//
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// Copyright 2007-2008 Christian Henning
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//
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// Distributed under the Boost Software License, Version 1.0
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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//
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#ifndef BOOST_GIL_IO_ROW_BUFFER_HELPER_HPP
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#define BOOST_GIL_IO_ROW_BUFFER_HELPER_HPP
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// TODO: Shall we move toolbox to core?
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#include <boost/gil/extension/toolbox/metafunctions/is_bit_aligned.hpp>
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#include <boost/gil/extension/toolbox/metafunctions/is_homogeneous.hpp>
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#include <boost/gil/extension/toolbox/metafunctions/pixel_bit_size.hpp>
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#include <boost/gil/detail/mp11.hpp>
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#include <boost/gil/io/typedefs.hpp>
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#include <cstddef>
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#include <type_traits>
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#include <vector>
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namespace boost { namespace gil { namespace detail {
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template< typename Pixel
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, typename DummyT = void
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>
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struct row_buffer_helper
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{
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using element_t = Pixel;
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using buffer_t = std::vector<element_t>;
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using iterator_t = typename buffer_t::iterator;
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row_buffer_helper( std::size_t width
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, bool
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)
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: _row_buffer( width )
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{}
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element_t* data() { return &_row_buffer[0]; }
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iterator_t begin() { return _row_buffer.begin(); }
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iterator_t end() { return _row_buffer.end(); }
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buffer_t& buffer() { return _row_buffer; }
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private:
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buffer_t _row_buffer;
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};
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template <typename Pixel>
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struct row_buffer_helper
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<
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Pixel,
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typename std::enable_if
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<
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is_bit_aligned<Pixel>::value
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>::type
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>
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{
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using element_t = byte_t;
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using buffer_t = std::vector<element_t>;
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using pixel_type = Pixel;
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using iterator_t = bit_aligned_pixel_iterator<pixel_type>;
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row_buffer_helper(std::size_t width, bool in_bytes)
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: _c{( width * pixel_bit_size< pixel_type >::value) >> 3}
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, _r{width * pixel_bit_size< pixel_type >::value - (_c << 3)}
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{
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if (in_bytes)
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{
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_row_buffer.resize(width);
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}
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else
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{
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// add one byte if there are remaining bits
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_row_buffer.resize(_c + (_r != 0));
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}
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}
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element_t* data() { return &_row_buffer[0]; }
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iterator_t begin() { return iterator_t( &_row_buffer.front(),0 ); }
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iterator_t end() { return _r == 0 ? iterator_t( &_row_buffer.back() + 1, 0 )
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: iterator_t( &_row_buffer.back() , (int) _r );
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}
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buffer_t& buffer() { return _row_buffer; }
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private:
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// For instance 25 pixels of rgb2 type would be:
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// overall 25 pixels * 3 channels * 2 bits/channel = 150 bits
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// c = 18 bytes
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// r = 6 bits
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std::size_t _c; // number of full bytes
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std::size_t _r; // number of remaining bits
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buffer_t _row_buffer;
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};
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template<typename Pixel>
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struct row_buffer_helper
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<
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Pixel,
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typename std::enable_if
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<
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mp11::mp_and
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<
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typename is_bit_aligned<Pixel>::type,
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typename is_homogeneous<Pixel>::type
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>::value
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>
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>
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{
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using element_t = byte_t;
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using buffer_t = std::vector<element_t>;
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using pixel_type = Pixel;
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using iterator_t = bit_aligned_pixel_iterator<pixel_type>;
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row_buffer_helper( std::size_t width
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, bool in_bytes
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)
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: _c( ( width
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* num_channels< pixel_type >::value
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* channel_type< pixel_type >::type::num_bits
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)
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>> 3
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)
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, _r( width
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* num_channels< pixel_type >::value
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* channel_type< pixel_type >::type::num_bits
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- ( _c << 3 )
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)
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{
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if( in_bytes )
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{
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_row_buffer.resize( width );
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}
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else
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{
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// add one byte if there are remaining bits
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_row_buffer.resize( _c + ( _r!=0 ));
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}
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}
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element_t* data() { return &_row_buffer[0]; }
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iterator_t begin() { return iterator_t( &_row_buffer.front(),0 ); }
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iterator_t end() { return _r == 0 ? iterator_t( &_row_buffer.back() + 1, 0 )
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: iterator_t( &_row_buffer.back() , (int) _r );
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}
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buffer_t& buffer() { return _row_buffer; }
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private:
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// For instance 25 pixels of rgb2 type would be:
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// overall 25 pixels * 3 channels * 2 bits/channel = 150 bits
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// c = 18 bytes
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// r = 6 bits
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std::size_t _c; // number of full bytes
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std::size_t _r; // number of remaining bits
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buffer_t _row_buffer;
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};
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template <typename View, typename D = void>
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struct row_buffer_helper_view : row_buffer_helper<typename View::value_type>
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{
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row_buffer_helper_view(std::size_t width, bool in_bytes)
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: row_buffer_helper<typename View::value_type>(width, in_bytes)
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{}
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};
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template <typename View>
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struct row_buffer_helper_view
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<
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View,
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typename std::enable_if
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<
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is_bit_aligned<typename View::value_type>::value
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>::type
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> : row_buffer_helper<typename View::reference>
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{
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row_buffer_helper_view(std::size_t width, bool in_bytes)
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: row_buffer_helper<typename View::reference>(width, in_bytes)
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{}
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};
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} // namespace detail
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} // namespace gil
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} // namespace boost
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#endif
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