archive/iterators/mb_from_wchar.hpp

0001 #ifndef BOOST_ARCHIVE_ITERATORS_MB_FROM_WCHAR_HPP
0002 #define BOOST_ARCHIVE_ITERATORS_MB_FROM_WCHAR_HPP
0003
0004 // MS compatible compilers support #pragma once
0005 #if defined(_MSC_VER)
0006 # pragma once
0007 #endif
0008
0009 /////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
0010 // mb_from_wchar.hpp
0011
0012 // (C) Copyright 2002 Robert Ramey - http://www.rrsd.com .
0013 // Use, modification and distribution is subject to the Boost Software
0014 // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
0015 // http://www.boost.org/LICENSE_1_0.txt)
0016
0017 //  See http://www.boost.org for updates, documentation, and revision history.
0018
0019 #include <boost/assert.hpp>
0020 #include <cstddef> // size_t
0021 #include <cstring> // memcpy
0022 #ifndef BOOST_NO_CWCHAR
0023 #include <cwchar> //  mbstate_t
0024 #endif
0025 #include <boost/config.hpp>
0026 #if defined(BOOST_NO_STDC_NAMESPACE)
0027 namespace std{
0028     using ::mbstate_t;
0029     using ::memcpy;
0030 } // namespace std
0031 #endif
0032
0033 #include <boost/archive/detail/utf8_codecvt_facet.hpp>
0034 #include <boost/iterator/iterator_adaptor.hpp>
0035
0036 namespace boost {
0037 namespace archive {
0038 namespace iterators {
0039
0040 /////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
0041 // class used by text archives to translate wide strings and to char
0042 // strings of the currently selected locale
0043 template<class Base>    // the input iterator
0044 class mb_from_wchar
0045     : public boost::iterator_adaptor<
0046         mb_from_wchar<Base>,
0047         Base,
0048         wchar_t,
0049         single_pass_traversal_tag,
0050         char
0051     >
0052 {
0053     friend class boost::iterator_core_access;
0054
0055     typedef typename boost::iterator_adaptor<
0056         mb_from_wchar<Base>,
0057         Base,
0058         wchar_t,
0059         single_pass_traversal_tag,
0060         char
0061     > super_t;
0062
0063     typedef mb_from_wchar<Base> this_t;
0064
0065     char dereference_impl() {
0066         if(! m_full){
0067             fill();
0068             m_full = true;
0069         }
0070         return m_buffer[m_bnext];
0071     }
0072
0073     char dereference() const {
0074         return (const_cast<this_t *>(this))->dereference_impl();
0075     }
0076     // test for iterator equality
0077     bool equal(const mb_from_wchar<Base> & rhs) const {
0078         // once the value is filled, the base_reference has been incremented
0079         // so don't permit comparison anymore.
0080         return
0081             0 == m_bend
0082             && 0 == m_bnext
0083             && this->base_reference() == rhs.base_reference()
0084         ;
0085     }
0086
0087     void fill(){
0088         wchar_t value = * this->base_reference();
0089         const wchar_t *wend;
0090         char *bend;
0091         BOOST_VERIFY(
0092             m_codecvt_facet.out(
0093                 m_mbs,
0094                 & value, & value + 1, wend,
0095                 m_buffer, m_buffer + sizeof(m_buffer), bend
0096             )
0097             ==
0098             std::codecvt_base::ok
0099         );
0100         m_bnext = 0;
0101         m_bend = bend - m_buffer;
0102     }
0103
0104     void increment(){
0105         if(++m_bnext < m_bend)
0106             return;
0107         m_bend =
0108         m_bnext = 0;
0109         ++(this->base_reference());
0110         m_full = false;
0111     }
0112
0113     boost::archive::detail::utf8_codecvt_facet m_codecvt_facet;
0114     std::mbstate_t m_mbs;
0115     // buffer to handle pending characters
0116     char m_buffer[9 /* MB_CUR_MAX */];
0117     std::size_t m_bend;
0118     std::size_t m_bnext;
0119     bool m_full;
0120
0121 public:
0122     // make composable by using templated constructor
0123     template<class T>
0124     mb_from_wchar(T start) :
0125         super_t(Base(static_cast< T >(start))),
0126         m_mbs(std::mbstate_t()),
0127         m_bend(0),
0128         m_bnext(0),
0129         m_full(false)
0130     {}
0131     // intel 7.1 doesn't like default copy constructor
0132     mb_from_wchar(const mb_from_wchar & rhs) :
0133         super_t(rhs.base_reference()),
0134         m_mbs(rhs.m_mbs),
0135         m_bend(rhs.m_bend),
0136         m_bnext(rhs.m_bnext),
0137         m_full(rhs.m_full)
0138     {
0139         std::memcpy(m_buffer, rhs.m_buffer, sizeof(m_buffer));
0140     }
0141 };
0142
0143 } // namespace iterators
0144 } // namespace archive
0145 } // namespace boost
0146
0147 #endif // BOOST_ARCHIVE_ITERATORS_MB_FROM_WCHAR_HPP