eqlIgnoreCaseWtf16

pub fn eqlIgnoreCaseWtf16(a: []const u16, b: []const u16) bool {
    if (@inComptime() or builtin.os.tag != .windows) {
        // This function compares the strings code unit by code unit (aka u16-to-u16),
        // so any length difference implies inequality. In other words, there's no possible
        // conversion that changes the number of WTF-16 code units needed for the uppercase/lowercase
        // version in the conversion table since only codepoints <= max(u16) are eligible
        // for conversion at all.
        if (a.len != b.len) return false;

        for (a, b) |a_c, b_c| {
            // The slices are always WTF-16 LE, so need to convert the elements to native
            // endianness for the uppercasing
            const a_c_native = std.mem.littleToNative(u16, a_c);
            const b_c_native = std.mem.littleToNative(u16, b_c);
            if (a_c != b_c and toUpperWtf16(a_c_native) != toUpperWtf16(b_c_native)) {
                return false;
            }
        }
        return true;
    }
    // Use RtlEqualUnicodeString on Windows when not in comptime to avoid including a
    // redundant copy of the uppercase data.
    return ntdll.RtlEqualUnicodeString(&.init(a), &.init(b), .TRUE).toBool();
}