/*
* Copyright (C) 2014 Dr. John Lindsay <jlindsay@uoguelph.ca>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package whitebox.structures;
import whitebox.utilities.BitOps;
/**
* This class is used to create a 2-D array of booleans and is stored using
* individual bits, resulting in a much lower memory footprint than would
* occur with the equivalent boolean[][] array.
* @author johnlindsay
*/
public class BooleanBitArray1D {
private int columns = 0;
private int columnsInBytes = 0;
private byte[] data;
public BooleanBitArray1D(int size) {
this.columns = size;
columnsInBytes = (int)(Math.ceil(columns / 8.0));
data = new byte[columnsInBytes];
}
public void setValue(int location, boolean value) {
if (location < 0 || location >= columns) {
return;
}
// which byte-row and byte-col will it be in?
int colB = location / 8;
byte colOffset = (byte)(location % 8);
byte val = data[colB];
if (value) {
val = BitOps.setBit(val, colOffset);
} else {
val = BitOps.clearBit(val, colOffset);
}
data[colB] = val;
}
public boolean getValue(int location) {
if (location < 0 || location >= columns) {
return false;
}
// which byte-row and byte-col will it be in?
int colB = location / 8;
int colOffset = location % 8;
byte val = data[colB];
return BitOps.checkBit(val, colOffset);
}
public int getLength() {
return columns;
}
}