This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
Integrate:
[perl5.git] / regexec.c
index 8a52689..b761752 100644 (file)
--- a/regexec.c
+++ b/regexec.c
@@ -5,6 +5,17 @@
  * "One Ring to rule them all, One Ring to find them..."
  */
 
+/* This file contains functions for executing a regular expression.  See
+ * also regcomp.c which funnily enough, contains functions for compiling
+ * a regular expression.
+ *
+ * This file is also copied at build time to ext/re/re_exec.c, where
+ * it's built with -DPERL_EXT_RE_BUILD -DPERL_EXT_RE_DEBUG -DPERL_EXT.
+ * This causes the main functions to be compiled under new names and with
+ * debugging support added, which makes "use re 'debug'" work.
+ */
+
 /* NOTE: this is derived from Henry Spencer's regexp code, and should not
  * confused with the original package (see point 3 below).  Thanks, Henry!
  */
@@ -68,7 +79,7 @@
  ****    Alterations to Henry's code are...
  ****
  ****    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
- ****    2000, 2001, 2002, 2003, by Larry Wall and others
+ ****    2000, 2001, 2002, 2003, 2004, by Larry Wall and others
  ****
  ****    You may distribute under the terms of either the GNU General Public
  ****    License or the Artistic License, as specified in the README file.
@@ -87,6 +98,7 @@
 #define RF_warned      2               /* warned about big count? */
 #define RF_evaled      4               /* Did an EVAL with setting? */
 #define RF_utf8                8               /* String contains multibyte chars? */
+#define RF_false       16              /* odd number of nested negatives */
 
 #define UTF ((PL_reg_flags & RF_utf8) != 0)
 
@@ -952,6 +964,8 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        I32 doevery = (prog->reganch & ROPT_SKIP) == 0;
        char *m;
        STRLEN ln;
+       STRLEN lnc;
+       register STRLEN uskip;
        unsigned int c1;
        unsigned int c2;
        char *e;
@@ -962,7 +976,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        switch (OP(c)) {
        case ANYOF:
            if (do_utf8) {
-                while (s < strend) {
+                while (s + (uskip = UTF8SKIP(s)) <= strend) {
                      if ((ANYOF_FLAGS(c) & ANYOF_UNICODE) ||
                          !UTF8_IS_INVARIANT((U8)s[0]) ?
                          reginclass(c, (U8*)s, 0, do_utf8) :
@@ -974,7 +988,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                      }
                      else 
                           tmp = 1;
-                     s += UTF8SKIP(s);
+                     s += uskip;
                 }
            }
            else {
@@ -1007,10 +1021,12 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
            }
            break;
        case EXACTF:
-           m = STRING(c);
-           ln = STR_LEN(c);
+           m   = STRING(c);
+           ln  = STR_LEN(c);   /* length to match in octets/bytes */
+           lnc = (I32) ln;     /* length to match in characters */
            if (UTF) {
                STRLEN ulen1, ulen2;
+               U8 *sm = (U8 *) m;
                U8 tmpbuf1[UTF8_MAXLEN_UCLC+1];
                U8 tmpbuf2[UTF8_MAXLEN_UCLC+1];
 
@@ -1021,6 +1037,11 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                                    0, ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY);
                c2 = utf8n_to_uvchr(tmpbuf2, UTF8_MAXLEN_UCLC,
                                    0, ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY);
+               lnc = 0;
+               while (sm < ((U8 *) m + ln)) {
+                   lnc++;
+                   sm += UTF8SKIP(sm);
+               }
            }
            else {
                c1 = *(U8*)m;
@@ -1028,12 +1049,13 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
            }
            goto do_exactf;
        case EXACTFL:
-           m = STRING(c);
-           ln = STR_LEN(c);
+           m   = STRING(c);
+           ln  = STR_LEN(c);
+           lnc = (I32) ln;
            c1 = *(U8*)m;
            c2 = PL_fold_locale[c1];
          do_exactf:
-           e = HOP3c(strend, -(I32)ln, s);
+           e = HOP3c(strend, -((I32)lnc), s);
 
            if (norun && e < s)
                e = s;                  /* Due to minlen logic of intuit() */
@@ -1056,6 +1078,8 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                STRLEN len, foldlen;
                
