Removing so_locations once is enough.
[p5sagit/p5-mst-13.2.git] / regexec.c
index 7dbf6dc..9a7e91b 100644 (file)
--- a/regexec.c
+++ b/regexec.c
@@ -25,7 +25,7 @@
 #    define PERL_IN_XSUB_RE
 #  endif
 /* need access to debugger hooks */
-#  ifndef DEBUGGING
+#  if defined(PERL_EXT_RE_DEBUG) && !defined(DEBUGGING)
 #    define DEBUGGING
 #  endif
 #endif
 #  define Perl_regexec_flags my_regexec
 #  define Perl_regdump my_regdump
 #  define Perl_regprop my_regprop
+#  define Perl_re_intuit_start my_re_intuit_start
 /* *These* symbols are masked to allow static link. */
 #  define Perl_pregexec my_pregexec
 #  define Perl_reginitcolors my_reginitcolors 
+
+#  define PERL_NO_GET_CONTEXT
 #endif 
 
 /*SUPPRESS 112*/
 #define PERL_IN_REGEXEC_C
 #include "perl.h"
 
+#ifdef PERL_IN_XSUB_RE
+#  if defined(PERL_CAPI) || defined(PERL_OBJECT)
+#    include "XSUB.h"
+#  endif
+#endif
+
 #include "regcomp.h"
 
 #define RF_tainted     1               /* tainted information used? */
  * Forwards.
  */
 
-#define REGINCLASS(p,c)  (*(p) ? reginclass(p,c) : ANYOF_TEST(p,c))
+#define REGINCLASS(p,c)  (ANYOF_FLAGS(p) ? reginclass(p,c) : ANYOF_BITMAP_TEST(p,c))
 #define REGINCLASSUTF8(f,p)  (ARG1(f) ? reginclassutf8(f,p) : swash_fetch((SV*)PL_regdata->data[ARG2(f)],p))
 
 #define CHR_SVLEN(sv) (UTF ? sv_len_utf8(sv) : SvCUR(sv))
 #define HOPc(pos,off) ((char*)HOP(pos,off))
 #define HOPMAYBEc(pos,off) ((char*)HOPMAYBE(pos,off))
 
+static void restore_pos(pTHXo_ void *arg);
+
+
 STATIC CHECKPOINT
 S_regcppush(pTHX_ I32 parenfloor)
 {
@@ -242,22 +254,374 @@ S_cache_re(pTHX_ regexp *prog)
     PL_reg_re = prog;    
 }
 
