This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
avoid clearing @_ at all for faster subroutine calls; fix bugs
[perl5.git] / regexec.c
index 0ac9173..d55c5be 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*/
@@ -62,7 +66,7 @@
  *
  ****    Alterations to Henry's code are...
  ****
- ****    Copyright (c) 1991-1998, Larry Wall
+ ****    Copyright (c) 1991-1999, 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.
  * regular-expression syntax might require a total rethink.
  */
 #include "EXTERN.h"
+#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? */
 #define        STATIC  static
 #endif
 
-#ifndef PERL_OBJECT
-typedef I32 CHECKPOINT;
-
 /*
  * Forwards.
  */
 
-static I32 regmatch _((regnode *prog));
-static I32 regrepeat _((regnode *p, I32 max));
-static I32 regrepeat_hard _((regnode *p, I32 max, I32 *lp));
-static I32 regtry _((regexp *prog, char *startpos));
-
-static bool reginclass _((char *p, I32 c));
-static bool reginclassutf8 _((regnode *f, U8* p));
-static CHECKPOINT regcppush _((I32 parenfloor));
-static char * regcppop _((void));
-#endif
-
-#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 CHR_DIST(a,b) (UTF ? utf8_distance(a,b) : a - b)
 
-static char * reghop _((unsigned char *pos, I32 off));
-static char * reghopmaybe _((unsigned char *pos, I32 off));
-#define HOP(pos,off) (UTF ? reghop(pos, off) : (pos + off))
-#define HOPMAYBE(pos,off) (UTF ? reghopmaybe(pos, off) : (pos + off))
+#define reghop_c(pos,off) ((char*)reghop((U8*)pos, off))
+#define reghopmaybe_c(pos,off) ((char*)reghopmaybe((U8*)pos, off))
+#define HOP(pos,off) (UTF ? reghop((U8*)pos, off) : (U8*)(pos + off))
+#define HOPMAYBE(pos,off) (UTF ? reghopmaybe((U8*)pos, off) : (U8*)(pos + off))
+#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
-regcppush(I32 parenfloor)
+S_regcppush(pTHX_ I32 parenfloor)
 {
     dTHR;
     int retval = PL_savestack_ix;
@@ -128,8 +131,8 @@ regcppush(I32 parenfloor)
 
     SSCHECK(i + 5);
     for (p = PL_regsize; p > parenfloor; p--) {
-       SSPUSHPTR(PL_regendp[p]);
-       SSPUSHPTR(PL_regstartp[p]);
+       SSPUSHINT(PL_regendp[p]);
+       SSPUSHINT(PL_regstartp[p]);
        SSPUSHPTR(PL_reg_start_tmp[p]);
        SSPUSHINT(p);
     }
@@ -152,13 +155,13 @@ regcppush(I32 parenfloor)
                                lastcp, PL_savestack_ix) : 0); regcpblow(lastcp)
 
 STATIC char *
-regcppop(void)
+S_regcppop(pTHX)
 {
     dTHR;
     I32 i = SSPOPINT;
     U32 paren = 0;
     char *input;
-    char *tmps;
+    I32 tmps;
     assert(i == SAVEt_REGCONTEXT);
     i = SSPOPINT;
     input = (char *) SSPOPPTR;
@@ -167,16 +170,16 @@ regcppop(void)
     for (i -= 3; i > 0; i -= 4) {
        paren = (U32)SSPOPINT;
        PL_reg_start_tmp[paren] = (char *) SSPOPPTR;
-       PL_regstartp[paren] = (char *) SSPOPPTR;
-       tmps = (char*)SSPOPPTR;
+       PL_regstartp[paren] = SSPOPINT;
+       tmps = SSPOPINT;
        if (paren <= *PL_reglastparen)
            PL_regendp[paren] = tmps;
        DEBUG_r(
            PerlIO_printf(Perl_debug_log,
                          "     restoring \\%d to %d(%d)..%d%s\n",
-                         paren, PL_regstartp[paren] - PL_regbol
-                         PL_reg_start_tmp[paren] - PL_regbol,
-                         PL_regendp[paren] - PL_regbol
+                         paren, PL_regstartp[paren], 
+                         PL_reg_start_tmp[paren] - PL_bostr,
+                         PL_regendp[paren], 
                          (paren > *PL_reglastparen ? "(no)" : ""));
        );
     }
@@ -189,12 +192,33 @@ regcppop(void)
     );
     for (paren = *PL_reglastparen + 1; paren <= PL_regnpar; paren++) {
        if (paren > PL_regsize)
-           PL_regstartp[paren] = Nullch;
-       PL_regendp[paren] = Nullch;
+           PL_regstartp[paren] = -1;
+       PL_regendp[paren] = -1;
     }
     return input;
 }
 
+STATIC char *
+S_regcp_set_to(pTHX_ I32 ss)
+{
+    dTHR;
+    I32 tmp = PL_savestack_ix;
+
+    PL_savestack_ix = ss;
+    regcppop();
+    PL_savestack_ix = tmp;
+    return Nullch;
+}
+
+typedef struct re_cc_state
+{
+    I32 ss;
+    regnode *node;
+    struct re_cc_state *prev;
+    CURCUR *cc;
+    regexp *re;
+} re_cc_state;
+
 #define regcpblow(cp) LEAVE_SCOPE(cp)
 
 /*
@@ -205,7 +229,7 @@ regcppop(void)
  - pregexec - match a regexp against a string
  */
 I32
-pregexec(register regexp *prog, char *stringarg, register char *strend,
+Perl_pregexec(pTHX_ register regexp *prog, char *stringarg, register char *strend,
         char *strbeg, I32 minend, SV *screamer, U32 nosave)
 /* strend: pointer to null at end of string */
 /* strbeg: real beginning of string */
@@ -216,13 +240,432 @@ pregexec(register regexp *prog, char *stringarg, register char *strend,
        regexec_flags(prog, stringarg, strend, strbeg, minend, screamer, NULL, 
                      nosave ? 0 : REXEC_COPY_STR);
 }
-  
+
+STATIC void
+S_cache_re(pTHX_ regexp *prog)
+{
+    dTHR;
+    PL_regprecomp = prog->precomp;             /* Needed for FAIL. */
+#ifdef DEBUGGING
+    PL_regprogram = prog->program;
+#endif
+    PL_regnpar = prog->nparens;
+    PL_regdata = prog->data;    
+    PL_reg_re = prog;    
+}
+
+/* 
+ * 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.
+
+   REx compiler's optimizer found 4 possible hints:
+       a) Anchored substring;
+       b) Fixed substring;
+       c) Whether we are anchored (beginning-of-line or \G);
+       d) First node (of those at offset 0) which may distingush positions;
+   We use 'a', 'b', multiline-part of 'c', and try to find a position in the
+   string which does not contradict any of them.
+ */
+
+char *
+Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
+                    char *strend, U32 flags, re_scream_pos_data *data)
+{
+    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;
+#ifdef DEBUGGING
+    char *i_strpos = strpos;
+#endif
+
+    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;
+       }
+       /* 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)
+       Perl_croak(aTHX_ "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 - i_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 "other" substring. */
+       /* XXXX May be hopelessly wrong for UTF... */
+       if (!other_last)
+           other_last = strpos - 1;
+       if (check == prog->float_substr) {
+         do_other_anchored:
+           {
+               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)))
+                   /* EMPTY */;
+               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 - i_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 - i_strpos)));
+                   t = s - prog->anchored_offset;
+                   other_last = s - 1;
+                   s = s1;
+                   if (t == strpos)
+                       goto try_at_start;
+                   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 - i_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 - i_strpos)));
+                   other_last = s - 1;
+                   s = s1;
+                   if (t == strpos)
+                       goto try_at_start;
+                   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') {
+           /* Eventually fbm_*() should handle this, but often
+              anchored_offset is not 0, so this check will not be wasted. */
+           /* XXXX In the code below we prefer to look for "^" even in
+              presence of anchored substrings.  And we search even
+              beyond the found float position.  These pessimizations
+              are historical artefacts only.  */
+         find_anchor:
+           while (t < strend - prog->minlen) {
+               if (*t == '\n') {
+                   if (t < s - prog->check_offset_min) {
+                       if (prog->anchored_substr) {
+                           /* We definitely contradict the found anchored
+                              substr.  Due to the above check we do not
+                              contradict "check" substr.
+                              Thus we can arrive here only if check substr
+                              is float.  Redo checking for "other"=="fixed".
+                            */
+                           strpos = t + 1;                         
+                           DEBUG_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m at offset %ld, rescanning for anchored from offset %ld...\n",
+                               PL_colors[0],PL_colors[1], (long)(strpos - i_strpos), (long)(strpos - i_strpos + prog->anchored_offset)));
+                           goto do_other_anchored;
+                       }
+                       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 - i_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 - i_strpos)));
+                   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;
+       }
+       DEBUG_r( if (ml_anch)
+           PerlIO_printf(Perl_debug_log, "Does not contradict /%s^%s/m...\n",
+                       PL_colors[0],PL_colors[1]);
+       );
+      success_at_start:
+       if (!(prog->reganch & ROPT_NAUGHTY)     /* XXXX If strpos moved? */
+           && --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 - i_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
  */
 I32
-regexec_flags(register regexp *prog, char *stringarg, register char *strend,
-             char *strbeg, I32 minend, SV *screamer, void *data, U32 flags)
+Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *strend,
+             char *strbeg, I32 minend, SV *sv, void *data, U32 flags)
 /* strend: pointer to null at end of string */
 /* strbeg: real beginning of string */
 /* minend: end of match must be >=minend after stringarg. */
@@ -236,7 +679,6 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
     register I32 tmp;
     I32 minlen;                /* must match at least this many chars */
     I32 dontbother = 0;        /* how many characters not to try at end */
-    CURCUR cc;
     I32 start_shift = 0;               /* Offset of the start to find
                                         constant substr. */            /* CC */
     I32 end_shift = 0;                 /* Same for the end. */         /* CC */
@@ -244,19 +686,16 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
     char *scream_olds;
     SV* oreplsv = GvSV(PL_replgv);
 
