package org.hwo.bitfields;

import java.util.ArrayList;
import java.util.List;

import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

public class BitField {

	private	Integer		value;
	private List<Field> fields;
	
	public BitField()
	{
		this.fields = new ArrayList<Field>();
		
		initialize();
	}

	public BitField(Element fieldsNode)
	{
		this.fields = new ArrayList<Field>();
		
		NodeList fields = fieldsNode.getElementsByTagName("Field");
		for (int i=0;i<fields.getLength();i++)
		{
			Element fieldNode = (Element)fields.item(i);
			int start = 0,
				len = 1;
			
			if (fieldNode.getAttribute("len") != null)
				len = Integer.decode(fieldNode.getAttribute("len"));
			if (fieldNode.getAttribute("start") != null)
				start = Integer.decode(fieldNode.getAttribute("start"));
			
			this.fields.add(new Field(this,start,len,fieldNode.getTextContent()));
		}
	}
	
	private void initialize()
	{
		for (int i=0;i<32;i++)
			this.fields.add(new Field(this, i, 1));
	}
	
	public synchronized String toText(int value)
	{
		this.value = value;
		return toText();
	}
	public synchronized String toText()
	{
		StringBuilder sb = new StringBuilder();
		
		if (value != null)
		{
			for (Field field:this.fields)
			{
				String st = field.toText();
				if (st != null)
				{
					if (sb.length() > 0)
						sb.append(", ");
					sb.append(st);
				}
			}
		}
		return sb.toString();
	}
	
	public synchronized Integer getValue()
	{
		return this.value;
	}
	
	public synchronized void setValue(Integer value)
	{
		this.value = value;
	}

	public synchronized int getValue(int start,int len)
	{
		if (value == null)
			return 0;
		return (value >> start) & (-1 >> (Integer.SIZE - len));
	}
	
	public synchronized void setValue(int value,int start,int len)
	{
		if (this.value == null)
			this.value = 0;
		
		this.value &= ~((-1 >> (Integer.SIZE - len)) << start);
		this.value |= (value & (-1 >> (Integer.SIZE - len))) << start;
	}

	
}