/*

 * Copyright (C) 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

 */

#ifndef WTF_MathExtras_h

#define WTF_MathExtras_h

#include <cmath>

#include <float.h>

#include <stdlib.h>

#if OS(SOLARIS)

#include <ieeefp.h>

#endif

#if OS(OPENBSD)

#include <sys/types.h>

#include <machine/ieee.h>

#endif

#if COMPILER(MSVC)

#if OS(WINCE)

#include <stdlib.h>

#endif

#include <limits>

#endif

#ifndef M_PI

const double piDouble = 3.14159265358979323846;

const float piFloat = 3.14159265358979323846f;

#else

const double piDouble = M_PI;

const float piFloat = static_cast<float>(M_PI);

#endif

#ifndef M_PI_2

const double piOverTwoDouble = 1.57079632679489661923;

const float piOverTwoFloat = 1.57079632679489661923f;

#else

const double piOverTwoDouble = M_PI_2;

const float piOverTwoFloat = static_cast<float>(M_PI_2);

#endif

#ifndef M_PI_4

const double piOverFourDouble = 0.785398163397448309616;

const float piOverFourFloat = 0.785398163397448309616f;

#else

const double piOverFourDouble = M_PI_4;

const float piOverFourFloat = static_cast<float>(M_PI_4);

#endif

#if OS(DARWIN)

// Work around a bug in the Mac OS X libc where ceil(-0.1) return +0.

inline double wtf_ceil(double x) { return copysign(ceil(x), x); }

#define ceil(x) wtf_ceil(x)

#endif

#if OS(SOLARIS)

#ifndef isfinite

inline bool isfinite(double x) { return finite(x) && !isnand(x); }

#endif

#ifndef isinf

inline bool isinf(double x) { return !finite(x) && !isnand(x); }

#endif

#ifndef signbit

inline bool signbit(double x) { return x < 0.0; } // FIXME: Wrong for negative 0.

#endif

#endif

#if OS(OPENBSD)

#ifndef isfinite

inline bool isfinite(double x) { return finite(x); }

#endif

#ifndef signbit

inline bool signbit(double x) { struct ieee_double *p = (struct ieee_double *)&x; return p->dbl_sign; }

#endif

#endif

#if COMPILER(MSVC) || COMPILER(RVCT)

// We must not do 'num + 0.5' or 'num - 0.5' because they can cause precision loss.

static double round(double num)

{

    double integer = ceil(num);

    if (num > 0)

        return integer - num > 0.5 ? integer - 1.0 : integer;

    return integer - num >= 0.5 ? integer - 1.0 : integer;

}

static float roundf(float num)

{

    float integer = ceilf(num);

    if (num > 0)

        return integer - num > 0.5f ? integer - 1.0f : integer;

    return integer - num >= 0.5f ? integer - 1.0f : integer;

}

inline long long llround(double num) { return static_cast<long long>(round(num)); }

inline long long llroundf(float num) { return static_cast<long long>(roundf(num)); }

inline long lround(double num) { return static_cast<long>(round(num)); }

inline long lroundf(float num) { return static_cast<long>(roundf(num)); }

inline double trunc(double num) { return num > 0 ? floor(num) : ceil(num); }

#endif

#if COMPILER(MSVC)

// The 64bit version of abs() is already defined in stdlib.h which comes with VC10

#if COMPILER(MSVC9_OR_LOWER)

inline long long abs(long long num) { return _abs64(num); }

#endif

inline bool isinf(double num) { return !_finite(num) && !_isnan(num); }

inline bool isnan(double num) { return !!_isnan(num); }

inline bool signbit(double num) { return _copysign(1.0, num) < 0; }

inline double nextafter(double x, double y) { return _nextafter(x, y); }

inline float nextafterf(float x, float y) { return x > y ? x - FLT_EPSILON : x + FLT_EPSILON; }

inline double copysign(double x, double y) { return _copysign(x, y); }

inline int isfinite(double x) { return _finite(x); }

// Work around a bug in Win, where atan2(+-infinity, +-infinity) yields NaN instead of specific values.

inline double wtf_atan2(double x, double y)

{

    double posInf = std::numeric_limits<double>::infinity();

    double negInf = -std::numeric_limits<double>::infinity();

    double nan = std::numeric_limits<double>::quiet_NaN();

    double result = nan;

    if (x == posInf && y == posInf)

        result = piOverFourDouble;

    else if (x == posInf && y == negInf)

        result = 3 * piOverFourDouble;

    else if (x == negInf && y == posInf)

        result = -piOverFourDouble;

    else if (x == negInf && y == negInf)

        result = -3 * piOverFourDouble;

    else

        result = ::atan2(x, y);

    return result;

}

// Work around a bug in the Microsoft CRT, where fmod(x, +-infinity) yields NaN instead of x.

inline double wtf_fmod(double x, double y) { return (!isinf(x) && isinf(y)) ? x : fmod(x, y); }

// Work around a bug in the Microsoft CRT, where pow(NaN, 0) yields NaN instead of 1.

inline double wtf_pow(double x, double y) { return y == 0 ? 1 : pow(x, y); }

#define atan2(x, y) wtf_atan2(x, y)

#define fmod(x, y) wtf_fmod(x, y)

#define pow(x, y) wtf_pow(x, y)

#endif // COMPILER(MSVC)

inline double deg2rad(double d)  { return d * piDouble / 180.0; }

inline double rad2deg(double r)  { return r * 180.0 / piDouble; }

inline double deg2grad(double d) { return d * 400.0 / 360.0; }

inline double grad2deg(double g) { return g * 360.0 / 400.0; }

inline double turn2deg(double t) { return t * 360.0; }

inline double deg2turn(double d) { return d / 360.0; }

inline double rad2grad(double r) { return r * 200.0 / piDouble; }

inline double grad2rad(double g) { return g * piDouble / 200.0; }

inline float deg2rad(float d)  { return d * piFloat / 180.0f; }

inline float rad2deg(float r)  { return r * 180.0f / piFloat; }

inline float deg2grad(float d) { return d * 400.0f / 360.0f; }

inline float grad2deg(float g) { return g * 360.0f / 400.0f; }

inline float turn2deg(float t) { return t * 360.0f; }

inline float deg2turn(float d) { return d / 360.0f; }

inline float rad2grad(float r) { return r * 200.0f / piFloat; }

inline float grad2rad(float g) { return g * piFloat / 200.0f; }

#if !COMPILER(MSVC) && !COMPILER(WINSCW) && !(COMPILER(RVCT) && (OS(SYMBIAN) || PLATFORM(BREWMP)))

using std::isfinite;

using std::isinf;

using std::isnan;

using std::signbit;

#endif

#endif // #ifndef WTF_MathExtras_h