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/src/FreeImage/Source/OpenEXR/Imath/ImathMath.h

https://bitbucket.org/cabalistic/ogredeps/
C++ Header | 208 lines | 89 code | 22 blank | 97 comment | 1 complexity | 4cefb3318b10acdae9ca963459d36d8e MD5 | raw file
  1///////////////////////////////////////////////////////////////////////////
  2//
  3// Copyright (c) 2002, Industrial Light & Magic, a division of Lucas
  4// Digital Ltd. LLC
  5// 
  6// All rights reserved.
  7// 
  8// Redistribution and use in source and binary forms, with or without
  9// modification, are permitted provided that the following conditions are
 10// met:
 11// *       Redistributions of source code must retain the above copyright
 12// notice, this list of conditions and the following disclaimer.
 13// *       Redistributions in binary form must reproduce the above
 14// copyright notice, this list of conditions and the following disclaimer
 15// in the documentation and/or other materials provided with the
 16// distribution.
 17// *       Neither the name of Industrial Light & Magic nor the names of
 18// its contributors may be used to endorse or promote products derived
 19// from this software without specific prior written permission. 
 20// 
 21// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 22// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 23// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 24// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 25// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 26// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 27// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 28// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 29// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 30// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 31// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 32//
 33///////////////////////////////////////////////////////////////////////////
 34
 35
 36
 37#ifndef INCLUDED_IMATHMATH_H
 38#define INCLUDED_IMATHMATH_H
 39
 40//----------------------------------------------------------------------------
 41//
 42//	ImathMath.h
 43//
 44//	This file contains template functions which call the double-
 45//	precision math functions defined in math.h (sin(), sqrt(),
 46//	exp() etc.), with specializations that call the faster
 47//	single-precision versions (sinf(), sqrtf(), expf() etc.)
 48//	when appropriate.
 49//
 50//	Example:
 51//
 52//	    double x = Math<double>::sqrt (3);	// calls ::sqrt(double);
 53//	    float  y = Math<float>::sqrt (3);	// calls ::sqrtf(float);
 54//
 55//	When would I want to use this?
 56//
 57//	You may be writing a template which needs to call some function
 58//	defined in math.h, for example to extract a square root, but you
 59//	don't know whether to call the single- or the double-precision
 60//	version of this function (sqrt() or sqrtf()):
 61//
 62//	    template <class T>
 63//	    T
 64//	    glorp (T x)
 65//	    {
 66//		return sqrt (x + 1);		// should call ::sqrtf(float)
 67//	    }					// if x is a float, but we
 68//						// don't know if it is
 69//
 70//	Using the templates in this file, you can make sure that
 71//	the appropriate version of the math function is called:
 72//
 73//	    template <class T>
 74//	    T
 75//	    glorp (T x, T y)
 76//	    {
 77//		return Math<T>::sqrt (x + 1);	// calls ::sqrtf(float) if x
 78//	    }					// is a float, ::sqrt(double)
 79//	    					// otherwise
 80//
 81//----------------------------------------------------------------------------
 82
 83#include "ImathPlatform.h"
 84#include "ImathLimits.h"
 85#include <math.h>
 86
 87namespace Imath {
 88
 89
 90template <class T>
 91struct Math
 92{
 93   static T	acos  (T x)		{return ::acos (double(x));}	
 94   static T	asin  (T x)		{return ::asin (double(x));}
 95   static T	atan  (T x)		{return ::atan (double(x));}
 96   static T	atan2 (T x, T y)	{return ::atan2 (double(x), double(y));}
