/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef nsMathUtils_h__

#define nsMathUtils_h__

#include "nscore.h"

#include <cmath>

#include <float.h>

#if defined(XP_SOLARIS)

#include <ieeefp.h>

#endif

/*

 * round

 */

inline double

NS_round(double aNum)

{

  return aNum >= 0.0 ? floor(aNum + 0.5) : ceil(aNum - 0.5);

}

inline float

NS_roundf(float aNum)

{

  return aNum >= 0.0f ? floorf(aNum + 0.5f) : ceilf(aNum - 0.5f);

}

inline int32_t

NS_lround(double aNum)

{

  return aNum >= 0.0 ? int32_t(aNum + 0.5) : int32_t(aNum - 0.5);

}

/* NS_roundup30 rounds towards infinity for positive and       */

/* negative numbers.                                           */

#if defined(XP_WIN32) && defined(_M_IX86) && !defined(__GNUC__) && !defined(__clang__)

inline int32_t NS_lroundup30(float x)

{

  /* Code derived from Laurent de Soras' paper at             */

  /* http://ldesoras.free.fr/doc/articles/rounding_en.pdf     */

  /* Rounding up on Windows is expensive using the float to   */

  /* int conversion and the floor function. A faster          */

  /* approach is to use f87 rounding while assuming the       */

  /* default rounding mode of rounding to the nearest         */

  /* integer. This rounding mode, however, actually rounds    */

  /* to the nearest integer so we add the floating point      */

  /* number to itself and add our rounding factor before      */

  /* doing the conversion to an integer. We then do a right   */

  /* shift of one bit on the integer to divide by two.        */

  /* This routine doesn't handle numbers larger in magnitude  */

  /* than 2^30 but this is fine for NSToCoordRound because    */

  /* Coords are limited to 2^30 in magnitude.                 */

  static const double round_to_nearest = 0.5f;

  int i;

  __asm {

    fld     x                   ; load fp argument

    fadd    st, st(0)           ; double it

    fadd    round_to_nearest    ; add the rounding factor

    fistp   dword ptr i         ; convert the result to int

  }

  return i >> 1;                /* divide by 2 */

}

#endif /* XP_WIN32 && _M_IX86 && !__GNUC__ */

inline int32_t

NS_lroundf(float aNum)

{

  return aNum >= 0.0f ? int32_t(aNum + 0.5f) : int32_t(aNum - 0.5f);

}

/*

 * hypot.  We don't need a super accurate version of this, if a platform

 * turns up with none of the possibilities below it would be okay to fall

 * back to sqrt(x*x + y*y).

 */

inline double

NS_hypot(double aNum1, double aNum2)

{

#ifdef __GNUC__

  return __builtin_hypot(aNum1, aNum2);

#elif defined _WIN32

  return _hypot(aNum1, aNum2);

#else

  return hypot(aNum1, aNum2);

#endif

}

/**

 * Check whether a floating point number is finite (not +/-infinity and not a

 * NaN value).

 */

inline bool

NS_finite(double aNum)

{

#ifdef WIN32

  // NOTE: '!!' casts an int to bool without spamming MSVC warning C4800.

  return !!_finite(aNum);

#else

  return std::isfinite(aNum);

#endif

}

/**

 * Returns the result of the modulo of x by y using a floored division.

 * fmod(x, y) is using a truncated division.

 * The main difference is that the result of this method will have the sign of

 * y while the result of fmod(x, y) will have the sign of x.

 */

inline double

NS_floorModulo(double aNum1, double aNum2)

{

  return (aNum1 - aNum2 * floor(aNum1 / aNum2));

}

#endif