/////////////////////////////////////////////////////////////////////////////// | |
// width.hpp | |
// | |
// Copyright 2008 Eric Niebler. Distributed under the Boost | |
// Software License, Version 1.0. (See accompanying file | |
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
#ifndef BOOST_XPRESSIVE_DETAIL_UTILITY_WIDTH_HPP_EAN_04_07_2006 | |
#define BOOST_XPRESSIVE_DETAIL_UTILITY_WIDTH_HPP_EAN_04_07_2006 | |
// MS compatible compilers support #pragma once | |
#if defined(_MSC_VER) && (_MSC_VER >= 1020) | |
# pragma once | |
#endif | |
#include <climits> // for INT_MAX | |
#include <boost/mpl/size_t.hpp> | |
namespace boost { namespace xpressive { namespace detail | |
{ | |
typedef mpl::size_t<INT_MAX / 2 - 1> unknown_width; | |
struct width; | |
bool is_unknown(width const &that); | |
/////////////////////////////////////////////////////////////////////////////// | |
// width | |
struct width | |
{ | |
width(std::size_t val = 0) | |
: value_(val) | |
{ | |
} | |
bool operator !() const | |
{ | |
return !this->value_; | |
} | |
width &operator +=(width const &that) | |
{ | |
this->value_ = | |
!is_unknown(*this) && !is_unknown(that) | |
? this->value_ + that.value_ | |
: unknown_width(); | |
return *this; | |
} | |
width &operator |=(width const &that) | |
{ | |
this->value_ = | |
this->value_ == that.value_ | |
? this->value_ | |
: unknown_width(); | |
return *this; | |
} | |
std::size_t value() const | |
{ | |
return this->value_; | |
} | |
private: | |
std::size_t value_; | |
}; | |
inline bool is_unknown(width const &that) | |
{ | |
return unknown_width::value == that.value(); | |
} | |
inline bool operator ==(width const &left, width const &right) | |
{ | |
return left.value() == right.value(); | |
} | |
inline bool operator !=(width const &left, width const &right) | |
{ | |
return left.value() != right.value(); | |
} | |
inline width operator +(width left, width const &right) | |
{ | |
return left += right; | |
} | |
inline width operator |(width left, width const &right) | |
{ | |
return left |= right; | |
} | |
}}} // namespace boost::xpressive::detail | |
#endif |