Commit 83c9d1ca authored by Dão Gottwald's avatar Dão Gottwald
Browse files

merge backout

parents 348c2b9f 5e32254e

mfbt/CheckedInt.h

+34 −24
Original line number Diff line number Diff line
@@ -209,6 +209,8 @@ struct PositionOfSignBit 


template<typename IntegerType>

struct MinValue

{

    static IntegerType value()

    {

      // Bitwise ops may return a larger type, that's why we cast explicitly.

      // In C++, left bit shifts on signed values is undefined by the standard
@@ -216,20 +218,23 @@ struct MinValue 
      // Notice that signed-to-unsigned conversions are always well-defined in

      // the standard as the value congruent to 2**n, as expected. By contrast,

      // unsigned-to-signed is only well-defined if the value is representable.

    static const IntegerType value =

        IsSigned<IntegerType>::value

      return IsSigned<IntegerType>::value

             ? IntegerType(typename UnsignedType<IntegerType>::Type(1)

                             << PositionOfSignBit<IntegerType>::value)

             : IntegerType(0);

    }

};



template<typename IntegerType>

struct MaxValue

{

    static IntegerType value()

    {

      // Tricksy, but covered by the unit test.

    // Relies heavily on the type of MinValue<IntegerType>::value

      // Relies heavily on the return type of MinValue<IntegerType>::value()

      // being IntegerType.

    static const IntegerType value = ~MinValue<IntegerType>::value;

      return ~MinValue<IntegerType>::value();

    }

};



/*
@@ -273,7 +278,8 @@ struct IsInRangeImpl<T, U, true, true> 
{

    static bool run(U x)

    {

      return x <= MaxValue<T>::value && x >= MinValue<T>::value;

      return x <= MaxValue<T>::value() &&

             x >= MinValue<T>::value();

    }

};
@@ -282,7 +288,7 @@ struct IsInRangeImpl<T, U, false, false> 
{

    static bool run(U x)

    {

      return x <= MaxValue<T>::value;

      return x <= MaxValue<T>::value();

    }

};
@@ -291,7 +297,9 @@ struct IsInRangeImpl<T, U, true, false> 
{

    static bool run(U x)

    {

      return sizeof(T) > sizeof(U) || x <= U(MaxValue<T>::value);

      return sizeof(T) > sizeof(U)

             ? true

             : x <= U(MaxValue<T>::value());

    }

};
@@ -302,7 +310,7 @@ struct IsInRangeImpl<T, U, false, true> 
    {

      return sizeof(T) >= sizeof(U)

             ? x >= 0

             : x >= 0 && x <= U(MaxValue<T>::value);

             : x >= 0 && x <= U(MaxValue<T>::value());

    }

};
@@ -358,8 +366,8 @@ struct IsMulValidImpl<T, true, false> 
{

    static bool run(T x, T y)

    {

      const T max = MaxValue<T>::value;

      const T min = MinValue<T>::value;

      const T max = MaxValue<T>::value();

      const T min = MinValue<T>::value();



      if (x == 0 || y == 0)

        return true;
@@ -382,7 +390,8 @@ struct IsMulValidImpl<T, false, false> 
{

    static bool run(T x, T y)

    {

      return y == 0 ||  x <= MaxValue<T>::value / y;

      return y == 0 ||

             x <= MaxValue<T>::value() / y;

    }

};
@@ -398,8 +407,9 @@ inline bool 
IsDivValid(T x, T y)

{

  // Keep in mind that in the signed case, min/-1 is invalid because abs(min)>max.

  return y != 0 &&

         !(IsSigned<T>::value && x == MinValue<T>::value && y == T(-1));

  return IsSigned<T>::value

         ? (y != 0) && (x != MinValue<T>::value() || y != T(-1))

         : y != 0;

}



// This is just to shut up msvc warnings about negating unsigned ints.

mfbt/tests/TestCheckedInt.cpp

+5 −5
Original line number Diff line number Diff line
@@ -96,8 +96,8 @@ void test() 
  VERIFY(sizeof(unsignedT) == sizeof(T));

  VERIFY(detail::IsSigned<unsignedT>::value == false);



  const CheckedInt<T> max(detail::MaxValue<T>::value);

  const CheckedInt<T> min(detail::MinValue<T>::value);

  const CheckedInt<T> max(detail::MaxValue<T>::value());

  const CheckedInt<T> min(detail::MinValue<T>::value());



  // Check min() and max(), since they are custom implementations and a mistake there

  // could potentially NOT be caught by any other tests... while making everything wrong!
@@ -394,10 +394,10 @@ void test() 
    if (isUSigned) \

      VERIFY_IS_VALID_IF(CheckedInt<T>(U(-1)), isTSigned); \

    if (sizeof(U) > sizeof(T)) \

      VERIFY_IS_INVALID(CheckedInt<T>(U(detail::MaxValue<T>::value) + 1)); \

    VERIFY_IS_VALID_IF(CheckedInt<T>(detail::MaxValue<U>::value), \

      VERIFY_IS_INVALID(CheckedInt<T>(U(detail::MaxValue<T>::value())+1)); \

    VERIFY_IS_VALID_IF(CheckedInt<T>(detail::MaxValue<U>::value()), \

      (sizeof(T) > sizeof(U) || ((sizeof(T) == sizeof(U)) && (isUSigned || !isTSigned)))); \

    VERIFY_IS_VALID_IF(CheckedInt<T>(detail::MinValue<U>::value), \

    VERIFY_IS_VALID_IF(CheckedInt<T>(detail::MinValue<U>::value()), \

      isUSigned == false ? 1 : \

      bool(isTSigned) == false ? 0 : \

      sizeof(T) >= sizeof(U)); \