boost/interprocess/streams/bufferstream.hpp
//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////
//
// This file comes from SGI's sstream file. Modified by Ion Gaztanaga 2005-2012.
// Changed internal SGI string to a buffer. Added efficient
// internal buffer get/set/swap functions, so that we can obtain/establish the
// internal buffer without any reallocation or copy. Kill those temporaries!
///////////////////////////////////////////////////////////////////////////////
/*
* Copyright (c) 1998
* Silicon Graphics Computer Systems, Inc.
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Silicon Graphics makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*/
//!\file
//!This file defines basic_bufferbuf, basic_ibufferstream,
//!basic_obufferstream, and basic_bufferstream classes. These classes
//!represent streamsbufs and streams whose sources or destinations
//!are fixed size character buffers.
#ifndef BOOST_INTERPROCESS_BUFFERSTREAM_HPP
#define BOOST_INTERPROCESS_BUFFERSTREAM_HPP
#include <boost/interprocess/detail/config_begin.hpp>
#include <boost/interprocess/detail/workaround.hpp>
#include <iosfwd>
#include <ios>
#include <istream>
#include <ostream>
#include <string> // char traits
#include <cstddef> // ptrdiff_t
#include <boost/assert.hpp>
#include <boost/interprocess/interprocess_fwd.hpp>
namespace boost { namespace interprocess {
//!A streambuf class that controls the transmission of elements to and from
//!a basic_xbufferstream. The elements are transmitted from a to a fixed
//!size buffer
template <class CharT, class CharTraits>
class basic_bufferbuf
: public std::basic_streambuf<CharT, CharTraits>
{
public:
typedef CharT char_type;
typedef typename CharTraits::int_type int_type;
typedef typename CharTraits::pos_type pos_type;
typedef typename CharTraits::off_type off_type;
typedef CharTraits traits_type;
typedef std::basic_streambuf<char_type, traits_type> base_t;
public:
//!Constructor.
//!Does not throw.
explicit basic_bufferbuf(std::ios_base::openmode mode
= std::ios_base::in | std::ios_base::out)
: base_t(), m_mode(mode), m_buffer(0), m_length(0)
{}
//!Constructor. Assigns formatting buffer.
//!Does not throw.
explicit basic_bufferbuf(CharT *buf, std::size_t length,
std::ios_base::openmode mode
= std::ios_base::in | std::ios_base::out)
: base_t(), m_mode(mode), m_buffer(buf), m_length(length)
{ this->set_pointers(); }
virtual ~basic_bufferbuf(){}
public:
//!Returns the pointer and size of the internal buffer.
//!Does not throw.
std::pair<CharT *, std::size_t> buffer() const
{ return std::pair<CharT *, std::size_t>(m_buffer, m_length); }
//!Sets the underlying buffer to a new value
//!Does not throw.
void buffer(CharT *buf, std::size_t length)
{ m_buffer = buf; m_length = length; this->set_pointers(); }
/// @cond
private:
void set_pointers()
{
// The initial read position is the beginning of the buffer.
if(m_mode & std::ios_base::in)
this->setg(m_buffer, m_buffer, m_buffer + m_length);
// The initial write position is the beginning of the buffer.
if(m_mode & std::ios_base::out)
this->setp(m_buffer, m_buffer + m_length);
}
protected:
virtual int_type underflow()
{
// Precondition: gptr() >= egptr(). Returns a character, if available.
return this->gptr() != this->egptr() ?