-STATIC void
-S_restore_pos(pTHX_ void *arg)
+/* 
+ * Need to implement the following flags for reg_anch:
+ *
+ * USE_INTUIT_NOML             - Useful to call re_intuit_start() first
+ * USE_INTUIT_ML
+ * INTUIT_AUTORITATIVE_NOML    - Can trust a positive answer
+ * INTUIT_AUTORITATIVE_ML
+ * INTUIT_ONCE_NOML            - Intuit can match in one location only.
+ * INTUIT_ONCE_ML
+ *
+ * Another flag for this function: SECOND_TIME (so that float substrs
+ * with giant delta may be not rechecked).
+ */
+
+/* Assumptions: if ANCH_GPOS, then strpos is anchored. XXXX Check GPOS logic */
+
+/* If SCREAM, then SvPVX(sv) should be compatible with strpos and strend.
+   Otherwise, only SvCUR(sv) is used to get strbeg. */
+
+/* XXXX We assume that strpos is strbeg unless sv. */
+
+/* A failure to find a constant substring means that there is no need to make
+   an expensive call to REx engine, thus we celebrate a failure.  Similarly,
+   finding a substring too deep into the string means that less calls to
+   regtry() should be needed. */
+
+char *
+Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
+                    char *strend, U32 flags, re_scream_pos_data *data)
 {
-    dTHR;
-    if (PL_reg_eval_set) {
-       if (PL_reg_oldsaved) {
-           PL_reg_re->subbeg = PL_reg_oldsaved;
-           PL_reg_re->sublen = PL_reg_oldsavedlen;
-           RX_MATCH_COPIED_on(PL_reg_re);
+    register I32 start_shift;
+    /* Should be nonnegative! */
+    register I32 end_shift;
+    register char *s;
+    register SV *check;
+    char *t;
+    I32 ml_anch;
+    char *tmp;
+    register char *other_last = Nullch;
+
+    DEBUG_r( if (!PL_colorset) reginitcolors() );
+    DEBUG_r(PerlIO_printf(Perl_debug_log,
+                     "%sGuessing start of match, REx%s `%s%.60s%s%s' against `%s%.*s%s%s'...\n",
+                     PL_colors[4],PL_colors[5],PL_colors[0],
+                     prog->precomp,
+                     PL_colors[1],
+                     (strlen(prog->precomp) > 60 ? "..." : ""),
+                     PL_colors[0],
+                     (strend - strpos > 60 ? 60 : strend - strpos),
+                     strpos, PL_colors[1],
+                     (strend - strpos > 60 ? "..." : ""))
+       );
+
+    if (prog->minlen > strend - strpos) {
+       DEBUG_r(PerlIO_printf(Perl_debug_log, "String too short...\n"));
+       goto fail;
+    }
+    if (prog->reganch & ROPT_ANCH) {   /* Match at beg-of-str or after \n */
+       ml_anch = !( (prog->reganch & ROPT_ANCH_SINGLE)
+                    || ( (prog->reganch & ROPT_ANCH_BOL)
+                         && !PL_multiline ) ); /* Check after \n? */
+
+       if ((prog->check_offset_min == prog->check_offset_max) && !ml_anch) {
+           /* Substring at constant offset from beg-of-str... */
+           I32 slen;
+
+           if ( !(prog->reganch & ROPT_ANCH_GPOS) /* Checked by the caller */
+                && (sv && (strpos + SvCUR(sv) != strend)) ) {
+               DEBUG_r(PerlIO_printf(Perl_debug_log, "Not at start...\n"));
+               goto fail;
+           }
+           PL_regeol = strend;                 /* Used in HOP() */
+           s = HOPc(strpos, prog->check_offset_min);
+           if (SvTAIL(prog->check_substr)) {
+               slen = SvCUR(prog->check_substr);       /* >= 1 */
+
+               if ( strend - s > slen || strend - s < slen - 1 
+                    || (strend - s == slen && strend[-1] != '\n')) {
+                   DEBUG_r(PerlIO_printf(Perl_debug_log, "String too long...\n"));
+                   goto fail_finish;
+               }
+               /* Now should match s[0..slen-2] */
+               slen--;
+               if (slen && (*SvPVX(prog->check_substr) != *s
+                            || (slen > 1
+                                && memNE(SvPVX(prog->check_substr), s, slen)))) {
+                 report_neq:
+                   DEBUG_r(PerlIO_printf(Perl_debug_log, "String not equal...\n"));
+                   goto fail_finish;
+               }
+           }
+           else if (*SvPVX(prog->check_substr) != *s
+                    || ((slen = SvCUR(prog->check_substr)) > 1
+                        && memNE(SvPVX(prog->check_substr), s, slen)))
+               goto report_neq;
+           goto success_at_start;
        }
-       PL_reg_magic->mg_len = PL_reg_oldpos;
-       PL_reg_eval_set = 0;
-       PL_curpm = PL_reg_oldcurpm;
-    }  
-}
+       /* Match is anchored, but substr is not anchored wrt beg-of-str. */
+       s = strpos;
+       start_shift = prog->check_offset_min; /* okay to underestimate on CC */
+       /* Should be nonnegative! */
+       end_shift = prog->minlen - start_shift -
+           CHR_SVLEN(prog->check_substr) + (SvTAIL(prog->check_substr) != 0);
+       if (!ml_anch) {
+           I32 end = prog->check_offset_max + CHR_SVLEN(prog->check_substr)
+                                        - (SvTAIL(prog->check_substr) != 0);
+           I32 eshift = strend - s - end;
+
+           if (end_shift < eshift)
+               end_shift = eshift;
+       }
+    }
+    else {                             /* Can match at random position */
+       ml_anch = 0;
+       s = strpos;
+       start_shift = prog->check_offset_min; /* okay to underestimate on CC */
+       /* Should be nonnegative! */
+       end_shift = prog->minlen - start_shift -