                if (c1 == c2) {
+                   /* Upper and lower of 1st char are equal -
+                    * probably not a "letter". */
                    while (s <= e) {
                        c = utf8n_to_uvchr((U8*)s, UTF8_MAXLEN, &len,
                                           ckWARN(WARN_UTF8) ?
@@ -1160,7 +1184,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                tmp = ((OP(c) == BOUND ?
                        isALNUM_uni(tmp) : isALNUM_LC_uvchr(UNI_TO_NATIVE(tmp))) != 0);
                LOAD_UTF8_CHARCLASS(alnum,"a");
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (tmp == !(OP(c) == BOUND ?
                                 swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8) :
                                 isALNUM_LC_utf8((U8*)s)))
@@ -1169,7 +1193,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                        if ((norun || regtry(prog, s)))
                            goto got_it;
                    }
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
@@ -1203,14 +1227,14 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                tmp = ((OP(c) == NBOUND ?
                        isALNUM_uni(tmp) : isALNUM_LC_uvchr(UNI_TO_NATIVE(tmp))) != 0);
                LOAD_UTF8_CHARCLASS(alnum,"a");
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (tmp == !(OP(c) == NBOUND ?
                                 swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8) :
                                 isALNUM_LC_utf8((U8*)s)))
                        tmp = !tmp;
                    else if ((norun || regtry(prog, s)))
                        goto got_it;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
@@ -1232,7 +1256,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case ALNUM:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(alnum,"a");
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1241,7 +1265,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
@@ -1261,7 +1285,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case ALNUML:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (isALNUM_LC_utf8((U8*)s)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1270,7 +1294,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
@@ -1290,7 +1314,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case NALNUM:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(alnum,"a");
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1299,7 +1323,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
@@ -1319,7 +1343,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case NALNUML:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!isALNUM_LC_utf8((U8*)s)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1328,7 +1352,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
@@ -1348,7 +1372,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case SPACE:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(space," ");
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (*s == ' ' || swash_fetch(PL_utf8_space,(U8*)s, do_utf8)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1357,7 +1381,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
@@ -1377,7 +1401,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case SPACEL:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (*s == ' ' || isSPACE_LC_utf8((U8*)s)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1386,7 +1410,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
@@ -1406,7 +1430,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case NSPACE:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(space," ");
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!(*s == ' ' || swash_fetch(PL_utf8_space,(U8*)s, do_utf8))) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1415,7 +1439,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
@@ -1435,7 +1459,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case NSPACEL:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!(*s == ' ' || isSPACE_LC_utf8((U8*)s))) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1444,7 +1468,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
@@ -1464,7 +1488,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case DIGIT:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(digit,"0");
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (swash_fetch(PL_utf8_digit,(U8*)s, do_utf8)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1473,7 +1497,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
@@ -1493,7 +1517,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case DIGITL:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (isDIGIT_LC_utf8((U8*)s)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1502,7 +1526,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
@@ -1522,7 +1546,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case NDIGIT:
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS(digit,"0");
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!swash_fetch(PL_utf8_digit,(U8*)s, do_utf8)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1531,7 +1555,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
@@ -1551,7 +1575,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
        case NDIGITL:
            PL_reg_flags |= RF_tainted;
            if (do_utf8) {
-               while (s < strend) {
+               while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!isDIGIT_LC_utf8((U8*)s)) {
                        if (tmp && (norun || regtry(prog, s)))
                            goto got_it;
@@ -1560,7 +1584,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *sta
                    }
                    else
                        tmp = 1;
-                   s += UTF8SKIP(s);
+                   s += uskip;
                }
            }
            else {
@@ -3190,7 +3214,10 @@ S_regmatch(pTHX_ regnode *prog)
                                      "%*s  already tried at this position...\n",
                                      REPORT_CODE_OFF+PL_regindent*2, "")
                        );
-                       sayNO_SILENT;
+                       if (PL_reg_flags & RF_false)
+                           sayYES;
+                       else
+                           sayNO_SILENT;
                    }
                    PL_reg_poscache[o] |= (1<<b);
                }
@@ -3339,7 +3366,7 @@ S_regmatch(pTHX_ regnode *prog)
            CHECKPOINT lastcp;
        
