using System;
namespace hwo.bitworks
{
	public class ADDX : MultipleBitsSource
	{
		LogicBase[] srcA,srcB;
		ADD[] add;

		public ADDX(LogicBase[] sourcesA,LogicBase[] sourcesB)
		{
			int l	= sourcesA.Length > sourcesB.Length ? sourcesA.Length : sourcesB.Length;

			srcA	= new LogicBase[l];
			srcB	= new LogicBase[l];
			add		= new ADD[l];

			Array.Copy(sourcesA,srcA,sourcesA.Length);
			Array.Copy(sourcesB,srcB,sourcesB.Length);

			for (int n=sourcesA.Length; n < l; n++){
				srcA[n] = Constants.ZERO;
			}
			for (int n=sourcesB.Length; n < l; n++){
				srcB[n] = Constants.ZERO;
			}

			LogicBase lb = Constants.ZERO;

			for (int n=0;n<add.Length;n++){
				add[n] = new ADD(srcA[n],srcB[n],lb);
				lb = add[n].getLogicalBase(1);
			}
		}

		public override int getBits()
		{
			return add.Length + 1;
		}

		public override bool bitValue(int bit)
		{
			if (bit > add.Length){
				throw new IndexOutOfRangeException(String.Format("ADDX supplies {0} bits, but bit #{1} requested",add.Length+1,bit));
			} else if (bit == add.Length){
				return add[bit-1].bitValue(1);
			} else {
				return add[bit].bitValue(0);
			}
		}

		public override identity.BitIdentity getBitIdentity(int bit){
			if (bit == add.Length){
				return add[bit-1].getBitIdentity(1);
			} else {
				return add[bit].getBitIdentity(0);
			}
		}

	}
}