+           CHR_SVLEN(prog->check_substr) + (SvTAIL(prog->check_substr) != 0);
+    }
+
+#ifdef DEBUGGING       /* 7/99: reports of failure (with the older version) */
+    if (end_shift < 0)
+       croak("panic: end_shift");
+#endif
+
+    check = prog->check_substr;
+  restart:
+    /* Find a possible match in the region s..strend by looking for
+       the "check" substring in the region corrected by start/end_shift. */
+    if (flags & REXEC_SCREAM) {
+       char *strbeg = SvPVX(sv);       /* XXXX Assume PV_force() on SCREAM! */
+       I32 p = -1;                     /* Internal iterator of scream. */
+       I32 *pp = data ? data->scream_pos : &p;
+
+       if (PL_screamfirst[BmRARE(check)] >= 0
+           || ( BmRARE(check) == '\n'
+                && (BmPREVIOUS(check) == SvCUR(check) - 1)
+                && SvTAIL(check) ))
+           s = screaminstr(sv, check, 
+                           start_shift + (s - strbeg), end_shift, pp, 0);
+       else
+           goto fail_finish;
+       if (data)
+           *data->scream_olds = s;
+    }
+    else
+       s = fbm_instr((unsigned char*)s + start_shift,
+                     (unsigned char*)strend - end_shift,
+                     check, PL_multiline ? FBMrf_MULTILINE : 0);
+
+    /* Update the count-of-usability, remove useless subpatterns,
+       unshift s.  */
+
+    DEBUG_r(PerlIO_printf(Perl_debug_log, "%s %s substr `%s%.*s%s'%s%s",
+                         (s ? "Found" : "Did not find"),
+                         ((check == prog->anchored_substr) ? "anchored" : "floating"),
+                         PL_colors[0],
+                         SvCUR(check) - (SvTAIL(check)!=0), SvPVX(check),
+                         PL_colors[1], (SvTAIL(check) ? "$" : ""),
+                         (s ? " at offset " : "...\n") ) );
+
+    if (!s)
+       goto fail_finish;
+
+    /* Finish the diagnostic message */
+    DEBUG_r(PerlIO_printf(Perl_debug_log, "%ld...\n", (long)(s - strpos)) );
+
+    /* Got a candidate.  Check MBOL anchoring, and the *other* substr.
+       Start with the other substr.
+       XXXX no SCREAM optimization yet - and a very coarse implementation
+       XXXX /ttx+/ results in anchored=`ttx', floating=`x'.  floating will
+               *always* match.  Probably should be marked during compile...
+       Probably it is right to do no SCREAM here...
+     */
+
+    if (prog->float_substr && prog->anchored_substr) {
+       /* Take into account the anchored substring. */
+       /* XXXX May be hopelessly wrong for UTF... */
+       if (!other_last)
+           other_last = strpos - 1;
+       if (check == prog->float_substr) {
+               char *last = s - start_shift, *last1, *last2;
+               char *s1 = s;
+
+               tmp = PL_bostr;
+               t = s - prog->check_offset_max;
+               if (s - strpos > prog->check_offset_max  /* signed-corrected t > strpos */
+                   && (!(prog->reganch & ROPT_UTF8)
+                       || (PL_bostr = strpos, /* Used in regcopmaybe() */
+                           (t = reghopmaybe_c(s, -(prog->check_offset_max)))
+                           && t > strpos)))
+                   ;
+               else
+                   t = strpos;
+               t += prog->anchored_offset;
+               if (t <= other_last)
+                   t = other_last + 1;
+               PL_bostr = tmp;
+               last2 = last1 = strend - prog->minlen;
+               if (last < last1)
+                   last1 = last;
+ /* XXXX It is not documented what units *_offsets are in.  Assume bytes.  */
+               /* On end-of-str: see comment below. */
+               s = fbm_instr((unsigned char*)t,
+                             (unsigned char*)last1 + prog->anchored_offset
+                                + SvCUR(prog->anchored_substr)
+                                - (SvTAIL(prog->anchored_substr)!=0),
+                             prog->anchored_substr, PL_multiline ? FBMrf_MULTILINE : 0);
+               DEBUG_r(PerlIO_printf(Perl_debug_log, "%s anchored substr `%s%.*s%s'%s",
+                       (s ? "Found" : "Contradicts"),
+                       PL_colors[0],
+                         SvCUR(prog->anchored_substr)
+                         - (SvTAIL(prog->anchored_substr)!=0),
+                         SvPVX(prog->anchored_substr),
+                         PL_colors[1], (SvTAIL(prog->anchored_substr) ? "$" : "")));
+               if (!s) {
+                   if (last1 >= last2) {
+                       DEBUG_r(PerlIO_printf(Perl_debug_log,
+                                               ", giving up...\n"));
+                       goto fail_finish;
+                   }
+                   DEBUG_r(PerlIO_printf(Perl_debug_log,
+                       ", trying floating at offset %ld...\n",
+                       (long)(s1 + 1 - strpos)));
+                   PL_regeol = strend;                 /* Used in HOP() */
+                   other_last = last1 + prog->anchored_offset;
+                   s = HOPc(last, 1);
+                   goto restart;
+               }
+               else {
+                   DEBUG_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n",
+                         (long)(s - strpos)));
+                   t = s - prog->anchored_offset;
+                   other_last = s - 1;
+                   if (t == strpos)
