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Diffstat (limited to 'regex/engine.c')
| -rw-r--r-- | regex/engine.c | 1019 |
1 files changed, 1019 insertions, 0 deletions
diff --git a/regex/engine.c b/regex/engine.c new file mode 100644 index 0000000..919fe3f --- /dev/null +++ b/regex/engine.c @@ -0,0 +1,1019 @@ +/* + * The matching engine and friends. This file is #included by regexec.c + * after suitable #defines of a variety of macros used herein, so that + * different state representations can be used without duplicating masses + * of code. + */ + +#ifdef SNAMES +#define matcher smatcher +#define fast sfast +#define slow sslow +#define dissect sdissect +#define backref sbackref +#define step sstep +#define print sprint +#define at sat +#define match smat +#endif +#ifdef LNAMES +#define matcher lmatcher +#define fast lfast +#define slow lslow +#define dissect ldissect +#define backref lbackref +#define step lstep +#define print lprint +#define at lat +#define match lmat +#endif + +/* another structure passed up and down to avoid zillions of parameters */ +struct match { + struct re_guts *g; + int eflags; + regmatch_t *pmatch; /* [nsub+1] (0 element unused) */ + char *offp; /* offsets work from here */ + char *beginp; /* start of string -- virtual NUL precedes */ + char *endp; /* end of string -- virtual NUL here */ + char *coldp; /* can be no match starting before here */ + char **lastpos; /* [nplus+1] */ + STATEVARS; + states st; /* current states */ + states fresh; /* states for a fresh start */ + states tmp; /* temporary */ + states empty; /* empty set of states */ +}; + +#include "engine.ih" + +#ifdef REDEBUG +#define SP(t, s, c) print(m, t, s, c, stdout) +#define AT(t, p1, p2, s1, s2) at(m, t, p1, p2, s1, s2) +#define NOTE(str) { if (m->eflags®_TRACE) printf("=%s\n", (str)); } +#else +#define SP(t, s, c) /* nothing */ +#define AT(t, p1, p2, s1, s2) /* nothing */ +#define NOTE(s) /* nothing */ +#endif + +/* + - matcher - the actual matching engine + == static int matcher(register struct re_guts *g, char *string, \ + == size_t nmatch, regmatch_t pmatch[], int eflags); + */ +static int /* 0 success, REG_NOMATCH failure */ +matcher(g, string, nmatch, pmatch, eflags) +register struct re_guts *g; +char *string; +size_t nmatch; +regmatch_t pmatch[]; +int eflags; +{ + register char *endp; + register int i; + struct match mv; + register struct match *m = &mv; + register char *dp; + const register sopno gf = g->firststate+1; /* +1 for OEND */ + const register sopno gl = g->laststate; + char *start; + char *stop; + + /* simplify the situation where possible */ + if (g->cflags®_NOSUB) + nmatch = 0; + if (eflags®_STARTEND) { + start = string + pmatch[0].rm_so; + stop = string + pmatch[0].rm_eo; + } else { + start = string; + stop = start + strlen(start); + } + if (stop < start) + return(REG_INVARG); + + /* prescreening; this does wonders for this rather slow code */ + if (g->must != NULL) { + for (dp = start; dp < stop; dp++) + if (*dp == g->must[0] && stop - dp >= g->mlen && + memcmp(dp, g->must, (size_t)g->mlen) == 0) + break; + if (dp == stop) /* we didn't find g->must */ + return(REG_NOMATCH); + } + + /* match struct setup */ + m->g = g; + m->eflags = eflags; + m->pmatch = NULL; + m->lastpos = NULL; + m->offp = string; + m->beginp = start; + m->endp = stop; + STATESETUP(m, 4); + SETUP(m->st); + SETUP(m->fresh); + SETUP(m->tmp); + SETUP(m->empty); + CLEAR(m->empty); + + /* this loop does only one repetition except for backrefs */ + for (;;) { + endp = fast(m, start, stop, gf, gl); + if (endp == NULL) { /* a miss */ + STATETEARDOWN(m); + return(REG_NOMATCH); + } + if (nmatch == 0 && !g->backrefs) + break; /* no further info needed */ + + /* where? */ + assert(m->coldp != NULL); + for (;;) { + NOTE("finding start"); + endp = slow(m, m->coldp, stop, gf, gl); + if (endp != NULL) + break; + assert(m->coldp < m->endp); + m->coldp++; + } + if (nmatch == 1 && !g->backrefs) + break; /* no further info needed */ + + /* oh my, he wants the subexpressions... */ + if (m->pmatch == NULL) + m->pmatch = (regmatch_t *)malloc((m->g->nsub + 1) * + sizeof(regmatch_t)); + if (m->pmatch == NULL) { + STATETEARDOWN(m); + return(REG_ESPACE); + } + for (i = 1; i <= m->g->nsub; i++) + m->pmatch[i].rm_so = m->pmatch[i].rm_eo = -1; + if (!g->backrefs && !(m->eflags®_BACKR)) { + NOTE("dissecting"); + dp = dissect(m, m->coldp, endp, gf, gl); + } else { + if (g->nplus > 0 && m->lastpos == NULL) + m->lastpos = (char **)malloc((g->nplus+1) * + sizeof(char *)); + if (g->nplus > 0 && m->lastpos == NULL) { + free(m->pmatch); + STATETEARDOWN(m); + return(REG_ESPACE); + } + NOTE("backref dissect"); + dp = backref(m, m->coldp, endp, gf, gl, (sopno)0); + } + if (dp != NULL) + break; + + /* uh-oh... we couldn't find a subexpression-level match */ + assert(g->backrefs); /* must be back references doing it */ + assert(g->nplus == 0 || m->lastpos != NULL); + for (;;) { + if (dp != NULL || endp <= m->coldp) + break; /* defeat */ + NOTE("backoff"); + endp = slow(m, m->coldp, endp-1, gf, gl); + if (endp == NULL) + break; /* defeat */ + /* try it on a shorter possibility */ +#ifndef NDEBUG + for (i = 1; i <= m->g->nsub; i++) { + assert(m->pmatch[i].rm_so == -1); + assert(m->pmatch[i].rm_eo == -1); + } +#endif + NOTE("backoff dissect"); + dp = backref(m, m->coldp, endp, gf, gl, (sopno)0); + } + assert(dp == NULL || dp == endp); + if (dp != NULL) /* found a shorter one */ + break; + + /* despite initial appearances, there is no match here */ + NOTE("false alarm"); + start = m->coldp + 1; /* recycle starting later */ + assert(start <= stop); + } + + /* fill in the details if requested */ + if (nmatch > 0) { + pmatch[0].rm_so = m->coldp - m->offp; + pmatch[0].rm_eo = endp - m->offp; + } + if (nmatch > 1) { + assert(m->pmatch != NULL); + for (i = 1; i < nmatch; i++) + if (i <= m->g->nsub) + pmatch[i] = m->pmatch[i]; + else { + pmatch[i].rm_so = -1; + pmatch[i].rm_eo = -1; + } + } + + if (m->pmatch != NULL) + free((char *)m->pmatch); + if (m->lastpos != NULL) + free((char *)m->lastpos); + STATETEARDOWN(m); + return(0); +} + +/* + - dissect - figure out what matched what, no back references + == static char *dissect(register struct match *m, char *start, \ + == char *stop, sopno startst, sopno stopst); + */ +static char * /* == stop (success) always */ +dissect(m, start, stop, startst, stopst) +register struct match *m; +char *start; +char *stop; +sopno startst; +sopno stopst; +{ + register int i; + register sopno ss; /* start sop of current subRE */ + register sopno es; /* end sop of current subRE */ + register char *sp; /* start of string matched by it */ + register char *stp; /* string matched by it cannot pass here */ + register char *rest; /* start of rest of string */ + register char *tail; /* string unmatched by rest of RE */ + register sopno ssub; /* start sop of subsubRE */ + register sopno esub; /* end sop of subsubRE */ + register char *ssp; /* start of string matched by subsubRE */ + register char *sep; /* end of string matched by subsubRE */ + register char *oldssp; /* previous ssp */ + register char *dp; + + AT("diss", start, stop, startst, stopst); + sp = start; + for (ss = startst; ss < stopst; ss = es) { + /* identify end of subRE */ + es = ss; + switch (OP(m->g->strip[es])) { + case OPLUS_: + case OQUEST_: + es += OPND(m->g->strip[es]); + break; + case OCH_: + while (OP(m->g->strip[es]) != O_CH) + es += OPND(m->g->strip[es]); + break; + } + es++; + + /* figure out what it matched */ + switch (OP(m->g->strip[ss])) { + case OEND: + assert(nope); + break; + case OCHAR: + sp++; + break; + case OBOL: + case OEOL: + case OBOW: + case OEOW: + break; + case OANY: + case OANYOF: + sp++; + break; + case OBACK_: + case O_BACK: + assert(nope); + break; + /* cases where length of match is hard to find */ + case OQUEST_: + stp = stop; + for (;;) { + /* how long could this one be? */ + rest = slow(m, sp, stp, ss, es); + assert(rest != NULL); /* it did match */ + /* could the rest match the rest? */ + tail = slow(m, rest, stop, es, stopst); + if (tail == stop) + break; /* yes! */ + /* no -- try a shorter match for this one */ + stp = rest - 1; + assert(stp >= sp); /* it did work */ + } + ssub = ss + 1; + esub = es - 1; + /* did innards match? */ + if (slow(m, sp, rest, ssub, esub) != NULL) { + dp = dissect(m, sp, rest, ssub, esub); + assert(dp == rest); + } else /* no */ + assert(sp == rest); + sp = rest; + break; + case OPLUS_: + stp = stop; + for (;;) { + /* how long could this one be? */ + rest = slow(m, sp, stp, ss, es); + assert(rest != NULL); /* it did match */ + /* could the rest match the rest? */ + tail = slow(m, rest, stop, es, stopst); + if (tail == stop) + break; /* yes! */ + /* no -- try a shorter match for this one */ + stp = rest - 1; + assert(stp >= sp); /* it did work */ + } + ssub = ss + 1; + esub = es - 1; + ssp = sp; + oldssp = ssp; + for (;;) { /* find last match of innards */ + sep = slow(m, ssp, rest, ssub, esub); + if (sep == NULL || sep == ssp) + break; /* failed or matched null */ + oldssp = ssp; /* on to next try */ + ssp = sep; + } + if (sep == NULL) { + /* last successful match */ + sep = ssp; + ssp = oldssp; + } + assert(sep == rest); /* must exhaust substring */ + assert(slow(m, ssp, sep, ssub, esub) == rest); + dp = dissect(m, ssp, sep, ssub, esub); + assert(dp == sep); + sp = rest; + break; + case OCH_: + stp = stop; + for (;;) { + /* how long could this one be? */ + rest = slow(m, sp, stp, ss, es); + assert(rest != NULL); /* it did match */ + /* could the rest match the rest? */ + tail = slow(m, rest, stop, es, stopst); + if (tail == stop) + break; /* yes! */ + /* no -- try a shorter match for this one */ + stp = rest - 1; + assert(stp >= sp); /* it did work */ + } + ssub = ss + 1; + esub = ss + OPND(m->g->strip[ss]) - 1; + assert(OP(m->g->strip[esub]) == OOR1); + for (;;) { /* find first matching branch */ + if (slow(m, sp, rest, ssub, esub) == rest) + break; /* it matched all of it */ + /* that one missed, try next one */ + assert(OP(m->g->strip[esub]) == OOR1); + esub++; + assert(OP(m->g->strip[esub]) == OOR2); + ssub = esub + 1; + esub += OPND(m->g->strip[esub]); + if (OP(m->g->strip[esub]) == OOR2) + esub--; + else + assert(OP(m->g->strip[esub]) == O_CH); + } + dp = dissect(m, sp, rest, ssub, esub); + assert(dp == rest); + sp = rest; + break; + case O_PLUS: + case O_QUEST: + case OOR1: + case OOR2: + case O_CH: + assert(nope); + break; + case OLPAREN: + i = OPND(m->g->strip[ss]); + assert(0 < i && i <= m->g->nsub); + m->pmatch[i].rm_so = sp - m->offp; + break; + case ORPAREN: + i = OPND(m->g->strip[ss]); + assert(0 < i && i <= m->g->nsub); + m->pmatch[i].rm_eo = sp - m->offp; + break; + default: /* uh oh */ + assert(nope); + break; + } + } + + assert(sp == stop); + return(sp); +} + +/* + - backref - figure out what matched what, figuring in back references + == static char *backref(register struct match *m, char *start, \ + == char *stop, sopno startst, sopno stopst, sopno lev); + */ +static char * /* == stop (success) or NULL (failure) */ +backref(m, start, stop, startst, stopst, lev) +register struct match *m; +char *start; +char *stop; +sopno startst; +sopno stopst; +sopno lev; /* PLUS nesting level */ +{ + register int i; + register sopno ss; /* start sop of current subRE */ + register char *sp; /* start of string matched by it */ + register sopno ssub; /* start sop of subsubRE */ + register sopno esub; /* end sop of subsubRE */ + register char *ssp; /* start of string matched by subsubRE */ + register char *dp; + register size_t len; + register int hard; + register sop s; + register regoff_t offsave; + register cset *cs; + + AT("back", start, stop, startst, stopst); + sp = start; + + /* get as far as we can with easy stuff */ + hard = 0; + for (ss = startst; !hard && ss < stopst; ss++) + switch (OP(s = m->g->strip[ss])) { + case OCHAR: + if (sp == stop || *sp++ != (char)OPND(s)) + return(NULL); + break; + case OANY: + if (sp == stop) + return(NULL); + sp++; + break; + case OANYOF: + cs = &m->g->sets[OPND(s)]; + if (sp == stop || !CHIN(cs, *sp++)) + return(NULL); + break; + case OBOL: + if ( (sp == m->beginp && !(m->eflags®_NOTBOL)) || + (sp < m->endp && *(sp-1) == '\n' && + (m->g->cflags®_NEWLINE)) ) + { /* yes */ } + else + return(NULL); + break; + case OEOL: + if ( (sp == m->endp && !(m->eflags®_NOTEOL)) || + (sp < m->endp && *sp == '\n' && + (m->g->cflags®_NEWLINE)) ) + { /* yes */ } + else + return(NULL); + break; + case OBOW: + if (( (sp == m->beginp && !(m->eflags®_NOTBOL)) || + (sp < m->endp && *(sp-1) == '\n' && + (m->g->cflags®_NEWLINE)) || + (sp > m->beginp && + !ISWORD(*(sp-1))) ) && + (sp < m->endp && ISWORD(*sp)) ) + { /* yes */ } + else + return(NULL); + break; + case OEOW: + if (( (sp == m->endp && !