001 /*
002 Copyright (c) 1996-2011, Damon Hart-Davis
003 All rights reserved.
004
005 Redistribution and use in source and binary forms, with or without
006 modification, are permitted provided that the following conditions are
007 met:
008
009 * Redistributions of source code must retain the above copyright
010 notice, this list of conditions and the following disclaimer.
011
012 * Redistributions in binary form must reproduce the above copyright
013 notice, this list of conditions and the following disclaimer in the
014 documentation and/or other materials provided with the
015 distribution.
016
017 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
018 IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
019 TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
020 PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
021 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
022 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
023 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
024 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
025 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
026 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
027 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
028 */
029 package org.hd.d.pg2k.svrCore;
030
031 import java.io.IOException;
032 import java.io.OutputStream;
033 import java.util.zip.Deflater;
034 import java.util.zip.DeflaterOutputStream;
035
036 /**Like GZIPOutputStream but no GZIP header or checksum.
037 * This is meant to give maximum compression and assumes error
038 * checking/recovery is done elsewhere.
039 */
040 public final class DefOutputStream extends DeflaterOutputStream
041 {
042 /**Creates a new output stream with the specified buffer size.
043 * Forces use of the best possible compression at the possible
044 * expense of CPU time.
045 * <p>
046 * This compressed stream is wrapped with neither GZIP nor ZLIB
047 * headers/checksums to minimise overheads; we'd better be doing
048 * error detection and correction elsewhere!
049 *
050 * @param out the output stream
051 * @param size the output buffer size;
052 * changing this from the default of 512 bytes is unlikely
053 * to improve performance
054 */
055 private DefOutputStream(final OutputStream out, final int size)
056 // throws IOException
057 { super(out, new Deflater(Deflater.BEST_COMPRESSION, true), size); }
058
059 /**Creates a new output stream with a default buffer size.
060 * @param out the output stream
061 */
062 public DefOutputStream(final OutputStream out)
063 // throws IOException
064 { this(out, 512); }
065
066 /**Writes array of bytes to the compressed output stream; blocking.
067 * @exception IOException if an I/O error has occurred
068 */
069 @Override
070 public synchronized void write(final byte[] buf, final int off, final int len)
071 throws IOException
072 { super.write(buf, off, len); }
073
074 /**Finishes writing compressed data to the output stream without closing it.
075 * @exception IOException if an I/O error has occurred
076 */
077 @Override
078 public synchronized void finish()
079 throws IOException
080 {
081 if(!def.finished())
082 {
083 def.finish();
084 while(!def.finished()) { deflate(); }
085 }
086 }
087
088 /**Writes remaining compressed data to the output stream and closes it.
089 * Frees underlying (memory and non-memory) resources also.
090 * @exception IOException if an I/O error has occurred
091 */
092 @Override
093 public synchronized void close()
094 throws IOException
095 {
096 finish();
097 def.end(); // Ensure that resources are freed immediately; not waiting for finalize().
098 out.close();
099 }
100 }