libcruft-util/maths.cpp

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/*
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* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
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*
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* Copyright 2010-2014 Danny Robson <danny@nerdcruft.net>
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*/
#include "maths.hpp"
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#include "debug.hpp"
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#include "float.hpp"
#include <cmath>
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#include <type_traits>
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
T
util::log2up (T v)
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{
return log2 ((v << 1) - 1);
}
template uint32_t util::log2up (uint32_t);
template uint64_t util::log2up (uint64_t);
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
T
util::log2 (T v)
{
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static_assert (std::is_integral<T>::value,
"log2 is only implemented for integers");
T l = 0;
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while (v >>= 1)
++l;
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return l;
}
template uint8_t util::log2 (uint8_t);
template uint16_t util::log2 (uint16_t);
template uint32_t util::log2 (uint32_t);
template uint64_t util::log2 (uint64_t);
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///////////////////////////////////////////////////////////////////////////////
namespace util {
template <>
unsigned
digits (const uint32_t &v)
{
return (v >= 1000000000) ? 10 :
(v >= 100000000) ? 9 :
(v >= 10000000) ? 8 :
(v >= 1000000) ? 7 :
(v >= 100000) ? 6 :
(v >= 10000) ? 5 :
(v >= 1000) ? 4 :
(v >= 100) ? 3 :
(v >= 10) ? 2 :
1;
}
}
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
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std::enable_if_t<
std::is_integral<T>::value, T
>
util::round_pow2 (T value)
{
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using return_type = std::enable_if_t<std::is_integral<T>::value, T>;
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--value;
for (unsigned i = 1; i < sizeof (T) * 8; i <<= 1) {
value |= value >> i;
}
++value;
return (return_type)value;
}
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//-----------------------------------------------------------------------------
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);
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///////////////////////////////////////////////////////////////////////////////
template const float util::PI<float>;
template const double util::PI<double>;
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///////////////////////////////////////////////////////////////////////////////
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// Simple instantiations. Some functions aren't used internally to the library
// so it's easier to instantiate early and check for broken code at library
// build time.
template float util::limit (float, float, float);
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template float util::smoothstep (float, float, float);
template double util::smoothstep (double, double, double);