70 lines
1.7 KiB
C++
70 lines
1.7 KiB
C++
#ifndef MBGL_UTIL_JPEG_READER_HPP
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#define MBGL_UTIL_JPEG_READER_HPP
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#include <mbgl/platform/default/image_reader.hpp>
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// jpeg
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extern "C"
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{
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#include <jpeglib.h>
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}
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#include <boost/iostreams/stream.hpp>
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namespace mbgl { namespace util {
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template <typename T>
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class jpeg_reader : public image_reader
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{
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public:
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using source_type = T;
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using input_stream = boost::iostreams::stream<source_type>;
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const static unsigned BUF_SIZE = 4096;
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private:
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struct jpeg_stream_wrapper
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{
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jpeg_source_mgr manager;
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input_stream * stream;
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JOCTET buffer[BUF_SIZE];
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};
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struct jpeg_info_guard
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{
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jpeg_info_guard(jpeg_decompress_struct * cinfo)
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: i_(cinfo) {}
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~jpeg_info_guard()
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{
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jpeg_destroy_decompress(i_);
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}
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jpeg_decompress_struct * i_;
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};
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private:
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source_type source_;
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input_stream stream_;
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unsigned width_;
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unsigned height_;
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public:
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jpeg_reader(char const* data, size_t size);
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~jpeg_reader();
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unsigned width() const;
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unsigned height() const;
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inline bool has_alpha() const { return false; }
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inline bool premultiplied_alpha() const { return true; }
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void read(unsigned x,unsigned y, unsigned w, unsigned h, char *image);
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private:
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void init();
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static void on_error(j_common_ptr cinfo);
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static void on_error_message(j_common_ptr cinfo);
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static void init_source(j_decompress_ptr cinfo);
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static boolean fill_input_buffer(j_decompress_ptr cinfo);
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static void skip(j_decompress_ptr cinfo, long count);
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static void term(j_decompress_ptr cinfo);
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static void attach_stream(j_decompress_ptr cinfo, input_stream* in);
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};
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}}
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#endif // MBGL_UTIL_JPEG_READER_HPP
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