###

#

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
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)
: reader_(reader), pos_(pos)
{
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_)
{
reader_.skip(buffer_start_, pos_);
}
++pos_;
skip_scanline_ = true;
read_scanline_ = true;
}
bool equal(scanline_read_iterator const& rhs) const
{
return pos_ == rhs.pos_;
}
typename base_t::reference dereference() const
{
if (read_scanline_)
{
reader_.read(buffer_start_, pos_);
}
skip_scanline_ = false;
read_scanline_ = false;
return buffer_start_;
}
private:
Reader& reader_;
mutable int pos_ = 0;
mutable bool read_scanline_ = true;
mutable bool skip_scanline_ = true;
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_ = nullptr;
};
#if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
#pragma warning(pop)
#endif
} // namespace gil
} // namespace boost
#endif
boost::gil::scanline_read_iterator
Input iterator to read images.
Definition: scanline_read_iterator.hpp:31
boost
defined(BOOST_NO_CXX17_HDR_MEMORY_RESOURCE)
Definition: algorithm.hpp:36