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package com.webcodepro.shrinkit;

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

import com.webcodepro.shrinkit.io.LittleEndianByteInputStream;

/**
 * The Header Block contains information and content
 * about a single entry (be it a file or disk image).
 * 
 * Note that we need to support multiple versions of the NuFX
 * archive format.  Some details may be invalid, depending on
 * version, and those are documented in the getter methods.
 * 
 * @author [email protected]
 * @see Apple II File Type Note $E0/$8002
 */
public class HeaderBlock {
	private int headerCrc;
	private int attribCount;
	private int versionNumber;
	private long totalThreads;
	private int fileSysId;
	private int fileSysInfo;
	private long access;
	private long fileType;
	private long extraType;
	private int storageType;
	private Date createWhen;
	private Date modWhen;
	private Date archiveWhen;
	private int optionSize;
	private byte[] optionListBytes;
	private byte[] attribBytes;
	private String filename;
	private String rawFilename;
	private long headerSize = 0;
	private List threads = new ArrayList();
	
	/**
	 * Create the Header Block.  This is done dynamically since
	 * the Header Block size varies significantly.
	 */
	public HeaderBlock(LittleEndianByteInputStream bs) throws IOException {
		int type = bs.seekFileType(4);
		if (type == 0) {
			throw new IOException("Unable to decode this archive.");  // FIXME - NLS
		}
		headerCrc = bs.readWord();
		attribCount = bs.readWord();
		versionNumber = bs.readWord();
		totalThreads = bs.readLong();
		fileSysId = bs.readWord();
		fileSysInfo = bs.readWord();
		access = bs.readLong();
		fileType = bs.readLong();
		extraType = bs.readLong();
		storageType = bs.readWord();
		createWhen = bs.readDate();
		modWhen = bs.readDate();
		archiveWhen = bs.readDate();
		// Read the mysterious option_list
		if (versionNumber >= 1) {
			optionSize = bs.readWord();
			if (optionSize > 0) {
				optionListBytes = bs.readBytes(optionSize-2);
			}
		}
		// Compute attribute bytes that exist and read (if needed)
		int sizeofAttrib = attribCount - 58;
		if (versionNumber >= 1) {
			if (optionSize == 0) sizeofAttrib -= 2;
			else sizeofAttrib -= optionSize;
		}
		if (sizeofAttrib > 0) {
			attribBytes = bs.readBytes(sizeofAttrib);
		}
		// Read the (defunct) filename
		int length = bs.readWord();
		if (length > 0) {
			rawFilename = new String(bs.readBytes(length));
		}
		if (rawFilename == null) {
			rawFilename = "Unknown";
		}
	}
	/**
	 * Read in all data threads.  All ThreadRecords are read and then
	 * each thread's data is read (per NuFX spec).
	 */
	public void readThreads(LittleEndianByteInputStream bs) throws IOException {
		for (long l=0; l getThreadRecords() {
		return threads;
	}
	public void setThreadRecords(List threads) {
		this.threads = threads;
	}
	public long getHeaderSize() {
		return headerSize;
	}
}