X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=regexec.c;h=57000cf7659a21e21c927340e17d8fb76fa69f7f;hb=14870ecde11bcf4aefbaa822f23042d2bbd7bd0a;hp=bb63eda2e638706471b8095e85135f925e32df9e;hpb=9ef589d8078fdf16316dec772c00e81b3c38fd22;p=p5sagit%2Fp5-mst-13.2.git diff --git a/regexec.c b/regexec.c index bb63eda..57000cf 100644 --- a/regexec.c +++ b/regexec.c @@ -1,3 +1,10 @@ +/* regexec.c + */ + +/* + * "One Ring to rule them all, One Ring to find them..." + */ + /* NOTE: this is derived from Henry Spencer's regexp code, and should not * confused with the original package (see point 3 below). Thanks, Henry! */ @@ -7,23 +14,14 @@ * blame Henry for some of the lack of readability. */ -/* $RCSfile: regexec.c,v $$Revision: 4.0.1.2 $$Date: 91/06/07 11:50:33 $ - * - * $Log: regexec.c,v $ - * Revision 4.0.1.2 91/06/07 11:50:33 lwall - * patch4: new copyright notice - * patch4: // wouldn't use previous pattern if it started with a null character - * - * Revision 4.0.1.1 91/04/12 09:07:39 lwall - * patch1: regexec only allocated space for 9 subexpresssions - * - * Revision 4.0 91/03/20 01:39:16 lwall - * 4.0 baseline. - * - */ +/* The names of the functions have been changed from regcomp and + * regexec to pregcomp and pregexec in order to avoid conflicts + * with the POSIX routines of the same names. +*/ +/*SUPPRESS 112*/ /* - * regcomp and regexec -- regsub and regerror are not used in perl + * pregcomp and pregexec -- regsub and regerror are not used in perl * * Copyright (c) 1986 by University of Toronto. * Written by Henry Spencer. Not derived from licensed software. @@ -44,7 +42,7 @@ * **** Alterations to Henry's code are... **** - **** Copyright (c) 1991, Larry Wall + **** Copyright (c) 1991-1997, Larry Wall **** **** You may distribute under the terms of either the GNU General Public **** License or the Artistic License, as specified in the README file. @@ -62,449 +60,530 @@ #endif #ifdef DEBUGGING -int regnarrate = 0; +static I32 regnarrate = 0; +static char* regprogram = 0; #endif -#define isALNUM(c) (isascii(c) && (isalpha(c) || isdigit(c) || c == '_')) -#define isSPACE(c) (isascii(c) && isspace(c)) -#define isDIGIT(c) (isascii(c) && isdigit(c)) -#define isUPPER(c) (isascii(c) && isupper(c)) +/* Current curly descriptor */ +typedef struct curcur CURCUR; +struct curcur { + int parenfloor; /* how far back to strip paren data */ + int cur; /* how many instances of scan we've matched */ + int min; /* the minimal number of scans to match */ + int max; /* the maximal number of scans to match */ + int minmod; /* whether to work our way up or down */ + char * scan; /* the thing to match */ + char * next; /* what has to match after it */ + char * lastloc; /* where we started matching this scan */ + CURCUR * oldcc; /* current curly before we started this one */ +}; -/* - * regexec and friends - */ +static CURCUR* regcc; + +typedef I32 CHECKPOINT; + +static CHECKPOINT regcppush _((I32 parenfloor)); +static char * regcppop _((void)); + +static CHECKPOINT +regcppush(parenfloor) +I32 parenfloor; +{ + int retval = savestack_ix; + int i = (regsize - parenfloor) * 3; + int p; + + SSCHECK(i + 5); + for (p = regsize; p > parenfloor; p--) { + SSPUSHPTR(regendp[p]); + SSPUSHPTR(regstartp[p]); + SSPUSHINT(p); + } + SSPUSHINT(regsize); + SSPUSHINT(*reglastparen); + SSPUSHPTR(reginput); + SSPUSHINT(i + 3); + SSPUSHINT(SAVEt_REGCONTEXT); + return retval; +} + +static char * +regcppop() +{ + I32 i = SSPOPINT; + U32 paren = 0; + char *input; + char *tmps; + assert(i == SAVEt_REGCONTEXT); + i = SSPOPINT; + input = (char *) SSPOPPTR; + *reglastparen = SSPOPINT; + regsize = SSPOPINT; + for (i -= 3; i > 0; i -= 3) { + paren = (U32)SSPOPINT; + regstartp[paren] = (char *) SSPOPPTR; + tmps = (char*)SSPOPPTR; + if (paren <= *reglastparen) + regendp[paren] = tmps; + } + for (paren = *reglastparen + 1; paren <= regnpar; paren++) { + if (paren > regsize) + regstartp[paren] = Nullch; + regendp[paren] = Nullch; + } + return input; +} + +#define regcpblow(cp) leave_scope(cp) /* - * Global work variables for regexec(). + * pregexec and friends */ -static char *regprecomp; -static char *reginput; /* String-input pointer. */ -static char regprev; /* char before regbol, \n if none */ -static char *regbol; /* Beginning of input, for ^ check. */ -static char *regeol; /* End of input, for $ check. */ -static char **regstartp; /* Pointer to startp array. */ -static char **regendp; /* Ditto for endp. */ -static char *reglastparen; /* Similarly for lastparen. */ -static char *regtill; - -static int regmyp_size = 0; -static char **regmystartp = Null(char**); -static char **regmyendp = Null(char**); /* * Forwards. */ -STATIC int regtry(); -STATIC int regmatch(); -STATIC int regrepeat(); -extern int multiline; +static I32 regmatch _((char *prog)); +static I32 regrepeat _((char *p, I32 max)); +static I32 regtry _((regexp *prog, char *startpos)); +static bool reginclass _((char *p, I32 c)); + +static bool regtainted; /* tainted information used? */ /* - - regexec - match a regexp against a string + - pregexec - match a regexp against a string */ -int -regexec(prog, stringarg, strend, strbeg, minend, screamer, safebase) +I32 +pregexec(prog, stringarg, strend, strbeg, minend, screamer, safebase) register regexp *prog; char *stringarg; register