boost/gil/io/scanline_read_iterator.hpp
//
// Copyright 2007-2008 Christian Henning
//
// 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
//
#ifndef BOOST_GIL_IO_SCANLINE_READ_ITERATOR_HPP
#define BOOST_GIL_IO_SCANLINE_READ_ITERATOR_HPP
#include <boost/gil/io/error.hpp>
#include <boost/gil/io/typedefs.hpp>
#include <boost/iterator/iterator_facade.hpp>
#include <iterator>
#include <memory>
#include <vector>
namespace boost { namespace gil {
#if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
#pragma warning(push)
#pragma warning(disable:4512) //assignment operator could not be generated
#endif
/// Input iterator to read images.
template< typename Reader >
class scanline_read_iterator : public boost::iterator_facade< scanline_read_iterator< Reader >
, byte_t*
, std::input_iterator_tag
>
{
private:
using base_t = boost::iterator_facade
<
scanline_read_iterator<Reader>,
byte_t*,
std::input_iterator_tag
>;
public:
scanline_read_iterator( Reader& reader
, int pos = 0
)
: _pos( pos )
, _read_scanline( true )
, _skip_scanline( true )
, _reader( reader )
{
_buffer = std::make_shared< buffer_t >( buffer_t( _reader._scanline_length ));
_buffer_start = &_buffer->front();
}
private:
friend class boost::iterator_core_access;
void increment()
{
if( _skip_scanline == true )
{
_reader.skip( _buffer_start
, _pos
);
}
++_pos;
_skip_scanline = true;
_read_scanline = true;
}
bool equal( const scanline_read_iterator& rhs ) const
{
return _pos == rhs._pos;
}
typename base_t::reference dereference() const
{
if( _read_scanline == true )
{
_reader.read( _buffer_start
, _pos
);
}
_skip_scanline = false;
_read_scanline = false;
return _buffer_start;
}
private:
Reader& _reader;
mutable int _pos;
mutable bool _read_scanline;
mutable bool _skip_scanline;
using buffer_t = std::vector<byte_t>;
using buffer_ptr_t = std::shared_ptr<buffer_t>;
buffer_ptr_t _buffer;
mutable byte_t* _buffer_start;
};
#if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
#pragma warning(pop)
#endif
} // namespace gil
} // namespace boost
#endif