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/*
Copyright 2007-2012 Christian Henning, Andreas Pokorny, Lubomir Bourdev
Use, modification and distribution are subject to 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_EXTENSION_IO_JPEG_DETAIL_SCANLINE_READ_HPP
#define BOOST_GIL_EXTENSION_IO_JPEG_DETAIL_SCANLINE_READ_HPP
////////////////////////////////////////////////////////////////////////////////////////
/// \file
/// \brief
/// \author Christian Henning, Andreas Pokorny, Lubomir Bourdev \n
///
/// \date 2007-2012 \n
///
////////////////////////////////////////////////////////////////////////////////////////
#include <csetjmp>
#include <vector>
#include <boost/gil/io/base.hpp>
#include <boost/gil/io/conversion_policies.hpp>
#include <boost/gil/io/reader_base.hpp>
#include <boost/gil/io/device.hpp>
#include <boost/gil/io/scanline_read_iterator.hpp>
#include <boost/gil/io/typedefs.hpp>
#include <boost/gil/extension/io/jpeg/detail/reader_backend.hpp>
#include <boost/gil/extension/io/jpeg/detail/base.hpp>
#include <boost/gil/extension/io/jpeg/detail/is_allowed.hpp>
namespace boost { namespace gil {
#if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
#pragma warning(push)
#pragma warning(disable:4611) //interaction between '_setjmp' and C++ object destruction is non-portable
#endif
///
/// JPEG Scanline Reader
///
template< typename Device >
class scanline_reader< Device
, jpeg_tag
>
: public reader_backend< Device
, jpeg_tag
>
{
public:
typedef jpeg_tag tag_t;
typedef reader_backend < Device, tag_t > backend_t;
typedef scanline_reader< Device, tag_t > this_t;
typedef scanline_read_iterator< this_t > iterator_t;
public:
scanline_reader( Device& device
, const image_read_settings< jpeg_tag >& settings
)
: reader_backend< Device
, jpeg_tag
>( device
, settings
)
{
initialize();
}
void read( byte_t* dst
, int
)
{
// Fire exception in case of error.
if( setjmp( this->_mark )) { this->raise_error(); }
// read data
read_scanline( dst );
}
/// Skip over a scanline.
void skip( byte_t* dst, int )
{
// Fire exception in case of error.
if( setjmp( this->_mark )) { this->raise_error(); }
// read data
read_scanline( dst );
}
iterator_t begin() { return iterator_t( *this ); }
iterator_t end() { return iterator_t( *this, this->_info._height ); }
private:
void initialize()
{
this->get()->dct_method = this->_settings._dct_method;
io_error_if( jpeg_start_decompress( this->get() ) == false
, "Cannot start decompression." );
switch( this->_info._color_space )
{
case JCS_GRAYSCALE:
{
this->_scanline_length = this->_info._width;
break;
}
case JCS_RGB:
//!\todo add Y'CbCr? We loose image quality when reading JCS_YCbCr as JCS_RGB
case JCS_YCbCr:
{
this->_scanline_length = this->_info._width * num_channels< rgb8_view_t >::value;
break;
}
case JCS_CMYK:
//!\todo add Y'CbCrK? We loose image quality when reading JCS_YCCK as JCS_CMYK
case JCS_YCCK:
{
this->get()->out_color_space = JCS_CMYK;
this->_scanline_length = this->_info._width * num_channels< cmyk8_view_t >::value;
break;
}
default: { io_error( "Unsupported jpeg color space." ); }
}
}
void read_scanline( byte_t* dst )
{
JSAMPLE *row_adr = reinterpret_cast< JSAMPLE* >( dst );
// Read data.
io_error_if( jpeg_read_scanlines( this->get()
, &row_adr
, 1
) != 1
, "jpeg_read_scanlines: fail to read JPEG file"
);
}
};
#if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
#pragma warning(pop)
#endif
} // namespace gil
} // namespace boost
#endif
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