Unicode Specials block bug

[manoe]

Libyang/yanglint cannot match characters of Unicode Specials block.

The function ly_pat_compile_xmlschema_chblocks_xmlschema2perl() responsible to translate Yang patterns containing Unicode blocks to PCRE2-compatible Perl-based regular expressions with character ranges assumes that each range literal is 19 char long. However, the Specials Unicode block is "special". It contains the disjoint U+FEFF character, and the range U+FFF0-U+FFFD. The original implementation only copies the first 19 chars of the literal, that is \x{FEFF}|\x{FFF0}. The expression is valid unfortunately, however only matches U+FEFF and U+FFF0.

The correction changes the ublock2urange two dimensional char array to a struct array, which is populated during compilation time also with the individual literal lengths to preserve performance (assuming, that the original intention for hard-coding URANGE_LEN was to avoid strlen calls).

Corresponding unit and component tests are also submitted.

[michalvasko]

Okay, thanks, seems this should be fixed but no need to add the length into the struct, a few strlen() calls do not make any difference so please adjust it.

[manoe]

CIFuzz keeps failing, however, based on the logs I cannot tell what went wrong. Can I get a little bit help with fuzzing?