package ch.werner_randelshofer.activation;

/*
Copyright (C) 1999-99 Werner Randelshofer
werner.randelshofer@mythen.ch
http://www.mythen.ch/w.randelshofer/
    
Permission to use this release of IFFCTD is hereby
granted without fee provided that the complete copyright
notice and this permission notice appear in all copies
and in supporting documentation.
*/

import java.io.*;
import java.net.*;
import ch.werner_randelshofer.iff.*;

/**
This content type detector can identify IFF files.

@author	Werner Randelshofer, Staldenmattweg 2, CH-6405 Immensee, Switzerland.
@version	1998-06-12	Created.
*/
public class IFFCTD
implements ContentTypeDetector
	{
	/**
	Return the number of bytes needed to
	determine the content type.
	*/ 
	public int getMinimalDeterminableDataLength()
		{
		return 12;
		}

	/**
	Return the base MIME Type of this data. This method is
	expected to ALWAYS return a valid (non-null) MIME Type.
	I suggest that if the DataTypeDetector implementation cannot 
	determine the type of the data, it use the convention of
	returning "application/octet-stream".

	<p>Returns "x-iff/*contenttype*" for IFF FORM files, where as
	*contenttype* stands for the FORM type. e.g. returns "x-iff/ANIM"
	for IFF ANIM files.	.
	<br>Returns "x-iff/LIST" for IFF LIST files.
	<br>Returns "x-iff/CAT" for IFF CAT files.


	@param	the first few bytes of the data file.
	@return MIME Type
	*/
	public String getContentType(byte[] dataSnippet)
		{
		int fileID =
			(dataSnippet[0] & 0xff) << 24 |
			(dataSnippet[1] & 0xff) << 16|
			(dataSnippet[2] & 0xff) << 8 |
			(dataSnippet[3] & 0xff);
		int contentID =
			(dataSnippet[8] & 0xff) << 24 |
			(dataSnippet[9] & 0xff) << 16|
			(dataSnippet[10] & 0xff) << 8 |
			(dataSnippet[11] & 0xff);

		if (IFFContext.isFormType(contentID))
			{
			if (fileID == IFFContext.FORM_ID)
				{
				return "x-iff/" + IFFContext.idToString(contentID);
				}
			else if (fileID == IFFContext.CAT_ID)
				{
				return "x-iff/cat";
				}
			else if (fileID == IFFContext.LIST_ID)
				{
				return "x-iff/" + IFFContext.idToString(contentID);
				}
			}
		
		return ContentTypeDetector.CONTENT_TYPE_UNKNOWN;
		}
	}