diff options
Diffstat (limited to 'regexec.c')
| -rw-r--r-- | regexec.c | 28 |
1 files changed, 26 insertions, 2 deletions
@@ -1528,6 +1528,9 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, break; do_exactf_utf8: + { + unsigned expansion; + /* If one of the operands is in utf8, we can't use the simpler * folding above, due to the fact that many different characters @@ -1540,13 +1543,33 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, ? utf8_length((U8 *) pat_string, (U8 *) pat_end) : ln; - /* Set the end position to the final character available */ - e = HOP3c(strend, -1, s); + /* We have 'lnc' characters to match in the pattern, but because of + * multi-character folding, each character in the target can match + * up to 3 characters (Unicode guarantees it will never exceed + * this) if it is utf8-encoded; and up to 2 if not (based on the + * fact that the Latin 1 folds are already determined, and the + * only multi-char fold in that range is the sharp-s folding to + * 'ss'. Thus, a pattern character can match as little as 1/3 of a + * string character. Adjust lnc accordingly, always matching at + * least 1 */ + expansion = (utf8_target) ? UTF8_MAX_FOLD_CHAR_EXPAND : 2; + lnc = (lnc < expansion) ? 1 : lnc / expansion; + + /* As in the non-UTF8 case, if we have to match 3 characters, and + * only 2 are left, it's guaranteed to fail, so don't start a + * match that would require us to go beyond the end of the string + */ + e = HOP3c(strend, -((I32)lnc), s); if (!reginfo && e < s) { e = s; /* Due to minlen logic of intuit() */ } + /* XXX Note that we could recalculate e every so-often through the + * loop to stop earlier, as the worst case expansion above will + * rarely be met, and as we go along we would usually find that e + * moves further to the left. Unclear if worth the expense */ + while (s <= e) { char *my_strend= (char *)strend; if (foldEQ_utf8_flags(s, &my_strend, 0, utf8_target, @@ -1558,6 +1581,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, s += UTF8SKIP(s); } break; + } case BOUNDL: PL_reg_flags |= RF_tainted; FBC_BOUND(isALNUM_LC, |