MaimMim Man in the middle minetest interceptor

- prototype
- between client and server, allow to capture all exchanges and potentially change them
- created to capture server maps in laby
- first test get only MapBlock, support version serialization version 28
  - prepartion for 29 with zstd but untested.

java/org/artisanlogiciel/games/minetest/MapNode.java

@@ -0,0 +1,99 @@
+package org.artisanlogiciel.games.minetest;
+
+import org.artisanlogiciel.games.minetest.core.PacketException;
+import org.artisanlogiciel.games.minetest.core.Serialize;
+
+import java.nio.ByteBuffer;
+import java.util.List;
+
+public class MapNode {
+	/*
+		Main content
+	*/
+	short param0;
+
+	/*
+		Misc parameter. Initialized to 0.
+		- For light_propagates() blocks, this is light intensity,
+		  stored logarithmically from 0 to LIGHT_MAX.
+		  Sunlight is LIGHT_SUN, which is LIGHT_MAX+1.
+		  - Contains 2 values, day- and night lighting. Each takes 4 bits.
+		- Uhh... well, most blocks have light or nothing in here.
+	*/
+	byte param1;
+
+	/*
+		The second parameter. Initialized to 0.
+		E.g. direction for torches and flowing water.
+	*/
+	byte param2;
+
+    public void deSerialize(ByteBuffer buffer)
+            throws PacketException
+    {
+        // version >= 24
+		param0 = (short) Serialize.readU16(buffer);
+        buffer.position(buffer.position() + 2);
+        param1 = (byte) Serialize.readU8(buffer);
+        buffer.position(buffer.position() + 1);
+		param2 = (byte) Serialize.readU8(buffer);
+        // network specific ...
+        // readU8(is);
+
+    }
+
+	// Deserialize bulk node data
+	public static void deSerializeBulk(ByteBuffer buffer, int version,
+									   List<MapNode> nodes, int nodecount,
+									   int content_width, int params_width)
+		throws PacketException
+	{
+		byte[] intern = buffer.array();
+		int initialOffset = buffer.position();
+
+		// Deserialize content
+		if(content_width == 1)
+		{
+			for(int i=0; i<nodecount; i++) {
+				nodes.add(i, new MapNode());
+				nodes.get(i).param0 = (short) Serialize.readU8( intern, initialOffset + i, intern.length);
+			}
+		}
+		else if(content_width == 2)
+		{
+			for(int i=0; i<nodecount; i++) {
+				nodes.add(i, new MapNode());
+				nodes.get(i).param0 = (short) Serialize.readU8( intern, initialOffset + (i*2), intern.length);
+			}
+		}
+
+		// Deserialize param1
+		int start1 = initialOffset + (content_width * nodecount);
+		for(int i=0; i<nodecount; i++) {
+			nodes.get(i).param1 = (byte) Serialize.readU8( intern, start1 + i, intern.length);
+		}
+
+		// Deserialize param2
+		int start2 = initialOffset + ((content_width + 1) * nodecount);
+		if(content_width == 1)
+		{
+			for(int i=0; i<nodecount; i++) {
+				MapNode node = nodes.get(i);
+				node.param2 = (byte) Serialize.readU8( intern, start2 + i, intern.length);
+				if(node.param0 > 0x7F){
+					node.param0 <<= 4;
+					node.param0 |= (node.param2&0xF0)>>4;
+					node.param2 &= 0x0F;
+				}
+			}
+		}
+		else if(content_width == 2)
+		{
+			for(int i=0; i<nodecount; i++) {
+				nodes.get(i).param2 = (byte) Serialize.readU8(intern, start2 + i, intern.length);
+			}
+		}
+
+	}
+
+}