Occasionally I find that I need to compare signed and unsigned int values. This understandably throws warnings. So I wrote the following helpful functions to safely compare the values when needed. Obviously I try not to, but there’s times when I’m forced to.
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template<typename T1, typename T2> typename std::enable_if<std::is_same<T1,signed int>::value,bool>::type SignedUnsignedEquality(T1 i, T2 u) { if(i < 0) return false; return u == static_cast<unsigned int>(i); } template<typename T1, typename T2> typename std::enable_if<std::is_same<T1,unsigned int>::value,bool>::type SignedUnsignedEquality(T1 u, T2 i) { return SignedUnsignedEquality(i,u); } template<typename T1, typename T2> typename std::enable_if<std::is_same<T1,signed int>::value,bool>::type SignedUnsignedLessThan(T1 i, T2 u) { if(i < 0) return true; return static_cast<unsigned int>(i) < u; } template<typename T1, typename T2> typename std::enable_if<std::is_same<T1,unsigned int>::value,bool>::type SignedUnsignedLessThan(T1 u, T2 i) { if(i < 0) return false; return u < static_cast<unsigned int>(i); } template<typename T1, typename T2> typename std::enable_if<std::is_same<T1,signed int>::value,bool>::type SignedUnsignedGreaterThan(T1 i, T2 u) { if(i < 0) return false; return static_cast<unsigned int>(i) > u; } template<typename T1, typename T2> typename std::enable_if<std::is_same<T1,unsigned int>::value,bool>::type SignedUnsignedGreaterThan(T1 u, T2 i) { if(i < 0) return true; return u > static_cast<unsigned int>(i); } template<typename T1, typename T2> bool SignedUnsignedLessThanEqual(T1 p1, T2 p2) { return SignedUnsignedEquality(p1,p2) || SignedUnsignedLessThan(p1,p2); } template<typename T1, typename T2> bool SignedUnsignedGreaterThanEqual(T1 p1, T2 p2) { return SignedUnsignedEquality(p1,p2) || SignedUnsignedGreaterThan(p1,p2); } |
It allows me to compare signed int and unsigned int values as either the left or right parameters.