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

  1///////////////////////////////////////////////////////////////////////////
  2//
  3// Copyright (c) 2002, Industrial Light & Magic, a division of Lucas
  4// Digital Ltd. LLC
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 33///////////////////////////////////////////////////////////////////////////
 34
 35
 36
 37#ifndef INCLUDED_IMATHLIMITS_H
 38#define INCLUDED_IMATHLIMITS_H
 39
 40//----------------------------------------------------------------
 41//
 42//	Limitations of the basic C++ numerical data types
 43//
 44//----------------------------------------------------------------
 45
 46#include <float.h>
 47#include <limits.h>
 48
 49//------------------------------------------
 50// In Windows, min and max are macros.  Yay.
 51//------------------------------------------
 52
 53#if defined _WIN32 || defined _WIN64
 54    #ifdef min
 55        #undef min
 56    #endif
 57    #ifdef max
 58        #undef max
 59    #endif
 60#endif
 61
 62namespace Imath {
 63
 64
 65//-----------------------------------------------------------------
 66//
 67// Template class limits<T> returns information about the limits
 68// of numerical data type T:
 69//
 70//	min()		largest possible negative value of type T
 71//
 72//	max()		largest possible positive value of type T
 73//
 74//	smallest()	smallest possible positive value of type T
 75//			(for float and double: smallest normalized
 76//			positive value)
 77//
 78//	epsilon()	smallest possible e of type T, for which
 79//			1 + e != 1
 80//
 81//	isIntegral()	returns true if T is an integral type
 82//
 83//	isSigned()	returns true if T is signed
 84//
 85// Class limits<T> is useful to implement template classes or
 86// functions which depend on the limits of a numerical type
 87// which is not known in advance; for example:
 88//
 89//	template <class T> max (T x[], int n)
 90//	{
 91//	    T m = limits<T>::min();
 92//
 93//	    for (int i = 0; i < n; i++)
 94//		if (m < x[i])
 95//		    m = x[i];
 96//
 97//	    return m;
 98//	}
 99//
100// Class limits<T> has been implemented for the following types:
101//
102//	char, signed char, unsigned char
103//	short, unsigned short
104//	int, unsigned int
105//	long, unsigned long
106//	float
107//	double
108//	long double
109//
110// Class limits<T> has only static member functions, all of which
111// are implemented as inlines.  No objects of type limits<T> are
112// ever created.
113//
114//-----------------------------------------------------------------
115
116
117template <class T> struct limits
118{
119    static T	min();
120    static T	max();
121    static T	smallest();
122    static T	epsilon();
123    static bool	isIntegral();
124    static bool	isSigned();
125};
126
127
128//---------------
129// Implementation
130//---------------
131
132template <>
133struct limits <char>
134{
135    static char			min()		{return CHAR_MIN;}
136    static char			max()		{return CHAR_MAX;}
137    static char			smallest()	{return 1;}
138    static char			epsilon()	{return 1;}
139    static bool			isIntegral()	{return true;}
140    static bool			isSigned()	{return (char) ~0 < 0;}
141};
142
143template <>
144struct limits <signed char>
145{
146    static signed char		min()		{return SCHAR_MIN;}
147    static signed char		max()		{return SCHAR_MAX;}
148    static signed char		smallest()	{return 1;}
149    static signed char		epsilon()	{return 1;}
150    static bool			isIntegral()	{return true;}
151    static bool			isSigned()	{return true;}
152};
153
154template <>
155struct limits <unsigned char>
156{
157    static unsigned char	min()		{return 0;}
158    static unsigned char	max()		{return UCHAR_MAX;}
159    static unsigned char	smallest()	{return 1;}
160    static unsigned char	epsilon()	{return 1;}
161    static bool			isIntegral()	{return true;}
162    static bool			isSigned()	{return false;}
163};
164
165template <>
166struct limits <short>
167{
168    static short		min()		{return SHRT_MIN;}
169    static short		max()		{return SHRT_MAX;}
170    static short		smallest()	{return 1;}
171    static short		epsilon()	{return 1;}
172    static bool			isIntegral()	{return true;}
173    static bool			isSigned()	{return true;}
174};
175
176template <>
177struct limits <unsigned short>
178{
179    static unsigned short	min()		{return 0;}
180    static unsigned short	max()		{return USHRT_MAX;}
181    static unsigned short	smallest()	{return 1;}
182    static unsigned short	epsilon()	{return 1;}
183    static bool			isIntegral()	{return true;}
184    static bool			isSigned()	{return false;}
185};
186
187template <>
188struct limits <int>
189{
190    static int			min()		{return INT_MIN;}
191    static int			max()		{return INT_MAX;}
192    static int			smallest()	{return 1;}
193    static int			epsilon()	{return 1;}
194    static bool			isIntegral()	{return true;}
195    static bool			isSigned()	{return true;}
196};
197
198template <>
199struct limits <unsigned int>
200{
201    static unsigned int		min()		{return 0;}
202    static unsigned int		max()		{return UINT_MAX;}
203    static unsigned int		smallest()	{return 1;}
204    static unsigned int		epsilon()	{return 1;}
205    static bool			isIntegral()	{return true;}
206    static bool			isSigned()	{return false;}
207};
208
209template <>
210struct limits <long>
211{
212    static long			min()		{return LONG_MIN;}
213    static long			max()		{return LONG_MAX;}
214    static long			smallest()	{return 1;}
215    static long			epsilon()	{return 1;}
216    static bool			isIntegral()	{return true;}
217    static bool			isSigned()	{return true;}
218};
219
220template <>
221struct limits <unsigned long>
222{
223    static unsigned long	min()		{return 0;}
224    static unsigned long	max()		{return ULONG_MAX;}
225    static unsigned long	smallest()	{return 1;}
226    static unsigned long	epsilon()	{return 1;}
227    static bool			isIntegral()	{return true;}
228    static bool			isSigned()	{return false;}
229};
230
231template <>
232struct limits <float>
233{
234    static float		min()		{return -FLT_MAX;}
235    static float		max()		{return FLT_MAX;}
236    static float		smallest()	{return FLT_MIN;}
237    static float		epsilon()	{return FLT_EPSILON;}
238    static bool			isIntegral()	{return false;}
239    static bool			isSigned()	{return true;}
240};
241
242template <>
243struct limits <double>
244{
245    static double		min()		{return -DBL_MAX;}
246    static double		max()		{return DBL_MAX;}
247    static double		smallest()	{return DBL_MIN;}
248    static double		epsilon()	{return DBL_EPSILON;}
249    static bool			isIntegral()	{return false;}
250    static bool			isSigned()	{return true;}
251};
252
253template <>
254struct limits <long double>
255{
256    static long double		min()		{return -LDBL_MAX;}
257    static long double		max()		{return LDBL_MAX;}
258    static long double		smallest()	{return LDBL_MIN;}
259    static long double		epsilon()	{return LDBL_EPSILON;}
260    static bool			isIntegral()	{return false;}
261    static bool			isSigned()	{return true;}
262};
263
264
265} // namespace Imath
266
267#endif