ecency-mobile/ios/Pods/boost-for-react-native/boost/graph/numeric_values.hpp

53 lines
1.6 KiB
C++

// (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