-    cc.cur = 0;
-    cc.oldcc = 0;
-    PL_regcc = &cc;
+    PL_regcc = 0;
 
-    PL_regprecomp = prog->precomp;             /* Needed for error messages. */
+    cache_re(prog);
 #ifdef DEBUGGING
     PL_regnarrate = PL_debug & 512;
-    PL_regprogram = prog->program;
 #endif
 
     /* Be paranoid... */
     if (prog == NULL || startpos == NULL) {
-       croak("NULL regexp parameter");
+       Perl_croak(aTHX_ "NULL regexp parameter");
        return 0;
     }
 
@@ -272,13 +711,13 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
     }
 
     /* Check validity of program. */
-    if (UCHARAT(prog->program) != MAGIC) {
-       FAIL("corrupted regexp program");
+    if (UCHARAT(prog->program) != REG_MAGIC) {
+       Perl_croak(aTHX_ "corrupted regexp program");
     }
 
-    PL_regnpar = prog->nparens;
     PL_reg_flags = 0;
     PL_reg_eval_set = 0;
+    PL_reg_maxiter = 0;
 
     if (prog->reganch & ROPT_UTF8)
        PL_reg_flags |= RF_utf8;
@@ -286,6 +725,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
     /* Mark beginning of line for ^ and lookbehind. */
     PL_regbol = startpos;
     PL_bostr  = strbeg;
+    PL_reg_sv = sv;
 
     /* Mark end of line for $ (and such) */
     PL_regeol = strend;
@@ -293,98 +733,99 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
     /* see how far we have to get to not match where we matched before */
     PL_regtill = startpos+minend;
 
+    /* We start without call_cc context.  */
+    PL_reg_call_cc = 0;
+
     /* 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);
-       if (screamer) {
-           if (PL_screamfirst[BmRARE(prog->check_substr)] >= 0)
-                   s = screaminstr(screamer, 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, 0);
-       if (!s) {
-           ++BmUSEFUL(prog->check_substr);     /* hooray */
-           goto phooey;        /* not present */
-       }
-       else if (s - stringarg > prog->check_offset_max &&
-                (UTF 
-                   ? ((t = reghopmaybe(s, -(prog->check_offset_max))) && t >= stringarg)
-                   : (t = s - prog->check_offset_max) != 0
-                )
-               )
-       {
-           ++BmUSEFUL(prog->check_substr);     /* hooray/2 */
-           s = t;
+           PL_reg_ganch = startpos;
+       if (prog->reganch & ROPT_ANCH_GPOS) {
+           if (s > PL_reg_ganch)
+               goto phooey;
+           s = PL_reg_ganch;
        }
-       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;
-       }
-       else
-           s = startpos;
     }
 
-    DEBUG_r(
-       PerlIO_printf(Perl_debug_log, 
-                     "Matching `%.60s%s' against `%.*s%s'\n",
-                     prog->precomp, 
+    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],
                      (strend - startpos > 60 ? 60 : strend - startpos),
-                     startpos, 
+                     startpos, PL_colors[1],
                      (strend - startpos > 60 ? "..." : ""))
        );
 
-    PL_regdata = prog->data;
-
     /* 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))
+    if (prog->reganch & (ROPT_ANCH & ~ROPT_ANCH_GPOS)) {
+       if (s == startpos && regtry(prog, startpos))
            goto got_it;
-       else if (!(prog->reganch & ROPT_ANCH_GPOS) &&
-                (PL_multiline || (prog->reganch & ROPT_IMPLICIT)
-                 || (prog->reganch & ROPT_ANCH_MBOL)))
+       else if (PL_multiline || (prog->reganch & ROPT_IMPLICIT)
+                || (prog->reganch & ROPT_ANCH_MBOL)) /* XXXX SBOL? */
        {
+           char *end;
+
            if (minlen)
                dontbother = minlen - 1;
-           strend = HOP(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 utf8skip here */
-                   if (s < strend && regtry(prog, s))
+           if (prog->check_substr) {
+               if (s == startpos)
+                   goto after_try;
+               while (1) {
+                   if (regtry(prog, s))
                        goto got_it;
-               }
+                 after_try:
+                   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;
+    } else if (prog->reganch & ROPT_ANCH_GPOS) {
+       if (regtry(prog, PL_reg_ganch))
+           goto got_it;
+       goto phooey;
     }
 
     /* 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) {
@@ -420,11 +861,13 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
        I32 back_min = 
            prog->anchored_substr ? prog->anchored_offset : prog->float_min_offset;
        I32 delta = back_max - back_min;
-       char *last = HOP(strend, 0-(CHR_SVLEN(must) + back_min)); /* Cannot start after this */
+       char *last = HOPc(strend,       /* Cannot start after this */
+                         -(I32)(CHR_SVLEN(must)
+                                - (SvTAIL(must) != 0) + back_min));
        char *last1;            /* Last position checked before */
 
        if (s > PL_bostr)
-           last1 = HOP(s, -1);
+           last1 = HOPc(s, -1);
        else
            last1 = s - 1;      /* bogus */
 
@@ -432,21 +875,22 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
           check_substr==must. */
        scream_pos = -1;
        dontbother = end_shift;
-       strend = HOP(strend, -dontbother);
+       strend = HOPc(strend, -dontbother);
        while ( (s <= last) &&
-               (screamer 
-                ? (s = screaminstr(screamer, must, HOP(s, back_min) - strbeg,
+               ((flags & REXEC_SCREAM) 
+                ? (s = screaminstr(sv, must, HOPc(s, back_min) - strbeg,
                                    end_shift, &scream_pos, 0))
                 : (s = fbm_instr((unsigned char*)HOP(s, back_min),
-                                 (unsigned char*)strend, must, 0))) ) {
-           if (HOP(s, -back_max) > last1) {
-               last1 = HOP(s, -back_min);
-               s = HOP(s, -back_max);
+                                 (unsigned char*)strend, must, 
+                                 PL_multiline ? FBMrf_MULTILINE : 0))) ) {
+           if (HOPc(s, -back_max) > last1) {
+               last1 = HOPc(s, -back_min);
+               s = HOPc(s, -back_max);
            }
            else {
-               char *t = (last1 >= PL_bostr) ? HOP(last1, 1) : last + 1;
+               char *t = (last1 >= PL_bostr) ? HOPc(last1, 1) : last1 + 1;
 
-               last1 = HOP(s, -back_min);
+               last1 = HOPc(s, -back_min);
                s = t;          
            }
            if (UTF) {
@@ -472,12 +916,12 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
 