(m->eflags®_NOTEOL)) || + (sp < m->endp && *sp == '\n' && + (m->g->cflags®_NEWLINE)) || + (sp < m->endp && !ISWORD(*sp)) ) && + (sp > m->beginp && ISWORD(*(sp-1))) ) + { /* yes */ } + else + return(NULL); + break; + case O_QUEST: + break; + case OOR1: /* matches null but needs to skip */ + ss++; + s = m->g->strip[ss]; + do { + assert(OP(s) == OOR2); + ss += OPND(s); + } while (OP(s = m->g->strip[ss]) != O_CH); + /* note that the ss++ gets us past the O_CH */ + break; + default: /* have to make a choice */ + hard = 1; + break; + } + if (!hard) { /* that was it! */ + if (sp != stop) + return(NULL); + return(sp); + } + ss--; /* adjust for the for's final increment */ + + /* the hard stuff */ + AT("hard", sp, stop, ss, stopst); + s = m->g->strip[ss]; + switch (OP(s)) { + case OBACK_: /* the vilest depths */ + i = OPND(s); + assert(0 < i && i <= m->g->nsub); + if (m->pmatch[i].rm_eo == -1) + return(NULL); + assert(m->pmatch[i].rm_so != -1); + len = m->pmatch[i].rm_eo - m->pmatch[i].rm_so; + assert(stop - m->beginp >= len); + if (sp > stop - len) + return(NULL); /* not enough left to match */ + ssp = m->offp + m->pmatch[i].rm_so; + if (memcmp(sp, ssp, len) != 0) + return(NULL); + while (m->g->strip[ss] != SOP(O_BACK, i)) + ss++; + return(backref(m, sp+len, stop, ss+1, stopst, lev)); + break; + case OQUEST_: /* to null or not */ + dp = backref(m, sp, stop, ss+1, stopst, lev); + if (dp != NULL) + return(dp); /* not */ + return(backref(m, sp, stop, ss+OPND(s)+1, stopst, lev)); + break; + case OPLUS_: + assert(m->lastpos != NULL); + assert(lev+1 <= m->g->nplus); + m->lastpos[lev+1] = sp; + return(backref(m, sp, stop, ss+1, stopst, lev+1)); + break; + case O_PLUS: + if (sp == m->lastpos[lev]) /* last pass matched null */ + return(backref(m, sp, stop, ss+1, stopst, lev-1)); + /* try another pass */ + m->lastpos[lev] = sp; + dp = backref(m, sp, stop, ss-OPND(s)+1, stopst, lev); + if (dp == NULL) + return(backref(m, sp, stop, ss+1, stopst, lev-1)); + else + return(dp); + break; + case OCH_: /* find the right one, if any */ + ssub = ss + 1; + esub = ss + OPND(s) - 1; + assert(OP(m->g->strip[esub]) == OOR1); + for (;;) { /* find first matching branch */ + dp = backref(m, sp, stop, ssub, esub, lev); + if (dp != NULL) + return(dp); + /* that one missed, try next one */ + if (OP(m->g->strip[esub]) == O_CH) + return(NULL); /* there is none */ + esub++; + assert(OP(m->g->strip[esub]) == OOR2); + ssub = esub + 1; + esub += OPND(m->g->strip[esub]); + if (OP(m->g->strip[esub]) == OOR2) + esub--; + else + assert(OP(m->g->strip[esub]) == O_CH); + } + break; + case OLPAREN: /* must undo assignment if rest fails */ + i = OPND(s); + assert(0 < i && i <= m->g->nsub); + offsave = m->pmatch[i].rm_so; + m->pmatch[i].rm_so = sp - m->offp; + dp = backref(m, sp, stop, ss+1, stopst, lev); + if (dp != NULL) + return(dp); + m->pmatch[i].rm_so = offsave; + return(NULL); + break; + case ORPAREN: /* must undo assignment if rest fails */ + i = OPND(s); + assert(0 < i && i <= m->g->nsub); + offsave = m->pmatch[i].rm_eo; + m->pmatch[i].rm_eo = sp - m->offp; + dp = backref(m, sp, stop, ss+1, stopst, lev); + if (dp != NULL) + return(dp); + m->pmatch[i].rm_eo = offsave; + return(NULL); + break; + default: /* uh oh */ + assert(nope); + break; + } + + /* "can't