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/* -*- 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>
/*
* 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);
#elif defined(XP_DARWIN)
// Darwin has deprecated |finite| and recommends |isfinite|. The former is
// not present in the iOS SDK.
return std::isfinite(aNum);
#else
return finite(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
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