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/*******************************************************************************
* Copyright (c) 2005, 2006 QNX Software Systems and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* QNX - Initial API and implementation
*******************************************************************************/
package org.eclipse.cdt.internal.core.pdom.db;
import java.io.IOException;
import org.eclipse.core.runtime.CoreException;
/**
* @author Doug Schaefer
*
*/
public class Chunk {
private final Database db;
private final int index;
private final byte[] buffer;
Chunk lruPrev;
Chunk lruNext;
private boolean dirty;
Chunk(Database db, int index) throws CoreException {
this.db = db;
this.index = index;
buffer = new byte[Database.CHUNK_SIZE];
try {
db.file.seek(index * Database.CHUNK_SIZE);
db.file.read(buffer, 0, Database.CHUNK_SIZE);
} catch (IOException e) {
throw new CoreException(new DBStatus(e));
}
}
public final void save() throws CoreException {
if (!dirty)
return;
if (index == 0 && getInt(0) != 11)
return;
try {
db.file.seek(index * Database.CHUNK_SIZE);
db.file.write(buffer, 0, Database.CHUNK_SIZE);
dirty = false;
} catch (IOException e) {
throw new CoreException(new DBStatus(e));
}
}
public void putByte(int offset, byte value) {
dirty = true;
buffer[offset % Database.CHUNK_SIZE] = value;
}
public byte getByte(int offset) {
return buffer[offset % Database.CHUNK_SIZE];
}
public byte[] getBytes(int offset, int length) {
byte[] bytes = new byte[length];
System.arraycopy(buffer, offset % Database.CHUNK_SIZE, bytes, 0, length);
return bytes;
}
public void putBytes(int offset, byte[] bytes) {
dirty = true;
System.arraycopy(bytes, 0, buffer, offset % Database.CHUNK_SIZE, bytes.length);
}
public void putInt(int offset, int value) {
dirty = true;
int i = offset % Database.CHUNK_SIZE;
buffer[i++] = (byte)((value >>> 24) & 0xff);
buffer[i++] = (byte)((value >>> 16) & 0xff);
buffer[i++] = (byte)((value >>> 8) & 0xff);
buffer[i] = (byte)(value & 0xff);
}
public int getInt(int offset) {
int i = offset % Database.CHUNK_SIZE;
return ((buffer[i] & 0xff) << 24)
| ((buffer[i + 1] & 0xff) << 16)
| ((buffer[i + 2] & 0xff) << 8)
| (buffer[i + 3] & 0xff);
}
public void putChar(int offset, char value) {
dirty = true;
int i = offset % Database.CHUNK_SIZE;
buffer[i] = (byte)((value >>> 8) & 0xff);
buffer[i + 1] = (byte)(value & 0xff);
}
public char getChar(int offset) {
int i = offset % Database.CHUNK_SIZE;
return (char)(((buffer[i] & 0xff) << 8) + (buffer[i + 1] & 0xff));
}
void clear(int offset, int length) {
dirty = true;
int i = offset % Database.CHUNK_SIZE;
while (length > 0) {
buffer[i++] = 0;
--length;
}
}
void free() throws CoreException {
save();
db.freeChunk(index);
}
}
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