            /* We suppose that the next guy does not need
-              backtracking: in particular, it is of constant length,
+              backtracking: in particular, it is of constant non-zero length,
               and has no parenths to influence future backrefs. */
            ln = ARG1(scan);  /* min to match */
            n  = ARG2(scan);  /* max to match */
@@ -3358,15 +3385,6 @@ S_regmatch(pTHX_ regnode *prog)
                minmod = 0;
                if (ln && regrepeat_hard(scan, ln, &l) < ln)
                    sayNO;
-               /* if we matched something zero-length we don't need to
-                  backtrack - capturing parens are already defined, so
-                  the caveat in the maximal case doesn't apply
-
-                  XXXX if ln == 0, we can redo this check first time
-                  through the following loop
-               */
-               if (ln && l == 0)
-                   n = ln;     /* don't backtrack */
                locinput = PL_reginput;
                if (HAS_TEXT(next) || JUMPABLE(next)) {
                    regnode *text_node = next;
@@ -3376,19 +3394,8 @@ S_regmatch(pTHX_ regnode *prog)
                    if (! HAS_TEXT(text_node)) c1 = c2 = -1000;
                    else {
                        if (PL_regkind[(U8)OP(text_node)] == REF) {
-                           I32 n, ln;
-                           n = ARG(text_node);  /* which paren pair */
-                           ln = PL_regstartp[n];
-                           /* assume yes if we haven't seen CLOSEn */
-                           if (
-                               (I32)*PL_reglastparen < n ||
-                               ln == -1 ||
-                               ln == PL_regendp[n]
-                           ) {
-                               c1 = c2 = -1000;
-                               goto assume_ok_MM;
-                           }
-                           c1 = *(PL_bostr + ln);
+                           c1 = c2 = -1000;
+                           goto assume_ok_MM;
                        }
                        else { c1 = (U8)*STRING(text_node); }
                        if (OP(text_node) == EXACTF || OP(text_node) == REFF)
@@ -3403,8 +3410,7 @@ S_regmatch(pTHX_ regnode *prog)
                    c1 = c2 = -1000;
            assume_ok_MM:
                REGCP_SET(lastcp);
-               /* This may be improved if l == 0.  */
-               while (n >= ln || (n == REG_INFTY && ln > 0 && l)) { /* ln overflow ? */
+               while (n >= ln || (n == REG_INFTY && ln > 0)) { /* ln overflow ? */
                    /* If it could work, try it. */
                    if (c1 == -1000 ||
                        UCHARAT(PL_reginput) == c1 ||
@@ -3435,13 +3441,6 @@ S_regmatch(pTHX_ regnode *prog)
            }
            else {
                n = regrepeat_hard(scan, n, &l);
-               /* if we matched something zero-length we don't need to
-                  backtrack, unless the minimum count is zero and we
-                  are capturing the result - in that case the capture
-                  being defined or not may affect later execution
-               */
-               if (n != 0 && l == 0 && !(paren && ln == 0))
-                   ln = n;     /* don't backtrack */
                locinput = PL_reginput;
                DEBUG_r(
                    PerlIO_printf(Perl_debug_log,
@@ -3458,19 +3457,8 @@ S_regmatch(pTHX_ regnode *prog)
                        if (! HAS_TEXT(text_node)) c1 = c2 = -1000;
                        else {
                            if (PL_regkind[(U8)OP(text_node)] == REF) {
-                               I32 n, ln;
-                               n = ARG(text_node);  /* which paren pair */
-                               ln = PL_regstartp[n];
-                               /* assume yes if we haven't seen CLOSEn */
-                               if (
-                                   (I32)*PL_reglastparen < n ||
-                                   ln == -1 ||
-                                   ln == PL_regendp[n]
-                               ) {
-                                   c1 = c2 = -1000;
-                                   goto assume_ok_REG;
-                               }
-                               c1 = *(PL_bostr + ln);
+                               c1 = c2 = -1000;
+                               goto assume_ok_REG;
                            }
                            else { c1 = (U8)*STRING(text_node); }
 
@@ -3567,19 +3555,8 @@ S_regmatch(pTHX_ regnode *prog)
                if (! HAS_TEXT(text_node)) c1 = c2 = -1000;
                else {
                    if (PL_regkind[(U8)OP(text_node)] == REF) {
-                       I32 n, ln;
-                       n = ARG(text_node);  /* which paren pair */
-                       ln = PL_regstartp[n];
-                       /* assume yes if we haven't seen CLOSEn */
-                       if (
-                           (I32)*PL_reglastparen < n ||
-                           ln == -1 ||
-                           ln == PL_regendp[n]
-                       ) {
-                           c1 = c2 = -1000;
-                           goto assume_ok_easy;
-                       }
-                       s = (U8*)PL_bostr + ln;
+                       c1 = c2 = -1000;
+                       goto assume_ok_easy;
                    }
                    else { s = (U8*)STRING(text_node); }
 
@@ -3873,6 +3850,7 @@ S_regmatch(pTHX_ regnode *prog)
            }
            else
                PL_reginput = locinput;
+           PL_reg_flags ^= RF_false;
            goto do_ifmatch;
        case IFMATCH:
            n = 1;
@@ -3888,6 +3866,8 @@ S_regmatch(pTHX_ regnode *prog)
          do_ifmatch:
            inner = NEXTOPER(NEXTOPER(scan));
            if (regmatch(inner) != n) {
+               if (n == 0)
+                   PL_reg_flags ^= RF_false;
              say_no:
                if (logical) {
                    logical = 0;
@@ -3897,6 +3877,8 @@ S_regmatch(pTHX_ regnode *prog)
                else
                    sayNO;
            }
+           if (n == 0)
+               PL_reg_flags ^= RF_false;
          say_yes:
            if (logical) {
                logical = 0;
@@ -4263,7 +4245,7 @@ S_regrepeat(pTHX_ regnode *p, I32 max)
 /*
  - regrepeat_hard - repeatedly match something, report total lenth and length
  *
- * The repeater is supposed to have constant length.
+ * The repeater is supposed to have constant non-zero length.
  */
 
 STATIC I32