char *strend; /* pointer to null at end of string */ char *strbeg; /* real beginning of string */ -int minend; /* end of match must be at least minend after stringarg */ -STR *screamer; -int safebase; /* no need to remember string in subbase */ +I32 minend; /* end of match must be at least minend after stringarg */ +SV *screamer; +I32 safebase; /* no need to remember string in subbase */ { - register char *s; - register int i; - register char *c; - register char *string = stringarg; - register int tmp; - int minlen = 0; /* must match at least this many chars */ - int dontbother = 0; /* how many characters not to try at end */ - - /* Be paranoid... */ - if (prog == NULL || string == NULL) { - fatal("NULL regexp parameter"); - return(0); - } + register char *s; + register char *c; + register char *startpos = stringarg; + register I32 tmp; + I32 minlen = 0; /* must match at least this many chars */ + I32 dontbother = 0; /* how many characters not to try at end */ + CURCUR cc; + + cc.cur = 0; + cc.oldcc = 0; + regcc = &cc; + +#ifdef DEBUGGING + regnarrate = debug & 512; + regprogram = prog->program; +#endif + + /* Be paranoid... */ + if (prog == NULL || startpos == NULL) { + croak("NULL regexp parameter"); + return 0; + } + + if (startpos == strbeg) /* is ^ valid at stringarg? */ + regprev = '\n'; + else { + regprev = stringarg[-1]; + if (!multiline && regprev == '\n') + regprev = '\0'; /* force ^ to NOT match */ + } - if (string == strbeg) /* is ^ valid at stringarg? */ - regprev = '\n'; + regprecomp = prog->precomp; + /* Check validity of program. */ + if (UCHARAT(prog->program) != MAGIC) { + FAIL("corrupted regexp program"); + } + + regnpar = prog->nparens; + regtainted = FALSE; + + /* If there is a "must appear" string, look for it. */ + s = startpos; + if (prog->regmust != Nullsv && + !(prog->reganch & ROPT_ANCH_GPOS) && + (!(prog->reganch & ROPT_ANCH_BOL) + || (multiline && prog->regback >= 0)) ) + { + if (stringarg == strbeg && screamer) { + if (screamfirst[BmRARE(prog->regmust)] >= 0) + s = screaminstr(screamer,prog->regmust); + else + s = Nullch; + } + else + s = fbm_instr((unsigned char*)s, (unsigned char*)strend, + prog->regmust); + if (!s) { + ++BmUSEFUL(prog->regmust); /* hooray */ + goto phooey; /* not present */ + } + else if (prog->regback >= 0) { + s -= prog->regback; + if (s < startpos) + s = startpos; + minlen = prog->regback + SvCUR(prog->regmust); + } + else if (!prog->naughty && --BmUSEFUL(prog->regmust) < 0) { /* boo */ + SvREFCNT_dec(prog->regmust); + prog->regmust = Nullsv; /* disable regmust */ + s = startpos; + } else { - regprev = stringarg[-1]; - if (!multiline && regprev == '\n') - regprev = '\0'; /* force ^ to NOT match */ + s = startpos; + minlen = SvCUR(prog->regmust); } - regprecomp = prog->precomp; - /* Check validity of program. */ - if (UCHARAT(prog->program) != MAGIC) { - FAIL("corrupted regexp program"); + } + + /* Mark beginning of line for ^ . */ + regbol = startpos; + + /* Mark end of line for $ (and such) */ + regeol = strend; + + /* see how far we have to get to not match where we matched before */ + regtill = startpos+minend; + + /* Simplest case: anchored match need be tried only once. */ + /* [unless only anchor is BOL and multiline is set] */ + if (prog->reganch & ROPT_ANCH) { + if (regtry(prog, startpos)) + goto got_it; + else if (!(prog->reganch & ROPT_ANCH_GPOS) && + (multiline || (prog->reganch & ROPT_IMPLICIT))) + { + if (minlen) + dontbother = minlen - 1; + strend -= dontbother; + /* for multiline we only have to try after newlines */ + if (s > startpos) + s--; + while (s < strend) { + if (*s++ == '\n') { + if (s < strend && regtry(prog, s)) + goto got_it; + } + } } + goto phooey; + } - if (prog->do_folding) { - safebase = FALSE; - i = strend - string; - New(1101,c,i+1,char); - (void)bcopy(string, c, i+1); - string = c; - strend = string + i; - for (s = string; s < strend; s++) - if (isUPPER(*s)) - *s = tolower(*s); + /* Messy cases: unanchored match. */ + if (prog->regstart) { + if (prog->reganch & ROPT_SKIP) { /* we have /x+whatever/ */ + /* it must be a one character string */ + char ch = SvPVX(prog->regstart)[0]; + while (s < strend) { + if (*s == ch) { + if (regtry(prog, s)) + goto got_it; + s++; + while (s < strend && *s == ch) + s++; + } + s++; + } + } + else if (SvTYPE(prog->regstart) == SVt_PVBM) { + /* We know what string it must start with. */ + while ((s = fbm_instr((unsigned char*)s, + (unsigned char*)strend, prog->regstart)) != NULL) + { + if (regtry(prog, s)) + goto got_it; + s++; + } } + else { /* Optimized fbm_instr: */ + c = SvPVX(prog->regstart); + while ((s = ninstr(s, strend, c, c + SvCUR(prog->regstart))) != NULL) + { + if (regtry(prog, s)) + goto got_it; + s++; + } + } + goto phooey; + } + /*SUPPRESS 560*/ + if (c = prog->regstclass) { + I32 doevery = (prog->reganch & ROPT_SKIP) == 0; - /* If there is a "must appear" string, look for it. */ - s = string; - if (prog->regmust != Nullstr && - (!