dungeon/libs/glm/gtx/bit.inl
2017-09-17 14:45:57 +02:00

93 lines
2.5 KiB
C++

/// @ref gtx_bit
/// @file glm/gtx/bit.inl
namespace glm
{
///////////////////
// highestBitValue
template <typename genIUType>
GLM_FUNC_QUALIFIER genIUType highestBitValue(genIUType Value)
{
genIUType tmp = Value;
genIUType result = genIUType(0);
while(tmp)
{
result = (tmp & (~tmp + 1)); // grab lowest bit
tmp &= ~result; // clear lowest bit
}
return result;
}
template <typename T, precision P, template <typename, precision> class vecType>
GLM_FUNC_QUALIFIER vecType<T, P> highestBitValue(vecType<T, P> const & v)
{
return detail::functor1<T, T, P, vecType>::call(highestBitValue, v);
}
///////////////////
// lowestBitValue
template <typename genIUType>
GLM_FUNC_QUALIFIER genIUType lowestBitValue(genIUType Value)
{
return (Value & (~Value + 1));
}
template <typename T, precision P, template <typename, precision> class vecType>
GLM_FUNC_QUALIFIER vecType<T, P> lowestBitValue(vecType<T, P> const & v)
{
return detail::functor1<T, T, P, vecType>::call(lowestBitValue, v);
}
///////////////////
// powerOfTwoAbove
template <typename genType>
GLM_FUNC_QUALIFIER genType powerOfTwoAbove(genType value)
{
return isPowerOfTwo(value) ? value : highestBitValue(value) << 1;
}
template <typename T, precision P, template <typename, precision> class vecType>
GLM_FUNC_QUALIFIER vecType<T, P> powerOfTwoAbove(vecType<T, P> const & v)
{
return detail::functor1<T, T, P, vecType>::call(powerOfTwoAbove, v);
}
///////////////////
// powerOfTwoBelow
template <typename genType>
GLM_FUNC_QUALIFIER genType powerOfTwoBelow(genType value)
{
return isPowerOfTwo(value) ? value : highestBitValue(value);
}
template <typename T, precision P, template <typename, precision> class vecType>
GLM_FUNC_QUALIFIER vecType<T, P> powerOfTwoBelow(vecType<T, P> const & v)
{
return detail::functor1<T, T, P, vecType>::call(powerOfTwoBelow, v);
}
/////////////////////
// powerOfTwoNearest
template <typename genType>
GLM_FUNC_QUALIFIER genType powerOfTwoNearest(genType value)
{
if(isPowerOfTwo(value))
return value;
genType const prev = highestBitValue(value);
genType const next = prev << 1;
return (next - value) < (value - prev) ? next : prev;
}
template <typename T, precision P, template <typename, precision> class vecType>
GLM_FUNC_QUALIFIER vecType<T, P> powerOfTwoNearest(vecType<T, P> const & v)
{
return detail::functor1<T, T, P, vecType>::call(powerOfTwoNearest, v);
}
}//namespace glm