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      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
     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 <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 
    126 inline bool isinf(double num) { return !_finite(num) && !_isnan(num); }
    127 inline bool isnan(double num) { return !!_isnan(num); }
    128 inline bool signbit(double num) { return _copysign(1.0, num) < 0; }
    129 
    130 inline double nextafter(double x, double y) { return _nextafter(x, y); }
    131 inline float nextafterf(float x, float y) { return x > y ? x - FLT_EPSILON : x + FLT_EPSILON; }
    132 
    133 inline double copysign(double x, double y) { return _copysign(x, y); }
    134 inline int isfinite(double x) { return _finite(x); }
    135 
    136 // Work around a bug in Win, where atan2(+-infinity, +-infinity) yields NaN instead of specific values.
    137 inline double wtf_atan2(double x, double y)
    138 {
    139     double posInf = std::numeric_limits<double>::infinity();
    140     double negInf = -std::numeric_limits<double>::infinity();
    141     double nan = std::numeric_limits<double>::quiet_NaN();
    142 
    143     double result = nan;
    144 
    145     if (x == posInf && y == posInf)
    146         result = piOverFourDouble;
    147     else if (x == posInf && y == negInf)
    148         result = 3 * piOverFourDouble;
    149     else if (x == negInf && y == posInf)
    150         result = -piOverFourDouble;
    151     else if (x == negInf && y == negInf)
    152         result = -3 * piOverFourDouble;
    153     else
    154         result = ::atan2(x, y);
    155 
    156     return result;
    157 }
    158 
    159 // Work around a bug in the Microsoft CRT, where fmod(x, +-infinity) yields NaN instead of x.
    160 inline double wtf_fmod(double x, double y) { return (!isinf(x) && isinf(y)) ? x : fmod(x, y); }
    161 
    162 // Work around a bug in the Microsoft CRT, where pow(NaN, 0) yields NaN instead of 1.
    163 inline double wtf_pow(double x, double y) { return y == 0 ? 1 : pow(x, y); }
    164 
    165 #define atan2(x, y) wtf_atan2(x, y)
    166 #define fmod(x, y) wtf_fmod(x, y)
    167 #define pow(x, y) wtf_pow(x, y)
    168 
    169 #endif // COMPILER(MSVC)
    170 
    171 inline double deg2rad(double d)  { return d * piDouble / 180.0; }
    172 inline double rad2deg(double r)  { return r * 180.0 / piDouble; }
    173 inline double deg2grad(double d) { return d * 400.0 / 360.0; }
    174 inline double grad2deg(double g) { return g * 360.0 / 400.0; }
    175 inline double turn2deg(double t) { return t * 360.0; }
    176 inline double deg2turn(double d) { return d / 360.0; }
    177 inline double rad2grad(double r) { return r * 200.0 / piDouble; }
    178 inline double grad2rad(double g) { return g * piDouble / 200.0; }
    179 
    180 inline float deg2rad(float d)  { return d * piFloat / 180.0f; }
    181 inline float rad2deg(float r)  { return r * 180.0f / piFloat; }
    182 inline float deg2grad(float d) { return d * 400.0f / 360.0f; }
    183 inline float grad2deg(float g) { return g * 360.0f / 400.0f; }
    184 inline float turn2deg(float t) { return t * 360.0f; }
    185 inline float deg2turn(float d) { return d / 360.0f; }
    186 inline float rad2grad(float r) { return r * 200.0f / piFloat; }
    187 inline float grad2rad(float g) { return g * piFloat / 200.0f; }
    188 
    189 // ANDROID
    190 // TODO: Upstream to webkit.org
    191 #if !COMPILER(MSVC) && !COMPILER(RVCT) && !COMPILER(WINSCW)
    192 using std::isfinite;
    193 using std::isinf;
    194 using std::isnan;
    195 using std::signbit;
    196 #endif
    197 
    198 #endif // #ifndef WTF_MathExtras_h
    199