        if (minlen)
            dontbother = minlen - 1;
-       strend = HOP(strend, -dontbother);      /* don't bother with what can't match */
+       strend = HOPc(strend, -dontbother);     /* don't bother with what can't match */
        tmp = 1;
        /* We know what class it must start with. */
        switch (OP(c)) {
        case ANYOFUTF8:
-           cc = (char *) OPERAND(c);
+           cc = MASK(c);
            while (s < strend) {
                if (REGINCLASSUTF8(c, (U8*)s)) {
                    if (tmp && regtry(prog, s))
@@ -491,7 +935,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
            }
            break;
        case ANYOF:
-           cc = (char *) OPERAND(c);
+           cc = MASK(c);
            while (s < strend) {
                if (REGINCLASS(cc, *s)) {
                    if (tmp && regtry(prog, s))
@@ -531,12 +975,15 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
        case BOUNDUTF8:
            if (minlen) {
                dontbother++;
-               strend = reghop(strend, -1);
+               strend = reghop_c(strend, -1);
            }
-           tmp = (I32)(s != startpos) ? utf8_to_uv(reghop(s, -1), 0) : PL_regprev;
+           tmp = (I32)(s != startpos) ? utf8_to_uv(reghop((U8*)s, -1), 0) : PL_regprev;
            tmp = ((OP(c) == BOUND ? isALNUM_uni(tmp) : isALNUM_LC_uni(tmp)) != 0);
            while (s < strend) {
-               if (tmp == !(OP(c) == BOUND ? swash_fetch(PL_utf8_alnum, s) : isALNUM_LC_utf8(s))) {
+               if (tmp == !(OP(c) == BOUND ?
+                            swash_fetch(PL_utf8_alnum, (U8*)s) :
+                            isALNUM_LC_utf8((U8*)s)))
+               {
                    tmp = !tmp;
                    if (regtry(prog, s))
                        goto got_it;
@@ -572,12 +1019,14 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
        case NBOUNDUTF8:
            if (minlen) {
                dontbother++;
-               strend = reghop(strend, -1);
+               strend = reghop_c(strend, -1);
            }
-           tmp = (I32)(s != startpos) ? utf8_to_uv(reghop(s, -1), 0) : PL_regprev;
+           tmp = (I32)(s != startpos) ? utf8_to_uv(reghop((U8*)s, -1), 0) : PL_regprev;
            tmp = ((OP(c) == NBOUND ? isALNUM_uni(tmp) : isALNUM_LC_uni(tmp)) != 0);
            while (s < strend) {
-               if (tmp == !(OP(c) == NBOUND ? swash_fetch(PL_utf8_alnum, s) : isALNUM_LC_utf8(s)))
+               if (tmp == !(OP(c) == NBOUND ?
+                            swash_fetch(PL_utf8_alnum, (U8*)s) :
+                            isALNUM_LC_utf8((U8*)s)))
                    tmp = !tmp;
                else if (regtry(prog, s))
                    goto got_it;
@@ -601,7 +1050,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
            break;
        case ALNUMUTF8:
            while (s < strend) {
-               if (swash_fetch(PL_utf8_alnum, s)) {
+               if (swash_fetch(PL_utf8_alnum, (U8*)s)) {
                    if (tmp && regtry(prog, s))
                        goto got_it;
                    else
@@ -629,7 +1078,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
        case ALNUMLUTF8:
            PL_reg_flags |= RF_tainted;
            while (s < strend) {
-               if (isALNUM_LC_utf8(s)) {
+               if (isALNUM_LC_utf8((U8*)s)) {
                    if (tmp && regtry(prog, s))
                        goto got_it;
                    else
@@ -655,7 +1104,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
            break;
        case NALNUMUTF8:
            while (s < strend) {
-               if (!swash_fetch(PL_utf8_alnum, s)) {
+               if (!swash_fetch(PL_utf8_alnum, (U8*)s)) {
                    if (tmp && regtry(prog, s))
                        goto got_it;
                    else
@@ -683,7 +1132,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
        case NALNUMLUTF8:
            PL_reg_flags |= RF_tainted;
            while (s < strend) {
-               if (!isALNUM_LC_utf8(s)) {
+               if (!isALNUM_LC_utf8((U8*)s)) {
                    if (tmp && regtry(prog, s))
                        goto got_it;
                    else
@@ -709,7 +1158,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
            break;
        case SPACEUTF8:
            while (s < strend) {
-               if (*s == ' ' || swash_fetch(PL_utf8_space,s)) {
+               if (*s == ' ' || swash_fetch(PL_utf8_space,(U8*)s)) {
                    if (tmp && regtry(prog, s))
                        goto got_it;
                    else
@@ -737,7 +1186,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
        case SPACELUTF8:
            PL_reg_flags |= RF_tainted;
            while (s < strend) {
-               if (*s == ' ' || isSPACE_LC_utf8(s)) {
+               if (*s == ' ' || isSPACE_LC_utf8((U8*)s)) {
                    if (tmp && regtry(prog, s))
                        goto got_it;
                    else
@@ -763,7 +1212,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
            break;
        case NSPACEUTF8:
            while (s < strend) {
-               if (!(*s == ' ' || swash_fetch(PL_utf8_space,s))) {
+               if (!(*s == ' ' || swash_fetch(PL_utf8_space,(U8*)s))) {
                    if (tmp && regtry(prog, s))
                        goto got_it;
                    else
@@ -791,7 +1240,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
        case NSPACELUTF8:
            PL_reg_flags |= RF_tainted;
            while (s < strend) {
-               if (!(*s == ' ' || isSPACE_LC_utf8(s))) {
+               if (!(*s == ' ' || isSPACE_LC_utf8((U8*)s))) {
                    if (tmp && regtry(prog, s))
                        goto got_it;
                    else
@@ -817,7 +1266,35 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
            break;
        case DIGITUTF8:
            while (s < strend) {
-               if (swash_fetch(PL_utf8_digit,s)) {
+               if (swash_fetch(PL_utf8_digit,(U8*)s)) {
+                   if (tmp && regtry(prog, s))
+                       goto got_it;
+                   else
+                       tmp = doevery;
+               }
+               else
+                   tmp = 1;
+               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
@@ -843,7 +1320,35 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
            break;
        case NDIGITUTF8:
            while (s < strend) {
-               if (!swash_fetch(PL_utf8_digit,s)) {
+               if (!swash_fetch(PL_utf8_digit,(U8*)s)) {
+                   if (tmp && regtry(prog, s))
+                       goto got_it;
+                   else
+                       tmp = doevery;
+               }
+               else
+                   tmp = 1;
+               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
@@ -862,20 +1367,34 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
            char *last;
            I32 oldpos = scream_pos;
 
-           if (screamer) {
-               last = screaminstr(screamer, prog->float_substr, s - strbeg,
+           if (flags & REXEC_SCREAM) {
+               last = screaminstr(sv, prog->float_substr, s - strbeg,
                                   end_shift, &scream_pos, 1); /* last one */
-               if (!last) {
+               if (!last)
                    last = scream_olds; /* Only one occurence. */
-               }
            }
            else {
                STRLEN len;
                char *little = SvPV(prog->float_substr, len);
-               last = rninstr(s, strend, little, little + len);
+
+               if (SvTAIL(prog->float_substr)) {
+                   if (memEQ(strend - len + 1, little, len - 1))
+                       last = strend - len + 1;
+                   else if (!PL_multiline)
+                       last = memEQ(strend - len, little, len) 
+                           ? strend - len : Nullch;
+                   else
+                       goto find_last;
+               } else {
+                 find_last:
+                   if (len) 
+                       last = rninstr(s, strend, little, little + len);
+                   else
+                       last = strend;  /* matching `$' */
+               }
            }
            if (last == NULL) goto phooey; /* Should not happen! */
-           dontbother = strend - last - 1;
+           dontbother = strend - last + prog->float_min_offset;
        }
        if (minlen && (dontbother < minlen))
            dontbother = minlen - 1;
@@ -883,11 +1402,8 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
        /* We don't know much -- general case. */
        if (UTF) {
            for (;;) {
-               if (regtry(prog, s)) {
-                   strend += dontbother;  /* this one's always in bytes! */
-                   dontbother = 0;
+               if (regtry(prog, s))
                    goto got_it;
-               }
                if (s >= strend)
                    break;
                s += UTF8SKIP(s);
@@ -905,44 +1421,42 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
     goto phooey;
 
 got_it:
-    strend = HOP(strend, dontbother);  /* uncheat */
-    prog->subbeg = strbeg;
-    prog->subend = strend;
     RX_MATCH_TAINTED_set(prog, PL_reg_flags & RF_tainted);
 
+    if (PL_reg_eval_set) {
+       /* Preserve the current value of $^R */
+       if (oreplsv != GvSV(PL_replgv))
+           sv_setsv(oreplsv, GvSV(PL_replgv));/* So that when GvSV(replgv) is
+                                                 restored, the value remains
+                                                 the same. */
+       restore_pos(aTHXo_ 0);
+    }
+
     /* make sure $`, $&, $', and $digit will work later */
-    if (strbeg != prog->subbase) {     /* second+ //g match.  */
-       if (!(flags & REXEC_COPY_STR)) {
-           if (prog->subbase) {
-               Safefree(prog->subbase);
-               prog->subbase = Nullch;
-           }
+    if ( !(flags & REXEC_NOT_FIRST) ) {
+       if (RX_MATCH_COPIED(prog)) {
+           Safefree(prog->subbeg);
+           RX_MATCH_COPIED_off(prog);
        }
-       else {
-           I32 i = strend - startpos + (stringarg - strbeg);
+       if (flags & REXEC_COPY_STR) {
+           I32 i = PL_regeol - 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);
-               }
-           }
+           prog->subbeg = s;
+           prog->sublen = i;
+           RX_MATCH_COPIED_on(prog);
+       }
+       else {
+           prog->subbeg = strbeg;
+           prog->sublen = PL_regeol - strbeg;  /* strend may have been modified */
        }
     }
-    /* Preserve the current value of $^R */
-    if (oreplsv != GvSV(PL_replgv)) {
-       sv_setsv(oreplsv, GvSV(PL_replgv));/* So that when GvSV(replgv) is
-                                          restored, the value remains
-                                          the same. */
-    }
+    
     return 1;
 
 phooey:
+    if (PL_reg_eval_set)
+       restore_pos(aTHXo_ 0);
     return 0;
 }
 
@@ -950,15 +1464,17 @@ phooey:
  - regtry - try match at specific point
  */
 STATIC I32                     /* 0 failure, 1 success */
-regtry(regexp *prog, char *startpos)
+S_regtry(pTHX_ regexp *prog, char *startpos)
 {
     dTHR;
     register I32 i;
-    register char **sp;
-    register char **ep;
+    register I32 *sp;
+    register I32 *ep;
     CHECKPOINT lastcp;
 
     if ((prog->reganch & ROPT_EVAL_SEEN) && !PL_reg_eval_set) {
+       MAGIC *mg;
+
        PL_reg_eval_set = RS_init;
        DEBUG_r(DEBUG_s(
            PerlIO_printf(Perl_debug_log, "  setting stack tmpbase at %i\n",
@@ -971,13 +1487,52 @@ regtry(regexp *prog, char *startpos)
        /* Apparently this is not needed, judging by wantarray. */
        /* SAVEINT(cxstack[cxstack_ix].blk_gimme);
           cxstack[cxstack_ix].blk_gimme = G_SCALAR; */
+
+       if (PL_reg_sv) {
+           /* Make $_ available to executed code. */
+           if (PL_reg_sv != DEFSV) {
+               /* SAVE_DEFSV does *not* suffice here for USE_THREADS */
+               SAVESPTR(DEFSV);
+               DEFSV = PL_reg_sv;
+           }
+       
+           if (!(SvTYPE(PL_reg_sv) >= SVt_PVMG && SvMAGIC(PL_reg_sv) 
+                 && (mg = mg_find(PL_reg_sv, 'g')))) {
+               /* prepare for quick setting of pos */
+               sv_magic(PL_reg_sv, (SV*)0, 'g', Nullch, 0);
+               mg = mg_find(PL_reg_sv, 'g');
+               mg->mg_len = -1;
+           }
+           PL_reg_magic    = mg;
+           PL_reg_oldpos   = mg->mg_len;
+           SAVEDESTRUCTOR(restore_pos, 0);
+        }
+       if (!PL_reg_curpm)
+           New(22,PL_reg_curpm, 1, PMOP);
+       PL_reg_curpm->op_pmregexp = prog;
+       PL_reg_oldcurpm = PL_curpm;
+       PL_curpm = PL_reg_curpm;
+       if (RX_MATCH_COPIED(prog)) {
+           /*  Here is a serious problem: we cannot rewrite subbeg,
+               since it may be needed if this match fails.  Thus
+               $` inside (?{}) could fail... */
+           PL_reg_oldsaved = prog->subbeg;
+           PL_reg_oldsavedlen = prog->sublen;
+           RX_MATCH_COPIED_off(prog);
+       }
+       else
+           PL_reg_oldsaved = Nullch;
+       prog->subbeg = PL_bostr;
+       prog->sublen = PL_regeol - PL_bostr; /* strend may have been modified */
     }
+    prog->startp[0] = startpos - PL_bostr;
     PL_reginput = startpos;
     PL_regstartp = prog->startp;
     PL_regendp = prog->endp;
     PL_reglastparen = &prog->lastparen;
     prog->lastparen = 0;
     PL_regsize = 0;
+    DEBUG_r(PL_reg_starttry = startpos);
     if (PL_reg_start_tmpl <= prog->nparens) {
        PL_reg_start_tmpl = prog->nparens*3/2 + 3;
         if(PL_reg_start_tmp)
@@ -986,18 +1541,20 @@ regtry(regexp *prog, char *startpos)
             New(22,PL_reg_start_tmp, PL_reg_start_tmpl, char*);
     }
 
