mapnik/src/image_reader.cpp
2013-07-19 01:09:17 -04:00

106 lines
3.3 KiB
C++

/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2011 Artem Pavlenko
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*****************************************************************************/
// mapnik
#include <mapnik/image_reader.hpp>
#include <mapnik/image_util.hpp>
#include <mapnik/factory.hpp>
namespace mapnik
{
typedef factory<image_reader,std::string,
image_reader* (*)(std::string const&)> ImageReaderFactory;
typedef factory<image_reader,std::string,
image_reader* (*)(char const*, std::size_t)> MemImageReaderFactory;
inline boost::optional<std::string> type_from_bytes(char const* data, size_t size)
{
typedef boost::optional<std::string> result_type;
if (size >= 4)
{
unsigned int magic = (data[0] << 24) | (data[1] << 16) | (data[2] << 8) | data[3];
if (magic == 0x89504E47U)
{
return result_type("png");
}
else if (magic == 0x49492A00 || magic == 0x4D4D002A)
{
return result_type("tiff");
}
}
if (size>=2)
{
unsigned int magic = ((data[0] << 8) | data[1]) & 0xffff;
if (magic == 0xffd8)
{
return result_type("jpeg");
}
}
if (size>=12)
{
if (data[0] == 'R' && data[1] == 'I' && data[2] == 'F' && data[3] == 'F' &&
data[8] == 'W' && data[9] == 'E' && data[10] == 'B' && data[11] == 'P')
{
return result_type("webp");
}
}
return result_type();
}
bool register_image_reader(std::string const& type,image_reader* (* fun)(std::string const&))
{
return ImageReaderFactory::instance().register_product(type,fun);
}
bool register_image_reader(std::string const& type,image_reader* (* fun)(char const*, std::size_t))
{
return MemImageReaderFactory::instance().register_product(type,fun);
}
image_reader* get_image_reader(char const* data, size_t size)
{
boost::optional<std::string> type = type_from_bytes(data,size);
if (type)
return MemImageReaderFactory::instance().create_object(*type, data,size);
return 0;
}
image_reader* get_image_reader(std::string const& filename,std::string const& type)
{
return ImageReaderFactory::instance().create_object(type,filename);
}
image_reader* get_image_reader(std::string const& filename)
{
boost::optional<std::string> type = type_from_filename(filename);
if (type)
{
return ImageReaderFactory::instance().create_object(*type,filename);
}
return 0;
}
}