wtf/MathExtras.h

   1 /*
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   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
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   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.
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  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
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  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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  25
  26 #ifndef WTF_MathExtras_h
  27 #define WTF_MathExtras_h
  28
  29 #include <algorithm>
  30 #include <cmath>
  31 #include <float.h>
  32 #include <limits>
  33 #include <stdlib.h>
  34
  35 #if OS(SOLARIS)
  36 #include <ieeefp.h>
  37 #endif
  38
  39 #if OS(OPENBSD)
  40 #include <sys/types.h>
  41 #include <machine/ieee.h>
  42 #endif
  43
  44 #if COMPILER(MSVC)
  45 #if OS(WINCE)
  46 #include <stdlib.h>
  47 #endif
  48 #include <limits>
  49 #endif
  50
  51 #ifndef M_PI
  52 const double piDouble = 3.14159265358979323846;
  53 const float piFloat = 3.14159265358979323846f;
  54 #else
  55 const double piDouble = M_PI;
  56 const float piFloat = static_cast<float>(M_PI);
  57 #endif
  58
  59 #ifndef M_PI_2
  60 const double piOverTwoDouble = 1.57079632679489661923;
  61 const float piOverTwoFloat = 1.57079632679489661923f;
  62 #else
  63 const double piOverTwoDouble = M_PI_2;
  64 const float piOverTwoFloat = static_cast<float>(M_PI_2);
  65 #endif
  66
  67 #ifndef M_PI_4
  68 const double piOverFourDouble = 0.785398163397448309616;
  69 const float piOverFourFloat = 0.785398163397448309616f;
  70 #else
  71 const double piOverFourDouble = M_PI_4;
  72 const float piOverFourFloat = static_cast<float>(M_PI_4);
  73 #endif
  74
  75 #if OS(DARWIN)
  76
  77 // Work around a bug in the Mac OS X libc where ceil(-0.1) return +0.
  78 inline double wtf_ceil(double x) { return copysign(ceil(x), x); }
  79
  80 #define ceil(x) wtf_ceil(x)
  81
  82 #endif
  83
  84 #if OS(SOLARIS)
  85
  86 #ifndef isfinite
  87 inline bool isfinite(double x) { return finite(x) && !isnand(x); }
  88 #endif
  89 #ifndef isinf
  90 inline bool isinf(double x) { return !finite(x) && !isnand(x); }
  91 #endif
  92 #ifndef signbit
  93 inline bool signbit(double x) { return copysign(1.0, x) < 0; }
  94 #endif
  95
  96 #endif
  97
  98 #if OS(OPENBSD)
  99
 100 #ifndef isfinite
 101 inline bool isfinite(double x) { return finite(x); }
 102 #endif
 103 #ifndef signbit
 104 inline bool signbit(double x) { struct ieee_double *p = (struct ieee_double *)&x; return p->dbl_sign; }
 105 #endif
 106
 107 #endif
 108
 109 #if COMPILER(MSVC) || (COMPILER(RVCT) && !(RVCT_VERSION_AT_LEAST(3, 0, 0, 0)))
 110
 111 // We must not do 'num + 0.5' or 'num - 0.5' because they can cause precision loss.
 112 static double round(double num)
 113 {
 114     double integer = ceil(num);
 115     if (num > 0)
 116         return integer - num > 0.5 ? integer - 1.0 : integer;
 117     return integer - num >= 0.5 ? integer - 1.0 : integer;
 118 }
 119 static float roundf(float num)
 120 {
 121     float integer = ceilf(num);
 122     if (num > 0)
 123         return integer - num > 0.5f ? integer - 1.0f : integer;
 124     return integer - num >= 0.5f ? integer - 1.0f : integer;
 125 }
 126 inline long long llround(double num) { return static_cast<long long>(round(num)); }
 127 inline long long llroundf(float num) { return static_cast<long long>(roundf(num)); }
 128 inline long lround(double num) { return static_cast<long>(round(num)); }
 129 inline long lroundf(float num) { return static_cast<long>(roundf(num)); }
 130 inline double trunc(double num) { return num > 0 ? floor(num) : ceil(num); }
 131
 132 #endif
 133
 134 #if COMPILER(MSVC)
 135 // The 64bit version of abs() is already defined in stdlib.h which comes with VC10
 136 #if COMPILER(MSVC9_OR_LOWER)
 137 inline long long abs(long long num) { return _abs64(num); }
 138 #endif
 139
 140 inline bool isinf(double num) { return !_finite(num) && !_isnan(num); }
 141 inline bool isnan(double num) { return !!_isnan(num); }
 142 inline bool signbit(double num) { return _copysign(1.0, num) < 0; }
 143
 144 inline double nextafter(double x, double y) { return _nextafter(x, y); }
 145 inline float nextafterf(float x, float y) { return x > y ? x - FLT_EPSILON : x + FLT_EPSILON; }
 146
 147 inline double copysign(double x, double y) { return _copysign(x, y); }
 148 inline int isfinite(double x) { return _finite(x); }
 149
 150 // MSVC's math.h does not currently supply log2.
 151 inline double log2(double num)
 152 {
 153     // This constant is roughly M_LN2, which is not provided by default on Windows.
 154     return log(num) / 0.693147180559945309417232121458176568;
 155 }
 156
 157 // Work around a bug in Win, where atan2(+-infinity, +-infinity) yields NaN instead of specific values.