+    /* XXXX What this code is doing here?!!!  There should be no need
+       to do this again and again, PL_reglastparen should take care of
+       this!  */
     sp = prog->startp;
     ep = prog->endp;
     if (prog->nparens) {
-       for (i = prog->nparens; i >= 0; i--) {
-           *sp++ = NULL;
-           *ep++ = NULL;
+       for (i = prog->nparens; i >= 1; i--) {
+           *++sp = -1;
+           *++ep = -1;
        }
     }
     REGCP_SET;
     if (regmatch(prog->program + 1)) {
-       prog->startp[0] = startpos;
-       prog->endp[0] = PL_reginput;
+       prog->endp[0] = PL_reginput - PL_bostr;
        return 1;
     }
     REGCP_UNWIND;
@@ -1019,7 +1576,7 @@ regtry(regexp *prog, char *startpos)
  * advantage of machines that use a register save mask on subroutine entry.
  */
 STATIC I32                     /* 0 failure, 1 success */
-regmatch(regnode *prog)
+S_regmatch(pTHX_ regnode *prog)
 {
     dTHR;
     register regnode *scan;    /* Current node. */
@@ -1057,17 +1614,31 @@ regmatch(regnode *prog)
            int docolor = *PL_colors[0];
            int taill = (docolor ? 10 : 7); /* 3 chars for "> <" */
            int l = (PL_regeol - locinput > taill ? taill : PL_regeol - locinput);
+           /* The part of the string before starttry has one color
+              (pref0_len chars), between starttry and current
+              position another one (pref_len - pref0_len chars),
+              after the current position the third one.
+              We assume that pref0_len <= pref_len, otherwise we
+              decrease pref0_len.  */
            int pref_len = (locinput - PL_bostr > (5 + taill) - l 
                            ? (5 + taill) - l : locinput - PL_bostr);
+           int pref0_len = pref_len  - (locinput - PL_reg_starttry);
 
            if (l + pref_len < (5 + taill) && l < PL_regeol - locinput)
                l = ( PL_regeol - locinput > (5 + taill) - pref_len 
                      ? (5 + taill) - pref_len : PL_regeol - locinput);
+           if (pref0_len < 0)
+               pref0_len = 0;
+           if (pref0_len > pref_len)
+               pref0_len = pref_len;
            regprop(prop, scan);
            PerlIO_printf(Perl_debug_log, 
-                         "%4i <%s%.*s%s%s%s%.*s%s>%*s|%3d:%*s%s\n",
+                         "%4i <%s%.*s%s%s%.*s%s%s%s%.*s%s>%*s|%3d:%*s%s\n",
                          locinput - PL_bostr, 
-                         PL_colors[2], pref_len, locinput - pref_len, PL_colors[3],
+                         PL_colors[4], pref0_len, 
+                         locinput - pref_len, PL_colors[5],
+                         PL_colors[2], pref_len - pref0_len, 
+                         locinput - pref_len + pref0_len, PL_colors[3],
                          (docolor ? "" : "> <"),
                          PL_colors[0], l, locinput, PL_colors[1],
                          15 - l - pref_len + 1,
@@ -1104,7 +1675,7 @@ regmatch(regnode *prog)
                break;
            sayNO;
        case GPOS:
-           if (locinput == PL_regbol)
+           if (locinput == PL_reg_ganch)
                break;
            sayNO;
        case EOL:
@@ -1130,7 +1701,7 @@ regmatch(regnode *prog)
            break;
        case SANYUTF8:
            if (nextchr & 0x80) {
-               locinput += utf8skip[nextchr];
+               locinput += PL_utf8skip[nextchr];
                if (locinput > PL_regeol)
                    sayNO;
                nextchr = UCHARAT(locinput);
@@ -1147,7 +1718,7 @@ regmatch(regnode *prog)
            break;
        case ANYUTF8:
            if (nextchr & 0x80) {
-               locinput += utf8skip[nextchr];
+               locinput += PL_utf8skip[nextchr];
                if (locinput > PL_regeol)
                    sayNO;
                nextchr = UCHARAT(locinput);
@@ -1157,14 +1728,14 @@ regmatch(regnode *prog)
                sayNO;
            nextchr = UCHARAT(++locinput);
            break;
-       case ANY:
+       case REG_ANY:
            if (!nextchr && locinput >= PL_regeol || nextchr == '\n')
                sayNO;
            nextchr = UCHARAT(++locinput);
            break;
        case EXACT:
-           s = (char *) OPERAND(scan);
-           ln = UCHARAT(s++);
+           s = STRING(scan);
+           ln = STR_LEN(scan);
            /* Inline the first character, for speed. */
            if (UCHARAT(s) != nextchr)
                sayNO;
@@ -1179,8 +1750,8 @@ regmatch(regnode *prog)
            PL_reg_flags |= RF_tainted;
            /* FALL THROUGH */
        case EXACTF:
-           s = (char *) OPERAND(scan);
-           ln = UCHARAT(s++);
+           s = STRING(scan);
+           ln = STR_LEN(scan);
 