happen" */ + assert(nope); + /* NOTREACHED */ + return((char *)NULL); /* dummy */ +} + +/* + - fast - step through the string at top speed + == static char *fast(register struct match *m, char *start, \ + == char *stop, sopno startst, sopno stopst); + */ +static char * /* where tentative match ended, or NULL */ +fast(m, start, stop, startst, stopst) +register struct match *m; +char *start; +char *stop; +sopno startst; +sopno stopst; +{ + register states st = m->st; + register states fresh = m->fresh; + register states tmp = m->tmp; + register char *p = start; + register int c = (start == m->beginp) ? OUT : *(start-1); + register int lastc; /* previous c */ + register int flagch; + register int i; + register char *coldp; /* last p after which no match was underway */ + + CLEAR(st); + SET1(st, startst); + st = step(m->g, startst, stopst, st, NOTHING, st); + ASSIGN(fresh, st); + SP("start", st, *p); + coldp = NULL; + for (;;) { + /* next character */ + lastc = c; + c = (p == m->endp) ? OUT : *p; + if (EQ(st, fresh)) + coldp = p; + + /* is there an EOL and/or BOL between lastc and c? */ + flagch = '\0'; + i = 0; + if ( (lastc == '\n' && m->g->cflags®_NEWLINE) || + (lastc == OUT && !(m->eflags®_NOTBOL)) ) { + flagch = BOL; + i = m->g->nbol; + } + if ( (c == '\n' && m->g->cflags®_NEWLINE) || + (c == OUT && !(m->eflags®_NOTEOL)) ) { + flagch = (flagch == BOL) ? BOLEOL : EOL; + i += m->g->neol; + } + if (i != 0) { + for (; i > 0; i--) + st = step(m->g, startst, stopst, st, flagch, st); + SP("boleol", st, c); + } + + /* how about a word boundary? */ + if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) && + (c != OUT && ISWORD(c)) ) { + flagch = BOW; + } + if ( (lastc != OUT && ISWORD(lastc)) && + (flagch == EOL || (c != OUT && !ISWORD(c))) ) { + flagch = EOW; + } + if (flagch == BOW || flagch == EOW) { + st = step(m->g, startst, stopst, st, flagch, st); + SP("boweow", st, c); + } + + /* are we done? */ + if (ISSET(st, stopst) || p == stop) + break; /* NOTE BREAK OUT */ + + /* no, we must deal with this character */ + ASSIGN(tmp, st); + ASSIGN(st, fresh); + assert(c != OUT); + st = step(m->g, startst, stopst, tmp, c, st); + SP("aft", st, c); + assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st)); + p++; + } + + assert(coldp != NULL); + m->coldp = coldp; + if (ISSET(st, stopst)) + return(p+1); + else + return(NULL); +} + +/* + - slow - step through the string more deliberately + == static char *slow(register struct match *m, char *start, \ + == char *stop, sopno startst, sopno stopst); + */ +static char * /* where it ended */ +slow(m, start, stop, startst, stopst) +register struct match *m; +char *start; +char *stop; +sopno startst; +sopno stopst; +{ + register states st = m->st; + register states empty = m->empty; + register states tmp = m->tmp; + register char *p = start; + register int c = (start == m->beginp) ? OUT : *(start-1); + register int lastc; /* previous c */ + register int flagch; + register int i; + register char *matchp; /* last p at which a match ended */ + + AT("slow", start, stop, startst, stopst); + CLEAR(st); + SET1(st, startst); + SP("sstart", st, *p); + st = step(m->g, startst, stopst, st, NOTHING, st); + matchp = NULL; + for (;;) { + /* next character */ + lastc = c; + c = (p == m->endp) ? OUT : *p; + + /* is there an EOL and/or BOL between lastc and c? */ + flagch = '\0'; + i = 0; + if ( (lastc == '\n' && m->g->cflags®_NEWLINE) || + (lastc == OUT && !