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maths: make round_pow2 constexpr

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This commit is contained in:
Danny Robson 2017-01-04 22:40:06 +11:00
parent d156bb436b
commit c4ca41d6c4
2 changed files with 14 additions and 28 deletions
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27
maths.cpp
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@ -52,33 +52,6 @@ template uint32_t util::log2 (uint32_t);
template uint64_t util::log2 (uint64_t);
///////////////////////////////////////////////////////////////////////////////
template <typename T>
std::enable_if_t<
std::is_integral<T>::value, T
>
util::round_pow2 (T value)
{
using return_type = std::enable_if_t<std::is_integral<T>::value, T>;
--value;
for (unsigned i = 1; i < sizeof (T) * 8; i <<= 1) {
value |= value >> i;
}
++value;
return (return_type)value;
}
//-----------------------------------------------------------------------------
template uint8_t util::round_pow2 (uint8_t);
template uint16_t util::round_pow2 (uint16_t);
template uint32_t util::round_pow2 (uint32_t);
template uint64_t util::round_pow2 (uint64_t);
///////////////////////////////////////////////////////////////////////////////
template const float util::PI<float>;
template const double util::PI<double>;

15
maths.hpp
View File

@ -245,10 +245,23 @@ namespace util {
//-----------------------------------------------------------------------------
template <typename T>
constexpr
std::enable_if_t<
std::is_integral<T>::value, T
>
round_pow2 (T value);
round_pow2 (T value)
{
using return_type = std::enable_if_t<std::is_integral<T>::value, T>;
--value;
for (unsigned i = 1; i < sizeof (T) * 8; i <<= 1) {
value |= value >> i;
}
++value;
return (return_type)value;
}
//-----------------------------------------------------------------------------