| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.commons.sanselan.common; |
| |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| public class BitInputStreamFlexible extends InputStream |
| implements |
| BinaryConstants |
| { |
| // TODO should be byte order conscious, ie TIFF for reading |
| // samples size<8 - shuoldn't that effect their order within byte? |
| private final InputStream is; |
| |
| public BitInputStreamFlexible(InputStream is) |
| { |
| this.is = is; |
| // super(is); |
| } |
| |
| @Override |
| public int read() throws IOException |
| { |
| if (cacheBitsRemaining > 0) |
| throw new IOException("BitInputStream: incomplete bit read"); |
| return is.read(); |
| } |
| |
| private int cache; |
| private int cacheBitsRemaining = 0; |
| private long bytesRead = 0; |
| |
| public final int readBits(int count) throws IOException |
| { |
| |
| if (count <= 32) // catch-all |
| { |
| int result = 0; |
| // int done = 0; |
| |
| if (cacheBitsRemaining > 0) |
| { |
| if (count >= cacheBitsRemaining) |
| { |
| result = ((1 << cacheBitsRemaining) - 1) & cache; |
| count -= cacheBitsRemaining; |
| cacheBitsRemaining = 0; |
| } |
| else |
| { |
| // cache >>= count; |
| cacheBitsRemaining -= count; |
| result = ((1 << count) - 1) & (cache >> cacheBitsRemaining); |
| count = 0; |
| } |
| } |
| while (count >= 8) |
| { |
| cache = is.read(); |
| if (cache < 0) |
| throw new IOException("couldn't read bits"); |
| // System.out.println("cache 1: " + cache + " (" |
| // + Integer.toHexString(cache) + ", " |
| // + Integer.toBinaryString(cache) + ")"); |
| bytesRead++; |
| result = (result << 8) | (0xff & cache); |
| count -= 8; |
| } |
| if (count > 0) |
| { |
| cache = is.read(); |
| if (cache < 0) |
| throw new IOException("couldn't read bits"); |
| // System.out.println("cache 2: " + cache + " (" |
| // + Integer.toHexString(cache) + ", " |
| // + Integer.toBinaryString(cache) + ")"); |
| bytesRead++; |
| cacheBitsRemaining = 8 - count; |
| result = (result << count) |
| | (((1 << count) - 1) & (cache >> cacheBitsRemaining)); |
| count = 0; |
| } |
| |
| return result; |
| } |
| |
| throw new IOException("BitInputStream: unknown error"); |
| |
| } |
| |
| public void flushCache() |
| { |
| cacheBitsRemaining = 0; |
| } |
| |
| public long getBytesRead() |
| { |
| return bytesRead; |
| } |
| } |