208 lines
4.4 KiB
C++
208 lines
4.4 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 2010-2014 Danny Robson <danny@nerdcruft.net>
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*/
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#ifndef __MATHS_HPP
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#define __MATHS_HPP
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#include <type_traits>
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#include <utility>
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template <typename T>
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T
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abs (T value)
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{ return value > 0 ? value : -value; }
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template <typename T>
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constexpr T
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pow2 (T value)
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{ return value * value; }
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template <typename T>
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bool
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is_pow2 [[gnu::pure]] (T value);
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template <typename T>
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T
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log2 [[gnu::pure]] (T val);
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template <typename T>
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T
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log2up [[gnu::pure]] (T val);
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template <typename T>
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double
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rootsquare [[gnu::pure]] (T a, T b);
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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 [[gnu::pure]] (T value, U size);
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template <typename T>
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T
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round_pow2 [[gnu::pure]] (T value);
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template <typename T>
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bool
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is_integer [[gnu::pure]] (const T& value);
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template <typename T>
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unsigned
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digits [[gnu::pure]] (const T& value);
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template <typename T, typename U>
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T
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divup (const T a, const U b)
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{ return (a + b - 1) / b; }
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/**
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* Check if two floating point numbers are approximately equal. Returns true
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* if the difference is less than a percentage of each individual value.
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*
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* @e maximum percentage difference for equal values
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*/
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template <typename T>
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bool
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almost_equal (const T &a, const T &b)
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{ return a == b; }
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template <>
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bool
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almost_equal (const float &a, const float &b);
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template <>
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bool
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almost_equal (const double &a, const double &b);
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template <typename Ta, typename Tb>
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typename std::enable_if<
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std::is_arithmetic<Ta>::value && std::is_arithmetic<Tb>::value,
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bool
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>::type
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almost_equal (Ta a, Tb b) {
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return almost_equal <decltype(a + b)> (static_cast<decltype(a + b)>(a),
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static_cast<decltype(a + b)>(b));
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}
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template <typename Ta, typename Tb>
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typename std::enable_if<
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!std::is_arithmetic<Ta>::value || !std::is_arithmetic<Tb>::value,
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bool
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>::type
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almost_equal (const Ta &a, const Tb &b)
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{ return a == b; }
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// Useful for explictly ignore equality warnings
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wfloat-equal"
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template <typename T, typename U>
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bool
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exactly_equal (const T &a, const U &b)
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{ return a == b; }
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#pragma GCC diagnostic pop
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template <typename T>
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bool
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almost_zero (T a)
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{ return almost_equal (a, 0); }
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template <typename T>
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bool
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exactly_zero (T a)
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{ return exactly_equal (a, static_cast<T> (0)); }
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//-----------------------------------------------------------------------------
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constexpr double PI = 3.141592653589793238462643;
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constexpr double
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to_degrees (double radians) {
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return radians * 180 / PI;
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}
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constexpr double
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to_radians (double degrees) {
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return degrees / 180 * PI;
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}
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//-----------------------------------------------------------------------------
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/// Variadic minimum
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template <typename T>
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constexpr T
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min (const T a)
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{ return a; }
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template <typename T, typename U, typename ...Args>
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constexpr typename std::common_type<T, U>::type
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min (const T a , const U b , const Args &...args )
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{ return min ( b < a ? b : a, args...); }
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//-----------------------------------------------------------------------------
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/// Variadic maximum
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template <typename T>
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constexpr T
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max (const T a)
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{ return a; }
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template <typename T, typename ...Args>
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constexpr T
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max (const T a , const T b , const Args &...args )
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{ return max ( b > a ? b : a, args...); }
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//-----------------------------------------------------------------------------
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template <typename T>
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int sign (T val);
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//-----------------------------------------------------------------------------
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template <typename T, typename U, typename V>
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T
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limit (const T &&val, const U &&hi, const V &&lo) {
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return val > hi ? hi:
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val < lo ? lo:
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std::move (val);
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}
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#include "maths.ipp"
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#endif // __MATHS_HPP
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