cloudy-agn/src/png++-0.2.5/packed_pixel.hpp

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2015-10-11 00:20:17 +00:00
/*
* Copyright (C) 2007,2008 Alex Shulgin
*
* This file is part of png++ the C++ wrapper for libpng. PNG++ is free
* software; the exact copying conditions are as follows:
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
* NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef PNGPP_PACKED_PIXEL_HPP_INCLUDED
#define PNGPP_PACKED_PIXEL_HPP_INCLUDED
#include "types.hpp"
namespace png
{
namespace detail
{
template< size_t bits > class allowed_bit_depth;
template<> class allowed_bit_depth< 1 > {};
template<> class allowed_bit_depth< 2 > {};
template<> class allowed_bit_depth< 4 > {};
} // namespace detail
/**
* \brief The packed pixel class template.
*
* \see packed_gray_pixel, packed_index_pixel
*/
template< size_t bits >
class packed_pixel
: detail::allowed_bit_depth< bits >
{
public:
packed_pixel(byte value = 0)
: m_value(value & get_bit_mask())
{
}
operator byte() const
{
return m_value;
}
static size_t const get_bit_depth()
{
return bits;
}
static byte const get_bit_mask()
{
return (1 << bits) - 1;
}
private:
byte m_value;
};
} // namespace png
#endif // PNGPP_PACKED_PIXEL_HPP_INCLUDED