268 lines
7.7 KiB
C++
268 lines
7.7 KiB
C++
///////////////////////////////////////////////////////////////////////////
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//
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// Copyright (c) 2002, Industrial Light & Magic, a division of Lucas
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// Digital Ltd. LLC
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//
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Industrial Light & Magic nor the names of
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// its contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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///////////////////////////////////////////////////////////////////////////
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#ifndef INCLUDED_IMATHLIMITS_H
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#define INCLUDED_IMATHLIMITS_H
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//----------------------------------------------------------------
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//
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// Limitations of the basic C++ numerical data types
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//
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//----------------------------------------------------------------
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#include <float.h>
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#include <limits.h>
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//------------------------------------------
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// In Windows, min and max are macros. Yay.
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//------------------------------------------
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#if defined _WIN32 || defined _WIN64
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#ifdef min
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#undef min
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#endif
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#ifdef max
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#undef max
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#endif
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#endif
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namespace Imath {
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//-----------------------------------------------------------------
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//
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// Template class limits<T> returns information about the limits
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// of numerical data type T:
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//
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// min() largest possible negative value of type T
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//
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// max() largest possible positive value of type T
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//
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// smallest() smallest possible positive value of type T
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// (for float and double: smallest normalized
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// positive value)
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//
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// epsilon() smallest possible e of type T, for which
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// 1 + e != 1
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//
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// isIntegral() returns true if T is an integral type
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//
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// isSigned() returns true if T is signed
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//
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// Class limits<T> is useful to implement template classes or
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// functions which depend on the limits of a numerical type
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// which is not known in advance; for example:
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//
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// template <class T> max (T x[], int n)
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// {
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// T m = limits<T>::min();
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//
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// for (int i = 0; i < n; i++)
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// if (m < x[i])
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// m = x[i];
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//
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// return m;
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// }
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//
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// Class limits<T> has been implemented for the following types:
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//
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// char, signed char, unsigned char
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// short, unsigned short
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// int, unsigned int
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// long, unsigned long
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// float
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// double
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// long double
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//
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// Class limits<T> has only static member functions, all of which
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// are implemented as inlines. No objects of type limits<T> are
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// ever created.
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//
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//-----------------------------------------------------------------
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template <class T> struct limits
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{
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static T min();
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static T max();
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static T smallest();
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static T epsilon();
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static bool isIntegral();
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static bool isSigned();
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};
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//---------------
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// Implementation
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//---------------
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template <>
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struct limits <char>
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{
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static char min() {return CHAR_MIN;}
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static char max() {return CHAR_MAX;}
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static char smallest() {return 1;}
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static char epsilon() {return 1;}
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static bool isIntegral() {return true;}
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static bool isSigned() {return (char) ~0 < 0;}
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};
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template <>
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struct limits <signed char>
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{
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static signed char min() {return SCHAR_MIN;}
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static signed char max() {return SCHAR_MAX;}
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static signed char smallest() {return 1;}
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static signed char epsilon() {return 1;}
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static bool isIntegral() {return true;}
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static bool isSigned() {return true;}
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};
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template <>
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struct limits <unsigned char>
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{
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static unsigned char min() {return 0;}
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static unsigned char max() {return UCHAR_MAX;}
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static unsigned char smallest() {return 1;}
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static unsigned char epsilon() {return 1;}
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static bool isIntegral() {return true;}
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static bool isSigned() {return false;}
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};
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template <>
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struct limits <short>
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{
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static short min() {return SHRT_MIN;}
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static short max() {return SHRT_MAX;}
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static short smallest() {return 1;}
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static short epsilon() {return 1;}
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static bool isIntegral() {return true;}
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static bool isSigned() {return true;}
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};
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template <>
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struct limits <unsigned short>
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{
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static unsigned short min() {return 0;}
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static unsigned short max() {return USHRT_MAX;}
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static unsigned short smallest() {return 1;}
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static unsigned short epsilon() {return 1;}
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static bool isIntegral() {return true;}
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static bool isSigned() {return false;}
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};
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template <>
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struct limits <int>
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{
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static int min() {return INT_MIN;}
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static int max() {return INT_MAX;}
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static int smallest() {return 1;}
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static int epsilon() {return 1;}
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static bool isIntegral() {return true;}
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static bool isSigned() {return true;}
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};
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template <>
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struct limits <unsigned int>
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{
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static unsigned int min() {return 0;}
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static unsigned int max() {return UINT_MAX;}
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static unsigned int smallest() {return 1;}
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static unsigned int epsilon() {return 1;}
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static bool isIntegral() {return true;}
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static bool isSigned() {return false;}
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};
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template <>
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struct limits <long>
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{
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static long min() {return LONG_MIN;}
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static long max() {return LONG_MAX;}
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static long smallest() {return 1;}
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static long epsilon() {return 1;}
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static bool isIntegral() {return true;}
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static bool isSigned() {return true;}
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};
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template <>
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struct limits <unsigned long>
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{
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static unsigned long min() {return 0;}
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static unsigned long max() {return ULONG_MAX;}
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static unsigned long smallest() {return 1;}
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static unsigned long epsilon() {return 1;}
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static bool isIntegral() {return true;}
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static bool isSigned() {return false;}
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};
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template <>
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struct limits <float>
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{
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static float min() {return -FLT_MAX;}
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static float max() {return FLT_MAX;}
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static float smallest() {return FLT_MIN;}
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static float epsilon() {return FLT_EPSILON;}
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static bool isIntegral() {return false;}
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static bool isSigned() {return true;}
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};
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template <>
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struct limits <double>
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{
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static double min() {return -DBL_MAX;}
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static double max() {return DBL_MAX;}
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static double smallest() {return DBL_MIN;}
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static double epsilon() {return DBL_EPSILON;}
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static bool isIntegral() {return false;}
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static bool isSigned() {return true;}
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};
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template <>
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struct limits <long double>
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{
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static long double min() {return -LDBL_MAX;}
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static long double max() {return LDBL_MAX;}
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static long double smallest() {return LDBL_MIN;}
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static long double epsilon() {return LDBL_EPSILON;}
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static bool isIntegral() {return false;}
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static bool isSigned() {return true;}
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};
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} // namespace Imath
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#endif
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