63 lines
1.7 KiB
C++
63 lines
1.7 KiB
C++
#include <mbgl/platform/default/image_reader.hpp>
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#include <mbgl/platform/default/png_reader.hpp>
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#include <mbgl/platform/default/jpeg_reader.hpp>
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#include <boost/optional.hpp>
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#include <boost/iostreams/device/array.hpp>
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namespace mbgl { namespace util {
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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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std::unique_ptr<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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{
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if (*type == "png")
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{
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return std::make_unique<png_reader<boost::iostreams::array_source>>(data, size);
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}
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else if (*type == "jpeg")
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{
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return std::make_unique<jpeg_reader<boost::iostreams::array_source>>(data, size);
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}
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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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