001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.imaging.common.mylzw;
018
019import java.io.IOException;
020import java.io.InputStream;
021
022public class BitsToByteInputStream extends InputStream {
023    private final MyBitInputStream is;
024    private final int desiredDepth;
025
026    public BitsToByteInputStream(final MyBitInputStream is, final int desiredDepth) {
027        this.is = is;
028        this.desiredDepth = desiredDepth;
029    }
030
031    @Override
032    public int read() throws IOException {
033        return readBits(8);
034    }
035
036    public int readBits(final int bitCount) throws IOException {
037        int i = is.readBits(bitCount);
038        if (bitCount < desiredDepth) {
039            i <<= (desiredDepth - bitCount);
040        } else if (bitCount > desiredDepth) {
041            i >>= (bitCount - desiredDepth);
042        }
043
044        return i;
045    }
046
047    public int[] readBitsArray(final int sampleBits, final int length) throws IOException {
048        final int[] result = new int[length];
049
050        for (int i = 0; i < length; i++) {
051            result[i] = readBits(sampleBits);
052        }
053
054        return result;
055    }
056}