flag^=1];
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nle = j->reliste[flag];
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nl->inst = 0;
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/* Add first instruction to current list */
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_rrenewemptythread(tl, progp->startinst, ms, s);
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/* Execute machine until current list is empty */
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for(tlp=tl; tlp->inst; tlp++){
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for(inst=tlp->inst; ; inst = inst->u2.next){
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switch(inst->type){
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case RUNE: /* regular character */
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if(inst->u1.r == r)
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if(_renewthread(nl, inst->u2.next, ms, &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->u1.subid].s.rsp = s;
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continue;
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case RBRA:
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tlp->se.m[inst->u1.subid].e.rep = 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->u2.next, ms, &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->u2.next, ms, &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(s == j->reol || 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->u1.cp->end;
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for(rp = inst->u1.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->u2.next, ms, &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->u1.cp->end;
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for(rp = inst->u1.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)
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if(_renewthread(nl, inst->u2.next, ms, &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->u1.right, ms, &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.rep = s;
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if(mp != 0)
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_renewmatch(mp, ms, &tlp->se);
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break;
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}
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break;
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}
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}
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if(s == j->reol)
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break;
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checkstart = j->startchar && nl->inst==0;
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s++;
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}while(r);
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return match;
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}
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static int
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rregexec2(Reprog *progp, /* program to run */
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Rune *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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Reljunk *j
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)
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{
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Relist relist0[5*LISTSIZE], relist1[5*LISTSIZE];
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/* mark space */
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j->relist[0] = relist0;
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j->relist[1] = relist1;
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j->reliste[0] = relist0 + nelem(relist0) - 2;
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j->reliste[1] = relist1 + nelem(relist1) - 2;
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return rregexec1(progp, bol, mp, ms, j);
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}
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extern int
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rregexec(Reprog *progp, /* program to run */
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Rune *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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{
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Reljunk j;
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Relist relist0[LISTSIZE], relist1[LISTSIZE];
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int rv;
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/*
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* use user-specified starting/ending location if specified
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*/
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j.rstarts = bol;
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j.reol = 0;
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if(mp && ms>0){
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if(mp->s.sp)
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j.rstarts = mp->s.rsp;
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if(mp->e.ep)
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j.reol = mp->e.rep;
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}
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j.starttype = 0;
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j.startchar = 0;
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if(progp->startinst->type == RUNE && progp->startinst->u1.r < Runeself) {
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j.starttype = RUNE;
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j.startchar = progp->startinst->u1.r;
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}
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if(progp->startinst->type == BOL)
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j.starttype = BOL;
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/* mark space */
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j.relist[0] = relist0;
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j.relist[1] = relist1;
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j.reliste[0] = relist0 + nelem(relist0) - 2;
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j.reliste[1] = relist1 + nelem(relist1) - 2;
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rv = rregexec1(progp, bol, mp, ms, &j);
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if(rv >= 0)
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return rv;
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rv = rregexec2(progp, bol, mp, ms, &j);
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if(rv >= 0)
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return rv;
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return -1;
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}
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