tor-browser

The Tor Browser
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BasePoint.h (4050B)

      1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
      3 /* This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #ifndef MOZILLA_GFX_BASEPOINT_H_
      8 #define MOZILLA_GFX_BASEPOINT_H_
      9 
     10 #include <cmath>
     11 #include <ostream>
     12 #include <type_traits>
     13 #include "mozilla/Attributes.h"
     14 #include "Coord.h"
     15 
     16 namespace mozilla {
     17 namespace gfx {
     18 
     19 template <class T, typename EnableT = void>
     20 struct FloatType;
     21 
     22 template <typename T>
     23 struct FloatType<T, typename std::enable_if_t<std::is_integral_v<T>>> {
     24  using type = float;
     25 };
     26 
     27 template <typename T>
     28 struct FloatType<T, typename std::enable_if_t<std::is_floating_point_v<T>>> {
     29  using type = T;
     30 };
     31 
     32 template <typename Units, typename Rep>
     33 struct FloatType<IntCoordTyped<Units, Rep>> {
     34  using type = CoordTyped<Units, float>;
     35 };
     36 
     37 template <typename Units, typename Rep>
     38 struct FloatType<CoordTyped<Units, Rep>> {
     39  using type = CoordTyped<Units, Rep>;
     40 };
     41 
     42 template <typename T>
     43 using FloatType_t = typename FloatType<T>::type;
     44 
     45 /**
     46 * Do not use this class directly. Subclass it, pass that subclass as the
     47 * Sub parameter, and only use that subclass. This allows methods to safely
     48 * cast 'this' to 'Sub*'.
     49 */
     50 template <class T, class Sub, class Coord = T>
     51 struct BasePoint {
     52  union {
     53    struct {
     54      Coord x, y;
     55    };
     56    Coord components[2];
     57  };
     58 
     59  // Constructors
     60  constexpr BasePoint() : x(0), y(0) {}
     61  constexpr BasePoint(Coord aX, Coord aY) : x(aX), y(aY) {}
     62 
     63  MOZ_ALWAYS_INLINE Coord X() const { return x; }
     64  MOZ_ALWAYS_INLINE Coord Y() const { return y; }
     65 
     66  void MoveTo(Coord aX, Coord aY) {
     67    x = aX;
     68    y = aY;
     69  }
     70  void MoveBy(Coord aDx, Coord aDy) {
     71    x += aDx;
     72    y += aDy;
     73  }
     74 
     75  // Note that '=' isn't defined so we'll get the
     76  // compiler generated default assignment operator
     77 
     78  bool operator==(const Sub& aPoint) const {
     79    return x == aPoint.x && y == aPoint.y;
     80  }
     81  bool operator!=(const Sub& aPoint) const {
     82    return x != aPoint.x || y != aPoint.y;
     83  }
     84 
     85  Sub operator+(const Sub& aPoint) const {
     86    return Sub(x + aPoint.x, y + aPoint.y);
     87  }
     88  Sub operator-(const Sub& aPoint) const {
     89    return Sub(x - aPoint.x, y - aPoint.y);
     90  }
     91  Sub& operator+=(const Sub& aPoint) {
     92    x += aPoint.x;
     93    y += aPoint.y;
     94    return *static_cast<Sub*>(this);
     95  }
     96  Sub& operator-=(const Sub& aPoint) {
     97    x -= aPoint.x;
     98    y -= aPoint.y;
     99    return *static_cast<Sub*>(this);
    100  }
    101 
    102  Sub operator*(T aScale) const { return Sub(x * aScale, y * aScale); }
    103  Sub operator/(T aScale) const { return Sub(x / aScale, y / aScale); }
    104 
    105  Sub operator-() const { return Sub(-x, -y); }
    106 
    107  T DotProduct(const Sub& aPoint) const {
    108    return x.value * aPoint.x.value + y.value * aPoint.y.value;
    109  }
    110 
    111  FloatType_t<Coord> Length() const {
    112    return FloatType_t<Coord>(hypot(x.value, y.value));
    113  }
    114 
    115  T LengthSquare() const { return x.value * x.value + y.value * y.value; }
    116 
    117  // Round() is *not* rounding to nearest integer if the values are negative.
    118  // They are always rounding as floor(n + 0.5).
    119  // See https://bugzilla.mozilla.org/show_bug.cgi?id=410748#c14
    120  Sub& Round() {
    121    x = Coord(std::floor(T(x) + T(0.5f)));
    122    y = Coord(std::floor(T(y) + T(0.5f)));
    123    return *static_cast<Sub*>(this);
    124  }
    125 
    126  // "Finite" means not inf and not NaN
    127  bool IsFinite() const {
    128    using FloatType =
    129        std::conditional_t<std::is_same_v<T, float>, float, double>;
    130    return (std::isfinite(FloatType(x)) && std::isfinite(FloatType(y)));
    131  }
    132 
    133  void Clamp(Coord aMaxAbsValue) {
    134    x = std::clamp(x, -aMaxAbsValue, aMaxAbsValue);
    135    y = std::clamp(y, -aMaxAbsValue, aMaxAbsValue);
    136  }
    137 
    138  friend std::ostream& operator<<(std::ostream& stream,
    139                                  const BasePoint<T, Sub, Coord>& aPoint) {
    140    return stream << '(' << aPoint.x << ',' << aPoint.y << ')';
    141  }
    142 };
    143 
    144 }  // namespace gfx
    145 }  // namespace mozilla
    146 
    147 #endif /* MOZILLA_GFX_BASEPOINT_H_ */