ceph/src/boost/boost/xpressive/detail/utility/width.hpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // width.hpp
   3 //
   4 //  Copyright 2008 Eric Niebler. Distributed under the Boost
   5 //  Software License, Version 1.0. (See accompanying file
   6 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   7
   8 #ifndef BOOST_XPRESSIVE_DETAIL_UTILITY_WIDTH_HPP_EAN_04_07_2006
   9 #define BOOST_XPRESSIVE_DETAIL_UTILITY_WIDTH_HPP_EAN_04_07_2006
  10
  11 // MS compatible compilers support #pragma once
  12 #if defined(_MSC_VER)
  13 # pragma once
  14 #endif
  15
  16 #include <climits> // for INT_MAX
  17 #include <boost/mpl/size_t.hpp>
  18
  19 namespace boost { namespace xpressive { namespace detail
  20 {
  21
  22 typedef mpl::size_t<INT_MAX / 2 - 1> unknown_width;
  23 struct width;
  24 bool is_unknown(width const &that);
  25
  26 ///////////////////////////////////////////////////////////////////////////////
  27 // width
  28 struct width
  29 {
  30     width(std::size_t val = 0)
  31       : value_(val)
  32     {
  33     }
  34
  35     bool operator !() const
  36     {
  37         return !this->value_;
  38     }
  39
  40     width &operator +=(width const &that)
  41     {
  42         this->value_ =
  43             !is_unknown(*this) && !is_unknown(that)
  44           ? this->value_ + that.value_
  45           : unknown_width();
  46         return *this;
  47     }
  48
  49     width &operator |=(width const &that)
  50     {
  51         this->value_ =
  52             this->value_ == that.value_
  53           ? this->value_
  54           : unknown_width();
  55         return *this;
  56     }
  57
  58     std::size_t value() const
  59     {
  60         return this->value_;
  61     }
  62
  63 private:
  64     std::size_t value_;
  65 };
  66
  67 inline bool is_unknown(width const &that)
  68 {
  69     return unknown_width::value == that.value();
  70 }
  71
  72 inline bool operator ==(width const &left, width const &right)
  73 {
  74     return left.value() == right.value();
  75 }
  76
  77 inline bool operator !=(width const &left, width const &right)
  78 {
  79     return left.value() != right.value();
  80 }
  81
  82 inline width operator +(width left, width const &right)
  83 {
  84     return left += right;
  85 }
  86
  87 inline width operator |(width left, width const &right)
  88 {
  89     return left |= right;
  90 }
  91
  92 }}} // namespace boost::xpressive::detail
  93
  94 #endif