// (C) Copyright 2007-2009 Andrew Sutton | |
// | |
// Use, modification and distribution are subject to the | |
// Boost Software License, Version 1.0 (See accompanying file | |
// LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) | |
#ifndef BOOST_GRAPH_NUMERIC_VALUES_HPP | |
#define BOOST_GRAPH_NUMERIC_VALUES_HPP | |
#include <limits> | |
namespace boost | |
{ | |
#define BOOST_GRAPH_SPECIALIZE_NUMERIC_FLOAT(type) \ | |
template <> struct numeric_values<type> { \ | |
typedef type value_type; \ | |
static type zero() { return 0.0; } \ | |
static type infinity() { return std::numeric_limits<type>::infinity(); } \ | |
}; | |
/** | |
* This generic type reports various numeric values for some type. In the | |
* general case, numeric values simply treat their maximum value as infinity | |
* and the default-constructed value as 0. | |
* | |
* Specializations of this template can redefine the notions of zero and | |
* infinity for various types. For example, the class is specialized for | |
* floating point types to use the built in notion of infinity. | |
*/ | |
template <typename T> | |
struct numeric_values | |
{ | |
typedef T value_type; | |
static T zero() | |
{ return T(); } | |
static T infinity() | |
{ return (std::numeric_limits<T>::max)(); } | |
}; | |
// Specializations for floating point types refer to 0.0 and their infinity | |
// value defined by numeric_limits. | |
BOOST_GRAPH_SPECIALIZE_NUMERIC_FLOAT(float) | |
BOOST_GRAPH_SPECIALIZE_NUMERIC_FLOAT(double) | |
BOOST_GRAPH_SPECIALIZE_NUMERIC_FLOAT(long double) | |
#undef BOOST_GRAPH_SPECIALIZE_NUMERIC_VALUE | |
} | |
#endif |