while the __mo_lookup backend can verify that the translated message
ends with a null terminator, is has no way to know nplurals and thus
no way to verify that sufficiently many null terminators are present
in the string to satisfy all plural forms. the code in dcngettext was
already attempting to avoid reading past the end of the mo file
mapping, but failed to do so because the strlen call itself could
over-read. using strnlen instead allows us to avoid the problem.
this commit replaces the stub implementations with working message
translation functions. translation units are factored so as to prevent
pulling in the legacy, non-library-safe functions which use a global
textdomain in modern code which is using the versions with an explicit
domain argument. bind_textdomain_codeset is also placed in its own
file since it should not be needed by most programs.
this implementation is still missing some features: the LANGUAGE
environment variable (for multiple fallback languages) is not honored,
and non-default plural-form rules are not supported. these issues will
be addressed in a later commit.
one notable difference from the GNU implementation is that there is no
default path for loading translation files. in principle one could be
added, but since the documented correct usage is to call the
bindtextdomain function, a default path is probably unnecessary.
Rich Felker