diff options
Diffstat (limited to 'libregexp/regexec.c')
| -rw-r--r-- | libregexp/regexec.c | 232 |
1 files changed, 232 insertions, 0 deletions
diff --git a/libregexp/regexec.c b/libregexp/regexec.c new file mode 100644 index 0000000..b793df6 --- /dev/null +++ b/libregexp/regexec.c @@ -0,0 +1,232 @@ +#include <stdlib.h> +#include "plan9.h" +#include "regexp9.h" +#include "regcomp.h" + + +/* + * return 0 if no match + * >0 if a match + * <0 if we ran out of _relist space + */ +static int +regexec1(Reprog *progp, /* program to run */ + char *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; + char *s; + int i, checkstart; + Rune r, *rp, *ep; + int n; + Relist* tl; /* This list, next list */ + Relist* nl; + Relist* tle; /* ends of this and next list */ + Relist* nle; + int match; + char *p; + + match = 0; + checkstart = j->starttype; + if(mp) + for(i=0; i<ms; i++) { + mp[i].s.sp = 0; + mp[i].e.ep = 0; + } + j->relist[0][0].inst = 0; + j->relist[1][0].inst = 0; + + /* Execute machine once for each character, including terminal NUL */ + s = j->starts; + do{ + /* fast check for first char */ + if(checkstart) { + switch(j->starttype) { + case RUNE: + p = utfrune(s, j->startchar); + if(p == 0 || s == j->eol) + return match; + s = p; + break; + case BOL: + if(s == bol) + break; + p = utfrune(s, '\n'); + if(p == 0 || s == j->eol) + return match; + s = p; + break; + } + } + r = *(uchar*)s; + if(r < Runeself) + n = 1; + else + n = chartorune(&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 */ + if(match == 0) + _renewemptythread(tl, progp->startinst, ms, s); + + /* Execute machine until current list is empty */ + for(tlp=tl; tlp->inst; tlp++){ /* assignment = */ + for(inst = tlp->inst; ; inst = inst->u2.next){ + switch(inst->type){ + case RUNE: /* regular character */ + if(inst->u1.r == r){ + if(_renewthread(nl, inst->u2.next, ms, &tlp->se)==nle) + return -1; + } + break; + case LBRA: + tlp->se.m[inst->u1.subid].s.sp = s; + continue; + case RBRA: + tlp->se.m[inst->u1.subid].e.ep = s; + continue; + case ANY: + if(r != '\n') + if(_renewthread(nl, inst->u2.next, ms, &tlp->se)==nle) + return -1; + break; + case ANYNL: + if(_renewthread(nl, inst->u2.next, ms, &tlp->se)==nle) + return -1; + break; + case BOL: + if(s == bol || *(s-1) == '\n') + continue; + break; + case EOL: + if(s == j->eol || r == 0 || r == '\n') + continue; + break; + case CCLASS: + ep = inst->u1.cp->end; + for(rp = inst->u1.cp->spans; rp < ep; rp += 2) + if(r >= rp[0] && r <= rp[1]){ + if(_renewthread(nl, inst->u2.next, ms, &tlp->se)==nle) + return -1; + break; + } + break; + case NCCLASS: + ep = inst->u1.cp->end; + for(rp = inst->u1.cp->spans; rp < ep; rp += 2) + if(r >= rp[0] && r <= rp[1]) + break; + if(rp == ep) + if(_renewthread(nl, inst->u2.next, ms, &tlp->se)==nle) + return -1; + break; + case OR: + /* evaluate right choice later */ + if(_renewthread(tlp, inst->u1.right, ms, &tlp->se) == tle) + return -1; + /* efficiency: advance and re-evaluate */ + continue; + case END: /* Match! */ + match = 1; + tlp->se.m[0].e.ep = s; + if(mp != 0) + _renewmatch(mp, ms, &tlp->se); + break; + } + break; + } + } + if(s == j->eol) + break; + checkstart = j->starttype && nl->inst==0; + s += n; + }while(r); + return match; +} + +static int +regexec2(Reprog *progp, /* program to run */ + char *bol, /* string to run machine on */ + Resub *mp, /* subexpression elements */ + int ms, /* number of elements at mp */ + Reljunk *j +) +{ + int rv; + Relist *relist0, *relist1; + + /* mark space */ + relist0 = malloc(BIGLISTSIZE*sizeof(Relist)); + if(relist0 == nil) + return -1; + relist1 = malloc(BIGLISTSIZE*sizeof(Relist)); + if(relist1 == nil){ + free(relist1); + return -1; + } + j->relist[0] = relist0; + j->relist[1] = relist1; + j->reliste[0] = relist0 + BIGLISTSIZE - 2; + j->reliste[1] = relist1 + BIGLISTSIZE - 2; + + rv = regexec1(progp, bol, mp, ms, j); + free(relist0); + free(relist1); + return rv; +} + +extern int +regexec(Reprog *progp, /* program to run */ + char *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.starts = bol; + j.eol = 0; + if(mp && ms>0){ + if(mp->s.sp) + j.starts = mp->s.sp; + if(mp->e.ep) + j.eol = mp->e.ep; + } + j.starttype = 0; + j.startchar = 0; + if(progp->startinst->type == RUNE && progp->startinst->u1.r < Runeself) { + j.starttype = RUNE; + j.startchar = progp->startinst->u1.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 = regexec1(progp, bol, mp, ms, &j); + if(rv >= 0) + return rv; + rv = regexec2(progp, bol, mp, ms, &j); + if(rv >= 0) + return rv; + return -1; +} |