            if (UTF) {
                char *l = locinput;
@@ -1189,8 +1760,12 @@ regmatch(regnode *prog)
                while (s < e) {
                    if (l >= PL_regeol)
                        sayNO;
-                   if (utf8_to_uv(s, 0) != (c1 ? toLOWER_utf8(l) : toLOWER_LC_utf8(l)))
+                   if (utf8_to_uv((U8*)s, 0) != (c1 ?
+                                                 toLOWER_utf8((U8*)l) :
+                                                 toLOWER_LC_utf8((U8*)l)))
+                   {
                        sayNO;
+                   }
                    s += UTF8SKIP(s);
                    l += UTF8SKIP(l);
                }
@@ -1202,7 +1777,7 @@ regmatch(regnode *prog)
            /* Inline the first character, for speed. */
            if (UCHARAT(s) != nextchr &&
                UCHARAT(s) != ((OP(scan) == EXACTF)
-                              ? fold : fold_locale)[nextchr])
+                              ? PL_fold : PL_fold_locale)[nextchr])
                sayNO;
            if (PL_regeol - locinput < ln)
                sayNO;
@@ -1214,16 +1789,16 @@ regmatch(regnode *prog)
            nextchr = UCHARAT(locinput);
            break;
        case ANYOFUTF8:
-           s = (char *) OPERAND(scan);
+           s = MASK(scan);
            if (!REGINCLASSUTF8(scan, (U8*)locinput))
                sayNO;
            if (locinput >= PL_regeol)
                sayNO;
-           locinput += utf8skip[nextchr];
+           locinput += PL_utf8skip[nextchr];
            nextchr = UCHARAT(locinput);
            break;
        case ANYOF:
-           s = (char *) OPERAND(scan);
+           s = MASK(scan);
            if (nextchr < 0)
                nextchr = UCHARAT(locinput);
            if (!REGINCLASS(s, nextchr))
@@ -1251,9 +1826,12 @@ regmatch(regnode *prog)
                sayNO;
            if (nextchr & 0x80) {
                if (!(OP(scan) == ALNUMUTF8
-                     ? swash_fetch(PL_utf8_alnum, locinput) : isALNUM_LC_utf8(locinput)))
+                     ? swash_fetch(PL_utf8_alnum, (U8*)locinput)
+                     : isALNUM_LC_utf8((U8*)locinput)))
+               {
                    sayNO;
-               locinput += utf8skip[nextchr];
+               }
+               locinput += PL_utf8skip[nextchr];
                nextchr = UCHARAT(locinput);
                break;
            }
@@ -1281,9 +1859,12 @@ regmatch(regnode *prog)
                sayNO;
            if (nextchr & 0x80) {
                if (OP(scan) == NALNUMUTF8
-                     ? swash_fetch(PL_utf8_alnum, locinput) : isALNUM_LC_utf8(locinput))
+                   ? swash_fetch(PL_utf8_alnum, (U8*)locinput)
+                   : isALNUM_LC_utf8((U8*)locinput))
+               {
                    sayNO;
-               locinput += utf8skip[nextchr];
+               }
+               locinput += PL_utf8skip[nextchr];
                nextchr = UCHARAT(locinput);
                break;
            }
@@ -1318,14 +1899,15 @@ regmatch(regnode *prog)
        case BOUNDUTF8:
        case NBOUNDUTF8:
            /* was last char in word? */
-           ln = (locinput != PL_regbol) ? utf8_to_uv(reghop(locinput, -1), 0) : PL_regprev;
+           ln = (locinput != PL_regbol)
+               ? utf8_to_uv(reghop((U8*)locinput, -1), 0) : PL_regprev;
            if (OP(scan) == BOUNDUTF8 || OP(scan) == NBOUNDUTF8) {
                ln = isALNUM_uni(ln);
-               n = swash_fetch(PL_utf8_alnum, locinput);
+               n = swash_fetch(PL_utf8_alnum, (U8*)locinput);
            }
            else {
                ln = isALNUM_LC_uni(ln);
-               n = isALNUM_LC_utf8(locinput);
+               n = isALNUM_LC_utf8((U8*)locinput);
            }
            if (((!ln) == (!n)) == (OP(scan) == BOUNDUTF8 || OP(scan) == BOUNDLUTF8))
                sayNO;
@@ -1349,9 +1931,12 @@ regmatch(regnode *prog)
                sayNO;
            if (nextchr & 0x80) {
                if (!(OP(scan) == SPACEUTF8
-                     ? swash_fetch(PL_utf8_space,locinput) : isSPACE_LC_utf8(locinput)))
+                     ? swash_fetch(PL_utf8_space,(U8*)locinput)
+                     : isSPACE_LC_utf8((U8*)locinput)))
+               {
                    sayNO;
-               locinput += utf8skip[nextchr];
+               }
+               locinput += PL_utf8skip[nextchr];
                nextchr = UCHARAT(locinput);
                break;
            }
@@ -1379,9 +1964,12 @@ regmatch(regnode *prog)
                sayNO;
            if (nextchr & 0x80) {
                if (OP(scan) == NSPACEUTF8
-                     ? swash_fetch(PL_utf8_space,locinput) : isSPACE_LC_utf8(locinput))
+                   ? swash_fetch(PL_utf8_space,(U8*)locinput)
+                   : isSPACE_LC_utf8((U8*)locinput))
+               {
                    sayNO;
-               locinput += utf8skip[nextchr];
+               }
+               locinput += PL_utf8skip[nextchr];
                nextchr = UCHARAT(locinput);
                break;
            }
@@ -1390,16 +1978,31 @@ regmatch(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,locinput)))
+               if (OP(scan) == NDIGITUTF8
+                   ? swash_fetch(PL_utf8_digit,(U8*)locinput)
+                   : isDIGIT_LC_utf8((U8*)locinput))
+               {
                    sayNO;
-               locinput += utf8skip[nextchr];
+               }
+               locinput += PL_utf8skip[nextchr];
                nextchr = UCHARAT(locinput);
                break;
            }
@@ -1407,20 +2010,27 @@ regmatch(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;
            if (nextchr & 0x80) {
-               if (swash_fetch(PL_utf8_digit,locinput))
+               if (swash_fetch(PL_utf8_digit,(U8*)locinput))
                    sayNO;
-               locinput += utf8skip[nextchr];
+               locinput += PL_utf8skip[nextchr];
                nextchr = UCHARAT(locinput);
                break;
            }
@@ -1429,10 +2039,10 @@ regmatch(regnode *prog)
            nextchr = UCHARAT(++locinput);
            break;
        case CLUMP:
-           if (locinput >= PL_regeol || swash_fetch(PL_utf8_mark, locinput))
+           if (locinput >= PL_regeol || swash_fetch(PL_utf8_mark,(U8*)locinput))
                sayNO;
-           locinput += utf8skip[nextchr];
-           while (locinput < PL_regeol && swash_fetch(PL_utf8_mark, locinput))
+           locinput += PL_utf8skip[nextchr];
+           while (locinput < PL_regeol && swash_fetch(PL_utf8_mark,(U8*)locinput))
                locinput += UTF8SKIP(locinput);
            if (locinput > PL_regeol)
                sayNO;
@@ -1444,15 +2054,17 @@ regmatch(regnode *prog)
         case REF:
        case REFF:
            n = ARG(scan);  /* which paren pair */
-           s = PL_regstartp[n];
-           if (*PL_reglastparen < n || !s)
+           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 (s == PL_regendp[n])
+           if (ln == PL_regendp[n])
                break;
 
+           s = PL_bostr + ln;
            if (UTF && OP(scan) != REF) {       /* REF can do byte comparison */
                char *l = locinput;
-               char *e = PL_regendp[n];
+               char *e = PL_bostr + PL_regendp[n];
                /*
                 * Note that we can't do the "other character" lookup trick as
                 * in the 8-bit case (no pun intended) because in Unicode we
@@ -1462,7 +2074,7 @@ regmatch(regnode *prog)
                    while (s < e) {
                        if (l >= PL_regeol)
                            sayNO;
-                       if (toLOWER_utf8(s) != toLOWER_utf8(l))
+                       if (toLOWER_utf8((U8*)s) != toLOWER_utf8((U8*)l))
                            sayNO;
                        s += UTF8SKIP(s);
                        l += UTF8SKIP(l);
@@ -1472,7 +2084,7 @@ regmatch(regnode *prog)
                    while (s < e) {
                        if (l >= PL_regeol)
                            sayNO;
-                       if (toLOWER_LC_utf8(s) != toLOWER_LC_utf8(l))
+                       if (toLOWER_LC_utf8((U8*)s) != toLOWER_LC_utf8((U8*)l))
                            sayNO;
                        s += UTF8SKIP(s);
                        l += UTF8SKIP(l);
@@ -1487,9 +2099,9 @@ regmatch(regnode *prog)
            if (UCHARAT(s) != nextchr &&
                (OP(scan) == REF ||
                 (UCHARAT(s) != ((OP(scan) == REFF
-                                 ? fold : fold_locale)[nextchr]))))
+                                 ? PL_fold : PL_fold_locale)[nextchr]))))
                sayNO;
-           ln = PL_regendp[n] - s;
+           ln = PL_regendp[n] - ln;
            if (locinput + ln > PL_regeol)
                sayNO;
            if (ln > 1 && (OP(scan) == REF
@@ -1518,22 +2130,119 @@ regmatch(regnode *prog)
            n = ARG(scan);
            PL_op = (OP_4tree*)PL_regdata->data[n];
            DEBUG_r( PerlIO_printf(Perl_debug_log, "  re_eval 0x%x\n", PL_op) );
-           PL_curpad = AvARRAY((AV*)PL_regdata->data[n + 1]);
+           PL_curpad = AvARRAY((AV*)PL_regdata->data[n + 2]);
+           PL_regendp[0] = PL_reg_magic->mg_len = locinput - PL_bostr;
 
-           CALLRUNOPS();                       /* Scalar context. */
+           CALLRUNOPS(aTHX);                   /* Scalar context. */
            SPAGAIN;
            ret = POPs;
            PUTBACK;
            
