| /* |
| * 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.mylzw; |
| |
| import java.io.IOException; |
| import java.io.OutputStream; |
| |
| import org.apache.commons.sanselan.common.BinaryConstants; |
| |
| public class MyBitOutputStream extends OutputStream implements BinaryConstants |
| { |
| private final OutputStream os; |
| private final int byteOrder; |
| |
| public MyBitOutputStream(OutputStream os, int byteOrder) |
| { |
| this.byteOrder = byteOrder; |
| this.os = os; |
| } |
| |
| public void write(int value) throws IOException |
| { |
| writeBits(value, 8); |
| } |
| |
| private int bitsInCache = 0; |
| private int bitCache = 0; |
| |
| // TODO: in and out streams CANNOT accurately read/write 32bits at a time, |
| // as int will overflow. should have used a long |
| public void writeBits(int value, int SampleBits) throws IOException |
| { |
| int sampleMask = (1 << SampleBits) - 1; |
| value &= sampleMask; |
| |
| if (byteOrder == BYTE_ORDER_NETWORK) // MSB, so add to right |
| { |
| bitCache = (bitCache << SampleBits) | value; |
| } |
| else if (byteOrder == BYTE_ORDER_INTEL) // LSB, so add to left |
| { |
| bitCache = bitCache | (value << bitsInCache); |
| } |
| else |
| throw new IOException("Unknown byte order: " + byteOrder); |
| bitsInCache += SampleBits; |
| |
| while (bitsInCache >= 8) |
| { |
| if (byteOrder == BYTE_ORDER_NETWORK) // MSB, so write from left |
| { |
| int b = 0xff & (bitCache >> (bitsInCache - 8)); |
| actualWrite(b); |
| |
| bitsInCache -= 8; |
| } |
| else if (byteOrder == BYTE_ORDER_INTEL) // LSB, so write from right |
| { |
| int b = 0xff & bitCache; |
| actualWrite(b); |
| |
| bitCache >>= 8; |
| bitsInCache -= 8; |
| } |
| int remainderMask = (1 << bitsInCache) - 1; // unneccesary |
| bitCache &= remainderMask; // unneccesary |
| } |
| |
| } |
| |
| private int bytesWritten = 0; |
| |
| private void actualWrite(int value) throws IOException |
| { |
| os.write(value); |
| bytesWritten++; |
| } |
| |
| public void flushCache() throws IOException |
| { |
| if (bitsInCache > 0) |
| { |
| int bitMask = (1 << bitsInCache) - 1; |
| int b = bitMask & bitCache; |
| |
| if (byteOrder == BYTE_ORDER_NETWORK) // MSB, so write from left |
| { |
| b <<= 8 - bitsInCache; // left align fragment. |
| os.write(b); |
| } |
| else if (byteOrder == BYTE_ORDER_INTEL) // LSB, so write from right |
| { |
| os.write(b); |
| } |
| } |
| |
| bitsInCache = 0; |
| bitCache = 0; |
| } |
| |
| public int getBytesWritten() |
| { |
| return bytesWritten + ((bitsInCache > 0) ? 1 : 0); |
| } |
| |
| } |