mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-11-05 16:46:26 +00:00
130 lines
3.7 KiB
C++
130 lines
3.7 KiB
C++
/* -*- 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__
|
|
|
|
#define _USE_MATH_DEFINES /* needed for M_ constants on Win32 */
|
|
|
|
#include "nscore.h"
|
|
#include <cmath>
|
|
#include <float.h>
|
|
|
|
#ifdef 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);
|
|
#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
|