    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}