| /******************************************************************************* |
| * Copyright (c) 2000, 2003 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Common Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/cpl-v10.html |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| |
| package org.eclipse.cdt.internal.core.index.impl; |
| |
| import java.io.IOException; |
| import java.io.RandomAccessFile; |
| |
| /** |
| * A block is a container that can hold information (a list of file names, a list of |
| * words, ...), be saved on the disk and loaded in memory. |
| */ |
| |
| public abstract class Block { |
| /** |
| * Size of the block |
| */ |
| protected int blockSize; |
| |
| /** |
| * Field in which the information is stored |
| */ |
| protected Field field; |
| |
| public Block(int blockSize) { |
| this.blockSize= blockSize; |
| field= new Field(blockSize); |
| } |
| /** |
| * Empties the block. |
| */ |
| public void clear() { |
| field.clear(); |
| } |
| /** |
| * Flushes the block |
| */ |
| public void flush() { |
| } |
| /** |
| * Loads the block with the given number in memory, reading it from a RandomAccessFile. |
| */ |
| public void read(RandomAccessFile raf, int blockNum) throws IOException { |
| raf.seek(blockNum * (long) blockSize); |
| raf.readFully(field.buffer()); |
| } |
| /** |
| * Writes the block in a RandomAccessFile, giving it a block number. |
| */ |
| public void write(RandomAccessFile raf, int blockNum) throws IOException { |
| raf.seek(blockNum * (long) blockSize); |
| raf.write(field.buffer()); |
| } |
| } |