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