CharTraits::to_int_type(*this->gptr()) : CharTraits::eof();
}
virtual int_type pbackfail(int_type c = CharTraits::eof())
{
if(this->gptr() != this->eback()) {
if(!CharTraits::eq_int_type(c, CharTraits::eof())) {
if(CharTraits::eq(CharTraits::to_char_type(c), this->gptr()[-1])) {
this->gbump(-1);
return c;
}
else if(m_mode & std::ios_base::out) {
this->gbump(-1);
*this->gptr() = c;
return c;
}
else
return CharTraits::eof();
}
else {
this->gbump(-1);
return CharTraits::not_eof(c);
}
}
else
return CharTraits::eof();
}
virtual int_type overflow(int_type c = CharTraits::eof())
{
if(m_mode & std::ios_base::out) {
if(!CharTraits::eq_int_type(c, CharTraits::eof())) {
// if(!(m_mode & std::ios_base::in)) {
// if(this->pptr() != this->epptr()) {
// *this->pptr() = CharTraits::to_char_type(c);
// this->pbump(1);
// return c;
// }
// else
// return CharTraits::eof();
// }
// else {
if(this->pptr() == this->epptr()) {
//We can't append to a static buffer
return CharTraits::eof();
}
else {
*this->pptr() = CharTraits::to_char_type(c);
this->pbump(1);
return c;
}
// }
}
else // c is EOF, so we don't have to do anything
return CharTraits::not_eof(c);
}
else // Overflow always fails if it's read-only.
return CharTraits::eof();
}
virtual pos_type seekoff(off_type off, std::ios_base::seekdir dir,
std::ios_base::openmode mode
= std::ios_base::in | std::ios_base::out)
{
bool in = false;
bool out = false;
const std::ios_base::openmode inout =
std::ios_base::in | std::ios_base::out;
if((mode & inout) == inout) {
if(dir == std::ios_base::beg || dir == std::ios_base::end)
in = out = true;
}
else if(mode & std::ios_base::in)
in = true;
else if(mode & std::ios_base::out)
out = true;
if(!in && !out)
return pos_type(off_type(-1));
else if((in && (!(m_mode & std::ios_base::in) || this->gptr() == 0)) ||
(out && (!(m_mode & std::ios_base::out) || this->pptr() == 0)))
return pos_type(off_type(-1));
std::streamoff newoff;
switch(dir) {
case std::ios_base::beg:
newoff = 0;
break;
case std::ios_base::end:
newoff = static_cast<std::streamoff>(m_length);
break;
case std::ios_base::cur:
newoff = in ? static_cast<std::streamoff>(this->gptr() - this->eback())
: static_cast<std::streamoff>(this->pptr() - this->pbase());
break;
default:
return pos_type(off_type(-1));
}
off += newoff;
if(in) {
std::ptrdiff_t n = this->egptr() - this->eback();
if(off < 0 || off > n)
return pos_type(off_type(-1));
else
this->setg(this->eback(), this->eback() + off, this->eback() + n);
}
if(out) {
std::ptrdiff_t n = this->epptr() - this->pbase();
if(off < 0 || off > n)
return pos_type(off_type(-1));
else {
this->setp(this->pbase(), this->pbase() + n);
this->pbump(off);
}
}
return pos_type(off);
}
virtual pos_type seekpos(pos_type pos, std::ios_base::openmode mode
= std::ios_base::in | std::ios_base::out)
{ return seekoff(pos - pos_type(off_type(0)), std::ios_base::beg, mode); }
private:
std::ios_base::openmode m_mode;
CharT * m_buffer;
std::size_t m_length;
/// @endcond
};
//!A basic_istream class that uses a fixed size character buffer
//!as its formatting buffer.
template <class CharT, class CharTraits>
class basic_ibufferstream :
/// @cond
private basic_bufferbuf<CharT, CharTraits>,
/// @endcond
public std::basic_istream<CharT, CharTraits>
{
public: // Typedefs
typedef typename std::basic_ios
<CharT, CharTraits>::char_type char_type;
typedef typename std::basic_ios<char_type, CharTraits>::int_type int_type;
typedef typename std::basic_ios<char_type, CharTraits>::pos_type pos_type;
typedef typename std::basic_ios<char_type, CharTraits>::off_type off_type;
typedef typename std::basic_ios<char_type, CharTraits>::traits_type traits_type;
/// @cond
private:
typedef basic_bufferbuf<CharT, CharTraits> bufferbuf_t;
typedef std::basic_ios<char_type, CharTraits> basic_ios_t;
typedef std::basic_istream<char_type, CharTraits> base_t;
bufferbuf_t & get_buf() { return *this; }
const bufferbuf_t & get_buf() const{ return *this; }
/// @endcond
public:
//!Constructor.
