65 lines
1.6 KiB
C++
65 lines
1.6 KiB
C++
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* 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
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Copyright 2014 Danny Robson <danny@nerdcruft.net>
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*/
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#ifndef __UTIL_MATHS_IPP
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#define __UTIL_MATHS_IPP
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#else
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#error "Include only once"
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#endif
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#include <type_traits>
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///////////////////////////////////////////////////////////////////////////////
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template <typename T>
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constexpr T
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util::pow (T x, unsigned y)
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{
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if (y == 0)
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return T(1);
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return x * util::pow (x, y - 1);
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}
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///////////////////////////////////////////////////////////////////////////////
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/// Return a unit type with a sign that matches the provided value
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///
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/// We were using __builtin_signbit for the potential speedboost, but it causes
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/// problems with constexpr under clang. If you need speed then you'll probably
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/// have to handcode something.
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constexpr int
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sign (int v)
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{
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return std::signbit (v) ? -1 : 1;
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}
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//-----------------------------------------------------------------------------
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constexpr float
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sign (float v)
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{
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return std::signbit (v) ? -1.f : 1.f;
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}
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//-----------------------------------------------------------------------------
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constexpr double
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sign (double v)
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{
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return std::signbit (v) ? -1. : 1.f;
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}
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