89 lines
2.2 KiB
C++
89 lines
2.2 KiB
C++
/*
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* This file is part of libgim.
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*
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* libgim is free software: you can redistribute it and/or modify it under the
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* terms of the GNU General Public License as published by the Free Software
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* Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* libgim is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License
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* along with libgim. If not, see <http://www.gnu.org/licenses/>.
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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, typename U>
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typename std::common_type<T,U>::type
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align (T value, U size) {
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static_assert (std::is_integral<T>::value, "align requires integral types");
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static_assert (std::is_integral<U>::value, "align requires integral types");
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return divup (value, size) * size;
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}
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//-----------------------------------------------------------------------------
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template <typename T>
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constexpr T
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pow (T x, unsigned y)
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{
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return y == 0 ? 1 : x * 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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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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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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//-----------------------------------------------------------------------------
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template <>
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struct constants<float>
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{
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static constexpr float PI = PI_f;
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static constexpr float E = E_f;
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};
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template <>
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struct constants<double>
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{
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static constexpr double PI = PI_d;
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static constexpr double E = E_d;
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};
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