(prog->reganch & ROPT_ANCH) - || (multiline && prog->regback >= 0)) ) { - if (stringarg == strbeg && screamer) { - if (screamfirst[prog->regmust->str_rare] >= 0) - s = screaminstr(screamer,prog->regmust); - else - s = Nullch; + if (minlen) + dontbother = minlen - 1; + strend -= dontbother; /* don't bother with what can't match */ + tmp = 1; + /* We know what class it must start with. */ + switch (OP(c)) { + case ANYOF: + c = OPERAND(c); + while (s < strend) { + if (reginclass(c, *s)) { + if (tmp && regtry(prog, s)) + goto got_it; + else + tmp = doevery; } -#ifndef lint else - s = fbminstr((unsigned char*)s, (unsigned char*)strend, - prog->regmust); -#endif - if (!s) { - ++prog->regmust->str_u.str_useful; /* hooray */ - goto phooey; /* not present */ + tmp = 1; + s++; + } + break; + case BOUNDL: + regtainted = TRUE; + /* FALL THROUGH */ + case BOUND: + if (minlen) + dontbother++,strend--; + tmp = (s != startpos) ? UCHARAT(s - 1) : regprev; + tmp = ((OP(c) == BOUND ? isALNUM(tmp) : isALNUM_LC(tmp)) != 0); + while (s < strend) { + if (tmp == !(OP(c) == BOUND ? isALNUM(*s) : isALNUM_LC(*s))) { + tmp = !tmp; + if (regtry(prog, s)) + goto got_it; } - else if (prog->regback >= 0) { - s -= prog->regback; - if (s < string) - s = string; - minlen = prog->regback + prog->regmust->str_cur; + s++; + } + if ((minlen || tmp) && regtry(prog,s)) + goto got_it; + break; + case NBOUNDL: + regtainted = TRUE; + /* FALL THROUGH */ + case NBOUND: + if (minlen) + dontbother++,strend--; + tmp = (s != startpos) ? UCHARAT(s - 1) : regprev; + tmp = ((OP(c) == NBOUND ? isALNUM(tmp) : isALNUM_LC(tmp)) != 0); + while (s < strend) { + if (tmp == !(OP(c) == NBOUND ? isALNUM(*s) : isALNUM_LC(*s))) + tmp = !tmp; + else if (regtry(prog, s)) + goto got_it; + s++; + } + if ((minlen || !tmp) && regtry(prog,s)) + goto got_it; + break; + case ALNUM: + while (s < strend) { + if (isALNUM(*s)) { + if (tmp && regtry(prog, s)) + goto got_it; + else + tmp = doevery; } - else if (--prog->regmust->str_u.str_useful < 0) { /* boo */ - str_free(prog->regmust); - prog->regmust = Nullstr; /* disable regmust */ - s = string; + else + tmp = 1; + s++; + } + break; + case ALNUML: + regtainted = TRUE; + while (s < strend) { + if (isALNUM_LC(*s)) { + if (tmp && regtry(prog, s)) + goto got_it; + else + tmp = doevery; } - else { - s = string; - minlen = prog->regmust->str_cur; + else + tmp = 1; + s++; + } + break; + case NALNUM: + while (s < strend) { + if (!isALNUM(*s)) { + if (tmp && regtry(prog, s)) + goto got_it; + else + tmp = doevery; } - } - - /* Mark beginning of line for ^ . */ - regbol = string; - - /* Mark end of line for $ (and such) */ - regeol = strend; - - /* see how far we have to get to not match where we matched before */ - regtill = string+minend; - - /* Allocate our backreference arrays */ - if ( regmyp_size < prog->nparens + 1 ) { - /* Allocate or enlarge the arrays */ - regmyp_size = prog->nparens + 1; - if ( regmyp_size < 10 ) regmyp_size = 10; /* minimum */ - if ( regmystartp ) { - /* reallocate larger */ - Renew(regmystartp,regmyp_size,char*); - Renew(regmyendp, regmyp_size,char*); + else + tmp = 1; + s++; } - else { - /* Initial allocation */ - New(1102,regmystartp,regmyp_size,char*); - New(1102,regmyendp, regmyp_size,char*); + break; + case NALNUML: + regtainted = TRUE; + while (s < strend) { + if (!isALNUM_LC(*s)) { + if (tmp && regtry(prog, s)) + goto got_it; + else + tmp = doevery; + } + else + tmp = 1; + s++; } - - } - - /* Simplest case: anchored match need be tried only once. */ - /* [unless multiline is set] */ - if (prog->reganch & ROPT_ANCH) { - if (regtry(prog, string)) + break; + case SPACE: + while (s < strend) { + if (isSPACE(*s)) { + if (tmp && regtry(prog, s)) goto got_it; - else if (multiline) { - if (minlen) - dontbother = minlen - 1; - strend -= dontbother; - /* for multiline we only have to try after newlines */ - if (s > string) - s--; - while (s < strend) { - if (*s++ == '\n') { - if (s < strend && regtry(prog, s)) - goto got_it; - } - } + else + tmp = doevery; } - goto phooey; - } - - /* Messy cases: unanchored match. */ - if (prog->regstart) { - if (prog->reganch & ROPT_SKIP) { /* we have /x+whatever/ */ - /* it must be a one character string */ - i = prog->regstart->str_ptr[0]; - while (s < strend) { - if (*s == i) { - if (regtry(prog, s)) - goto got_it; - s++; - while (s < strend && *s == i) - s++; - } - s++; - } + else + tmp = 1; + s++; + } + break; + case SPACEL: + regtainted = TRUE; + while (s < strend) { + if (isSPACE_LC(*s)) { + if (tmp && regtry(prog, s)) + goto got_it; + else + tmp = doevery; } - else if (prog->regstart->str_pok == 3) { - /* We know what string it must start with. */ -#ifndef lint - while ((s = fbminstr((unsigned char*)s, - (unsigned char*)strend, prog->regstart)) != NULL) -#else - while (s = Nullch) -#endif - { - if (regtry(prog, s)) - goto got_it; - s++; - } + else + tmp = 1; + s++; + } + break; + case NSPACE: + while (s < strend) { + if (!isSPACE(*s)) { + if (tmp && regtry(prog, s)) + goto got_it; + else + tmp = doevery; } - else { - c = prog->regstart->str_ptr; - while ((s = ninstr(s, strend, - c, c + prog->regstart->str_cur )) != NULL) { - if (regtry(prog, s)) - goto got_it; - s++; - } + else + tmp = 1; + s++; + } + break; + case NSPACEL: + regtainted = TRUE; + while (s < strend) { + if (!isSPACE_LC(*s)) { + if (tmp && regtry(prog, s)) + goto got_it; + else + tmp = doevery; } - goto phooey; - } - if (c = prog->regstclass) { - int doevery = (prog->reganch & ROPT_SKIP) == 0; - - if (minlen) - dontbother = minlen - 1; - strend -= dontbother; /* don't bother with what can't match */ - tmp = 1; - /* We know what class it must start with. */ - switch (OP(c)) { - case ANYOF: - c = OPERAND(c); - while (s < strend) { - i = UCHARAT(s); - if (!