/*
 * $Id: Awk.java,v 1.13 2006-11-27 15:10:34 bacon Exp $
 */

package ase.awk;

import java.security.AccessController;
import java.security.PrivilegedAction;

public abstract class Awk
{
	// mode for open_source & close_source 
	public static final int SOURCE_READ = 1;
	public static final int SOURCE_WRITE = 2;

	static
	{
		//System.load ("c://projects//ase/awk/aseawk.dll");
		AccessController.doPrivileged (new PrivilegedAction ()
		{
			public Object run ()
			{
				System.load ("c://projects//ase/awk/aseawk.dll");
				return null;
			}
		});
	}

	private long handle;

	public Awk () throws Exception
	{
		open ();
	}

	/* == just in case == */
	protected void finalize ()
	{
		if (handle != 0) close ();
	}

	/* == native methods == */
	private native void open () throws Exception;
	public  native void close ();
	public  native void parse () throws Exception;
	public  native void run () throws Exception;

	private native void addbfn (String name, int min_args, int max_args);
	//private native int delbfn (String name);

	private native int setfilename (long run_id, String name);
	private native int setofilename (long run_id, String name);

	/* == builtin functions == */
	public void addBuiltinFunction (
		String name, int min_args, int max_args) throws Exception
	{
		addbfn (name, min_args, max_args);
	}

	/* == console name setters == */
	public void setInputConsoleName (Extio extio, String name) //throws Exception
	{
		/* TODO: setconsolename is not safe. for example, it can 
		 * crash the program if run_id is invalid. so this wrapper
		 * needs to do some sanity check. */
		//if (setconsolename (run_id, name) == -1)
		//	throw new Exception ("cannot set the consle name");
		setfilename (extio.getRunId(), name);
	}

	public void setOutputConsoleName (Extio extio, String name)
	{
		// TODO:
		setofilename (extio.getRunId(), name);
	}

	/* == recursion depth limiting == */
	protected int getMaxParseDepth ()
	{
		return 0;
	}
	protected int getMaxRunDepth ()
	{
		return 0;
	}

	/* == source code management == */
	protected abstract int openSource (int mode);
	protected abstract int closeSource (int mode);
	protected abstract int readSource (char[] buf, int len);
	protected abstract int writeSource (char[] buf, int len);

	/* == external io interface == */
	protected int openExtio (Extio extio)
	{
		int type = extio.getType ();
		if (type == Extio.TYPE_CONSOLE) return openConsole (extio);
		if (type == Extio.TYPE_FILE) return openFile (extio);
		if (type == Extio.TYPE_PIPE) return openPipe (extio);
		//if (type == Extio.TYPE_COPROC) return openCoproc (extio);
		return -1;
	}

	protected int closeExtio (Extio extio)
	{
		int type = extio.getType ();
		if (type == Extio.TYPE_CONSOLE) return closeConsole (extio);
		if (type == Extio.TYPE_FILE) return closeFile (extio);
		if (type == Extio.TYPE_PIPE) return closePipe (extio);
		//if (type == Extio.TYPE_COPROC) return closeCoproc (extio);
		return -1;
	}

	protected int readExtio (Extio extio, char[] buf, int len)
	{
		// this check is needed because 0 is used to indicate
		// the end of the stream. java streams can return 0 
		// if the data given is 0 bytes and it didn't reach 
		// the end of the stream. 
		if (len <= 0) return -1;

		int type = extio.getType ();
		if (type == Extio.TYPE_CONSOLE) 
			return readConsole (extio, buf, len);
		if (type == Extio.TYPE_FILE) 
			return readFile (extio, buf, len);
		if (type == Extio.TYPE_PIPE)
		 	return readPipe (extio, buf, len);
		//if (type == Extio.TYPE_COPROC)
		//	return readCoproc (extio, buf, len);
		return -1;
	}

	protected int writeExtio (Extio extio, char[] buf, int len)
	{
		if (len <= 0) return -1;

		int type = extio.getType ();
		if (type == Extio.TYPE_CONSOLE) 
			return writeConsole (extio, buf, len);
		if (type == Extio.TYPE_FILE) 
			return writeFile (extio, buf, len);
		if (type == Extio.TYPE_PIPE) 
			return writePipe (extio, buf, len);
		//if (type == Extio.TYPE_COPROC)
		//	return writeCoproc (extio, buf, len);
		return -1;
	}

	protected int flushExtio (Extio extio)
	{
		int type = extio.getType ();
		if (type == Extio.TYPE_CONSOLE) return flushConsole (extio);
		if (type == Extio.TYPE_FILE) return flushFile (extio);
		if (type == Extio.TYPE_PIPE) return flushPipe (extio);
		//if (type == Extio.TYPE_COPROC) return flushCoproc (extio);
		return -1;
	}

	protected int nextExtio (Extio extio)
	{
		int type = extio.getType ();
		if (type == Extio.TYPE_CONSOLE) return nextConsole (extio);
		return -1;
	}

	protected abstract int openConsole (Extio extio);
	protected abstract int closeConsole (Extio extio);
	protected abstract int readConsole (Extio extio, char[] buf, int len);
	protected abstract int writeConsole (Extio extio, char[] buf, int len);
	protected abstract int flushConsole (Extio extio);
	protected abstract int nextConsole (Extio extio);

	protected abstract int openFile (Extio extio);
	protected abstract int closeFile (Extio extio);
	protected abstract int readFile (Extio extio, char[] buf, int len);
	protected abstract int writeFile (Extio extio, char[] buf, int len); 
	protected abstract int flushFile (Extio extio);

	protected abstract int openPipe (Extio extio);
	protected abstract int closePipe (Extio extio);
	protected abstract int readPipe (Extio extio, char[] buf, int len);
	protected abstract int writePipe (Extio extio, char[] buf, int len); 
	protected abstract int flushPipe (Extio extio);
}