src/Rough/RoughAngle.hpp

   1 /*
   2 Copyright_License {
   3
   4   XCSoar Glide Computer - http://www.xcsoar.org/
   5   Copyright (C) 2000-2013 The XCSoar Project
   6   A detailed list of copyright holders can be found in the file "AUTHORS".
   7
   8   This program is free software; you can redistribute it and/or
   9   modify it under the terms of the GNU General Public License
  10   as published by the Free Software Foundation; either version 2
  11   of the License, or (at your option) any later version.
  12
  13   This program is distributed in the hope that it will be useful,
  14   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16   GNU General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with this program; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21 }
  22 */
  23
  24 #ifndef XCSOAR_ROUGH_ANGLE_HPP
  25 #define XCSOAR_ROUGH_ANGLE_HPP
  26
  27 #include "Math/fixed.hpp"
  28 #include "Compiler.h"
  29
  30 #include <type_traits>
  31
  32 #include <stdint.h>
  33
  34 /**
  35  * Store an rough angle, when the exact value is not needed.
  36  *
  37  * The accuracy is about 0.02 degrees.
  38  */
  39 class RoughAngle {
  40   int16_t value;
  41
  42   gcc_const
  43   static int16_t Import(Angle x) {
  44     return (int16_t)(x.Radians() * 4096);
  45   }
  46
  47   gcc_const
  48   static Angle Export(int16_t x) {
  49     return Angle::Radians(fixed(x) / 4096);
  50   }
  51
  52   constexpr
  53   RoughAngle(int16_t _value):value(_value) {}
  54
  55 public:
  56   RoughAngle() = default;
  57   RoughAngle(Angle _value):value(Import(_value)) {}
  58
  59   RoughAngle &operator=(Angle other) {
  60     value = Import(other);
  61     return *this;
  62   }
  63
  64   operator Angle() const {
  65     return Export(value);
  66   }
  67
  68   constexpr
  69   RoughAngle operator-(RoughAngle other) const {
  70     return RoughAngle(value - other.value);
  71   }
  72 };
  73
  74 static_assert(std::is_trivial<RoughAngle>::value, "type is not trivial");
  75
  76 #endif