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/*****************************************************************************
*
* This file is part of Mapnik (c++ mapping toolkit)
*
* Copyright (C) 2025 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 {
inline std::optional<std::string> type_from_bytes(char const* data, size_t size)
{
unsigned char const* header = reinterpret_cast<unsigned char const*>(data);
if (size >= 4)
{
unsigned int magic = (header[0] << 24) | (header[1] << 16) | (header[2] << 8) | header[3];
if (magic == 0x89504E47U)
{
return "png";
}
else if (magic == 0x49492A00U || magic == 0x4D4D002AU)
{
return "tiff";
}
}
if (size >= 2)
{
unsigned int magic = ((header[0] << 8) | header[1]) & 0xffff;
if (magic == 0xffd8)
{
return "jpeg";
}
}
if (size >= 12)
{
if (header[0] == 'R' && header[1] == 'I' && header[2] == 'F' && header[3] == 'F' && header[8] == 'W' &&
header[9] == 'E' && header[10] == 'B' && header[11] == 'P')
{
return "webp";
}
else if (header[9] == 'a' && header[10] == 'v' && header[11] == 'i' && header[12] == 'f')
{
return "avif";
}
}
return std::nullopt;
}
image_reader* get_image_reader(char const* data, size_t size)
{
auto const type = type_from_bytes(data, size);
if (type.has_value())
return factory<image_reader, std::string, char const*, size_t>::instance().create_object(*type, data, size);
else
throw image_reader_exception("image_reader: can't determine type from input data");
}
image_reader* get_image_reader(std::string const& filename, std::string const& type)
{
return factory<image_reader, std::string, std::string const&>::instance().create_object(type, filename);
}
image_reader* get_image_reader(std::string const& filename)
{
auto const type = type_from_filename(filename);
if (type.has_value())
{
return factory<image_reader, std::string, std::string const&>::instance().create_object(*type, filename);
}
else
{
throw image_reader_exception("image_reader: can't determine type from input data");
}
}
} // namespace mapnik
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