(c[i >> 3] & (1 << (i&7)))) { - if (tmp && regtry(prog, s)) - goto got_it; - else - tmp = doevery; - } - else - tmp = 1; - s++; - } - break; - case BOUND: - if (minlen) - dontbother++,strend--; - if (s != string) { - i = s[-1]; - tmp = isALNUM(i); - } + else + tmp = 1; + s++; + } + break; + case DIGIT: + while (s < strend) { + if (isDIGIT(*s)) { + if (tmp && regtry(prog, s)) + goto got_it; else - tmp = isALNUM(regprev); /* assume not alphanumeric */ - while (s < strend) { - i = *s; - if (tmp != isALNUM(i)) { - tmp = !tmp; - if (regtry(prog, s)) - goto got_it; - } - s++; - } - if ((minlen || tmp) && regtry(prog,s)) - goto got_it; - break; - case NBOUND: - if (minlen) - dontbother++,strend--; - if (s != string) { - i = s[-1]; - tmp = isALNUM(i); - } + tmp = doevery; + } + else + tmp = 1; + s++; + } + break; + case NDIGIT: + while (s < strend) { + if (!isDIGIT(*s)) { + if (tmp && regtry(prog, s)) + goto got_it; else - tmp = isALNUM(regprev); /* assume not alphanumeric */ - while (s < strend) { - i = *s; - if (tmp != isALNUM(i)) - tmp = !tmp; - else if (regtry(prog, s)) - goto got_it; - s++; - } - if ((minlen || !tmp) && regtry(prog,s)) - goto got_it; - break; - case ALNUM: - while (s < strend) { - i = *s; - if (isALNUM(i)) { - if (tmp && regtry(prog, s)) - goto got_it; - else - tmp = doevery; - } - else - tmp = 1; - s++; - } - break; - case NALNUM: - while (s < strend) { - i = *s; - if (!isALNUM(i)) { - if (tmp && regtry(prog, s)) - goto got_it; - else - tmp = doevery; - } - else - tmp = 1; - s++; - } - break; - case SPACE: - while (s < strend) { - if (isSPACE(*s)) { - if (tmp && regtry(prog, s)) - goto got_it; - else - tmp = doevery; - } - else - tmp = 1; - s++; - } - break; - case NSPACE: - while (s < strend) { - if (!isSPACE(*s)) { - if (tmp && regtry(prog, s)) - goto got_it; - else - tmp = doevery; - } - else - tmp = 1; - s++; - } - break; - case DIGIT: - while (s < strend) { - if (isDIGIT(*s)) { - if (tmp && regtry(prog, s)) - goto got_it; - else - tmp = doevery; - } - else - tmp = 1; - s++; - } - break; - case NDIGIT: - while (s < strend) { - if (!isDIGIT(*s)) { - if (tmp && regtry(prog, s)) - goto got_it; - else - tmp = doevery; - } - else - tmp = 1; - s++; - } - break; + tmp = doevery; } + else + tmp = 1; + s++; + } + break; } - else { - if (minlen) - dontbother = minlen - 1; - strend -= dontbother; - /* We don't know much -- general case. */ - do { - if (regtry(prog, s)) - goto got_it; - } while (s++ < strend); - } + } + else { + if (minlen) + dontbother = minlen - 1; + strend -= dontbother; + /* We don't know much -- general case. */ + do { + if (regtry(prog, s)) + goto got_it; + } while (s++ < strend); + } - /* Failure. */ - goto phooey; + /* Failure. */ + goto phooey; - got_it: - if ((!safebase && (prog->nparens || sawampersand)) || prog->do_folding){ - strend += dontbother; /* uncheat */ - if (safebase) /* no need for $digit later */ - s = strbeg; - else if (strbeg != prog->subbase) { - i = strend - string + (stringarg - strbeg); - s = nsavestr(strbeg,i); /* so $digit will work later */ - if (prog->subbase) - Safefree(prog->subbase); - prog->subbeg = prog->subbase = s; - prog->subend = s+i; - } - else - s = prog->subbase; - s += (stringarg - strbeg); - for (i = 0; i <= prog->nparens; i++) { - if (prog->endp[i]) { - prog->startp[i] = s + (prog->startp[i] - string); - prog->endp[i] = s + (prog->endp[i] - string); - } - } - if (prog->do_folding) - Safefree(string); +got_it: + strend += dontbother; /* uncheat */ + prog->subbeg = strbeg; + prog->subend = strend; + prog->exec_tainted = regtainted; + + /* make sure $`, $&, $', and $digit will work later */ + if (!safebase && (strbeg != prog->subbase)) { + I32 i = strend - startpos + (stringarg - strbeg); + s = savepvn(strbeg, i); + Safefree(prog->subbase); + prog->subbase = s; + prog->subbeg = prog->subbase; + prog->subend = prog->subbase + i; + s = prog->subbase + (stringarg - strbeg); + for (i = 0; i <= prog->nparens; i++) { + if (prog->endp[i]) { + prog->startp[i] = s + (prog->startp[i] - startpos); + prog->endp[i] = s + (prog->endp[i] - startpos); + } } - return(1); + } + return 1; - phooey: - if (prog->do_folding) - Safefree(string); - return(0); +phooey: + return 0; } /* - regtry - try match at specific point */ -static int /* 0 failure, 1 success */ -regtry(prog, string) +static I32 /* 0 failure, 1 success */ +regtry(prog, startpos) regexp *prog; -char *string; +char *startpos; { - register int i; - register char **sp; - register char **ep; - - reginput = string; - regstartp = prog->startp; - regendp = prog->endp; - reglastparen = &prog->lastparen; - prog->lastparen = 0; - - sp = prog->startp; - ep = prog->endp; - if (prog->nparens) { - for (i = prog->nparens; i >= 0; i--) { - *sp++ = NULL; - *ep++ = NULL; - } + register I32 i; + register char **sp; + register char **ep; + + reginput = startpos; + regstartp = prog->startp; + regendp = prog->endp; + reglastparen = &prog->lastparen; + prog->lastparen = 0; + regsize = 0; + + sp = prog->startp; + ep = prog->endp; + if (prog->nparens) { + for (i = prog->nparens; i >= 0; i--) { + *sp++ = NULL; + *ep++ = NULL; } - if (regmatch(prog->program + 1) && reginput >= regtill) { - prog->startp[0] = string; - prog->endp[0] = reginput; - return(1); - } else - return(0); + } + if (regmatch(prog->program + 1) && reginput >= regtill) { + prog->startp[0] = startpos; + prog->endp[0] = reginput; + return 1; + } + else + return 0; } /* @@ -521,276 +600,525 @@ char *string; * maybe save a little bit of pushing and popping on the stack. It also takes * advantage of machines that use a register save mask on subroutine entry. */ -static int /* 0 failure, 1 success */ +static I32 /* 0 failure, 1 success */ regmatch(prog) char *prog; { - register char *scan; /* Current node. */ - char *next; /* Next node. */ - register int nextchar; - register int n; /* no or next */ - register int ln; /* len or last */ - register char *s; /* operand or save */ - register char *locinput = reginput; - - nextchar = *locinput; - scan = prog; + register char *scan; /* Current node. */ + char *next; /* Next node. */ + register I32 nextchar; + register I32 n; /* no or next */ + register I32 ln; /* len or last */ + register char *s; /* operand or save */ + register char *locinput = reginput; + register I32 c1, c2; /* case fold search */ + int minmod = 0; #ifdef DEBUGGING - if (scan != NULL && regnarrate) - fprintf(stderr, "%s(\n", regprop(scan)); + static int regindent = 0; + regindent++; #endif - while (scan != NULL) { + + nextchar = UCHARAT(locinput); + scan = prog; + while (scan != NULL) { #ifdef DEBUGGING - if (regnarrate) - fprintf(stderr, "%s...\n", regprop(scan)); +#define sayYES goto yes +#define sayNO goto no +#define saySAME(x) if (x) goto yes; else goto no + if (regnarrate) { + PerlIO_printf(Perl_debug_log, "%*s%2d%-8.8s\t<%.10s>\n", regindent*2, "", + scan - regprogram, regprop(scan), locinput); + } +#else +#define sayYES return 1 +#define sayNO return 0 +#define saySAME(x) return x #endif #ifdef REGALIGN - next = scan + NEXT(scan); - if (next == scan) - next = NULL; + next = scan + NEXT(scan); + if (next == scan) + next = NULL; #else - next = regnext(scan); + next = regnext(scan); #endif - switch (OP(scan)) { - case BOL: - if (locinput == regbol ? regprev == '\n' : - ((nextchar || locinput < regeol) && - locinput[-1] == '\n') ) - { - /* regtill = regbol; */ - break; - } - return(0); - case EOL: - if ((nextchar || locinput < regeol) && nextchar != '\n') - return(0); - if (!multiline && regeol - locinput > 1) - return 0; - /* regtill = regbol; */ - break; - case ANY: - if ((nextchar == '\0' && locinput >= regeol) || - nextchar == '\n') - return(0); - nextchar = *++locinput; - break; - case EXACTLY: - s = OPERAND(scan); - ln = *s++; - /* Inline the first character, for speed. */ - if (*s != nextchar) - return(0); - if (regeol - locinput < ln) - return 0; - if (ln > 1 && bcmp(s, locinput, ln) != 0) - return(0); - locinput += ln; - nextchar = *locinput; - break; - case ANYOF: - s = OPERAND(scan); - if (nextchar < 0) - nextchar = UCHARAT(locinput); - if (s[nextchar >> 3] & (1 << (nextchar&7))) - return(0); - if (!nextchar && locinput >= regeol) - return 0; - nextchar = *++locinput; - break; - case ALNUM: - if (!nextchar) - return(0); - if (!isALNUM(nextchar)) - return(0); - nextchar = *++locinput; - break; - case NALNUM: - if (!nextchar && locinput >= regeol) - return(0); - if (isALNUM(nextchar)) - return(0); - nextchar = *++locinput; - break; - case NBOUND: - case BOUND: - if (locinput == regbol) /* was last char in word? */ - ln = isALNUM(regprev); - else - ln = isALNUM(locinput[-1]); - n = isALNUM(nextchar); /* is next char in word? */ - if ((ln == n) == (OP(scan) == BOUND)) - return(0); - break; - case SPACE: - if (!nextchar && locinput >= regeol) - return(0); - if (!isSPACE(nextchar)) - return(0); - nextchar = *++locinput; - break; - case NSPACE: - if (!nextchar) - return(0); - if (isSPACE(nextchar)) - return(0); - nextchar = *++locinput; - break; - case DIGIT: - if (!isDIGIT(nextchar)) - return(0); - nextchar = *++locinput; - break; - case NDIGIT: - if (!nextchar && locinput >= regeol) - return(0); - if (isDIGIT(nextchar)) - return(0); - nextchar = *++locinput; - break; - case REF: - n = ARG1(scan); /* which paren pair */ - s = regmystartp[n]; - if (!s) - return(0); - if (!regmyendp[n]) - return(0); - if (s == regmyendp[n]) - break; - /* Inline the first character, for speed. */ - if (*s != nextchar) - return(0); - ln = regmyendp[n] - s; - if (locinput + ln > regeol) - return 0; - if (ln > 1 && bcmp(s, locinput, ln) != 0) - return(0); - locinput += ln; - nextchar = *locinput; - break; - - case NOTHING: - break; - case BACK: - break; - case OPEN: - n = ARG1(scan); /* which paren pair */ - reginput = locinput; + switch (OP(scan)) { + case BOL: + if (locinput == regbol + ? regprev == '\n' + : ((nextchar || locinput < regeol) && locinput[-1] == '\n') ) + { + /* regtill = regbol; */ + break; + } + sayNO; + case MBOL: + if (locinput == regbol + ? regprev == '\n' + : ((nextchar || locinput < regeol) && locinput[-1] == '\n') ) + { + break; + } + sayNO; + case SBOL: + if (locinput == regbol && regprev == '\n') + break; + sayNO; + case GPOS: + if (locinput == regbol) + break; + sayNO; + case EOL: + if (multiline) + goto meol; + else + goto seol; + case MEOL: + meol: + if ((nextchar || locinput < regeol) && nextchar != '\n') + sayNO; + break; + case SEOL: + seol: + if ((nextchar || locinput < regeol) && nextchar != '\n') + sayNO; + if (regeol - locinput > 1) + sayNO; + break; + case SANY: + if (!nextchar && locinput >= regeol) + sayNO; + nextchar = UCHARAT(++locinput); + break; + case ANY: + if (!nextchar && locinput >= regeol || nextchar == '\n') + sayNO; + nextchar = UCHARAT(++locinput); + break; + case EXACT: + s = OPERAND(scan); + ln = *s++; + /* Inline the first character, for speed. */ + if (UCHARAT(s) != nextchar) + sayNO; + if (regeol - locinput < ln) + sayNO; + if (ln > 1 && memNE(s, locinput, ln)) + sayNO; + locinput += ln; + nextchar = UCHARAT(locinput); + break; + case EXACTFL: + regtainted = TRUE; + /* FALL THROUGH */ + case EXACTF: + s = OPERAND(scan); + ln = *s++; + /* Inline the first character, for speed. */ + if (UCHARAT(s) != nextchar && + UCHARAT(s) != ((OP(scan) == EXACTF) + ? fold : fold_locale)[nextchar]) + sayNO; + if (regeol - locinput < ln) + sayNO; + if (ln > 1 && (OP(scan) == EXACTF + ? ibcmp(s, locinput, ln) + : ibcmp_locale(s, locinput, ln))) + sayNO; + locinput += ln; + nextchar = UCHARAT(locinput); + break; + case ANYOF: + s = OPERAND(scan); + if (nextchar < 0) + nextchar = UCHARAT(locinput); + if (!reginclass(s, nextchar)) + sayNO; + if (!nextchar && locinput >= regeol) + sayNO; + nextchar = UCHARAT(++locinput); + break; + case ALNUML: + regtainted = TRUE; + /* FALL THROUGH */ + case ALNUM: + if (!nextchar) + sayNO; + if (!(OP(scan) == ALNUM + ? isALNUM(nextchar) : isALNUM_LC(nextchar))) + sayNO; + nextchar = UCHARAT(++locinput); + break; + case NALNUML: + regtainted = TRUE; + /* FALL THROUGH */ + case NALNUM: + if (!nextchar && locinput >= regeol) + sayNO; + if (OP(scan) == NALNUM + ? isALNUM(nextchar) : isALNUM_LC(nextchar)) + sayNO; + nextchar = UCHARAT(++locinput); + break; + case BOUNDL: + case NBOUNDL: + regtainted = TRUE; + /* FALL THROUGH */ + case BOUND: + case NBOUND: + /* was last char in word? */ + ln = (locinput != regbol) ? UCHARAT(locinput - 1) : regprev; + if (OP(scan) == BOUND || OP(scan) == NBOUND) { + ln = isALNUM(ln); + n = isALNUM(nextchar); + } + else { + ln = isALNUM_LC(ln); + n = isALNUM_LC(nextchar); + } + if (((!ln) == (!n)) == (OP(scan) == BOUND || OP(scan) == BOUNDL)) + sayNO; + break; + case SPACEL: + regtainted = TRUE; + /* FALL THROUGH */ + case SPACE: + if (!nextchar && locinput >= regeol) + sayNO; + if (!(OP(scan) == SPACE + ? isSPACE(nextchar) : isSPACE_LC(nextchar))) + sayNO; + nextchar = UCHARAT(++locinput); + break; + case NSPACEL: + regtainted = TRUE; + /* FALL THROUGH */ + case NSPACE: + if (!nextchar) + sayNO; + if (OP(scan) == SPACE + ? isSPACE(nextchar) : isSPACE_LC(nextchar)) + sayNO; + nextchar = UCHARAT(++locinput); + break; + case DIGIT: + if (!isDIGIT(nextchar)) + sayNO; + nextchar = UCHARAT(++locinput); + break; + case NDIGIT: + if (!nextchar && locinput >= regeol) + sayNO; + if (isDIGIT(nextchar)) + sayNO; + nextchar = UCHARAT(++locinput); + break; + case REF: + n = ARG1(scan); /* which paren pair */ + s = regstartp[n]; + if (!s) + sayNO; + if (!regendp[n]) + sayNO; + if (s == regendp[n]) + break; + /* Inline the first character, for speed. */ + if (UCHARAT(s) != nextchar) + sayNO; + ln = regendp[n] - s; + if (locinput + ln > regeol) + sayNO; + if (ln > 1 && memNE(s, locinput, ln)) + sayNO; + locinput += ln; + nextchar = UCHARAT(locinput); + break; + + case NOTHING: + break; + case BACK: + break; + case OPEN: + n = ARG1(scan); /* which paren pair */ + regstartp[n] = locinput; + if (n > regsize) + regsize = n; + break; + case CLOSE: + n = ARG1(scan); /* which paren pair */ + regendp[n] = locinput; + if (n > *reglastparen) + *reglastparen = n; + break; + case CURLYX: { + CURCUR cc; + CHECKPOINT cp = savestack_ix; + cc.oldcc = regcc; + regcc = &cc; + cc.parenfloor = *reglastparen; + cc.cur = -1; + cc.min = ARG1(scan); + cc.max = ARG2(scan); + cc.scan = NEXTOPER(scan) + 4; + cc.next = next; + cc.minmod = minmod; + cc.lastloc = 0; + reginput = locinput; + n = regmatch(PREVOPER(next)); /* start on the WHILEM */ + regcpblow(cp); + regcc = cc.oldcc; + saySAME(n); + } + /* NOT REACHED */ + case WHILEM: { + /* + * This is really hard to understand, because after we match + * what we're trying to match, we must make sure the rest of + * the RE is going to match for sure, and to do that we have + * to go back UP the parse tree by recursing ever deeper. And + * if it fails, we have to reset our parent's current state + * that we can try again after backing off. + */ + + CHECKPOINT cp; + CURCUR* cc = regcc; + n = cc->cur + 1; /* how many we know we matched */ + reginput = locinput; + +#ifdef DEBUGGING + if (regnarrate) + PerlIO_printf(Perl_debug_log, "%*s %ld %lx\n", regindent*2, "", + (long)n, (long)cc); +#endif - regmystartp[n] = locinput; /* for REF */ - if (regmatch(next)) { - /* - * Don't set startp if some later - * invocation of the same parentheses - * already has. - */ - if (regstartp[n] == NULL) - regstartp[n] = locinput; - return(1); - } else - return(0); - /* NOTREACHED */ - case CLOSE: { - n = ARG1(scan); /* which paren pair */ - reginput = locinput; - - regmyendp[n] = locinput; /* for REF */ - if (regmatch(next)) { - /* - * Don't set endp if some later - * invocation of the same parentheses - * already has. - */ - if (regendp[n] == NULL) { - regendp[n] = locinput; - if (n > *reglastparen) - *reglastparen = n; - } - return(1); - } else - return(0); - } - /*NOTREACHED*/ - case BRANCH: { - if (OP(next) != BRANCH) /* No choice. */ - next = NEXTOPER(scan); /* Avoid recursion. */ - else { - do { - reginput = locinput; - if (regmatch(NEXTOPER(scan))) - return(1); + /* If degenerate scan matches "", assume scan done. */ + + if (locinput == cc->lastloc && n >= cc->min) { + regcc = cc->oldcc; + ln = regcc->cur; + if (regmatch(cc->next)) + sayYES; + regcc->cur = ln; + regcc = cc; + sayNO; + } + + /* First just match a string of min scans. */ + + if (n < cc->min) { + cc->cur = n; + cc->lastloc = locinput; + if (regmatch(cc->scan)) + sayYES; + cc->cur = n - 1; + sayNO; + } + + /* Prefer next over scan for minimal matching. */ + + if (cc->minmod) { + regcc = cc->oldcc; + ln = regcc->cur; + cp = regcppush(cc->parenfloor); + if (regmatch(cc->next)) { + regcpblow(cp); + sayYES; /* All done. */ + } + regcppop(); + regcc->cur = ln; + regcc = cc; + + if (n >= cc->max) /* Maximum greed exceeded? */ + sayNO; + + /* Try scanning more and see if it helps. */ + reginput = locinput; + cc->cur = n; + cc->lastloc = locinput; + cp = regcppush(cc->parenfloor); + if (regmatch(cc->scan)) { + regcpblow(cp); + sayYES; + } + regcppop(); + cc->cur = n - 1; + sayNO; + } + + /* Prefer scan over next for maximal matching. */ + + if (n < cc->max) { /* More greed allowed? */ + cp = regcppush(cc->parenfloor); + cc->cur = n; + cc->lastloc = locinput; + if (regmatch(cc->scan)) { + regcpblow(cp); + sayYES; + } + regcppop(); /* Restore some previous $s? */ + reginput = locinput; + } + + /* Failed deeper matches of scan, so see if this one works. */ + regcc = cc->oldcc; + ln = regcc->cur; + if (regmatch(cc->next)) + sayYES; + regcc->cur = ln; + regcc = cc; + cc->cur = n - 1; + sayNO; + } + /* NOT REACHED */ + case BRANCH: { + if (OP(next) != BRANCH) /* No choice. */ + next = NEXTOPER(scan);/* Avoid recursion. */ + else { + int lastparen = *reglastparen; + do { + reginput = locinput; + if (regmatch(NEXTOPER(scan))) + sayYES; + for (n = *reglastparen; n > lastparen; n--) + regendp[n] = 0; + *reglastparen = n; + #ifdef REGALIGN - if (n = NEXT(scan)) - scan += n; - else - scan = NULL; + /*SUPPRESS 560*/ + if (n = NEXT(scan)) + scan += n; + else + scan = NULL; #else - scan = regnext(scan); + scan = regnext(scan); #endif - } while (scan != NULL && OP(scan) == BRANCH); - return(0); - /* NOTREACHED */ - } - } - break; - case CURLY: - ln = ARG1(scan); /* min to match */ - n = ARG2(scan); /* max to match */ - scan = NEXTOPER(scan) + 4; - goto repeat; - case STAR: - ln = 0; - n = 0; - scan = NEXTOPER(scan); - goto repeat; - case PLUS: - /* - * Lookahead to avoid useless match attempts - * when we know what character comes next. - */ - ln = 1; - n = 0; - scan = NEXTOPER(scan); - repeat: - if (OP(next) == EXACTLY) - nextchar = *(OPERAND(next)+1); - else - nextchar = -1000; - reginput = locinput; - n = regrepeat(scan, n); - if (!multiline && OP(next) == EOL && ln < n) - ln = n; /* why back off? */ - while (n >= ln) { - /* If it could work, try it. */ - if (nextchar == -1000 || *reginput == nextchar) - if (regmatch(next)) - return(1); - /* Couldn't or didn't -- back up. */ - n--; - reginput = locinput + n; - } - return(0); - case END: - reginput = locinput; /* put where regtry can find it */ - return(1); /* Success! */ - default: - printf("%x %d\n",scan,scan[1]); - FAIL("regexp memory corruption"); + } while (scan != NULL && OP(scan) == BRANCH); + sayNO; + /* NOTREACHED */ } - - scan = next; + } + break; + case MINMOD: + minmod = 1; + break; + case CURLY: + ln = ARG1(scan); /* min to match */ + n = ARG2(scan); /* max to match */ + scan = NEXTOPER(scan) + 4; + goto repeat; + case STAR: + ln = 0; + n = 32767; + scan = NEXTOPER(scan); + goto repeat; + case PLUS: + /* + * Lookahead to avoid useless match attempts + * when we know what character comes next. + */ + ln = 1; + n = 32767; + scan = NEXTOPER(scan); + repeat: + if (regkind[(U8)OP(next)] == EXACT) { + c1 = UCHARAT(OPERAND(next) + 1); + if (OP(next) == EXACTF) + c2 = fold[c1]; + else if (OP(next) == EXACTFL) + c2 = fold_locale[c1]; + else + c2 = c1; + } + else + c1 = c2 = -1000; + reginput = locinput; + if (minmod) { + minmod = 0; + if (ln && regrepeat(scan, ln) < ln) + sayNO; + while (n >= ln || (n == 32767 && ln > 0)) { /* ln overflow ? */ + /* If it could work, try it. */ + if (c1 == -1000 || + UCHARAT(reginput) == c1 || + UCHARAT(reginput) == c2) + { + if (regmatch(next)) + sayYES; + } + /* Couldn't or didn't -- back up. */ + reginput = locinput + ln; + if (regrepeat(scan, 1)) { + ln++; + reginput = locinput + ln; + } + else + sayNO; + } + } + else { + n = regrepeat(scan, n); + if (ln < n && regkind[(U8)OP(next)] == EOL && + (!multiline || OP(next) == SEOL)) + ln = n; /* why back off? */ + while (n >= ln) { + /* If it could work, try it. */ + if (c1 == -1000 || + UCHARAT(reginput) == c1 || + UCHARAT(reginput) == c2) + { + if (regmatch(next)) + sayYES; + } + /* Couldn't or didn't -- back up. */ + n--; + reginput = locinput + n; + } + } + sayNO; + case SUCCEED: + case END: + reginput = locinput; /* put where regtry can find it */ + sayYES; /* Success! */ + case IFMATCH: + reginput = locinput; + scan = NEXTOPER(scan); + if (!regmatch(scan)) + sayNO; + break; + case UNLESSM: + reginput = locinput; + scan = NEXTOPER(scan); + if (regmatch(scan)) + sayNO; + break; + default: + PerlIO_printf(PerlIO_stderr(), "%lx %d\n", + (unsigned long)scan, scan[1]); + FAIL("regexp memory corruption"); } + scan = next; + } - /* - * We get here only if there's trouble -- normally "case END" is - * the terminating point. - */ - FAIL("corrupted regexp pointers"); - /*NOTREACHED*/ -#ifdef lint - return 0; + /* + * We get here only if there's trouble -- normally "case END" is + * the terminating point. + */ + FAIL("corrupted regexp pointers"); + /*NOTREACHED*/ + sayNO; + +yes: +#ifdef DEBUGGING + regindent--; +#endif + return 1; + +no: +#ifdef DEBUGGING + regindent--; #endif + return 0; } /* @@ -801,70 +1129,144 @@ char *prog; * That was true before, but now we assume scan - reginput is the count, * rather than incrementing count on every character.] */ -static int +static I32 regrepeat(p, max) char *p; -int max; +I32 max; { - register char *scan; - register char *opnd; - register int c; - register char *loceol = regeol; - - scan = reginput; - if (max && max < loceol - scan) - loceol = scan + max; - opnd = OPERAND(p); - switch (OP(p)) { - case ANY: - while (scan < loceol && *scan != '\n') - scan++; - break; - case EXACTLY: /* length of string is 1 */ - opnd++; - while (scan < loceol && *opnd == *scan) - scan++; - break; - case ANYOF: - c = UCHARAT(scan); - while (scan < loceol && !(opnd[c >> 3] & (1 << (c & 7)))) { - scan++; - c = UCHARAT(scan); - } - break; - case ALNUM: - while (scan < loceol && isALNUM(*scan)) - scan++; - break; - case NALNUM: - while (scan < loceol && !isALNUM(*scan)) - scan++; - break; - case SPACE: - while (scan < loceol && isSPACE(*scan)) - scan++; - break; - case NSPACE: - while (scan < loceol && !isSPACE(*scan)) - scan++; - break; - case DIGIT: - while (scan < loceol && isDIGIT(*scan)) - scan++; - break; - case NDIGIT: - while (scan < loceol && !isDIGIT(*scan)) - scan++; - break; - default: /* Oh dear. Called inappropriately. */ - FAIL("internal regexp foulup"); - /* NOTREACHED */ + register char *scan; + register char *opnd; + register I32 c; + register char *loceol = regeol; + + scan = reginput; + if (max != 32767 && max < loceol - scan) + loceol = scan + max; + opnd = OPERAND(p); + switch (OP(p)) { + case ANY: + while (scan < loceol && *scan != '\n') + scan++; + break; + case SANY: + scan = loceol; + break; + case EXACT: /* length of string is 1 */ + c = UCHARAT(++opnd); + while (scan < loceol && UCHARAT(scan) == c) + scan++; + break; + case EXACTF: /* length of string is 1 */ + c = UCHARAT(++opnd); + while (scan < loceol && + (UCHARAT(scan) == c || UCHARAT(scan) == fold[c])) + scan++; + break; + case EXACTFL: /* length of string is 1 */ + regtainted = TRUE; + c = UCHARAT(++opnd); + while (scan < loceol && + (UCHARAT(scan) == c || UCHARAT(scan) == fold_locale[c])) + scan++; + break; + case ANYOF: + while (scan < loceol && reginclass(opnd, *scan)) + scan++; + break; + case ALNUM: + while (scan < loceol && isALNUM(*scan)) + scan++; + break; + case ALNUML: + regtainted = TRUE; + while (scan < loceol && isALNUM_LC(*scan)) + scan++; + break; + case NALNUM: + while (scan < loceol && !isALNUM(*scan)) + scan++; + break; + case NALNUML: + regtainted = TRUE; + while (scan < loceol && !isALNUM_LC(*scan)) + scan++; + break; + case SPACE: + while (scan < loceol && isSPACE(*scan)) + scan++; + break; + case SPACEL: + regtainted = TRUE; + while (scan < loceol && isSPACE_LC(*scan)) + scan++; + break; + case NSPACE: + while (scan < loceol && !isSPACE(*scan)) + scan++; + break; + case NSPACEL: + regtainted = TRUE; + while (scan < loceol && !isSPACE_LC(*scan)) + scan++; + break; + case DIGIT: + while (scan < loceol && isDIGIT(*scan)) + scan++; + break; + case NDIGIT: + while (scan < loceol && !isDIGIT(*scan)) + scan++; + break; + default: /* Called on something of 0 width. */ + break; /* So match right here or not at all. */ + } + + c = scan - reginput; + reginput = scan; + + return(c); +} + +/* + - regclass - determine if a character falls into a character class + */ + +static bool +reginclass(p, c) +register char *p; +register I32 c; +{ + char flags = *p; + bool match = FALSE; + + c &= 0xFF; + if (p[1 + (c >> 3)] & (1 << (c & 7))) + match = TRUE; + else if (flags & ANYOF_FOLD) { + I32 cf; + if (flags & ANYOF_LOCALE) { + regtainted = TRUE; + cf = fold_locale[c]; } + else + cf = fold[c]; + if (p[1 + (cf >> 3)] & (1 << (cf & 7))) + match = TRUE; + } - c = scan - reginput; - reginput = scan; + if (!match && (flags & ANYOF_ISA)) { + regtainted = TRUE; + + if (((flags & ANYOF_ALNUML) && isALNUM_LC(c)) || + ((flags & ANYOF_NALNUML) && !isALNUM_LC(c)) || + ((flags & ANYOF_SPACEL) && isSPACE_LC(c)) || + ((flags & ANYOF_NSPACEL) && !isSPACE_LC(c))) + { + match = TRUE; + } + } - return(c); + return match ^ ((flags & ANYOF_INVERT) != 0); } /* @@ -877,21 +1279,21 @@ char * regnext(p) register char *p; { - register int offset; + register I32 offset; - if (p == ®dummy) - return(NULL); + if (p == ®dummy) + return(NULL); - offset = NEXT(p); - if (offset == 0) - return(NULL); + offset = NEXT(p); + if (offset == 0) + return(NULL); #ifdef REGALIGN - return(p+offset); + return(p+offset); #else - if (OP(p) == BACK) - return(p-offset); - else - return(p+offset); + if (OP(p) == BACK) + return(p-offset); + else + return(p+offset); #endif }