    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.mylzw;
    018
    019import java.io.FilterInputStream;
    020import java.io.IOException;
    021
    022import org.apache.commons.imaging.common.Allocator;
    023
    024public class BitsToByteInputStream extends FilterInputStream {
    025    private final int desiredDepth;
    026
    027    public BitsToByteInputStream(final MyBitInputStream is, final int desiredDepth) {
    028        super(is);
    029        this.desiredDepth = desiredDepth;
    030    }
    031
    032    @Override
    033    public int read() throws IOException {
    034        return readBits(8);
    035    }
    036
    037    public int readBits(final int bitCount) throws IOException {
    038        int i = ((MyBitInputStream) in).readBits(bitCount);
    039        if (bitCount < desiredDepth) {
    040            i <<= desiredDepth - bitCount;
    041        } else if (bitCount > desiredDepth) {
    042            i >>= bitCount - desiredDepth;
    043        }
    044
    045        return i;
    046    }
    047
    048    public int[] readBitsArray(final int sampleBits, final int length) throws IOException {
    049        final int[] result = Allocator.intArray(length);
    050        for (int i = 0; i < length; i++) {
    051            result[i] = readBits(sampleBits);
    052        }
    053        return result;
    054    }
    055}