(m->eflags®_NOTBOL)) ) { + flagch = BOL; + i = m->g->nbol; + } + if ( (c == '\n' && m->g->cflags®_NEWLINE) || + (c == OUT && !(m->eflags®_NOTEOL)) ) { + flagch = (flagch == BOL) ? BOLEOL : EOL; + i += m->g->neol; + } + if (i != 0) { + for (; i > 0; i--) + st = step(m->g, startst, stopst, st, flagch, st); + SP("sboleol", st, c); + } + + /* how about a word boundary? */ + if ( (flagch == BOL || (lastc != OUT && !ISWORD(lastc))) && + (c != OUT && ISWORD(c)) ) { + flagch = BOW; + } + if ( (lastc != OUT && ISWORD(lastc)) && + (flagch == EOL || (c != OUT && !ISWORD(c))) ) { + flagch = EOW; + } + if (flagch == BOW || flagch == EOW) { + st = step(m->g, startst, stopst, st, flagch, st); + SP("sboweow", st, c); + } + + /* are we done? */ + if (ISSET(st, stopst)) + matchp = p; + if (EQ(st, empty) || p == stop) + break; /* NOTE BREAK OUT */ + + /* no, we must deal with this character */ + ASSIGN(tmp, st); + ASSIGN(st, empty); + assert(c != OUT); + st = step(m->g, startst, stopst, tmp, c, st); + SP("saft", st, c); + assert(EQ(step(m->g, startst, stopst, st, NOTHING, st), st)); + p++; + } + + return(matchp); +} + + +/* + - step - map set of states reachable before char to set reachable after + == static states step(register struct re_guts *g, sopno start, sopno stop, \ + == register states bef, int ch, register states aft); + == #define BOL (OUT+1) + == #define EOL (BOL+1) + == #define BOLEOL (BOL+2) + == #define NOTHING (BOL+3) + == #define BOW (BOL+4) + == #define EOW (BOL+5) + == #define CODEMAX (BOL+5) // highest code used + == #define NONCHAR(c) ((c) > CHAR_MAX) + == #define NNONCHAR (CODEMAX-CHAR_MAX) + */ +static states +step(g, start, stop, bef, ch, aft) +register struct re_guts *g; +sopno start; /* start state within strip */ +sopno stop; /* state after stop state within strip */ +register states bef; /* states reachable before */ +int ch; /* character or NONCHAR code */ +register states aft; /* states already known reachable after */ +{ + register cset *cs; + register sop s; + register sopno pc; + register onestate here; /* note, macros know this name */ + register sopno look; + register long i; + + for (pc = start, INIT(here, pc); pc != stop; pc++, INC(here)) { + s = g->strip[pc]; + switch (OP(s)) { + case OEND: + assert(pc == stop-1); + break; + case OCHAR: + /* only characters can match */ + assert(!NONCHAR(ch) || ch != (char)OPND(s)); + if (ch == (char)OPND(s)) + FWD(aft, bef, 1); + break; + case OBOL: + if (ch == BOL || ch == BOLEOL) + FWD(aft, bef, 1); + break; + case OEOL: + if (ch == EOL || ch == BOLEOL) + FWD(aft, bef, 1); + break; + case OBOW: + if (ch == BOW) + FWD(aft, bef, 1); + break; + case OEOW: + if (ch == EOW) + FWD(aft, bef, 1); + break; + case OANY: + if (!NONCHAR(ch)) + FWD(aft, bef, 1); + break; + case OANYOF: + cs = &g->sets[OPND(s)]; + if (!NONCHAR(ch) && CHIN(cs, ch)) + FWD(aft, bef, 1); + break; + case OBACK_: /* ignored here */ + case O_BACK: + FWD(aft, aft, 1); + break; + case OPLUS_: /* forward, this is just an empty */ + FWD(aft, aft, 1); + break; + case O_PLUS: /* both forward and back */ + FWD(aft, aft, 1); + i = ISSETBACK(aft, OPND(s)); + BACK(aft, aft, OPND(s)); + if (!i && ISSETBACK(aft, OPND(s))) { + /* oho, must reconsider loop body */ + pc -= OPND(s) + 1; + INIT(here, pc); + } + break; + case OQUEST_: /* two branches, both forward */ + FWD(aft, aft, 1); + FWD(aft, aft, OPND(s)); + break; + case O_QUEST: /* just an empty */ + FWD(aft, aft, 1); + break; + case OLPAREN: /* not significant here */ + case ORPAREN: + FWD(aft, aft, 1); + break; + case OCH_: /* mark the first two branches */ + FWD(aft, aft, 1); + assert(OP(g->strip[pc+OPND(s)]) == OOR2); + FWD(aft, aft, OPND(s)); + break; + case OOR1: /* done a branch, find the O_CH */ + if (ISSTATEIN(aft, here)) { + for (look = 1; + OP(s = g->strip[pc+look]) != O_CH; + look += OPND(s)) + assert(OP(s) == OOR2); + FWD(aft, aft, look); + } + break; + case OOR2: /* propagate OCH_'s marking */ + FWD(aft, aft, 1); + if (OP(g->strip[pc+OPND(s)]) != O_CH) { + assert(OP(g->strip[pc+OPND(s)]) == OOR2); + FWD(aft, aft, OPND(s)); + } + break; + case O_CH: /* just empty */ + FWD(aft, aft, 1); + break; + default: /* ooooops... */ + assert(nope); + break; + } + } + + return(aft); +} + +#ifdef REDEBUG +/* + - print - print a set of states + == #ifdef REDEBUG + == static void print(struct match *m, char *caption, states st, \ + == int ch, FILE *d); + == #endif + */ +static void +print(m, caption, st, ch, d) +struct match *m; +char *caption; +states st; +int ch; +FILE *d; +{ + register struct re_guts *g = m->g; + register int i; + register int first = 1; + + if (!(m->eflags®_TRACE)) + return; + + fprintf(d, "%s", caption); + if (ch != '\0') + fprintf(d, " %s", pchar(ch)); + for (i = 0; i < g->nstates; i++) + if (ISSET(st, i)) { + fprintf(d, "%s%d", (first) ? "\t" : ", ", i); + first = 0; + } + fprintf(d, "\n"); +} + +/* + - at - print current situation + == #ifdef REDEBUG + == static void at(struct match *m, char *title, char *start, char *stop, \ + == sopno startst, sopno stopst); + == #endif + */ +static void +at(m, title, start, stop, startst, stopst) +struct match *m; +char *title; +char *start; +char *stop; +sopno startst; +sopno stopst; +{ + if (!(m->eflags®_TRACE)) + return; + + printf("%s %s-", title, pchar(*start)); + printf("%s ", pchar(*stop)); + printf("%ld-%ld\n", (long)startst, (long)stopst); +} + +#ifndef PCHARDONE +#define PCHARDONE /* never again */ +/* + - pchar - make a character printable + == #ifdef REDEBUG + == static char *pchar(int ch); + == #endif + * + * Is this identical to regchar() over in debug.c? Well, yes. But a + * duplicate here avoids having a debugging-capable regexec.o tied to + * a matching debug.o, and this is convenient. It all disappears in + * the non-debug compilation anyway, so it doesn't matter much. + */ +static char * /* -> representation */ +pchar(ch) +int ch; +{ + static char pbuf[10]; + + if (isprint(ch) || ch == ' ') + sprintf(pbuf, "%c", ch); + else + sprintf(pbuf, "\\%o", ch); + return(pbuf); +} +#endif +#endif + +#undef matcher +#undef fast +#undef slow +#undef dissect +#undef backref +#undef step +#undef print +#undef at +#undef match |