Chris@102: //-----------------------------------------------------------------------------
Chris@102: // boost detail/templated_streams.hpp header file
Chris@102: // See http://www.boost.org for updates, documentation, and revision history.
Chris@102: //-----------------------------------------------------------------------------
Chris@102: //
Chris@102: // Copyright (c) 2013 John Maddock, Antony Polukhin
Chris@102: // 
Chris@102: //
Chris@102: // Distributed under the Boost Software License, Version 1.0. (See
Chris@102: // accompanying file LICENSE_1_0.txt or copy at
Chris@102: // http://www.boost.org/LICENSE_1_0.txt)
Chris@102: 
Chris@102: #ifndef BOOST_DETAIL_BASIC_POINTERBUF_HPP
Chris@102: #define BOOST_DETAIL_BASIC_POINTERBUF_HPP
Chris@102: 
Chris@102: // MS compatible compilers support #pragma once
Chris@102: #if defined(_MSC_VER)
Chris@102: # pragma once
Chris@102: #endif
Chris@102: 
Chris@102: #include "boost/config.hpp"
Chris@102: #include <streambuf>
Chris@102: 
Chris@102: namespace boost { namespace detail {
Chris@102: 
Chris@102: //
Chris@102: // class basic_pointerbuf:
Chris@102: // acts as a stream buffer which wraps around a pair of pointers:
Chris@102: //
Chris@102: template <class charT, class BufferT >
Chris@102: class basic_pointerbuf : public BufferT {
Chris@102: protected:
Chris@102:    typedef BufferT base_type;
Chris@102:    typedef basic_pointerbuf<charT, BufferT> this_type;
Chris@102:    typedef typename base_type::int_type int_type;
Chris@102:    typedef typename base_type::char_type char_type;
Chris@102:    typedef typename base_type::pos_type pos_type;
Chris@102:    typedef ::std::streamsize streamsize;
Chris@102:    typedef typename base_type::off_type off_type;
Chris@102: 
Chris@102: public:
Chris@102:    basic_pointerbuf() : base_type() { setbuf(0, 0); }
Chris@102:    const charT* getnext() { return this->gptr(); }
Chris@102: 
Chris@102: #ifndef BOOST_NO_USING_TEMPLATE
Chris@102:     using base_type::pptr;
Chris@102:     using base_type::pbase;
Chris@102: #else
Chris@102:     charT* pptr() const { return base_type::pptr(); }
Chris@102:     charT* pbase() const { return base_type::pbase(); }
Chris@102: #endif
Chris@102: 
Chris@102: protected:
Chris@102:    // VC mistakenly assumes that `setbuf` and other functions are not referenced.
Chris@102:    // Marking those functions with `inline` suppresses the warnings.
Chris@102:    // There must be no harm from marking virtual functions as inline: inline virtual
Chris@102:    // call can be inlined ONLY when the compiler knows the "exact class".
Chris@102:    inline base_type* setbuf(char_type* s, streamsize n);
Chris@102:    inline typename this_type::pos_type seekpos(pos_type sp, ::std::ios_base::openmode which);
Chris@102:    inline typename this_type::pos_type seekoff(off_type off, ::std::ios_base::seekdir way, ::std::ios_base::openmode which);
Chris@102: 
Chris@102: private:
Chris@102:    basic_pointerbuf& operator=(const basic_pointerbuf&);
Chris@102:    basic_pointerbuf(const basic_pointerbuf&);
Chris@102: };
Chris@102: 
Chris@102: template<class charT, class BufferT>
Chris@102: BufferT*
Chris@102: basic_pointerbuf<charT, BufferT>::setbuf(char_type* s, streamsize n)
Chris@102: {
Chris@102:    this->setg(s, s, s + n);
Chris@102:    return this;
Chris@102: }
Chris@102: 
Chris@102: template<class charT, class BufferT>
Chris@102: typename basic_pointerbuf<charT, BufferT>::pos_type
Chris@102: basic_pointerbuf<charT, BufferT>::seekoff(off_type off, ::std::ios_base::seekdir way, ::std::ios_base::openmode which)
Chris@102: {
Chris@102:    typedef typename boost::int_t<sizeof(way) * CHAR_BIT>::least cast_type;
Chris@102: 
Chris@102:    if(which & ::std::ios_base::out)
Chris@102:       return pos_type(off_type(-1));
Chris@102:    std::ptrdiff_t size = this->egptr() - this->eback();
Chris@102:    std::ptrdiff_t pos = this->gptr() - this->eback();
Chris@102:    charT* g = this->eback();
Chris@102:    switch(static_cast<cast_type>(way))
Chris@102:    {
Chris@102:    case ::std::ios_base::beg:
Chris@102:       if((off < 0) || (off > size))
Chris@102:          return pos_type(off_type(-1));
Chris@102:       else
Chris@102:          this->setg(g, g + off, g + size);
Chris@102:       break;
Chris@102:    case ::std::ios_base::end:
Chris@102:       if((off < 0) || (off > size))
Chris@102:          return pos_type(off_type(-1));
Chris@102:       else
Chris@102:          this->setg(g, g + size - off, g + size);
Chris@102:       break;
Chris@102:    case ::std::ios_base::cur:
Chris@102:    {
Chris@102:       std::ptrdiff_t newpos = static_cast<std::ptrdiff_t>(pos + off);
Chris@102:       if((newpos < 0) || (newpos > size))
Chris@102:          return pos_type(off_type(-1));
Chris@102:       else
Chris@102:          this->setg(g, g + newpos, g + size);
Chris@102:       break;
Chris@102:    }
Chris@102:    default: ;
Chris@102:    }
Chris@102: #ifdef BOOST_MSVC
Chris@102: #pragma warning(push)
Chris@102: #pragma warning(disable:4244)
Chris@102: #endif
Chris@102:    return static_cast<pos_type>(this->gptr() - this->eback());
Chris@102: #ifdef BOOST_MSVC
Chris@102: #pragma warning(pop)
Chris@102: #endif
Chris@102: }
Chris@102: 
Chris@102: template<class charT, class BufferT>
Chris@102: typename basic_pointerbuf<charT, BufferT>::pos_type
Chris@102: basic_pointerbuf<charT, BufferT>::seekpos(pos_type sp, ::std::ios_base::openmode which)
Chris@102: {
Chris@102:    if(which & ::std::ios_base::out)
Chris@102:       return pos_type(off_type(-1));
Chris@102:    off_type size = static_cast<off_type>(this->egptr() - this->eback());
Chris@102:    charT* g = this->eback();
Chris@102:    if(off_type(sp) <= size)
Chris@102:    {
Chris@102:       this->setg(g, g + off_type(sp), g + size);
Chris@102:    }
Chris@102:    return pos_type(off_type(-1));
Chris@102: }
Chris@102: 
Chris@102: }} // namespace boost::detail
Chris@102: 
Chris@102: #endif // BOOST_DETAIL_BASIC_POINTERBUF_HPP
Chris@102: