93 lines
2.9 KiB
C++
93 lines
2.9 KiB
C++
/*****************************************************************************
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*
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* This file is part of Mapnik (c++ mapping toolkit)
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*
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* Copyright (C) 2015 Artem Pavlenko
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*****************************************************************************/
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// mapnik
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#include <mapnik/image_reader.hpp>
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#include <mapnik/image_util.hpp>
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#include <mapnik/factory.hpp>
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namespace mapnik
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{
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inline boost::optional<std::string> type_from_bytes(char const* data, size_t size)
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{
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using result_type = boost::optional<std::string>;
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if (size >= 4)
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{
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unsigned int magic = (data[0] << 24) | (data[1] << 16) | (data[2] << 8) | data[3];
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if (magic == 0x89504E47U)
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{
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return result_type("png");
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}
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else if (magic == 0x49492A00 || magic == 0x4D4D002A)
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{
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return result_type("tiff");
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}
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}
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if (size>=2)
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{
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unsigned int magic = ((data[0] << 8) | data[1]) & 0xffff;
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if (magic == 0xffd8)
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{
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return result_type("jpeg");
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}
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}
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if (size>=12)
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{
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if (data[0] == 'R' && data[1] == 'I' && data[2] == 'F' && data[3] == 'F' &&
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data[8] == 'W' && data[9] == 'E' && data[10] == 'B' && data[11] == 'P')
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{
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return result_type("webp");
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}
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}
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return result_type();
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}
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image_reader* get_image_reader(char const* data, size_t size)
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{
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boost::optional<std::string> type = type_from_bytes(data,size);
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if (type)
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return factory<image_reader,std::string,char const*,size_t>::instance().create_object(*type, data,size);
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else
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throw image_reader_exception("image_reader: can't determine type from input data");
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}
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image_reader* get_image_reader(std::string const& filename,std::string const& type)
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{
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return factory<image_reader,std::string,std::string const&>::instance().create_object(type,filename);
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}
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image_reader* get_image_reader(std::string const& filename)
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{
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boost::optional<std::string> type = type_from_filename(filename);
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if (type)
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{
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return factory<image_reader,std::string,std::string const&>::instance().create_object(*type,filename);
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}
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else
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{
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throw image_reader_exception("image_reader: can't determine type from input data");
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}
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}
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}
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