+                       goto try_at_start;
+                   s = s1;
+                   goto try_at_offset;
+               }
+       }
+       else {          /* Take into account the floating substring. */
+               char *last, *last1;
+               char *s1 = s;
+
+               t = s - start_shift;
+               last1 = last = strend - prog->minlen + prog->float_min_offset;
+               if (last - t > prog->float_max_offset)
+                   last = t + prog->float_max_offset;
+               s = t + prog->float_min_offset;
+               if (s <= other_last)
+                   s = other_last + 1;
+ /* XXXX It is not documented what units *_offsets are in.  Assume bytes.  */
+               /* fbm_instr() takes into account exact value of end-of-str
+                  if the check is SvTAIL(ed).  Since false positives are OK,
+                  and end-of-str is not later than strend we are OK. */
+               s = fbm_instr((unsigned char*)s,
+                             (unsigned char*)last + SvCUR(prog->float_substr)
+                                 - (SvTAIL(prog->float_substr)!=0),
+                             prog->float_substr, PL_multiline ? FBMrf_MULTILINE : 0);
+               DEBUG_r(PerlIO_printf(Perl_debug_log, "%s floating substr `%s%.*s%s'%s",
+                       (s ? "Found" : "Contradicts"),
+                       PL_colors[0],
+                         SvCUR(prog->float_substr)
+                         - (SvTAIL(prog->float_substr)!=0),
+                         SvPVX(prog->float_substr),
+                         PL_colors[1], (SvTAIL(prog->float_substr) ? "$" : "")));
+               if (!s) {
+                   if (last1 == last) {
+                       DEBUG_r(PerlIO_printf(Perl_debug_log,
+                                               ", giving up...\n"));
+                       goto fail_finish;
+                   }
+                   DEBUG_r(PerlIO_printf(Perl_debug_log,
+                       ", trying anchored starting at offset %ld...\n",
+                       (long)(s1 + 1 - strpos)));
+                   other_last = last;
+                   PL_regeol = strend;                 /* Used in HOP() */
+                   s = HOPc(t, 1);
+                   goto restart;
+               }
+               else {
+                   DEBUG_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n",
+                         (long)(s - strpos)));
+                   other_last = s - 1;
+                   if (t == strpos)
+                       goto try_at_start;
+                   s = s1;
+                   goto try_at_offset;
+               }
+       }
+    }
+
+    t = s - prog->check_offset_max;
+    tmp = PL_bostr;
+    if (s - strpos > prog->check_offset_max  /* signed-corrected t > strpos */
+        && (!(prog->reganch & ROPT_UTF8)
+           || (PL_bostr = strpos, /* Used in regcopmaybe() */
+               ((t = reghopmaybe_c(s, -(prog->check_offset_max)))
+                && t > strpos)))) {
+       PL_bostr = tmp;
+       /* Fixed substring is found far enough so that the match
+          cannot start at strpos. */
+      try_at_offset:
+       if (ml_anch && t[-1] != '\n') {
+         find_anchor:          /* Eventually fbm_*() should handle this */
+           while (t < strend - prog->minlen) {
+               if (*t == '\n') {
+                   if (t < s - prog->check_offset_min) {
+                       s = t + 1;
+                       DEBUG_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m at offset %ld...\n",
+                           PL_colors[0],PL_colors[1], (long)(s - strpos)));
+                       goto set_useful;
+                   }
+                   DEBUG_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m, restarting at offset %ld...\n",
+                       PL_colors[0],PL_colors[1], (long)(t + 1 - strpos)));
+                   s = t + 1;
+                   goto restart;
+               }
+               t++;
+           }
+           DEBUG_r(PerlIO_printf(Perl_debug_log, "Did not find /%s^%s/m...\n",
+                       PL_colors[0],PL_colors[1]));
+           goto fail_finish;
+       }
+       s = t;
+      set_useful:
+       ++BmUSEFUL(prog->check_substr); /* hooray/5 */
+    }
+    else {
+       PL_bostr = tmp;
+       /* The found string does not prohibit matching at beg-of-str
+          - no optimization of calling REx engine can be performed,
+          unless it was an MBOL and we are not after MBOL. */
+      try_at_start:
+       /* Even in this situation we may use MBOL flag if strpos is offset
+          wrt the start of the string. */
+       if (ml_anch && sv
+           && (strpos + SvCUR(sv) != strend) && strpos[-1] != '\n') {
+           t = strpos;
+           goto find_anchor;
+       }
+      success_at_start:
+       if (!(prog->reganch & ROPT_NAUGHTY)
+           && --BmUSEFUL(prog->check_substr) < 0
+           && prog->check_substr == prog->float_substr) { /* boo */
+           /* If flags & SOMETHING - do not do it many times on the same match */
+           SvREFCNT_dec(prog->check_substr);
+           prog->check_substr = Nullsv;        /* disable */
+           prog->float_substr = Nullsv;        /* clear */
+           s = strpos;
+           prog->reganch &= ~RE_USE_INTUIT;
+       }
+       else
+           s = strpos;
+    }
 
