ImathLimits.h 7.67 KB
Newer Older
wester committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267
///////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2002, Industrial Light & Magic, a division of Lucas
// Digital Ltd. LLC
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
// *       Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// *       Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// *       Neither the name of Industrial Light & Magic nor the names of
// its contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
///////////////////////////////////////////////////////////////////////////



#ifndef INCLUDED_IMATHLIMITS_H
#define INCLUDED_IMATHLIMITS_H

//----------------------------------------------------------------
//
//	Limitations of the basic C++ numerical data types
//
//----------------------------------------------------------------

#include <float.h>
#include <limits.h>

//------------------------------------------
// In Windows, min and max are macros.  Yay.
//------------------------------------------

#if defined _WIN32 || defined _WIN64
    #ifdef min
        #undef min
    #endif
    #ifdef max
        #undef max
    #endif
#endif

namespace Imath {


//-----------------------------------------------------------------
//
// Template class limits<T> returns information about the limits
// of numerical data type T:
//
//	min()		largest possible negative value of type T
//
//	max()		largest possible positive value of type T
//
//	smallest()	smallest possible positive value of type T
//			(for float and double: smallest normalized
//			positive value)
//
//	epsilon()	smallest possible e of type T, for which
//			1 + e != 1
//
//	isIntegral()	returns true if T is an integral type
//
//	isSigned()	returns true if T is signed
//
// Class limits<T> is useful to implement template classes or
// functions which depend on the limits of a numerical type
// which is not known in advance; for example:
//
//	template <class T> max (T x[], int n)
//	{
//	    T m = limits<T>::min();
//
//	    for (int i = 0; i < n; i++)
//		if (m < x[i])
//		    m = x[i];
//
//	    return m;
//	}
//
// Class limits<T> has been implemented for the following types:
//
//	char, signed char, unsigned char
//	short, unsigned short
//	int, unsigned int
//	long, unsigned long
//	float
//	double
//	long double
//
// Class limits<T> has only static member functions, all of which
// are implemented as inlines.  No objects of type limits<T> are
// ever created.
//
//-----------------------------------------------------------------


template <class T> struct limits
{
    static T	min();
    static T	max();
    static T	smallest();
    static T	epsilon();
    static bool	isIntegral();
    static bool	isSigned();
};


//---------------
// Implementation
//---------------

template <>
struct limits <char>
{
    static char			min()		{return CHAR_MIN;}
    static char			max()		{return CHAR_MAX;}
    static char			smallest()	{return 1;}
    static char			epsilon()	{return 1;}
    static bool			isIntegral()	{return true;}
    static bool			isSigned()	{return (char) ~0 < 0;}
};

template <>
struct limits <signed char>
{
    static signed char		min()		{return SCHAR_MIN;}
    static signed char		max()		{return SCHAR_MAX;}
    static signed char		smallest()	{return 1;}
    static signed char		epsilon()	{return 1;}
    static bool			isIntegral()	{return true;}
    static bool			isSigned()	{return true;}
};

template <>
struct limits <unsigned char>
{
    static unsigned char	min()		{return 0;}
    static unsigned char	max()		{return UCHAR_MAX;}
    static unsigned char	smallest()	{return 1;}
    static unsigned char	epsilon()	{return 1;}
    static bool			isIntegral()	{return true;}
    static bool			isSigned()	{return false;}
};

template <>
struct limits <short>
{
    static short		min()		{return SHRT_MIN;}
    static short		max()		{return SHRT_MAX;}
    static short		smallest()	{return 1;}
    static short		epsilon()	{return 1;}
    static bool			isIntegral()	{return true;}
    static bool			isSigned()	{return true;}
};

template <>
struct limits <unsigned short>
{
    static unsigned short	min()		{return 0;}
    static unsigned short	max()		{return USHRT_MAX;}
    static unsigned short	smallest()	{return 1;}
    static unsigned short	epsilon()	{return 1;}
    static bool			isIntegral()	{return true;}
    static bool			isSigned()	{return false;}
};

template <>
struct limits <int>
{
    static int			min()		{return INT_MIN;}
    static int			max()		{return INT_MAX;}
    static int			smallest()	{return 1;}
    static int			epsilon()	{return 1;}
    static bool			isIntegral()	{return true;}
    static bool			isSigned()	{return true;}
};

template <>
struct limits <unsigned int>
{
    static unsigned int		min()		{return 0;}
    static unsigned int		max()		{return UINT_MAX;}
    static unsigned int		smallest()	{return 1;}
    static unsigned int		epsilon()	{return 1;}
    static bool			isIntegral()	{return true;}
    static bool			isSigned()	{return false;}
};

template <>
struct limits <long>
{
    static long			min()		{return LONG_MIN;}
    static long			max()		{return LONG_MAX;}
    static long			smallest()	{return 1;}
    static long			epsilon()	{return 1;}
    static bool			isIntegral()	{return true;}
    static bool			isSigned()	{return true;}
};

template <>
struct limits <unsigned long>
{
    static unsigned long	min()		{return 0;}
    static unsigned long	max()		{return ULONG_MAX;}
    static unsigned long	smallest()	{return 1;}
    static unsigned long	epsilon()	{return 1;}
    static bool			isIntegral()	{return true;}
    static bool			isSigned()	{return false;}
};

template <>
struct limits <float>
{
    static float		min()		{return -FLT_MAX;}
    static float		max()		{return FLT_MAX;}
    static float		smallest()	{return FLT_MIN;}
    static float		epsilon()	{return FLT_EPSILON;}
    static bool			isIntegral()	{return false;}
    static bool			isSigned()	{return true;}
};

template <>
struct limits <double>
{
    static double		min()		{return -DBL_MAX;}
    static double		max()		{return DBL_MAX;}
    static double		smallest()	{return DBL_MIN;}
    static double		epsilon()	{return DBL_EPSILON;}
    static bool			isIntegral()	{return false;}
    static bool			isSigned()	{return true;}
};

template <>
struct limits <long double>
{
    static long double		min()		{return -LDBL_MAX;}
    static long double		max()		{return LDBL_MAX;}
    static long double		smallest()	{return LDBL_MIN;}
    static long double		epsilon()	{return LDBL_EPSILON;}
    static bool			isIntegral()	{return false;}
    static bool			isSigned()	{return true;}
};


} // namespace Imath

#endif