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}