+    DEBUG_r(PerlIO_printf(Perl_debug_log, "%sGuessed:%s match at offset %ld\n",
+                         PL_colors[4], PL_colors[5], (long)(s - strpos)) );
+    return s;
+
+  fail_finish:                         /* Substring not found */
+    BmUSEFUL(prog->check_substr) += 5; /* hooray */
+  fail:
+    DEBUG_r(PerlIO_printf(Perl_debug_log, "%sMatch rejected by optimizer%s\n",
+                         PL_colors[4],PL_colors[5]));
+    return Nullch;
+}
 
 /*
  - regexec_flags - match a regexp against a string
@@ -319,6 +683,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
 
     PL_reg_flags = 0;
     PL_reg_eval_set = 0;
+    PL_reg_maxiter = 0;
 
     if (prog->reganch & ROPT_UTF8)
        PL_reg_flags |= RF_utf8;
@@ -339,103 +704,78 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
 
     /* If there is a "must appear" string, look for it. */
     s = startpos;
-    if (!(flags & REXEC_CHECKED) 
-       && prog->check_substr != Nullsv &&
-       !(prog->reganch & ROPT_ANCH_GPOS) &&
-       (!(prog->reganch & (ROPT_ANCH_BOL | ROPT_ANCH_MBOL))
-        || (PL_multiline && prog->check_substr == prog->anchored_substr)) )
-    {
-       char *t;
-       start_shift = prog->check_offset_min;   /* okay to underestimate on CC */
-       /* Should be nonnegative! */
-       end_shift = minlen - start_shift -
-           CHR_SVLEN(prog->check_substr) + (SvTAIL(prog->check_substr) != 0);
-       if (flags & REXEC_SCREAM) {
-           SV *c = prog->check_substr;
-
-           if (PL_screamfirst[BmRARE(c)] >= 0
-               || ( BmRARE(c) == '\n'
-                    && (BmPREVIOUS(c) == SvCUR(c) - 1)
-                    && SvTAIL(c) ))
-                   s = screaminstr(sv, prog->check_substr, 
-                                   start_shift + (stringarg - strbeg),
-                                   end_shift, &scream_pos, 0);
-           else
-                   s = Nullch;
-           scream_olds = s;
-       }
+
+    if (prog->reganch & ROPT_GPOS_SEEN) {
+       MAGIC *mg;
+
+       if (!(flags & REXEC_IGNOREPOS) && sv && SvTYPE(sv) >= SVt_PVMG
+           && SvMAGIC(sv) && (mg = mg_find(sv, 'g')) && mg->mg_len >= 0)
+           PL_reg_ganch = strbeg + mg->mg_len;
        else
-           s = fbm_instr((unsigned char*)s + start_shift,
-                         (unsigned char*)strend - end_shift,
-               prog->check_substr, PL_multiline ? FBMrf_MULTILINE : 0);
-       if (!s) {
-           ++BmUSEFUL(prog->check_substr);     /* hooray */
-           goto phooey;        /* not present */
-       }
-       else if (s - stringarg > prog->check_offset_max &&
-                (UTF 
-                   ? ((t = reghopmaybe_c(s, -(prog->check_offset_max))) && t >= stringarg)
-                   : (t = s - prog->check_offset_max) != 0
-                )
-               )
-       {
-           ++BmUSEFUL(prog->check_substr);     /* hooray/2 */
-           s = t;
-       }
-       else if (!(prog->reganch & ROPT_NAUGHTY)
-                  && --BmUSEFUL(prog->check_substr) < 0
-                  && prog->check_substr == prog->float_substr) { /* boo */
-           SvREFCNT_dec(prog->check_substr);
-           prog->check_substr = Nullsv;        /* disable */
-           prog->float_substr = Nullsv;        /* clear */
-           s = startpos;
+           PL_reg_ganch = startpos;
+       if (prog->reganch & ROPT_ANCH_GPOS) {
+           if (s > PL_reg_ganch)
+               goto phooey;
+           s = PL_reg_ganch;
        }
-       else
-           s = startpos;
     }
 
-    DEBUG_r(if (!PL_colorset) reginitcolors());
-    DEBUG_r(PerlIO_printf(Perl_debug_log, 
-                     "%sMatching%s `%s%.60s%s%s' against `%s%.*s%s%s'\n",
+    if (!(flags & REXEC_CHECKED) && prog->check_substr != Nullsv) {
+       re_scream_pos_data d;
+
+       d.scream_olds = &scream_olds;
+       d.scream_pos = &scream_pos;
+       s = re_intuit_start(prog, sv, s, strend, flags, &d);
+       if (!s)
+           goto phooey;        /* not present */
+    }
+
+    DEBUG_r( if (!PL_colorset) reginitcolors() );
+    DEBUG_r(PerlIO_printf(Perl_debug_log,
+                     "%sMatching REx%s `%s%.60s%s%s' against `%s%.*s%s%s'\n",
                      PL_colors[4],PL_colors[5],PL_colors[0],
                      prog->precomp,
                      PL_colors[1],
                      (strlen(prog->precomp) > 60 ? "..." : ""),
-                     PL_colors[0], 
+                     PL_colors[0],
                      (strend - startpos > 60 ? 60 : strend - startpos),
                      startpos, PL_colors[1],
                      (strend - startpos > 60 ? "..." : ""))
        );
 