 158 inline double wtf_atan2(double x, double y)
 159 {
 160     double posInf = std::numeric_limits<double>::infinity();
 161     double negInf = -std::numeric_limits<double>::infinity();
 162     double nan = std::numeric_limits<double>::quiet_NaN();
 163
 164     double result = nan;
 165
 166     if (x == posInf && y == posInf)
 167         result = piOverFourDouble;
 168     else if (x == posInf && y == negInf)
 169         result = 3 * piOverFourDouble;
 170     else if (x == negInf && y == posInf)
 171         result = -piOverFourDouble;
 172     else if (x == negInf && y == negInf)
 173         result = -3 * piOverFourDouble;
 174     else
 175         result = ::atan2(x, y);
 176
 177     return result;
 178 }
 179
 180 // Work around a bug in the Microsoft CRT, where fmod(x, +-infinity) yields NaN instead of x.
 181 inline double wtf_fmod(double x, double y) { return (!isinf(x) && isinf(y)) ? x : fmod(x, y); }
 182
 183 // Work around a bug in the Microsoft CRT, where pow(NaN, 0) yields NaN instead of 1.
 184 inline double wtf_pow(double x, double y) { return y == 0 ? 1 : pow(x, y); }
 185
 186 #define atan2(x, y) wtf_atan2(x, y)
 187 #define fmod(x, y) wtf_fmod(x, y)
 188 #define pow(x, y) wtf_pow(x, y)
 189
 190 #endif // COMPILER(MSVC)
 191
 192 inline double deg2rad(double d)  { return d * piDouble / 180.0; }
 193 inline double rad2deg(double r)  { return r * 180.0 / piDouble; }
 194 inline double deg2grad(double d) { return d * 400.0 / 360.0; }
 195 inline double grad2deg(double g) { return g * 360.0 / 400.0; }
 196 inline double turn2deg(double t) { return t * 360.0; }
 197 inline double deg2turn(double d) { return d / 360.0; }
 198 inline double rad2grad(double r) { return r * 200.0 / piDouble; }
 199 inline double grad2rad(double g) { return g * piDouble / 200.0; }
 200
 201 inline float deg2rad(float d)  { return d * piFloat / 180.0f; }
 202 inline float rad2deg(float r)  { return r * 180.0f / piFloat; }
 203 inline float deg2grad(float d) { return d * 400.0f / 360.0f; }
 204 inline float grad2deg(float g) { return g * 360.0f / 400.0f; }
 205 inline float turn2deg(float t) { return t * 360.0f; }
 206 inline float deg2turn(float d) { return d / 360.0f; }
 207 inline float rad2grad(float r) { return r * 200.0f / piFloat; }
 208 inline float grad2rad(float g) { return g * piFloat / 200.0f; }
 209
 210 inline int clampToInteger(double x)
 211 {
 212     const double intMax = static_cast<double>(std::numeric_limits<int>::max());
 213     const double intMin = static_cast<double>(std::numeric_limits<int>::min());
 214
 215     if (x >= intMax)
 216         return std::numeric_limits<int>::max();
 217     if (x <= intMin)
 218         return std::numeric_limits<int>::min();
 219     return static_cast<int>(x);
 220 }
 221
 222 inline float clampToFloat(double x)
 223 {
 224     const double floatMax = static_cast<double>(std::numeric_limits<float>::max());
 225     const double floatMin = -static_cast<double>(std::numeric_limits<float>::max());
 226
 227     if (x >= floatMax)
 228         return std::numeric_limits<float>::max();
 229     if (x <= floatMin)
 230         return -std::numeric_limits<float>::max();
 231     return static_cast<float>(x);
 232 }
 233
 234 inline int clampToPositiveInteger(double x)
 235 {
 236     const double intMax = static_cast<double>(std::numeric_limits<int>::max());
 237
 238     if (x >= intMax)
 239         return std::numeric_limits<int>::max();
 240     if (x <= 0)
 241         return 0;
 242     return static_cast<int>(x);
 243 }
 244
 245 inline int clampToInteger(float x)
 246 {
 247     const float intMax = static_cast<float>(std::numeric_limits<int>::max());
 248     const float intMin = static_cast<float>(std::numeric_limits<int>::min());
 249
 250     if (x >= intMax)
 251         return std::numeric_limits<int>::max();
 252     if (x <= intMin)
 253         return std::numeric_limits<int>::min();
 254     return static_cast<int>(x);
 255 }
 256
 257 inline int clampToPositiveInteger(float x)
 258 {
 259     const float intMax = static_cast<float>(std::numeric_limits<int>::max());
 260
 261     if (x >= intMax)
 262         return std::numeric_limits<int>::max();
 263     if (x <= 0)
 264         return 0;
 265     return static_cast<int>(x);
 266 }
 267
 268 inline int clampToInteger(unsigned x)
 269 {
 270     const unsigned intMax = static_cast<unsigned>(std::numeric_limits<int>::max());
 271
 272     if (x >= intMax)
 273         return std::numeric_limits<int>::max();
 274     return static_cast<int>(x);
 275 }
 276
 277 inline bool isWithinIntRange(float x)
 278 {
 279     return x > static_cast<float>(std::numeric_limits<int>::min()) && x < static_cast<float>(std::numeric_limits<int>::max());
 280 }
 281
 282 #if !COMPILER(MSVC) && !(COMPILER(RVCT) && PLATFORM(BREWMP)) && !OS(SOLARIS) && !OS(SYMBIAN)
 283 using std::isfinite;
 284 using std::isinf;
 285 using std::isnan;
 286 using std::signbit;
 287 #endif
 288
 289 #endif // #ifndef WTF_MathExtras_h