//!Does not throw.
basic_ibufferstream(std::ios_base::openmode mode = std::ios_base::in)
: //basic_ios_t() is called first (lefting it uninitialized) as it's a
//virtual base of basic_istream. The class will be initialized when
//basic_istream is constructed calling basic_ios_t::init().
//As bufferbuf_t's constructor does not throw there is no risk of
//calling the basic_ios_t's destructor without calling basic_ios_t::init()
bufferbuf_t(mode | std::ios_base::in)
, base_t(&get_buf())
{}
//!Constructor. Assigns formatting buffer.
//!Does not throw.
basic_ibufferstream(const CharT *buf, std::size_t length,
std::ios_base::openmode mode = std::ios_base::in)
: //basic_ios_t() is called first (lefting it uninitialized) as it's a
//virtual base of basic_istream. The class will be initialized when
//basic_istream is constructed calling basic_ios_t::init().
//As bufferbuf_t's constructor does not throw there is no risk of
//calling the basic_ios_t's destructor without calling basic_ios_t::init()
bufferbuf_t(const_cast<CharT*>(buf), length, mode | std::ios_base::in)
, base_t(&get_buf())
{}
~basic_ibufferstream(){};
public:
//!Returns the address of the stored
//!stream buffer.
basic_bufferbuf<CharT, CharTraits>* rdbuf() const
{ return const_cast<basic_bufferbuf<CharT, CharTraits>*>(&get_buf()); }
//!Returns the pointer and size of the internal buffer.
//!Does not throw.
std::pair<const CharT *, std::size_t> buffer() const
{ return get_buf().buffer(); }
//!Sets the underlying buffer to a new value. Resets
//!stream position. Does not throw.
void buffer(const CharT *buf, std::size_t length)
{ get_buf().buffer(const_cast<CharT*>(buf), length); }
};
//!A basic_ostream class that uses a fixed size character buffer
//!as its formatting buffer.
template <class CharT, class CharTraits>
class basic_obufferstream :
/// @cond
private basic_bufferbuf<CharT, CharTraits>,
/// @endcond
public std::basic_ostream<CharT, CharTraits>
{
public:
typedef typename std::basic_ios
<CharT, CharTraits>::char_type char_type;
typedef typename std::basic_ios<char_type, CharTraits>::int_type int_type;
typedef typename std::basic_ios<char_type, CharTraits>::pos_type pos_type;
typedef typename std::basic_ios<char_type, CharTraits>::off_type off_type;
typedef typename std::basic_ios<char_type, CharTraits>::traits_type traits_type;
/// @cond
private:
typedef basic_bufferbuf<CharT, CharTraits> bufferbuf_t;
typedef std::basic_ios<char_type, CharTraits> basic_ios_t;
typedef std::basic_ostream<char_type, CharTraits> base_t;
bufferbuf_t & get_buf() { return *this; }
const bufferbuf_t & get_buf() const{ return *this; }
/// @endcond
public:
//!Constructor.
//!Does not throw.
basic_obufferstream(std::ios_base::openmode mode = std::ios_base::out)
: //basic_ios_t() is called first (lefting it uninitialized) as it's a
//virtual base of basic_istream. The class will be initialized when
//basic_istream is constructed calling basic_ios_t::init().
//As bufferbuf_t's constructor does not throw there is no risk of
//calling the basic_ios_t's destructor without calling basic_ios_t::init()
bufferbuf_t(mode | std::ios_base::out)
, base_t(&get_buf())
{}
//!Constructor. Assigns formatting buffer.
//!Does not throw.
basic_obufferstream(CharT *buf, std::size_t length,
std::ios_base::openmode mode = std::ios_base::out)
: //basic_ios_t() is called first (lefting it uninitialized) as it's a
//virtual base of basic_istream. The class will be initialized when
//basic_istream is constructed calling basic_ios_t::init().
//As bufferbuf_t's constructor does not throw there is no risk of
//calling the basic_ios_t's destructor without calling basic_ios_t::init()
bufferbuf_t(buf, length, mode | std::ios_base::out)
, base_t(&get_buf())
{}
~basic_obufferstream(){}
public:
//!Returns the address of the stored
//!stream buffer.
basic_bufferbuf<CharT, CharTraits>* rdbuf() const
{ return const_cast<basic_bufferbuf<CharT, CharTraits>*>(&get_buf()); }
//!Returns the pointer and size of the internal buffer.
