On 01/28/2014 11:48 PM, Paul Eggert wrote: > > +/* The following functions exploit the commutativity and associativity of ^, > + and the fact that X ^ X is zero. POSIX requires that C equals > + either tolower (C) or toupper (C);
Unfortunately, while this is true, I'm not sure if it accurately covers all possible case-folded comparisons outside of the C locale. http://www.unicode.org/faq/casemap_charprop.html Consider the Greek locale, el_GR.UTF-8, which has two lower-case sigma: L'\x3c3' and L'\x3c2', but only one upper-case: L'\x3a3'. As a result, all three wchar_t values must compare case-insensitively to one another. Or consider titlecase characters, such as Unicode L'\x1c8' (Lj), which has both an uppercase mapping L'\x1c7' (LJ) and lowercase mapping L'\x1c9' (lj) - again, all three wchar_t values must compare case-insensitively to one another. Your hack is great at finding characters that have a case mapping, but not necessarily at finding all such characters that map to the same result when passed through towlower(towupper(c)). -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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