Create a unique sorting key for the UTF-8 string. If you need to compare UTF-8 strings regularly, e.g. for sorted containers such as
std::set<>, you should consider creating a collate key first and compare this key instead of the actual string.
The ustring::compare() methods as well as the relational operators
== != < > <= >= are quite costly because they have to deal with Unicode and the collation rules defined by the current locale. Converting both operands to UCS-4 is just the first of several costly steps involved when comparing ustrings. So be careful.
Definition at line 1160 of file ustring.cc.
const ScopedPtr<char> buf (g_utf8_collate_key(string_.data(), string_.size()));