//!Does not throw.
std::pair<CharT *, std::size_t> buffer() const
{ return get_buf().buffer(); }
//!Sets the underlying buffer to a new value. Resets
//!stream position. Does not throw.
void buffer(CharT *buf, std::size_t length)
{ get_buf().buffer(buf, length); }
};
//!A basic_iostream class that uses a fixed size character buffer
//!as its formatting buffer.
template <class CharT, class CharTraits>
class basic_bufferstream :
/// @cond
private basic_bufferbuf<CharT, CharTraits>,
/// @endcond
public std::basic_iostream<CharT, CharTraits>
{
public: // Typedefs
typedef typename std::basic_ios
<CharT, CharTraits>::char_type char_type;
typedef typename std::basic_ios<char_type, CharTraits>::int_type int_type;
typedef typename std::basic_ios<char_type, CharTraits>::pos_type pos_type;
typedef typename std::basic_ios<char_type, CharTraits>::off_type off_type;
typedef typename std::basic_ios<char_type, CharTraits>::traits_type traits_type;
/// @cond
private:
typedef basic_bufferbuf<CharT, CharTraits> bufferbuf_t;
typedef std::basic_ios<char_type, CharTraits> basic_ios_t;
typedef std::basic_iostream<char_type, CharTraits> base_t;
bufferbuf_t & get_buf() { return *this; }
const bufferbuf_t & get_buf() const{ return *this; }
/// @endcond
public:
//!Constructor.
//!Does not throw.
basic_bufferstream(std::ios_base::openmode mode
= std::ios_base::in | std::ios_base::out)
: //basic_ios_t() is called first (lefting it uninitialized) as it's a
//virtual base of basic_istream. The class will be initialized when
//basic_istream is constructed calling basic_ios_t::init().
//As bufferbuf_t's constructor does not throw there is no risk of
//calling the basic_ios_t's destructor without calling basic_ios_t::init()
bufferbuf_t(mode)
, base_t(&get_buf())
{}
//!Constructor. Assigns formatting buffer.
//!Does not throw.
basic_bufferstream(CharT *buf, std::size_t length,
std::ios_base::openmode mode
= std::ios_base::in | std::ios_base::out)
: //basic_ios_t() is called first (lefting it uninitialized) as it's a
//virtual base of basic_istream. The class will be initialized when
//basic_istream is constructed calling basic_ios_t::init().
//As bufferbuf_t's constructor does not throw there is no risk of
//calling the basic_ios_t's destructor without calling basic_ios_t::init()
bufferbuf_t(buf, length, mode)
, base_t(&get_buf())
{}
~basic_bufferstream(){}
public:
//!Returns the address of the stored
//!stream buffer.
basic_bufferbuf<CharT, CharTraits>* rdbuf() const
{ return const_cast<basic_bufferbuf<CharT, CharTraits>*>(&get_buf()); }
//!Returns the pointer and size of the internal buffer.
//!Does not throw.
std::pair<CharT *, std::size_t> buffer() const
{ return get_buf().buffer(); }
//!Sets the underlying buffer to a new value. Resets
//!stream position. Does not throw.
void buffer(CharT *buf, std::size_t length)
{ get_buf().buffer(buf, length); }
};
//Some typedefs to simplify usage
typedef basic_bufferbuf<char> bufferbuf;
typedef basic_bufferstream<char> bufferstream;
typedef basic_ibufferstream<char> ibufferstream;
typedef basic_obufferstream<char> obufferstream;
typedef basic_bufferbuf<wchar_t> wbufferbuf;
typedef basic_bufferstream<wchar_t> wbufferstream;
typedef basic_ibufferstream<wchar_t> wibufferstream;
typedef basic_obufferstream<wchar_t> wobufferstream;
}} //namespace boost { namespace interprocess {
#include <boost/interprocess/detail/config_end.hpp>
#endif /* BOOST_INTERPROCESS_BUFFERSTREAM_HPP */