+           PL_op = oop;
+           PL_curpad = ocurpad;
+           PL_curcop = ocurcop;
            if (logical) {
-               logical = 0;
+               if (logical == 2) {     /* Postponed subexpression. */
+                   regexp *re;
+                   MAGIC *mg = Null(MAGIC*);
+                   re_cc_state state;
+                   CHECKPOINT cp, lastcp;
+
+                   if(SvROK(ret) || SvRMAGICAL(ret)) {
+                       SV *sv = SvROK(ret) ? SvRV(ret) : ret;
+
+                       if(SvMAGICAL(sv))
+                           mg = mg_find(sv, 'r');
+                   }
+                   if (mg) {
+                       re = (regexp *)mg->mg_obj;
+                       (void)ReREFCNT_inc(re);
+                   }
+                   else {
+                       STRLEN len;
+                       char *t = SvPV(ret, len);
+                       PMOP pm;
+                       char *oprecomp = PL_regprecomp;
+                       I32 osize = PL_regsize;
+                       I32 onpar = PL_regnpar;
+
+                       pm.op_pmflags = 0;
+                       re = CALLREGCOMP(aTHX_ t, t + len, &pm);
+                       if (!(SvFLAGS(ret) 
+                             & (SVs_TEMP | SVs_PADTMP | SVf_READONLY)))
+                           sv_magic(ret,(SV*)ReREFCNT_inc(re),'r',0,0);
+                       PL_regprecomp = oprecomp;
+                       PL_regsize = osize;
+                       PL_regnpar = onpar;
+                   }
+                   DEBUG_r(
+                       PerlIO_printf(Perl_debug_log, 
+                                     "Entering embedded `%s%.60s%s%s'\n",
+                                     PL_colors[0],
+                                     re->precomp,
+                                     PL_colors[1],
+                                     (strlen(re->precomp) > 60 ? "..." : ""))
+                       );
+                   state.node = next;
+                   state.prev = PL_reg_call_cc;
+                   state.cc = PL_regcc;
+                   state.re = PL_reg_re;
+
+                   PL_regcc = 0;
+                   
+                   cp = regcppush(0);  /* Save *all* the positions. */
+                   REGCP_SET;
+                   cache_re(re);
+                   state.ss = PL_savestack_ix;
+                   *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)) {
+                       /* Even though we succeeded, we need to restore
+                          global variables, since we may be wrapped inside
+                          SUSPEND, thus the match may be not finished yet. */
+
+                       /* XXXX Do this only if SUSPENDed? */
+                       PL_reg_call_cc = state.prev;
+                       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;
+
+                       /* These are needed even if not SUSPEND. */
+                       ReREFCNT_dec(re);
+                       regcpblow(cp);
+                       sayYES;
+                   }
+                   DEBUG_r(
+                       PerlIO_printf(Perl_debug_log,
+                                     "%*s  failed...\n",
+                                     REPORT_CODE_OFF+PL_regindent*2, "")
+                       );
+                   ReREFCNT_dec(re);
+                   REGCP_UNWIND;
+                   regcppop();
+                   PL_reg_call_cc = state.prev;
+                   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);
+               logical = 0;
            }
            else
                sv_setsv(save_scalar(PL_replgv), ret);
-           PL_op = oop;
-           PL_curpad = ocurpad;
-           PL_curcop = ocurcop;
            break;
        }
        case OPEN:
@@ -1544,16 +2253,17 @@ regmatch(regnode *prog)
            break;
        case CLOSE:
            n = ARG(scan);  /* which paren pair */
-           PL_regstartp[n] = PL_reg_start_tmp[n];
-           PL_regendp[n] = locinput;
+           PL_regstartp[n] = PL_reg_start_tmp[n] - PL_bostr;
+           PL_regendp[n] = locinput - PL_bostr;
            if (n > *PL_reglastparen)
                *PL_reglastparen = n;
            break;
        case GROUPP:
            n = ARG(scan);  /* which paren pair */
-           sw = (*PL_reglastparen >= n && PL_regendp[n] != NULL);
+           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 {
@@ -1563,8 +2273,83 @@ regmatch(regnode *prog)
            }
            break;
        case LOGICAL:
-           logical = 1;
+           logical = scan->flags;
            break;
+/*******************************************************************
+ PL_regcc contains infoblock about the innermost (...)* loop, and
+ a pointer to the next outer infoblock.
+
+ Here is how Y(A)*Z is processed (if it is compiled into CURLYX/WHILEM):
+
+   1) After matching X, regnode for CURLYX is processed;
+
+   2) This regnode creates infoblock on the stack, and calls 
+      regmatch() recursively with the starting point at WHILEM node;
+
+   3) Each hit of WHILEM node tries to match A and Z (in the order
+      depending on the current iteration, min/max of {min,max} and
+      greediness).  The information about where are nodes for "A"
+      and "Z" is read from the infoblock, as is info on how many times "A"
+      was already matched, and greediness.
+
+   4) After A matches, the same WHILEM node is hit again.
+
+   5) Each time WHILEM is hit, PL_regcc is the infoblock created by CURLYX
+      of the same pair.  Thus when WHILEM tries to match Z, it temporarily
+      resets PL_regcc, since this Y(A)*Z can be a part of some other loop:
+      as in (Y(A)*Z)*.  If Z matches, the automaton will hit the WHILEM node
+      of the external loop.
+
+ Currently present infoblocks form a tree with a stem formed by PL_curcc
+ and whatever it mentions via ->next, and additional attached trees
+ corresponding to temporarily unset infoblocks as in "5" above.
+
+ In the following picture infoblocks for outer loop of 
+ (Y(A)*?Z)*?T are denoted O, for inner I.  NULL starting block
+ is denoted by x.  The matched string is YAAZYAZT.  Temporarily postponed
+ infoblocks are drawn below the "reset" infoblock.
+
+ In fact in the picture below we do not show failed matches for Z and T
+ by WHILEM blocks.  [We illustrate minimal matches, since for them it is
+ more obvious *why* one needs to *temporary* unset infoblocks.]
+
+  Matched      REx position    InfoBlocks      Comment
+               (Y(A)*?Z)*?T    x
+               Y(A)*?Z)*?T     x <- O
+  Y            (A)*?Z)*?T      x <- O
+  Y            A)*?Z)*?T       x <- O <- I
+  YA           )*?Z)*?T        x <- O <- I
+  YA           A)*?Z)*?T       x <- O <- I
+  YAA          )*?Z)*?T        x <- O <- I
+  YAA          Z)*?T           x <- O          # Temporary unset I
+                                    I
+
+  YAAZ         Y(A)*?Z)*?T     x <- O
+                                    I
+
+  YAAZY                (A)*?Z)*?T      x <- O
+                                    I
+
+  YAAZY                A)*?Z)*?T       x <- O <- I
+                                    I
+
+  YAAZYA       )*?Z)*?T        x <- O <- I     
+                                    I
+
+  YAAZYA       Z)*?T           x <- O          # Temporary unset I
+                                    I,I
+
+  YAAZYAZ      )*?T            x <- O
+                                    I,I
+
+  YAAZYAZ      T               x               # Temporary unset O
+                               O
+                               I,I
+
+  YAAZYAZT                     x
+                               O
+                               I,I
+ *******************************************************************/
        case CURLYX: {
                CURCUR cc;
                CHECKPOINT cp = PL_savestack_ix;
@@ -1592,7 +2377,7 @@ regmatch(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.
@@ -1617,7 +2402,8 @@ regmatch(regnode *prog)
 
                if (locinput == cc->lastloc && n >= cc->min) {
                    PL_regcc = cc->oldcc;
-                   ln = PL_regcc->cur;
+                   if (PL_regcc)
+                       ln = PL_regcc->cur;
                    DEBUG_r(
                        PerlIO_printf(Perl_debug_log,
                           "%*s  empty match detected, try continuation...\n",
@@ -1630,7 +2416,8 @@ regmatch(regnode *prog)
                                      "%*s  failed...\n",
                                      REPORT_CODE_OFF+PL_regindent*2, "")
                        );
-                   PL_regcc->cur = ln;
+                   if (PL_regcc)
+                       PL_regcc->cur = ln;
                    PL_regcc = cc;
                    sayNO;
                }
@@ -1652,11 +2439,57 @@ regmatch(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) {
                    PL_regcc = cc->oldcc;
-                   ln = PL_regcc->cur;
+                   if (PL_regcc)
+                       ln = PL_regcc->cur;
                    cp = regcppush(cc->parenfloor);
                    REGCP_SET;
                    if (regmatch(cc->next)) {
@@ -1665,14 +2498,15 @@ regmatch(regnode *prog)
                    }
                    REGCP_UNWIND;
                    regcppop();
-                   PL_regcc->cur = ln;
+                   if (PL_regcc)
+                       PL_regcc->cur = ln;
                    PL_regcc = cc;
 
                    if (n >= cc->max) { /* Maximum greed exceeded? */
-                       if (PL_dowarn && n >= REG_INFTY 
+                       if (ckWARN(WARN_UNSAFE) && n >= REG_INFTY 
                            && !(PL_reg_flags & RF_warned)) {
                            PL_reg_flags |= RF_warned;
-                           warn("%s limit (%d) exceeded",
+                           Perl_warner(aTHX_ WARN_UNSAFE, "%s limit (%d) exceeded",
                                 "Complex regular subexpression recursion",
                                 REG_INFTY - 1);
                        }
@@ -1726,21 +2560,26 @@ regmatch(regnode *prog)
                                      REPORT_CODE_OFF+PL_regindent*2, "")
                        );
                }
-               if (PL_dowarn && n >= REG_INFTY && !(PL_reg_flags & RF_warned)) {
+               if (ckWARN(WARN_UNSAFE) && n >= REG_INFTY 
+                       && !(PL_reg_flags & RF_warned)) {
                    PL_reg_flags |= RF_warned;
-                   warn("count exceeded %d", REG_INFTY - 1);
+                   Perl_warner(aTHX_ WARN_UNSAFE, "%s limit (%d) exceeded",
+                        "Complex regular subexpression recursion",
+                        REG_INFTY - 1);
                }
 
