LocalReader solution

src/main/java/koz01/java2/lab08/IndexReader.java

@@ -55,7 +55,48 @@ public class IndexReader {
 		return LocalFile;
 	}
 
-	private byte[] getData(FileChannel fc, int index) throws IOException {
-		return new byte[0];
+	private byte[] getData(FileChannel fc, int i) throws IOException {
+		// 0...3 - number of images
+		// 4 ... 7 - Position of 1. image data in file
+		// 8 ... 11 - Lenght of 1. image
+
+		// position_in_index = 4 + i*8
+
+		// position_of_image = readInt(position_in_index)
+		// size_of_image = readInt(position_in_index + 4)
+
+		// data = readData(position_of_image, size_of_image)
+		// return data
+
+		// go to position ... fc.position(position)
+		// read data .... fc.read(bb) - bb is ByteBuffer
+
+		// create ByteBuffer 8 bytes long
+		ByteBuffer bb = ByteBuffer.allocate(8);
+		fc.position(0);
+		fc.read(bb);
+		bb.flip();
+		int numberOfImages = bb.getInt();
+		if (i < 0 || numberOfImages <= i) {
+			return new byte[0];
+		}
+		bb.clear();
+		fc.position(4 + i * 8);
+		fc.read(bb);
+		bb.flip();
+		int position = bb.getInt();
+		int size = bb.getInt();
+
+		bb = ByteBuffer.allocate(size);
+		fc.position(position);
+		fc.read(bb);
+		bb.flip();
+		return bb.array();
+
+		// read data .... fc.read(bb) - bb is ByteBuffer
+		// bb.flip()
+		// bb.getInt(), bb.getInt()
+
+
 	}
 }