wtf/MathExtras.h

   1 /*
   2  * Copyright (C) 2006, 2007, 2008, 2009, 2010 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
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  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 <cmath>
  30 #include <float.h>
  31 #include <stdlib.h>
  32
  33 #if OS(SOLARIS)
  34 #include <ieeefp.h>
  35 #endif
  36
  37 #if OS(OPENBSD)
  38 #include <sys/types.h>
  39 #include <machine/ieee.h>
  40 #endif
  41
  42 #if COMPILER(MSVC)
  43 #if OS(WINCE)
  44 #include <stdlib.h>
  45 #endif
  46 #include <limits>
  47 #endif
  48
  49 #ifndef M_PI
  50 const double piDouble = 3.14159265358979323846;
  51 const float piFloat = 3.14159265358979323846f;
  52 #else
  53 const double piDouble = M_PI;
  54 const float piFloat = static_cast<float>(M_PI);
  55 #endif
  56
  57 #ifndef M_PI_4
  58 const double piOverFourDouble = 0.785398163397448309616;
  59 const float piOverFourFloat = 0.785398163397448309616f;
  60 #else
  61 const double piOverFourDouble = M_PI_4;
  62 const float piOverFourFloat = static_cast<float>(M_PI_4);
  63 #endif
  64
  65 #if OS(DARWIN)
  66
  67 // Work around a bug in the Mac OS X libc where ceil(-0.1) return +0.
  68 inline double wtf_ceil(double x) { return copysign(ceil(x), x); }
  69
  70 #define ceil(x) wtf_ceil(x)
  71
  72 #endif
  73
  74 #if OS(SOLARIS)
  75
  76 #ifndef isfinite
  77 inline bool isfinite(double x) { return finite(x) && !isnand(x); }
  78 #endif
  79 #ifndef isinf
  80 inline bool isinf(double x) { return !finite(x) && !isnand(x); }
  81 #endif
  82 #ifndef signbit
  83 inline bool signbit(double x) { return x < 0.0; } // FIXME: Wrong for negative 0.
  84 #endif
  85
  86 #endif
  87
  88 #if OS(OPENBSD)
  89
  90 #ifndef isfinite
  91 inline bool isfinite(double x) { return finite(x); }
  92 #endif
  93 #ifndef signbit
  94 inline bool signbit(double x) { struct ieee_double *p = (struct ieee_double *)&x; return p->dbl_sign; }
  95 #endif
  96
  97 #endif
  98
  99 #if COMPILER(MSVC) || COMPILER(RVCT)
 100
 101 // We must not do 'num + 0.5' or 'num - 0.5' because they can cause precision loss.
 102 static double round(double num)
 103 {
 104     double integer = ceil(num);
 105     if (num > 0)
 106         return integer - num > 0.5 ? integer - 1.0 : integer;
 107     return integer - num >= 0.5 ? integer - 1.0 : integer;
 108 }
 109 static float roundf(float num)
 110 {
 111     float integer = ceilf(num);
 112     if (num > 0)
 113         return integer - num > 0.5f ? integer - 1.0f : integer;
 114     return integer - num >= 0.5f ? integer - 1.0f : integer;
 115 }
 116 inline long long llround(double num) { return static_cast<long long>(round(num)); }
 117 inline long long llroundf(float num) { return static_cast<long long>(roundf(num)); }
 118 inline long lround(double num) { return static_cast<long>(round(num)); }
 119 inline long lroundf(float num) { return static_cast<long>(roundf(num)); }
 120 inline double trunc(double num) { return num > 0 ? floor(num) : ceil(num); }
 121
 122 #endif
 123
 124 #if COMPILER(MSVC)
 125 // The 64bit version of abs() is already defined in stdlib.h which comes with VC10
 126 #if COMPILER(MSVC9_OR_LOWER)
 127 inline long long abs(long long num) { return _abs64(num); }
 128 #endif
 129
 130 inline bool isinf(double num) { return !_finite(num) && !_isnan(num); }
 131 inline bool isnan(double num) { return !!_isnan(num); }
 132 inline bool signbit(double num) { return _copysign(1.0, num) < 0; }
 133
 134 inline double nextafter(double x, double y) { return _nextafter(x, y); }
 135 inline float nextafterf(float x, float y) { return x > y ? x - FLT_EPSILON : x + FLT_EPSILON; }
 136
 137 inline double copysign(double x, double y) { return _copysign(x, y); }
 138 inline int isfinite(double x) { return _finite(x); }
 139
 140 // Work around a bug in Win, where atan2(+-infinity, +-infinity) yields NaN instead of specific values.
 141 inline double wtf_atan2(double x, double y)
 142 {
 143     double posInf = std::numeric_limits<double>::infinity();
 144     double negInf = -std::numeric_limits<double>::infinity();
 145     double nan = std::numeric_limits<double>::quiet_NaN();
 146
 147     double result = nan;
 148
 149     if (x == posInf && y == posInf)
 150         result = piOverFourDouble;
 151     else if (x == posInf && y == negInf)
 152         result = 3 * piOverFourDouble;
 153     else if (x == negInf && y == posInf)
 154         result = -piOverFourDouble;
 155     else if (x == negInf && y == negInf)
 156         result = -3 * piOverFourDouble;
 157     else
 158         result = ::atan2(x, y);
 159
 160     return result;
 161 }
 162
 163 // Work around a bug in the Microsoft CRT, where fmod(x, +-infinity) yields NaN instead of x.
 164 inline double wtf_fmod(double x, double y) { return (!isinf(x) && isinf(y)) ? x : fmod(x, y); }
 165
 166 // Work around a bug in the Microsoft CRT, where pow(NaN, 0) yields NaN instead of 1.
 167 inline double wtf_pow(double x, double y) { return y == 0 ? 1 : pow(x, y); }
 168
 169 #define atan2(x, y) wtf_atan2(x, y)
 170 #define fmod(x, y) wtf_fmod(x, y)
 171 #define pow(x, y) wtf_pow(x, y)
 172
 173 #endif // COMPILER(MSVC)
 174
 175 inline double deg2rad(double d)  { return d * piDouble / 180.0; }
 176 inline double rad2deg(double r)  { return r * 180.0 / piDouble; }
 177 inline double deg2grad(double d) { return d * 400.0 / 360.0; }
 178 inline double grad2deg(double g) { return g * 360.0 / 400.0; }
 179 inline double turn2deg(double t) { return t * 360.0; }
 180 inline double deg2turn(double d) { return d / 360.0; }
 181 inline double rad2grad(double r) { return r * 200.0 / piDouble; }
 182 inline double grad2rad(double g) { return g * piDouble / 200.0; }
 183
 184 inline float deg2rad(float d)  { return d * piFloat / 180.0f; }
 185 inline float rad2deg(float r)  { return r * 180.0f / piFloat; }
 186 inline float deg2grad(float d) { return d * 400.0f / 360.0f; }
 187 inline float grad2deg(float g) { return g * 360.0f / 400.0f; }
 188 inline float turn2deg(float t) { return t * 360.0f; }
 189 inline float deg2turn(float d) { return d / 360.0f; }
 190 inline float rad2grad(float r) { return r * 200.0f / piFloat; }
 191 inline float grad2rad(float g) { return g * piFloat / 200.0f; }
 192
 193 #if !COMPILER(MSVC) && !COMPILER(WINSCW) && !(COMPILER(RVCT) && OS(SYMBIAN))
 194 using std::isfinite;
 195 using std::isinf;
 196 using std::isnan;
 197 using std::signbit;
 198 #endif
 199
 200 #endif // #ifndef WTF_MathExtras_h