                /* Failed deeper matches of scan, so see if this one works. */
                PL_regcc = cc->oldcc;
-               ln = PL_regcc->cur;
+               if (PL_regcc)
+                   ln = PL_regcc->cur;
                if (regmatch(cc->next))
                    sayYES;
                DEBUG_r(
                    PerlIO_printf(Perl_debug_log, "%*s  failed...\n",
                                  REPORT_CODE_OFF+PL_regindent*2, "")
                    );
-               PL_regcc->cur = ln;
+               if (PL_regcc)
+                   PL_regcc->cur = ln;
                PL_regcc = cc;
                cc->cur = n - 1;
                cc->lastloc = lastloc;
@@ -1771,7 +2610,7 @@ regmatch(regnode *prog)
                            sayYES;
                        REGCP_UNWIND;
                        for (n = *PL_reglastparen; n > lastparen; n--)
-                           PL_regendp[n] = 0;
+                           PL_regendp[n] = -1;
                        *PL_reglastparen = n;
                        scan = next;
                        /*SUPPRESS 560*/
@@ -1824,12 +2663,12 @@ regmatch(regnode *prog)
                    && !(paren && ln == 0))
                    ln = n;
                locinput = PL_reginput;
-               if (regkind[(U8)OP(next)] == EXACT) {
-                   c1 = UCHARAT(OPERAND(next) + 1);
+               if (PL_regkind[(U8)OP(next)] == EXACT) {
+                   c1 = (U8)*STRING(next);
                    if (OP(next) == EXACTF)
-                       c2 = fold[c1];
+                       c2 = PL_fold[c1];
                    else if (OP(next) == EXACTFL)
-                       c2 = fold_locale[c1];
+                       c2 = PL_fold_locale[c1];
                    else
                        c2 = c1;
                }
@@ -1845,11 +2684,12 @@ regmatch(regnode *prog)
                    {
                        if (paren) {
                            if (n) {
-                               PL_regstartp[paren] = HOP(PL_reginput, -l);
-                               PL_regendp[paren] = PL_reginput;
+                               PL_regstartp[paren] =
+                                   HOPc(PL_reginput, -l) - PL_bostr;
+                               PL_regendp[paren] = PL_reginput - PL_bostr;
                            }
                            else
-                               PL_regendp[paren] = NULL;
+                               PL_regendp[paren] = -1;
                        }
                        if (regmatch(next))
                            sayYES;
@@ -1880,12 +2720,12 @@ regmatch(regnode *prog)
                                  REPORT_CODE_OFF+PL_regindent*2, "", n, l)
                    );
                if (n >= ln) {
-                   if (regkind[(U8)OP(next)] == EXACT) {
-                       c1 = UCHARAT(OPERAND(next) + 1);
+                   if (PL_regkind[(U8)OP(next)] == EXACT) {
+                       c1 = (U8)*STRING(next);
                        if (OP(next) == EXACTF)
-                           c2 = fold[c1];
+                           c2 = PL_fold[c1];
                        else if (OP(next) == EXACTFL)
-                           c2 = fold_locale[c1];
+                           c2 = PL_fold_locale[c1];
                        else
                            c2 = c1;
                    }
@@ -1906,11 +2746,11 @@ regmatch(regnode *prog)
                            );
                        if (paren) {
                            if (n) {
-                               PL_regstartp[paren] = HOP(PL_reginput, -l);
-                               PL_regendp[paren] = PL_reginput;
+                               PL_regstartp[paren] = HOPc(PL_reginput, -l) - PL_bostr;
+                               PL_regendp[paren] = PL_reginput - PL_bostr;
                            }
                            else
-                               PL_regendp[paren] = NULL;
+                               PL_regendp[paren] = -1;
                        }
                        if (regmatch(next))
                            sayYES;
@@ -1918,7 +2758,7 @@ regmatch(regnode *prog)
                    }
                    /* Couldn't or didn't -- back up. */
                    n--;
-                   locinput = HOP(locinput, -l);
+                   locinput = HOPc(locinput, -l);
                    PL_reginput = locinput;
                }
            }
@@ -1957,12 +2797,12 @@ regmatch(regnode *prog)
            * Lookahead to avoid useless match attempts
            * when we know what character comes next.
            */
-           if (regkind[(U8)OP(next)] == EXACT) {
-               c1 = UCHARAT(OPERAND(next) + 1);
+           if (PL_regkind[(U8)OP(next)] == EXACT) {
+               c1 = (U8)*STRING(next);
                if (OP(next) == EXACTF)
-                   c2 = fold[c1];
+                   c2 = PL_fold[c1];
                else if (OP(next) == EXACTFL)
-                   c2 = fold_locale[c1];
+                   c2 = PL_fold_locale[c1];
                else
                    c2 = c1;
            }
@@ -1976,6 +2816,50 @@ regmatch(regnode *prog)
                    sayNO;
                locinput = PL_reginput;
                REGCP_SET;
+               if (c1 != -1000) {
+                   char *e = locinput + n - ln; /* Should not check after this */
+                   char *old = locinput;
+
+                   if (e >= PL_regeol || (n == REG_INFTY))
+                       e = PL_regeol - 1;
+                   while (1) {
+                       /* Find place 'next' could work */
+                       if (c1 == c2) {
+                           while (locinput <= e && *locinput != c1)
+                               locinput++;
+                       } else {
+                           while (locinput <= e 
+                                  && *locinput != c1
+                                  && *locinput != c2)
+                               locinput++;                         
+                       }
+                       if (locinput > e) 
+                           sayNO;
+                       /* PL_reginput == old now */
+                       if (locinput != old) {
+                           ln = 1;     /* Did some */
+                           if (regrepeat(scan, locinput - old) <
+                                locinput - old)
+                               sayNO;
+                       }
+                       /* PL_reginput == locinput now */
+                       if (paren) {
+                           if (ln) {
+                               PL_regstartp[paren] = HOPc(locinput, -1) - PL_bostr;
+                               PL_regendp[paren] = locinput - PL_bostr;
+                           }
+                           else
+                               PL_regendp[paren] = -1;
+                       }
+                       if (regmatch(next))
+                           sayYES;
+                       PL_reginput = locinput; /* Could be reset... */
+                       REGCP_UNWIND;
+                       /* Couldn't or didn't -- move forward. */
+                       old = locinput++;
+                   }
+               }
+               else
                while (n >= ln || (n == REG_INFTY && ln > 0)) { /* ln overflow ? */
                    /* If it could work, try it. */
                    if (c1 == -1000 ||
@@ -1984,11 +2868,11 @@ regmatch(regnode *prog)
                    {
                        if (paren) {
                            if (n) {
-                               PL_regstartp[paren] = HOP(PL_reginput, -1);
-                               PL_regendp[paren] = PL_reginput;
+                               PL_regstartp[paren] = HOPc(PL_reginput, -1) - PL_bostr;
+                               PL_regendp[paren] = PL_reginput - PL_bostr;
                            }
                            else
-                               PL_regendp[paren] = NULL;
+                               PL_regendp[paren] = -1;
                        }
                        if (regmatch(next))
                            sayYES;
@@ -2008,7 +2892,7 @@ regmatch(regnode *prog)
                CHECKPOINT lastcp;
                n = regrepeat(scan, n);
                locinput = PL_reginput;
-               if (ln < n && regkind[(U8)OP(next)] == EOL &&
+               if (ln < n && PL_regkind[(U8)OP(next)] == EOL &&
                    (!PL_multiline  || OP(next) == SEOL))
                    ln = n;                     /* why back off? */
                REGCP_SET;
@@ -2021,11 +2905,11 @@ regmatch(regnode *prog)
                            {
                                if (paren && n) {
                                    if (n) {
-                                       PL_regstartp[paren] = HOP(PL_reginput, -1);
-                                       PL_regendp[paren] = PL_reginput;
+                                       PL_regstartp[paren] = HOPc(PL_reginput, -1) - PL_bostr;
+                                       PL_regendp[paren] = PL_reginput - PL_bostr;
                                    }
                                    else
-                                       PL_regendp[paren] = NULL;
+                                       PL_regendp[paren] = -1;
                                }
                                if (regmatch(next))
                                    sayYES;
@@ -2033,7 +2917,7 @@ regmatch(regnode *prog)
                            }
                        /* Couldn't or didn't -- back up. */
                        n--;
-                       PL_reginput = locinput = HOP(locinput, -1);
+                       PL_reginput = locinput = HOPc(locinput, -1);
                    }
                }
                else {
@@ -2049,13 +2933,47 @@ regmatch(regnode *prog)
                            }
                        /* Couldn't or didn't -- back up. */
                        n--;
-                       PL_reginput = locinput = HOP(locinput, -1);
+                       PL_reginput = locinput = HOPc(locinput, -1);
                    }
                }
            }
            sayNO;
            break;
        case END:
+           if (PL_reg_call_cc) {
+               re_cc_state *cur_call_cc = PL_reg_call_cc;
+               CURCUR *cctmp = PL_regcc;
+               regexp *re = PL_reg_re;
+               CHECKPOINT cp, lastcp;
+               
+               cp = regcppush(0);      /* Save *all* the positions. */
+               REGCP_SET;
+               regcp_set_to(PL_reg_call_cc->ss); /* Restore parens of
+                                                   the caller. */
+               PL_reginput = locinput; /* Make position available to
+                                          the callcc. */
+               cache_re(PL_reg_call_cc->re);
+               PL_regcc = PL_reg_call_cc->cc;
+               PL_reg_call_cc = PL_reg_call_cc->prev;
+               if (regmatch(cur_call_cc->node)) {
+                   PL_reg_call_cc = cur_call_cc;
+                   regcpblow(cp);
+                   sayYES;
+               }
+               REGCP_UNWIND;
+               regcppop();
+               PL_reg_call_cc = cur_call_cc;
+               PL_regcc = cctmp;
+               PL_reg_re = re;
+               cache_re(re);
+
+               DEBUG_r(
+                   PerlIO_printf(Perl_debug_log,
+                                 "%*s  continuation failed...\n",
+                                 REPORT_CODE_OFF+PL_regindent*2, "")
+                   );
+               sayNO;
+           }
            if (locinput < PL_regtill)
                sayNO;                  /* Cannot match: too short. */
            /* Fall through */
@@ -2064,14 +2982,25 @@ regmatch(regnode *prog)
            sayYES;                     /* Success! */
        case SUSPEND:
            n = 1;
+           PL_reginput = locinput;
            goto do_ifmatch;        
        case UNLESSM:
            n = 0;
            if (scan->flags) {
-               s = HOPMAYBE(locinput, -scan->flags);
-               if (!s)
-                   goto say_yes;
-               PL_reginput = s;
+               if (UTF) {              /* XXXX This is absolutely
+                                          broken, we read before
+                                          start of string. */
+                   s = HOPMAYBEc(locinput, -scan->flags);
+                   if (!s)
+                       goto say_yes;
+                   PL_reginput = s;
+               }
+               else {
+                   if (locinput < PL_bostr + scan->flags) 
+                       goto say_yes;
+                   PL_reginput = locinput - scan->flags;
+                   goto do_ifmatch;
+               }
            }
            else
                PL_reginput = locinput;
@@ -2079,10 +3008,20 @@ regmatch(regnode *prog)
        case IFMATCH:
            n = 1;
            if (scan->flags) {
-               s = HOPMAYBE(locinput, -scan->flags);
-               if (!s)
-                   goto say_no;
-               PL_reginput = s;
+               if (UTF) {              /* XXXX This is absolutely
+                                          broken, we read before
+                                          start of string. */
+                   s = HOPMAYBEc(locinput, -scan->flags);
+                   if (!s || s < PL_bostr)
+                       goto say_no;
+                   PL_reginput = s;
+               }
+               else {
+                   if (locinput < PL_bostr + scan->flags) 
+                       goto say_no;
+                   PL_reginput = locinput - scan->flags;
+                   goto do_ifmatch;
+               }
            }
            else
                PL_reginput = locinput;
@@ -2118,7 +3057,7 @@ regmatch(regnode *prog)
        default:
            PerlIO_printf(PerlIO_stderr(), "%lx %d\n",
                          (unsigned long)scan, OP(scan));
-           FAIL("regexp memory corruption");
+           Perl_croak(aTHX_ "regexp memory corruption");
        }
        scan = next;
     }
@@ -2127,7 +3066,7 @@ regmatch(regnode *prog)
     * We get here only if there's trouble -- normally "case END" is
     * the terminating point.
     */
-    FAIL("corrupted regexp pointers");
+    Perl_croak(aTHX_ "corrupted regexp pointers");
     /*NOTREACHED*/
     sayNO;
 