 97   static T	cos   (T x)		{return ::cos (double(x));}
 98   static T	sin   (T x)		{return ::sin (double(x));}
 99   static T	tan   (T x)		{return ::tan (double(x));}
100   static T	cosh  (T x)		{return ::cosh (double(x));}
101   static T	sinh  (T x)		{return ::sinh (double(x));}
102   static T	tanh  (T x)		{return ::tanh (double(x));}
103   static T	exp   (T x)		{return ::exp (double(x));}
104   static T	log   (T x)		{return ::log (double(x));}
105   static T	log10 (T x)		{return ::log10 (double(x));}
106   static T	modf  (T x, T *iptr)
107   {
108        double ival;
109        T rval( ::modf (double(x),&ival));
110	*iptr = ival;
111	return rval;
112   }
113   static T	pow   (T x, T y)	{return ::pow (double(x), double(y));}
114   static T	sqrt  (T x)		{return ::sqrt (double(x));}
115   static T	ceil  (T x)		{return ::ceil (double(x));}
116   static T	fabs  (T x)		{return ::fabs (double(x));}
117   static T	floor (T x)		{return ::floor (double(x));}
118   static T	fmod  (T x, T y)	{return ::fmod (double(x), double(y));}
119   static T	hypot (T x, T y)	{return ::hypot (double(x), double(y));}
120};
121
122
123template <>
124struct Math<float>
125{
126   static float	acos  (float x)			{return ::acosf (x);}	
127   static float	asin  (float x)			{return ::asinf (x);}
128   static float	atan  (float x)			{return ::atanf (x);}
129   static float	atan2 (float x, float y)	{return ::atan2f (x, y);}
130   static float	cos   (float x)			{return ::cosf (x);}
131   static float	sin   (float x)			{return ::sinf (x);}
132   static float	tan   (float x)			{return ::tanf (x);}
133   static float	cosh  (float x)			{return ::coshf (x);}
134   static float	sinh  (float x)			{return ::sinhf (x);}
135   static float	tanh  (float x)			{return ::tanhf (x);}
136   static float	exp   (float x)			{return ::expf (x);}
137   static float	log   (float x)			{return ::logf (x);}
138   static float	log10 (float x)			{return ::log10f (x);}
139   static float	modf  (float x, float *y)	{return ::modff (x, y);}
140   static float	pow   (float x, float y)	{return ::powf (x, y);}
141   static float	sqrt  (float x)			{return ::sqrtf (x);}
142   static float	ceil  (float x)			{return ::ceilf (x);}
143   static float	fabs  (float x)			{return ::fabsf (x);}
144   static float	floor (float x)			{return ::floorf (x);}
145   static float	fmod  (float x, float y)	{return ::fmodf (x, y);}
146#if !defined(_MSC_VER)
147   static float	hypot (float x, float y)	{return ::hypotf (x, y);}
148#else
149   static float hypot (float x, float y)	{return ::sqrtf(x*x + y*y);}
150#endif
151};
152
153
154//--------------------------------------------------------------------------
155// Don Hatch's version of sin(x)/x, which is accurate for very small x.
156// Returns 1 for x == 0.
157//--------------------------------------------------------------------------
158
159template <class T>
160inline T
161sinx_over_x (T x)
162{
163    if (x * x < limits<T>::epsilon())
164	return T (1);
165    else
166	return Math<T>::sin (x) / x;
167}
168
169
170//--------------------------------------------------------------------------
171// Compare two numbers and test if they are "approximately equal":
172//
173// equalWithAbsError (x1, x2, e)
174//
175//	Returns true if x1 is the same as x2 with an absolute error of
176//	no more than e,
177//	
178//	abs (x1 - x2) <= e
179//
180// equalWithRelError (x1, x2, e)
181//
182//	Returns true if x1 is the same as x2 with an relative error of
183//	no more than e,
184//	
185//	abs (x1 - x2) <= e * x1
186//
187//--------------------------------------------------------------------------
188
189template <class T>
190inline bool
191equalWithAbsError (T x1, T x2, T e)
192{
193    return ((x1 > x2)? x1 - x2: x2 - x1) <= e;
194}
195
196
197template <class T>
198inline bool
199equalWithRelError (T x1, T x2, T e)
200{
201    return ((x1 > x2)? x1 - x2: x2 - x1) <= e * ((x1 > 0)? x1: -x1);
202}
203
204
205
206} // namespace Imath
207
208#endif