-    if (prog->reganch & ROPT_GPOS_SEEN) {
-       MAGIC *mg;
-
-       if (!(flags & REXEC_IGNOREPOS) && sv && SvTYPE(sv) >= SVt_PVMG
-           && SvMAGIC(sv) && (mg = mg_find(sv, 'g')) && mg->mg_len >= 0)
-           PL_reg_ganch = strbeg + mg->mg_len;
-       else
-           PL_reg_ganch = startpos;
-    }
-
     /* Simplest case:  anchored match need be tried only once. */
     /*  [unless only anchor is BOL and multiline is set] */
     if (prog->reganch & (ROPT_ANCH & ~ROPT_ANCH_GPOS)) {
-       if (regtry(prog, startpos))
+       if (s == startpos && regtry(prog, startpos))
            goto got_it;
        else if (PL_multiline || (prog->reganch & ROPT_IMPLICIT)
                 || (prog->reganch & ROPT_ANCH_MBOL)) /* XXXX SBOL? */
        {
+           char *end;
+
            if (minlen)
                dontbother = minlen - 1;
-           strend = HOPc(strend, -dontbother);
+           end = HOPc(strend, -dontbother) - 1;
            /* for multiline we only have to try after newlines */
-           if (s > startpos)
-               s--;
-           while (s < strend) {
-               if (*s++ == '\n') {     /* don't need PL_utf8skip here */
-                   if (s < strend && regtry(prog, s))
+           if (prog->check_substr) {
+               while (1) {
+                   if (regtry(prog, s))
                        goto got_it;
-               }
+                   if (s >= end)
+                       goto phooey;
+                   s = re_intuit_start(prog, sv, s + 1, strend, flags, NULL);
+                   if (!s)
+                       goto phooey;
+               }               
+           } else {
+               if (s > startpos)
+                   s--;
+               while (s < end) {
+                   if (*s++ == '\n') { /* don't need PL_utf8skip here */
+                       if (regtry(prog, s))
+                           goto got_it;
+                   }
+               }               
            }
        }
        goto phooey;
@@ -448,7 +788,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
     /* Messy cases:  unanchored match. */
     if (prog->anchored_substr && prog->reganch & ROPT_SKIP) { 
        /* we have /x+whatever/ */
-       /* it must be a one character string */
+       /* it must be a one character string (XXXX Except UTF?) */
        char ch = SvPVX(prog->anchored_substr)[0];
        if (UTF) {
            while (s < strend) {
@@ -900,6 +1240,34 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
                s += UTF8SKIP(s);
            }
            break;
+       case DIGITL:
+           PL_reg_flags |= RF_tainted;
+           while (s < strend) {
+               if (isDIGIT_LC(*s)) {
+                   if (tmp && regtry(prog, s))
+                       goto got_it;
+                   else
+                       tmp = doevery;
+               }
+               else
+                   tmp = 1;
+               s++;
+           }
+           break;
+       case DIGITLUTF8:
+           PL_reg_flags |= RF_tainted;
+           while (s < strend) {
+               if (isDIGIT_LC_utf8((U8*)s)) {
+                   if (tmp && regtry(prog, s))
+                       goto got_it;
+                   else
+                       tmp = doevery;
+               }
+               else
+                   tmp = 1;
+               s += UTF8SKIP(s);
+           }
+           break;
        case NDIGIT:
            while (s < strend) {
                if (!isDIGIT(*s)) {
@@ -926,6 +1294,34 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
                s += UTF8SKIP(s);
            }
            break;
+       case NDIGITL:
+           PL_reg_flags |= RF_tainted;
+           while (s < strend) {
+               if (!isDIGIT_LC(*s)) {
+                   if (tmp && regtry(prog, s))
+                       goto got_it;
+                   else
+                       tmp = doevery;
+               }
+               else
+                   tmp = 1;
+               s++;
+           }
+           break;
+       case NDIGITLUTF8:
+           PL_reg_flags |= RF_tainted;
+           while (s < strend) {
+               if (!isDIGIT_LC_utf8((U8*)s)) {
+                   if (tmp && regtry(prog, s))
+                       goto got_it;
+                   else
+                       tmp = doevery;
+               }
+               else
+                   tmp = 1;
+               s += UTF8SKIP(s);
+           }
+           break;
        }
     }
     else {
@@ -996,7 +1392,7 @@ got_it:
            sv_setsv(oreplsv, GvSV(PL_replgv));/* So that when GvSV(replgv) is
                                                  restored, the value remains
                                                  the same. */
-       restore_pos(0);
+       restore_pos(aTHXo_ 0);
     }
 
     /* make sure $`, $&, $', and $digit will work later */
@@ -1023,7 +1419,7 @@ got_it:
 
 phooey:
     if (PL_reg_eval_set)
-       restore_pos(0);
+       restore_pos(aTHXo_ 0);
     return 0;
 }
 