@@ -2153,7 +3092,7 @@ no:
  * rather than incrementing count on every character.  [Er, except utf8.]]
  */
 STATIC I32
-regrepeat(regnode *p, I32 max)
+S_regrepeat(pTHX_ regnode *p, I32 max)
 {
     dTHR;
     register char *scan;
@@ -2165,9 +3104,8 @@ regrepeat(regnode *p, I32 max)
     scan = PL_reginput;
     if (max != REG_INFTY && max < loceol - scan)
       loceol = scan + max;
-    opnd = (char *) OPERAND(p);
     switch (OP(p)) {
-    case ANY:
+    case REG_ANY:
        while (scan < loceol && *scan != '\n')
            scan++;
        break;
@@ -2189,21 +3127,21 @@ regrepeat(regnode *p, I32 max)
        }
        break;
     case EXACT:                /* length of string is 1 */
-       c = UCHARAT(++opnd);
+       c = (U8)*STRING(p);
        while (scan < loceol && UCHARAT(scan) == c)
            scan++;
        break;
     case EXACTF:       /* length of string is 1 */
-       c = UCHARAT(++opnd);
+       c = (U8)*STRING(p);
        while (scan < loceol &&
-              (UCHARAT(scan) == c || UCHARAT(scan) == fold[c]))
+              (UCHARAT(scan) == c || UCHARAT(scan) == PL_fold[c]))
            scan++;
        break;
     case EXACTFL:      /* length of string is 1 */
        PL_reg_flags |= RF_tainted;
-       c = UCHARAT(++opnd);
+       c = (U8)*STRING(p);
        while (scan < loceol &&
-              (UCHARAT(scan) == c || UCHARAT(scan) == fold_locale[c]))
+              (UCHARAT(scan) == c || UCHARAT(scan) == PL_fold_locale[c]))
            scan++;
        break;
     case ANYOFUTF8:
@@ -2214,6 +3152,7 @@ regrepeat(regnode *p, I32 max)
        }
        break;
     case ANYOF:
+       opnd = MASK(p);
        while (scan < loceol && REGINCLASS(opnd, *scan))
            scan++;
        break;
@@ -2223,7 +3162,7 @@ regrepeat(regnode *p, I32 max)
        break;
     case ALNUMUTF8:
        loceol = PL_regeol;
-       while (scan < loceol && swash_fetch(PL_utf8_alnum, scan)) {
+       while (scan < loceol && swash_fetch(PL_utf8_alnum, (U8*)scan)) {
            scan += UTF8SKIP(scan);
            hardcount++;
        }
@@ -2236,7 +3175,7 @@ regrepeat(regnode *p, I32 max)
     case ALNUMLUTF8:
        PL_reg_flags |= RF_tainted;
        loceol = PL_regeol;
-       while (scan < loceol && isALNUM_LC_utf8(scan)) {
+       while (scan < loceol && isALNUM_LC_utf8((U8*)scan)) {
            scan += UTF8SKIP(scan);
            hardcount++;
        }
@@ -2248,7 +3187,7 @@ regrepeat(regnode *p, I32 max)
        break;
     case NALNUMUTF8:
        loceol = PL_regeol;
-       while (scan < loceol && !swash_fetch(PL_utf8_alnum, scan)) {
+       while (scan < loceol && !swash_fetch(PL_utf8_alnum, (U8*)scan)) {
            scan += UTF8SKIP(scan);
            hardcount++;
        }
@@ -2261,7 +3200,7 @@ regrepeat(regnode *p, I32 max)
     case NALNUMLUTF8:
        PL_reg_flags |= RF_tainted;
        loceol = PL_regeol;
-       while (scan < loceol && !isALNUM_LC_utf8(scan)) {
+       while (scan < loceol && !isALNUM_LC_utf8((U8*)scan)) {
            scan += UTF8SKIP(scan);
            hardcount++;
        }
@@ -2272,7 +3211,7 @@ regrepeat(regnode *p, I32 max)
        break;
     case SPACEUTF8:
        loceol = PL_regeol;
-       while (scan < loceol && (*scan == ' ' || swash_fetch(PL_utf8_space,scan))) {
+       while (scan < loceol && (*scan == ' ' || swash_fetch(PL_utf8_space,(U8*)scan))) {
            scan += UTF8SKIP(scan);
            hardcount++;
        }
@@ -2285,7 +3224,7 @@ regrepeat(regnode *p, I32 max)
     case SPACELUTF8:
        PL_reg_flags |= RF_tainted;
        loceol = PL_regeol;
-       while (scan < loceol && (*scan == ' ' || isSPACE_LC_utf8(scan))) {
+       while (scan < loceol && (*scan == ' ' || isSPACE_LC_utf8((U8*)scan))) {
            scan += UTF8SKIP(scan);
            hardcount++;
        }
@@ -2296,7 +3235,7 @@ regrepeat(regnode *p, I32 max)
        break;
     case NSPACEUTF8:
        loceol = PL_regeol;
-       while (scan < loceol && !(*scan == ' ' || swash_fetch(PL_utf8_space,scan))) {
+       while (scan < loceol && !(*scan == ' ' || swash_fetch(PL_utf8_space,(U8*)scan))) {
            scan += UTF8SKIP(scan);
            hardcount++;
        }
@@ -2309,7 +3248,7 @@ regrepeat(regnode *p, I32 max)
     case NSPACELUTF8:
        PL_reg_flags |= RF_tainted;
        loceol = PL_regeol;
-       while (scan < loceol && !(*scan == ' ' || isSPACE_LC_utf8(scan))) {
+       while (scan < loceol && !(*scan == ' ' || isSPACE_LC_utf8((U8*)scan))) {
            scan += UTF8SKIP(scan);
            hardcount++;
        }
@@ -2320,7 +3259,7 @@ regrepeat(regnode *p, I32 max)
        break;
     case DIGITUTF8:
        loceol = PL_regeol;
-       while (scan < loceol && swash_fetch(PL_utf8_digit,scan)) {
+       while (scan < loceol && swash_fetch(PL_utf8_digit,(U8*)scan)) {
            scan += UTF8SKIP(scan);
            hardcount++;
        }
@@ -2332,7 +3271,7 @@ regrepeat(regnode *p, I32 max)
        break;
     case NDIGITUTF8:
        loceol = PL_regeol;
-       while (scan < loceol && !swash_fetch(PL_utf8_digit,scan)) {
+       while (scan < loceol && !swash_fetch(PL_utf8_digit,(U8*)scan)) {
            scan += UTF8SKIP(scan);
            hardcount++;
        }
@@ -2367,21 +3306,21 @@ regrepeat(regnode *p, I32 max)
  */
 
 STATIC I32
-regrepeat_hard(regnode *p, I32 max, I32 *lp)
+S_regrepeat_hard(pTHX_ regnode *p, I32 max, I32 *lp)
 {
     dTHR;
     register char *scan;
     register char *start;
     register char *loceol = PL_regeol;
     I32 l = 0;
-    I32 count = 0;
+    I32 count = 0, res = 1;
 
     if (!max)
        return 0;
 
     start = PL_reginput;
     if (UTF) {
-       while (PL_reginput < loceol && (scan = PL_reginput, regmatch(p))) {
+       while (PL_reginput < loceol && (scan = PL_reginput, res = regmatch(p))) {
            if (!count++) {
                l = 0;
                while (start < PL_reginput) {
@@ -2397,7 +3336,7 @@ regrepeat_hard(regnode *p, I32 max, I32 *lp)
        }
     }
     else {
-       while (PL_reginput < loceol && (scan = PL_reginput, regmatch(p))) {
+       while (PL_reginput < loceol && (scan = PL_reginput, res = regmatch(p))) {
            if (!count++) {
                *lp = l = PL_reginput - start;
                if (max != REG_INFTY && l*max < loceol - scan)
@@ -2407,45 +3346,68 @@ regrepeat_hard(regnode *p, I32 max, I32 *lp)
            }
        }
     }
-    if (PL_reginput < loceol)
+    if (!res)
        PL_reginput = scan;
     
     return count;
 }
 
 /*
- - regclass - determine if a character falls into a character class
+ - reginclass - determine if a character falls into a character class
  */
 
 STATIC bool
-reginclass(register char *p, register I32 c)
+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;
        if (flags & ANYOF_LOCALE) {
            PL_reg_flags |= RF_tainted;
-           cf = fold_locale[c];
+           cf = PL_fold_locale[c];
        }
        else
-           cf = fold[c];
-       if (ANYOF_TEST(p, cf))
+           cf = PL_fold[c];
+       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;
        }
@@ -2455,7 +3417,7 @@ reginclass(register char *p, register I32 c)
 }
 
 STATIC bool
-reginclassutf8(regnode *f, U8 *p)
+S_reginclassutf8(pTHX_ regnode *f, U8 *p)
 {                                           
     dTHR;
     char flags = ARG1(f);
@@ -2466,7 +3428,7 @@ reginclassutf8(regnode *f, U8 *p)
        match = TRUE;
     else if (flags & ANYOF_FOLD) {
        I32 cf;
-       char tmpbuf[10];
+       U8 tmpbuf[10];
        if (flags & ANYOF_LOCALE) {
            PL_reg_flags |= RF_tainted;
            uv_to_utf8(tmpbuf, toLOWER_LC_utf8(p));
@@ -2477,23 +3439,13 @@ reginclassutf8(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;
 }
 
-STATIC char *
-reghop(unsigned char *s, I32 off)
+STATIC U8 *
+S_reghop(pTHX_ U8 *s, I32 off)
 {                               
     dTHR;
     if (off >= 0) {
@@ -2514,8 +3466,8 @@ reghop(unsigned char *s, I32 off)
     return s;
 }
 
-STATIC char *
-reghopmaybe(unsigned char *s, I32 off)
+STATIC U8 *
+S_reghopmaybe(pTHX_ U8* s, I32 off)
 {
     dTHR;
     if (off >= 0) {
@@ -2541,3 +3493,25 @@ reghopmaybe(unsigned char *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;
+    }  
+}
+