/* 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. */
+ 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,
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,
goto fail_finish;
/* Finish the diagnostic message */
- DEBUG_r(PerlIO_printf(Perl_debug_log, "%ld...\n", (long)(s - strpos)) );
+ 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.
*/
if (prog->float_substr && prog->anchored_substr) {
- /* Take into account the anchored substring. */
+ /* 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;
|| (PL_bostr = strpos, /* Used in regcopmaybe() */
(t = reghopmaybe_c(s, -(prog->check_offset_max)))
&& t > strpos)))
- ;
+ /* EMPTY */;
else
t = strpos;
t += prog->anchored_offset;
}
DEBUG_r(PerlIO_printf(Perl_debug_log,
", trying floating at offset %ld...\n",
- (long)(s1 + 1 - strpos)));
+ (long)(s1 + 1 - i_strpos)));
PL_regeol = strend; /* Used in HOP() */
other_last = last1 + prog->anchored_offset;
s = HOPc(last, 1);
}
else {
DEBUG_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n",
- (long)(s - strpos)));
+ (long)(s - i_strpos)));
t = s - prog->anchored_offset;
other_last = s - 1;
+ s = s1;
if (t == strpos)
goto try_at_start;
- s = s1;
goto try_at_offset;
}
+ }
}
else { /* Take into account the floating substring. */
char *last, *last1;
}
DEBUG_r(PerlIO_printf(Perl_debug_log,
", trying anchored starting at offset %ld...\n",
- (long)(s1 + 1 - strpos)));
+ (long)(s1 + 1 - i_strpos)));
other_last = last;
PL_regeol = strend; /* Used in HOP() */
s = HOPc(t, 1);
}
else {
DEBUG_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n",
- (long)(s - strpos)));
+ (long)(s - i_strpos)));
other_last = s - 1;
+ s = s1;
if (t == strpos)
goto try_at_start;
- s = s1;
goto try_at_offset;
}
}
cannot start at strpos. */
try_at_offset:
if (ml_anch && t[-1] != '\n') {
- find_anchor: /* Eventually fbm_*() should handle this */
+ /* 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 - strpos)));
+ 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 - strpos)));
- s = t + 1;
+ PL_colors[0],PL_colors[1], (long)(t + 1 - i_strpos)));
+ strpos = s = t + 1;
goto restart;
}
t++;
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)
+ 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 */
}
DEBUG_r(PerlIO_printf(Perl_debug_log, "%sGuessed:%s match at offset %ld\n",
- PL_colors[4], PL_colors[5], (long)(s - strpos)) );
+ PL_colors[4], PL_colors[5], (long)(s - i_strpos)) );
return s;
fail_finish: /* Substring not found */
end = HOPc(strend, -dontbother) - 1;
/* for multiline we only have to try after newlines */
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);
projects / p5sagit/p5-mst-13.2.git / blobdiff