@@ -1072,7 +1468,7 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
            }
            PL_reg_magic    = mg;
            PL_reg_oldpos   = mg->mg_len;
-           SAVEDESTRUCTOR(S_restore_pos, 0);
+           SAVEDESTRUCTOR(restore_pos, 0);
         }
        if (!PL_reg_curpm)
            New(22,PL_reg_curpm, 1, PMOP);
@@ -1545,15 +1941,30 @@ S_regmatch(pTHX_ regnode *prog)
                sayNO;
            nextchr = UCHARAT(++locinput);
            break;
+       case DIGITL:
+           PL_reg_flags |= RF_tainted;
+           /* FALL THROUGH */
        case DIGIT:
-           if (!isDIGIT(nextchr))
+           if (!nextchr && locinput >= PL_regeol)
+               sayNO;
+           if (!(OP(scan) == DIGIT
+                 ? isDIGIT(nextchr) : isDIGIT_LC(nextchr)))
                sayNO;
            nextchr = UCHARAT(++locinput);
            break;
+       case DIGITLUTF8:
+           PL_reg_flags |= RF_tainted;
+           /* FALL THROUGH */
        case DIGITUTF8:
+           if (!nextchr)
+               sayNO;
            if (nextchr & 0x80) {
-               if (!(swash_fetch(PL_utf8_digit,(U8*)locinput)))
+               if (OP(scan) == NDIGITUTF8
+                   ? swash_fetch(PL_utf8_digit,(U8*)locinput)
+                   : isDIGIT_LC_utf8((U8*)locinput))
+               {
                    sayNO;
+               }
                locinput += PL_utf8skip[nextchr];
                nextchr = UCHARAT(locinput);
                break;
@@ -1562,13 +1973,20 @@ S_regmatch(pTHX_ regnode *prog)
                sayNO;
            nextchr = UCHARAT(++locinput);
            break;
+       case NDIGITL:
+           PL_reg_flags |= RF_tainted;
+           /* FALL THROUGH */
        case NDIGIT:
-           if (!nextchr && locinput >= PL_regeol)
+           if (!nextchr)
                sayNO;
-           if (isDIGIT(nextchr))
+           if (OP(scan) == DIGIT
+               ? isDIGIT(nextchr) : isDIGIT_LC(nextchr))
                sayNO;
            nextchr = UCHARAT(++locinput);
            break;
+       case NDIGITLUTF8:
+           PL_reg_flags |= RF_tainted;
+           /* FALL THROUGH */
        case NDIGITUTF8:
            if (!nextchr && locinput >= PL_regeol)
                sayNO;
@@ -1600,6 +2018,7 @@ S_regmatch(pTHX_ regnode *prog)
        case REFF:
            n = ARG(scan);  /* which paren pair */
            ln = PL_regstartp[n];
+           PL_reg_leftiter = PL_reg_maxiter;           /* Void cache */
            if (*PL_reglastparen < n || ln == -1)
                sayNO;                  /* Do not match unless seen CLOSEn. */
            if (ln == PL_regendp[n])
@@ -1744,6 +2163,10 @@ S_regmatch(pTHX_ regnode *prog)
                    *PL_reglastparen = 0;
                    PL_reg_call_cc = &state;
                    PL_reginput = locinput;
+
+                   /* XXXX This is too dramatic a measure... */
+                   PL_reg_maxiter = 0;
+
                    if (regmatch(re->program + 1)) {
                        ReREFCNT_dec(re);
                        regcpblow(cp);
@@ -1761,6 +2184,10 @@ S_regmatch(pTHX_ regnode *prog)
                    PL_regcc = state.cc;
                    PL_reg_re = state.re;
                    cache_re(PL_reg_re);
+
+                   /* XXXX This is too dramatic a measure... */
+                   PL_reg_maxiter = 0;
+
                    sayNO;
                }
                sw = SvTRUE(ret);
@@ -1788,6 +2215,7 @@ S_regmatch(pTHX_ regnode *prog)
            sw = (*PL_reglastparen >= n && PL_regendp[n] != -1);
            break;
        case IFTHEN:
+           PL_reg_leftiter = PL_reg_maxiter;           /* Void cache */
            if (sw)
                next = NEXTOPER(NEXTOPER(scan));
            else {
@@ -1826,7 +2254,7 @@ S_regmatch(pTHX_ regnode *prog)
                /*
                 * 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
+                * the REx 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.
@@ -1886,6 +2314,51 @@ S_regmatch(pTHX_ regnode *prog)
                    sayNO;
                }
 
+               if (scan->flags) {
+                   /* Check whether we already were at this position.
+                       Postpone detection until we know the match is not
+                       *that* much linear. */
+               if (!PL_reg_maxiter) {
+                   PL_reg_maxiter = (PL_regeol - PL_bostr + 1) * (scan->flags>>4);
+                   PL_reg_leftiter = PL_reg_maxiter;
+               }
+               if (PL_reg_leftiter-- == 0) {
+                   I32 size = (PL_reg_maxiter + 7)/8;
+                   if (PL_reg_poscache) {
+                       if (PL_reg_poscache_size < size) {
+                           Renew(PL_reg_poscache, size, char);
+                           PL_reg_poscache_size = size;
+                       }
+                       Zero(PL_reg_poscache, size, char);
+                   }
+                   else {
+                       PL_reg_poscache_size = size;
+                       Newz(29, PL_reg_poscache, size, char);
+                   }
+                   DEBUG_r(
+                       PerlIO_printf(Perl_debug_log,
+             "%sDetected a super-linear match, switching on caching%s...\n",
+                                     PL_colors[4], PL_colors[5])
+                       );
+               }
+               if (PL_reg_leftiter < 0) {
+                   I32 o = locinput - PL_bostr, b;
+
+                   o = (scan->flags & 0xf) - 1 + o * (scan->flags>>4);
+                   b = o % 8;
+                   o /= 8;
+                   if (PL_reg_poscache[o] & (1<<b)) {
+                   DEBUG_r(
+                       PerlIO_printf(Perl_debug_log,
+                                     "%*s  already tried at this position...\n",
+                                     REPORT_CODE_OFF+PL_regindent*2, "")
+                       );
+                       sayNO;
+                   }
+                   PL_reg_poscache[o] |= (1<<b);
+               }
+               }
+
                /* Prefer next over scan for minimal matching. */
 
