Function IsDigit

libraries/libvapours/source/util/util_format_string.cpp:42–44

        using FormatSpecifierFlagStorage = std::underlying_type<FormatSpecifierFlag>::type;

        constexpr ALWAYS_INLINE bool IsDigit(char c) {
            return '0' <= c && c <= '9';
        }

        constexpr ALWAYS_INLINE u32 ParseU32(const char *&str) {
            u32 value = 0;