JAVASTUFF

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class ItemSet
{
    private final static int FIRST_KEY_ITEM_ID = 1227;
    private final static int OFFSET_ITEMS_END = 0x2EE7;
    private final static int OFFSET_ITEMS_START = 0x10;
    private final static int OFFSET_ITEMS_SIZE = 0x8;


    private static int byte_to_uint(byte b)
    {
        return (int)(b) & 0xFF;
    }

    private static int byte_to_uint16_le(byte[] ref, int offset)
    {
        if(ref.length < offset + 2)
            throw new RuntimeException("Buffer overflowed - Offset " + offset);
        return byte_to_uint(ref[offset]) | (byte_to_uint(ref[offset + 1]) << 8);
    }

    private static void write_uint16_le(byte[] ref, int offset, int val)
    {
        if(ref.length < offset + 2)
            throw new RuntimeException("Buffer overflowed - Offset " + offset);
        ref[offset] = (byte)(val % 256);
        ref[offset+1] = (byte)(val / 256);
    }

    public static void main(String[] args) throws IOException
    {
        byte[] buffer;
        if (args.length == 1)
        {
            final Path path = Paths.get(args[0]);
            final Path output = Paths.get(args[0] + ".hacked");
            buffer = Files.readAllBytes(path);
            System.out.print("Read file size: " + buffer.length + " bytes.\n");

            for (int i = OFFSET_ITEMS_START; i < OFFSET_ITEMS_END; i += OFFSET_ITEMS_SIZE)
            {
                final int item_id = byte_to_uint16_le(buffer, i);
                final int item_count = byte_to_uint16_le(buffer, i+2);

                if (item_id == FIRST_KEY_ITEM_ID)
                {
                    break;
                }
                if (item_id != 0)
                {
                    System.out.print("Setting item id " + item_id + " from " + item_count + " to 999.\n");
                    write_uint16_le(buffer, i+2, 999);
                }
            }

            Files.write(output, buffer);
        }
        else
        {
            System.err.println("Incorret arguments.");
        }
    }
}