wtf/MathExtras.h

   1 /*
   2  * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef WTF_MathExtras_h
  27 #define WTF_MathExtras_h
  28
  29 #include <math.h>
  30 #include <stdlib.h>
  31 #include <time.h>
  32
  33 #if PLATFORM(SOLARIS) && COMPILER(GCC)
  34 #include <ieeefp.h>
  35 #endif
  36
  37 #if COMPILER(MSVC)
  38
  39 #include <xmath.h>
  40 #include <limits>
  41
  42 #if HAVE(FLOAT_H)
  43 #include <float.h>
  44 #endif
  45
  46 #endif
  47
  48 #ifndef M_PI
  49 const double piDouble = 3.14159265358979323846;
  50 const float piFloat = 3.14159265358979323846f;
  51 #else
  52 const double piDouble = M_PI;
  53 const float piFloat = static_cast<float>(M_PI);
  54 #endif
  55
  56 #ifndef M_PI_4
  57 const double piOverFourDouble = 0.785398163397448309616;
  58 const float piOverFourFloat = 0.785398163397448309616f;
  59 #else
  60 const double piOverFourDouble = M_PI_4;
  61 const float piOverFourFloat = static_cast<float>(M_PI_4);
  62 #endif
  63
  64 #if PLATFORM(SOLARIS) && COMPILER(GCC)
  65
  66 #ifndef isfinite
  67 inline bool isfinite(double x) { return finite(x) && !isnand(x); }
  68 #endif
  69 #ifndef isinf
  70 inline bool isinf(double x) { return !finite(x) && !isnand(x); }
  71 #endif
  72 #ifndef signbit
  73 inline bool signbit(double x) { return x < 0.0; } // FIXME: Wrong for negative 0.
  74 #endif
  75
  76 #endif
  77
  78 #if COMPILER(MSVC)
  79
  80 inline bool isinf(double num) { return !_finite(num) && !_isnan(num); }
  81 inline bool isnan(double num) { return !!_isnan(num); }
  82 inline long lround(double num) { return static_cast<long>(num > 0 ? num + 0.5 : ceil(num - 0.5)); }
  83 inline long lroundf(float num) { return static_cast<long>(num > 0 ? num + 0.5f : ceilf(num - 0.5f)); }
  84 inline double round(double num) { return num > 0 ? floor(num + 0.5) : ceil(num - 0.5); }
  85 inline float roundf(float num) { return num > 0 ? floorf(num + 0.5f) : ceilf(num - 0.5f); }
  86 inline bool signbit(double num) { return _copysign(1.0, num) < 0; }
  87 inline double trunc(double num) { return num > 0 ? floor(num) : ceil(num); }
  88
  89 inline double nextafter(double x, double y) { return _nextafter(x, y); }
  90 inline float nextafterf(float x, float y) { return x > y ? x - FLT_EPSILON : x + FLT_EPSILON; }
  91
  92 inline double copysign(double x, double y) { return _copysign(x, y); }
  93 inline int isfinite(double x) { return _finite(x); }
  94
  95 // Work around a bug in Win, where atan2(+-infinity, +-infinity) yields NaN instead of specific values.
  96 inline double wtf_atan2(double x, double y)
  97 {
  98     static double posInf = std::numeric_limits<double>::infinity();
  99     static double negInf = -std::numeric_limits<double>::infinity();
 100     static double nan = std::numeric_limits<double>::quiet_NaN();
 101
 102     double result = nan;
 103
 104     if (x == posInf && y == posInf)
 105         result = piOverFourDouble;
 106     else if (x == posInf && y == negInf)
 107         result = 3 * piOverFourDouble;
 108     else if (x == negInf && y == posInf)
 109         result = -piOverFourDouble;
 110     else if (x == negInf && y == negInf)
 111         result = -3 * piOverFourDouble;
 112     else
 113         result = ::atan2(x, y);
 114
 115     return result;
 116 }
 117
 118 // Work around a bug in the Microsoft CRT, where fmod(x, +-infinity) yields NaN instead of x.
 119 inline double wtf_fmod(double x, double y) { return (!isinf(x) && isinf(y)) ? x : fmod(x, y); }
 120
 121 // Work around a bug in the Microsoft CRT, where pow(NaN, 0) yields NaN instead of 1.
 122 inline double wtf_pow(double x, double y) { return y == 0 ? 1 : pow(x, y); }
 123
 124 #define atan2(x, y) wtf_atan2(x, y)
 125 #define fmod(x, y) wtf_fmod(x, y)
 126 #define pow(x, y) wtf_pow(x, y)
 127
 128 #if defined(_CRT_RAND_S)
 129 // Initializes the random number generator.
 130 inline void wtf_random_init()
 131 {
 132     // No need to initialize for rand_s.
 133 }
 134
 135 // Returns a pseudo-random number in the range [0, 1).
 136 inline double wtf_random()
 137 {
 138     unsigned u;
 139     rand_s(&u);
 140
 141     return static_cast<double>(u) / (static_cast<double>(UINT_MAX) + 1.0);
 142 }
 143 #endif // _CRT_RAND_S
 144
 145 #endif // COMPILER(MSVC)
 146
 147 #if !COMPILER(MSVC) || !defined(_CRT_RAND_S)
 148
 149 // Initializes the random number generator.
 150 inline void wtf_random_init()
 151 {
 152     srand(static_cast<unsigned>(time(0)));
 153 }
 154
 155 // Returns a pseudo-random number in the range [0, 1).
 156 inline double wtf_random()
 157 {
 158     return static_cast<double>(rand()) / (static_cast<double>(RAND_MAX) + 1.0);
 159 }
 160
 161 #endif // #if COMPILER(MSVC)
 162
 163 inline double deg2rad(double d)  { return d * piDouble / 180.0; }
 164 inline double rad2deg(double r)  { return r * 180.0 / piDouble; }
 165 inline double deg2grad(double d) { return d * 400.0 / 360.0; }
 166 inline double grad2deg(double g) { return g * 360.0 / 400.0; }
 167 inline double rad2grad(double r) { return r * 200.0 / piDouble; }
 168 inline double grad2rad(double g) { return g * piDouble / 200.0; }
 169
 170 inline float deg2rad(float d)  { return d * piFloat / 180.0f; }
 171 inline float rad2deg(float r)  { return r * 180.0f / piFloat; }
 172 inline float deg2grad(float d) { return d * 400.0f / 360.0f; }
 173 inline float grad2deg(float g) { return g * 360.0f / 400.0f; }
 174 inline float rad2grad(float r) { return r * 200.0f / piFloat; }
 175 inline float grad2rad(float g) { return g * piFloat / 200.0f; }
 176
 177 #endif // #ifndef WTF_MathExtras_h