/*******************************************************************************
 * Copyright (c) 2015 MINRES Technologies GmbH and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     MINRES Technologies GmbH - initial API and implementation
 *******************************************************************************/
package com.minres.scviewer.database;

public class BitVector {

	private final int width;
	
	private int[] packedValues;
	
	public BitVector(int netWidth) {
		this.width=netWidth;
		packedValues = new int[(netWidth+15)/16];
		for(int i=0; i<packedValues.length; i++) packedValues[i]=0;
	}

	public void setValue(int i, BitValue value) {
		int bitIndex = i*2;
		int wordOffset = bitIndex >> 5;
		int bitOffset = bitIndex & 31;
		packedValues[wordOffset] &= ~(3 << bitOffset);
		packedValues[wordOffset] |= value.ordinal() << bitOffset;
	}

	public char[] getValue() {
        int bitOffset = 0;
        int wordOffset = 0;
        char[] res = new char[width];
        // Copy values out of packed array
        for (int i = 0; i < width; i++) {
            int currentWord = (packedValues[wordOffset] >> bitOffset)&3;
        	res[width-i-1]=BitValue.fromInt(currentWord).toChar();
            bitOffset += 2;
            if (bitOffset == 32) {
                wordOffset++;
                bitOffset = 0;
            }
        }
		return res;
	}

	public void setValue(char[] value) {
		int bitIndex = width;
		int wordOffset = bitIndex >> 4;
		int bitOffset = (bitIndex * 2) % 32;
		for (int i = Math.min(value.length, width) - 1; i >= 0; i--) {
			packedValues[wordOffset] |= BitValue.fromChar(value[i]).ordinal() << bitOffset;
			bitOffset += 2;
			if (bitOffset == 32) {
				wordOffset++;
				bitOffset = 0;
			}
		}
	}

	public int getWidth() {
		return width;
	}

	public String toString(){
		return new String(getValue());
	}
	
	public String toHexString(){
		int resWidth=(width-1)/4+1;
		char[] value=getValue();
		char[] res = new char[resWidth];
		for(int i=resWidth-1; i>=0; i--){
			int digit=0;
			for(int j=3; j>=0; j--){
				if((4*i+j)>=value.length) continue;
				BitValue val = BitValue.fromChar(value[4*i+j]);
				switch(val) {
				case X:
				case Z:
					res[i]=val.toChar();
					continue;
				case ONE:
					digit+=1<<(3-j);
					break;
				default:
					break;
				}
			}
			res[i]=Character.forDigit(digit, 16); //((digit < 10) ? '0' + digit : 'a' + digit -10)
		}
		return new String(res);		
	}
	
	public long toUnsignedValue() {
		long res = 0;
        int bitOffset = 0;
        int wordOffset = 0;
        int currentWord = 0;
        // Copy values out of packed array
        for (int i = 0; i < width; i++) {
            if(bitOffset==0) currentWord = packedValues[wordOffset];
			switch (currentWord & 3) {
			case 1:
				res|=1<<i;
				break;
			case 2:
			case 3:
				return 0;
			default:
				break;
			}
            bitOffset += 2;
            if (bitOffset == 32) {
                wordOffset++;
                bitOffset = 0;
            } else {
                currentWord >>= 2;
            }
        }
        return res;
	}
	
	public long toSignedValue() {
		long res = 0;
        int bitOffset = 0;
        int wordOffset = 0;
        int currentWord = 0;
        int lastVal=0;
        // Copy values out of packed array
        for (int i = 0; i < width; i++) {
        	if(bitOffset==0) currentWord = packedValues[wordOffset];
        	lastVal=0;
			switch (currentWord & 3) {
			case 1:
				res|=1<<i;
				lastVal=1;
				break;
			case 2:
			case 3:
				return 0;
			default:
			}
            bitOffset += 2;
            if (bitOffset == 32) {
                wordOffset++;
                bitOffset = 0;
            } else {
                currentWord >>= 2;
            }
        }
        for(int i=width; i<64; i++) {
        	if(bitOffset==0) currentWord = packedValues[wordOffset];
        	res|=lastVal<<i;
        	bitOffset += 2;
            if (bitOffset == 32) {
                wordOffset++;
                bitOffset = 0;
            } else {
                currentWord >>= 2;
            }
        	
        }
		return res;
	}
}