- PCRE2_SIZE len;
- pcre2_substring_get_bynumber(md, matchnum,
- (PCRE2_UCHAR **)&expand_nstring[expand_nmax], &len);
- expand_nlength[expand_nmax++] = (int)len;
+ /* Although PCRE2 has a pcre2_substring_get_bynumber() conveneience, it
+ seems to return a bad pointer when a capture group had no data, eg. (.*)
+ matching zero letters. So use the underlying ovec and hope (!) that the
+ offsets are sane (including that case). Should we go further and range-
+ check each one vs. the subject string length? */
+ int off = matchnum * 2;
+ int len = ovec[off + 1] - ovec[off];
+ expand_nstring[expand_nmax] = string_copyn(subject + ovec[off], len);
+ expand_nlength[expand_nmax++] = len;