package com.xagasoft.gats;

import java.io.OutputStream;
import java.io.InputStream;

public class GatsInteger extends GatsObject
{
	private long iValue = 0;

	public GatsInteger()
	{
	}

	public GatsInteger( long iValue )
	{
		this.iValue = iValue;
	}

	public long getValue()
	{
		return iValue;
	}

	public void setValue( long iValue )
	{
		this.iValue = iValue;
	}

	public String toString()
	{
		return "" + iValue;
	}

	public int getType()
	{
		return GatsObject.INTEGER;
	};

	public void read( InputStream is, char cType ) throws java.io.IOException

	{
		iValue = readPackedInt( is );
	}

	public void write( OutputStream os ) throws java.io.IOException
	{
		os.write( (int)'i' );
		writePackedInt( os, iValue );
	}

	/**
	 * Possible TODO: have this return a Number, and construct either a Long
	 * or BigInteger when appropriate.
	 */
	public static long readPackedInt( InputStream is ) throws java.io.IOException
	{
		int b;
		long rOut = 0;
		boolean bNeg;
		
		b = is.read();
		bNeg = (b&0x40) == 0x40;
		rOut |= b&0x3F;
		int c = 0;
		while( (b&0x80) == 0x80 )
		{
			b = is.read();
			rOut |= (long)(b&0x7F) << (6+7*(c++));
		}
		if( bNeg )
			return -rOut;
		return rOut;
	}

	public static void writePackedInt( OutputStream os, long iIn ) throws java.io.IOException
	{
		int b;

		if( iIn < 0 )
		{
			iIn = -iIn;
			b = (int)(iIn&0x3F);
			if( iIn > b )
				b |= 0x80 | 0x40;
			else
				b |= 0x40;
		}
		else
		{
			b = (int)(iIn&0x3F);
			if( iIn > b )
				b |= 0x80;
		}
		os.write( b );
		iIn = iIn >> 6;

		while( iIn > 0 )
		{
			b = (int)(iIn&0x7F);
			if( iIn > b )
				b |= 0x80;
			os.write( b );
			iIn = iIn >> 7;
		}
	}
};