IndexSector.java

/*
  IndexSector.java

  (c) 2013 Ed Swartz

  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
 */
package v9t9.common.files;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

/**
 * @author ejs
 *
 */
public class IndexSector {

	public static IndexSector create(byte[] sec1) {
		IndexSector index = new IndexSector();

		for (int i = 0; i < sec1.length; i += 2) {
			int sec = ((sec1[i + 0] & 0xff) << 8) | (sec1[i + 1] & 0xff);
			if (sec != 0)
				index.entries.add(sec);
		}
		
		return index;
	}

	private List<Integer> entries;

	public IndexSector() {
		entries = new ArrayList<Integer>();
	}
	
	public byte[] toBytes() {
		byte[] sec = new byte[256];
		int i = 0;
		for (Integer n : entries) {
			sec[i] = (byte) (n >> 8);
			sec[i + 1] = (byte) (int) n;
			i += 2;
		}
		return sec;
	}

	public void remove(int indexSector) {
		entries.remove((Integer) indexSector);
	}
	public void add(int indexSector, String fileName, Catalog prevCatalog) throws IOException {
		CatalogEntry exist = prevCatalog.findEntry(fileName);
		if (exist != null) {
			int existIndex = entries.indexOf(exist.indexSector);
			if (existIndex < 0) 
				throw new IOException("inconsistent directory:  entry " + exist + " not in index sector");
			// replace
			entries.set(existIndex, indexSector);
			return;
		}

		if (entries.size() >= 128) {
			throw new IOException("directory full");
		}
		
		// insert in order
		for (CatalogEntry entry : prevCatalog.getEntries()) {
			if (entry.getFile().getFileName().compareTo(fileName) > 0) {
				int entIndex = entries.indexOf(entry.indexSector);
				if (entIndex < 0) 
					throw new IOException("inconsistent directory:  entry " + exist + " not in index sector");
				// insert
				entries.add(entIndex, indexSector);
				return;
			}
		}
		entries.add(indexSector);
	}
}