author | xdono |
Wed, 02 Jul 2008 12:55:45 -0700 | |
changeset 715 | f16baef3a20e |
parent 468 | 642c8c0be52e |
child 5506 | 202f599c92aa |
permissions | -rw-r--r-- |
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/* |
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* Copyright 1997-2008 Sun Microsystems, Inc. All Rights Reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Sun designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Sun in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
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* CA 95054 USA or visit www.sun.com if you need additional information or |
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* have any questions. |
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*/ |
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468
642c8c0be52e
6695553: Cleanup GPLv2+SPL legal notices in hat sources
ohair
parents:
2
diff
changeset
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/* |
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* The Original Code is HAT. The Initial Developer of the |
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* Original Code is Bill Foote, with contributions from others |
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468
642c8c0be52e
6695553: Cleanup GPLv2+SPL legal notices in hat sources
ohair
parents:
2
diff
changeset
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* at JavaSoft/Sun. |
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*/ |
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package com.sun.tools.hat.internal.parser; |
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import java.io.IOException; |
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import java.io.RandomAccessFile; |
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import java.nio.MappedByteBuffer; |
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import java.nio.channels.FileChannel; |
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/** |
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* Implementation of ReadBuffer using mapped file buffer |
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* |
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* @author A. Sundararajan |
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*/ |
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class MappedReadBuffer implements ReadBuffer { |
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private MappedByteBuffer buf; |
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MappedReadBuffer(MappedByteBuffer buf) { |
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this.buf = buf; |
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} |
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// factory method to create correct ReadBuffer for a given file |
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static ReadBuffer create(RandomAccessFile file) throws IOException { |
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FileChannel ch = file.getChannel(); |
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long size = ch.size(); |
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// if file size is more than 2 GB and when file mapping is |
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// configured (default), use mapped file reader |
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if (canUseFileMap() && (size <= Integer.MAX_VALUE)) { |
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MappedByteBuffer buf; |
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try { |
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buf = ch.map(FileChannel.MapMode.READ_ONLY, 0, size); |
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ch.close(); |
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return new MappedReadBuffer(buf); |
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} catch (IOException exp) { |
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exp.printStackTrace(); |
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System.err.println("File mapping failed, will use direct read"); |
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// fall through |
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} |
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} // else fall through |
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return new FileReadBuffer(file); |
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} |
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private static boolean canUseFileMap() { |
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// set jhat.disableFileMap to any value other than "false" |
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// to disable file mapping |
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String prop = System.getProperty("jhat.disableFileMap"); |
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return prop == null || prop.equals("false"); |
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} |
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private void seek(long pos) throws IOException { |
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assert pos <= Integer.MAX_VALUE : "position overflow"; |
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buf.position((int)pos); |
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} |
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public synchronized void get(long pos, byte[] res) throws IOException { |
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seek(pos); |
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buf.get(res); |
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} |
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public synchronized char getChar(long pos) throws IOException { |
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seek(pos); |
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return buf.getChar(); |
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} |
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public synchronized byte getByte(long pos) throws IOException { |
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seek(pos); |
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return buf.get(); |
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} |
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public synchronized short getShort(long pos) throws IOException { |
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seek(pos); |
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return buf.getShort(); |
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} |
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public synchronized int getInt(long pos) throws IOException { |
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seek(pos); |
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return buf.getInt(); |
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} |
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public synchronized long getLong(long pos) throws IOException { |
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seek(pos); |
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return buf.getLong(); |
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} |
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} |