//Java Source code for Range Coder
//By Sachin Garg, 2006
//
//This range coder is based upon the carry-less range coder 
//implementation by Dmitry Subbotin, and uses 64-bit variables 
//for improved performance.
//
//http://www.sachingarg.com/compression/entropy_coding/java_range_coder

public final class Order0Model {
	
	Order0Model() {
		Frequency=new int[NoOfSymbols+1];
		
		for(int i=0;i<NoOfSymbols+1;i++) {
			Frequency[i]=i;					
		}
	}

	void Update(int i) {
    	for(int j=i+1;j<Frequency.length;j++)
    		Frequency[j]++;

    	Rescale();
	}
	
	protected void Rescale() {
		if(Frequency[Frequency.length-1]>=RangeCoder64.MaxRange) {
			int Total=0;
			for(int i=1;i<Frequency.length-1;i++) {
				Total+=((Frequency[i]-Frequency[i-1])/2)+1;
				Frequency[i]=Frequency[i-1]+((Frequency[i]-Frequency[i-1])/2)+1;
			}
			Frequency[Frequency.length-1]=Total;
		}
	}

    protected final int NoOfSymbols=257; //256 + EOF
    protected int[] Frequency;
}