ExplainVarbit.java

// each variousSettings index represents the bits for either a varbit or a varp
Client
    int[] variousSettings = new int[2000];

// a VarBit's index is used to access variousSettings
// lsb is where to start reading bits
// msb is where to stop reading bits
VarBit
    static Varbit[] cache;
    int index;
    int lsb;
    int msb;
   
    static void unpackConfig() // read from varbit.dat into cache

// Object definitions are stored in cache as loc.dat.
// An object definition has a stream, a childIDs[] and a varbit.
//  - The stream is used to read data loaded from loc.dat
//  - The childIDs contain objects IDs for an object to "morph" into
//  - The varbit acts as an array index for VarBit.cache
ObjectDef
    Stream stream;
    int[] childIDs;
    int varbit;
   
    static void unpackConfig() // load loc.dat into stream

    ObjectDef forID(int id)
        ObjectDef def = ...;
        def.id = id;
        def.readValues();
        return def;

    void readValues() // read from loc.dat
        int type;
        do
            type = dataStream.readByte();
            if(type == 77)
                int varbit = dataStream.readShort();
                int childLength = data.readByte();
                if(childLength > 0)
                    childIDs = new int[childLength];
                    for(int i = 0; i < childLength; i++) 
                        childIDs[i] = data.readShort();
        while(type != 0);

    ObjectDef morph()
        VarBit vb = VarBit.cache[varbit];
        int index = vb.index;
        int lsb = vb.lsb;
        int msb = vb.msb;
        int bits = Client.variousSettings[index];
        int childIndex = bits >> lsb & MASKS[msb];
        int childID = childIDs[childIndex];
        return forID(childID);