                if (cc->minmod) {
@@ -2758,11 +3231,11 @@ STATIC bool
 S_reginclass(pTHX_ register char *p, register I32 c)
 {
     dTHR;
-    char flags = *p;
+    char flags = ANYOF_FLAGS(p);
     bool match = FALSE;
 
     c &= 0xFF;
-    if (ANYOF_TEST(p, c))
+    if (ANYOF_BITMAP_TEST(p, c))
        match = TRUE;
     else if (flags & ANYOF_FOLD) {
        I32 cf;
@@ -2772,17 +3245,40 @@ S_reginclass(pTHX_ register char *p, register I32 c)
        }
        else
            cf = PL_fold[c];
-       if (ANYOF_TEST(p, cf))
+       if (ANYOF_BITMAP_TEST(p, cf))
            match = TRUE;
     }
 
-    if (!match && (flags & ANYOF_ISA)) {
+    if (!match && (flags & ANYOF_CLASS)) {
        PL_reg_flags |= RF_tainted;
-
-       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)))
+       if (
+           (ANYOF_CLASS_TEST(p, ANYOF_ALNUM)   &&  isALNUM_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NALNUM)  && !isALNUM_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_SPACE)   &&  isSPACE_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NSPACE)  && !isSPACE_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_DIGIT)   &&  isDIGIT_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NDIGIT)  && !isDIGIT_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_ALNUMC)  &&  isALNUMC_LC(c)) ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NALNUMC) && !isALNUMC_LC(c)) ||
+           (ANYOF_CLASS_TEST(p, ANYOF_ALPHA)   &&  isALPHA_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NALPHA)  && !isALPHA_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_ASCII)   &&  isASCII(c))     ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NASCII)  && !isASCII(c))     ||
+           (ANYOF_CLASS_TEST(p, ANYOF_CNTRL)   &&  isCNTRL_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NCNTRL)  && !isCNTRL_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_GRAPH)   &&  isGRAPH_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NGRAPH)  && !isGRAPH_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_LOWER)   &&  isLOWER_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NLOWER)  && !isLOWER_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_PRINT)   &&  isPRINT_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NPRINT)  && !isPRINT_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_PUNCT)   &&  isPUNCT_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NPUNCT)  && !isPUNCT_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_UPPER)   &&  isUPPER_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NUPPER)  && !isUPPER_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_XDIGIT)  &&  isXDIGIT(c))    ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NXDIGIT) && !isXDIGIT(c))
+           ) /* How's that for a conditional? */
        {
            match = TRUE;
        }
@@ -2814,17 +3310,7 @@ S_reginclassutf8(pTHX_ regnode *f, U8 *p)
            match = TRUE;
     }
 
-    if (!match && (flags & ANYOF_ISA)) {
-       PL_reg_flags |= RF_tainted;
-
-       if (((flags & ANYOF_ALNUML)  && isALNUM_LC_utf8(p))  ||
-           ((flags & ANYOF_NALNUML) && !isALNUM_LC_utf8(p)) ||
-           ((flags & ANYOF_SPACEL)  && isSPACE_LC_utf8(p))  ||
-           ((flags & ANYOF_NSPACEL) && !isSPACE_LC_utf8(p)))
-       {
-           match = TRUE;
-       }
-    }
+    /* UTF8 combined with ANYOF_CLASS is ill-defined. */
 
     return (flags & ANYOF_INVERT) ? !match : match;
 }
@@ -2878,3 +3364,25 @@ S_reghopmaybe(pTHX_ U8* s, I32 off)
     }
     return s;
 }
+
+#ifdef PERL_OBJECT
+#define NO_XSLOCKS
+#include "XSUB.h"
+#endif
+
+static void
+restore_pos(pTHXo_ void *arg)
+{
+    dTHR;
+    if (PL_reg_eval_set) {
+       if (PL_reg_oldsaved) {
+           PL_reg_re->subbeg = PL_reg_oldsaved;
+           PL_reg_re->sublen = PL_reg_oldsavedlen;
+           RX_MATCH_COPIED_on(PL_reg_re);
+       }
+       PL_reg_magic->mg_len = PL_reg_oldpos;
+       PL_reg_eval_set = 0;
+       PL_curpm = PL_reg_oldcurpm;
+    }  
+}
+