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کد نوشته شده توسط Luc Pattyn





public static Size GetJpegImageSize(string filename) {

	FileStream stream=null;

	BinaryReader rdr=null;

	try {

		stream=File.OpenRead(filename);

		rdr=new BinaryReader(stream);

		// keep reading packets until we find one that contains Size info

		for(; ; ) {

			byte code=rdr.ReadByte();

			if(code!=0xFF) throw new ApplicationException(

					"Unexpected value in file "+filename);

			code=rdr.ReadByte();

			switch(code) {

				// filler byte

				case 0xFF:

					stream.Position--;

					break;

				// packets without data

				case 0xD0: case 0xD1: case 0xD2: case 0xD3: case 0xD4: 

				case 0xD5: case 0xD6: case 0xD7: case 0xD8: case 0xD9:

					break;

				// packets with size information

				case 0xC0: case 0xC1: case 0xC2: case 0xC3:

				case 0xC4: case 0xC5: case 0xC6: case 0xC7:

				case 0xC8: case 0xC9: case 0xCA: case 0xCB:

				case 0xCC: case 0xCD: case 0xCE: case 0xCF:

					ReadBEUshort(rdr);

					rdr.ReadByte();

					ushort h=ReadBEUshort(rdr);

					ushort w=ReadBEUshort(rdr);

					return new Size(w, h);

				// irrelevant variable-length packets

				default:

					int len=ReadBEUshort(rdr);

					stream.Position+=len-2;

					break;

			}

		}

	} finally {

		if(rdr!=null) rdr.Close();

		if(stream!=null) stream.Close();

	}

}



private static ushort ReadBEUshort(BinaryReader rdr) {

	ushort hi=rdr.ReadByte();

	hi<<=8;

	ushort lo=rdr.ReadByte();

	return (ushort)(hi|lo);

}

مرجع کد:
http://www.codeproject.com/script/co...11#xx2107805xx

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