ceph/src/boost/boost/detail/basic_pointerbuf.hpp

   1 //-----------------------------------------------------------------------------
   2 // boost detail/templated_streams.hpp header file
   3 // See http://www.boost.org for updates, documentation, and revision history.
   4 //-----------------------------------------------------------------------------
   5 //
   6 // Copyright (c) 2013 John Maddock, Antony Polukhin
   7 //
   8 //
   9 // Distributed under the Boost Software License, Version 1.0. (See
  10 // accompanying file LICENSE_1_0.txt or copy at
  11 // http://www.boost.org/LICENSE_1_0.txt)
  12
  13 #ifndef BOOST_DETAIL_BASIC_POINTERBUF_HPP
  14 #define BOOST_DETAIL_BASIC_POINTERBUF_HPP
  15
  16 // MS compatible compilers support #pragma once
  17 #if defined(_MSC_VER)
  18 # pragma once
  19 #endif
  20
  21 #include "boost/config.hpp"
  22 #include <streambuf>
  23
  24 namespace boost { namespace detail {
  25
  26 //
  27 // class basic_pointerbuf:
  28 // acts as a stream buffer which wraps around a pair of pointers:
  29 //
  30 template <class charT, class BufferT >
  31 class basic_pointerbuf : public BufferT {
  32 protected:
  33    typedef BufferT base_type;
  34    typedef basic_pointerbuf<charT, BufferT> this_type;
  35    typedef typename base_type::int_type int_type;
  36    typedef typename base_type::char_type char_type;
  37    typedef typename base_type::pos_type pos_type;
  38    typedef ::std::streamsize streamsize;
  39    typedef typename base_type::off_type off_type;
  40
  41 public:
  42    basic_pointerbuf() : base_type() { setbuf(0, 0); }
  43    const charT* getnext() { return this->gptr(); }
  44
  45 #ifndef BOOST_NO_USING_TEMPLATE
  46     using base_type::pptr;
  47     using base_type::pbase;
  48 #else
  49     charT* pptr() const { return base_type::pptr(); }
  50     charT* pbase() const { return base_type::pbase(); }
  51 #endif
  52
  53 protected:
  54    // VC mistakenly assumes that `setbuf` and other functions are not referenced.
  55    // Marking those functions with `inline` suppresses the warnings.
  56    // There must be no harm from marking virtual functions as inline: inline virtual
  57    // call can be inlined ONLY when the compiler knows the "exact class".
  58    inline base_type* setbuf(char_type* s, streamsize n);
  59    inline typename this_type::pos_type seekpos(pos_type sp, ::std::ios_base::openmode which);
  60    inline typename this_type::pos_type seekoff(off_type off, ::std::ios_base::seekdir way, ::std::ios_base::openmode which);
  61
  62 private:
  63    basic_pointerbuf& operator=(const basic_pointerbuf&);
  64    basic_pointerbuf(const basic_pointerbuf&);
  65 };
  66
  67 template<class charT, class BufferT>
  68 BufferT*
  69 basic_pointerbuf<charT, BufferT>::setbuf(char_type* s, streamsize n)
  70 {
  71    this->setg(s, s, s + n);
  72    return this;
  73 }
  74
  75 template<class charT, class BufferT>
  76 typename basic_pointerbuf<charT, BufferT>::pos_type
  77 basic_pointerbuf<charT, BufferT>::seekoff(off_type off, ::std::ios_base::seekdir way, ::std::ios_base::openmode which)
  78 {
  79    typedef typename boost::int_t<sizeof(way) * CHAR_BIT>::least cast_type;
  80
  81    if(which & ::std::ios_base::out)
  82       return pos_type(off_type(-1));
  83    std::ptrdiff_t size = this->egptr() - this->eback();
  84    std::ptrdiff_t pos = this->gptr() - this->eback();
  85    charT* g = this->eback();
  86    switch(static_cast<cast_type>(way))
  87    {
  88    case ::std::ios_base::beg:
  89       if((off < 0) || (off > size))
  90          return pos_type(off_type(-1));
  91       else
  92          this->setg(g, g + off, g + size);
  93       break;
  94    case ::std::ios_base::end:
  95       if((off < 0) || (off > size))
  96          return pos_type(off_type(-1));
  97       else
  98          this->setg(g, g + size - off, g + size);
  99       break;
 100    case ::std::ios_base::cur:
 101    {
 102       std::ptrdiff_t newpos = static_cast<std::ptrdiff_t>(pos + off);
 103       if((newpos < 0) || (newpos > size))
 104          return pos_type(off_type(-1));
 105       else
 106          this->setg(g, g + newpos, g + size);
 107       break;
 108    }
 109    default: ;
 110    }
 111 #ifdef BOOST_MSVC
 112 #pragma warning(push)
 113 #pragma warning(disable:4244)
 114 #endif
 115    return static_cast<pos_type>(this->gptr() - this->eback());
 116 #ifdef BOOST_MSVC
 117 #pragma warning(pop)
 118 #endif
 119 }
 120
 121 template<class charT, class BufferT>
 122 typename basic_pointerbuf<charT, BufferT>::pos_type
 123 basic_pointerbuf<charT, BufferT>::seekpos(pos_type sp, ::std::ios_base::openmode which)
 124 {
 125    if(which & ::std::ios_base::out)
 126       return pos_type(off_type(-1));
 127    off_type size = static_cast<off_type>(this->egptr() - this->eback());
 128    charT* g = this->eback();
 129    if(off_type(sp) <= size)
 130    {
 131       this->setg(g, g + off_type(sp), g + size);
 132    }
 133    return pos_type(off_type(-1));
 134 }
 135
 136 }} // namespace boost::detail
 137
 138 #endif // BOOST_DETAIL_BASIC_POINTERBUF_HPP
 139