path: root/bundles/org.eclipse.swt/Eclipse SWT OLE Win32/win32/org/eclipse/swt/ole/win32/Variant.java

/*******************************************************************************
 * Copyright (c) 2000, 2010 IBM Corporation and others.
 * 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
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.ole.win32;

import org.eclipse.swt.*;
import org.eclipse.swt.internal.ole.win32.*;
import org.eclipse.swt.internal.win32.*;
/**
 *
 * A Variant is a generic OLE mechanism for passing data of different types via a common interface.
 *
 * <p>It is used within the OleAutomation object for getting a property, setting a property or invoking
 * a method on an OLE Control or OLE Document.
 *
 */
public final class Variant {
	/**
	* The size in bytes of a native VARIANT struct.
	*/
	public static final int sizeof = VARIANT.sizeof;

	private short type; // OLE.VT_* type
	private boolean booleanData;
	private byte    byteData;
	private short   shortData;
	private char    charData;
	private int     intData;
	private long    longData;
	private float   floatData;
	private double  doubleData;
	private String  stringData;
	private int /*long*/     byRefPtr;
	private IDispatch dispatchData;
	private IUnknown unknownData;

	/**
	 * A shared Variant instance with type VT_NULL.
	 * 
	 * @since 3.7
	 */
	public static final Variant NULL;
	static {
		NULL = new Variant ();
		NULL.type = COM.VT_NULL;
	}

/**	 
 * Invokes platform specific functionality to copy a variant
 * into operating system memory.
 * <p>
 * <b>IMPORTANT:</b> This method is <em>not</em> part of the public
 * API for <code>Variant</code>. It is marked public only so that it
 * can be shared within the packages provided by SWT. It is not
 * available on all platforms, and should never be called from
 * application code.
 * </p>
 *
 * @param pVarDest destination pointer to a variant
 * @param varSrc source <code>Variant</code>
 *
 * @noreference This method is not intended to be referenced by clients.
 *
 * @since 3.3
 */
public static void win32_copy (int /*long*/ pVarDest, Variant varSrc) {
	varSrc.getData (pVarDest);
}

/**	 
 * Invokes platform specific functionality to wrap a variant
 * that was allocated in operating system memory.
 * <p>
 * <b>IMPORTANT:</b> This method is <em>not</em> part of the public
 * API for <code>Variant</code>. It is marked public only so that it
 * can be shared within the packages provided by SWT. It is not
 * available on all platforms, and should never be called from
 * application code.
 * </p>
 *
 * @param pVariant pointer to a variant
 *
 * @return a new <code>Variant</code>
 * 
 * @noreference This method is not intended to be referenced by clients.
 *
 * @since 3.3
 */
public static Variant win32_new (int /*long*/ pVariant) {
	Variant variant = new Variant ();
	variant.setData (pVariant);
	return variant;
}

/**
 * Create an empty Variant object with type VT_EMPTY.
 * 
 * @since 2.0
 */	
public Variant() {
	type = COM.VT_EMPTY;
}
/**
 * Create a Variant object which represents a Java float as a VT_R4.
 *
 * @param val the Java float value that this Variant represents
 *
 */
public Variant(float val) {
	type = COM.VT_R4;
	floatData = val;
}
/**
 * Create a Variant object which represents a Java double as a VT_R8.
 *
 * @param val the Java double value that this Variant represents
 *
 * @since 3.2
 */
public Variant(double val) {
	type = COM.VT_R8;
	doubleData = val;
}
/**
 * Create a Variant object which represents a Java int as a VT_I4.
 *
 * @param val the Java int value that this Variant represents
 *
 */
 public Variant(int val) {
	type = COM.VT_I4;
	intData = val;
}
/**
 * Create a Variant object which contains a reference to the data being transferred.
 *
 * <p>When creating a VT_BYREF Variant, you must give the full Variant type 
 * including VT_BYREF such as
 * 
 * <pre><code>short byRefType = OLE.VT_BSTR | OLE.VT_BYREF</code></pre>.
 *
 * @param ptr a pointer to the data being transferred.
 * @param byRefType the type of the data being transferred such as OLE.VT_BSTR | OLE.VT_BYREF
 *
 */
public Variant(int /*long*/ ptr, short byRefType) {
	type = byRefType;
	byRefPtr = ptr;
}
/**
 * Create a Variant object which represents an IDispatch interface as a VT_Dispatch.
 *
 * @param automation the OleAutomation object that this Variant represents
 * 
 */
public Variant(OleAutomation automation) {
	type = COM.VT_DISPATCH;
	dispatchData = new IDispatch(automation.getAddress());
}
/**
 * Create a Variant object which represents an IDispatch interface as a VT_Dispatch.
 * <p>The caller is expected to have appropriately invoked unknown.AddRef() before creating 
 * this Variant.
 * 
 * @since 2.0
 * 
 * @param idispatch the IDispatch object that this Variant represents
 * 
 */
public Variant(IDispatch idispatch) {
	type = COM.VT_DISPATCH;
	dispatchData = idispatch;
}
/**
 * Create a Variant object which represents an IUnknown interface as a VT_UNKNOWN.
 *
 * <p>The caller is expected to have appropriately invoked unknown.AddRef() before creating 
 * this Variant.
 *
 * @param unknown the IUnknown object that this Variant represents
 *
 */
public Variant(IUnknown unknown) {
	type = COM.VT_UNKNOWN;
	unknownData = unknown;
}
/**
 * Create a Variant object which represents a Java long as a VT_I8.
 *
 * @param val the Java long value that this Variant represents
 *
 * @since 3.2
 */
 public Variant(long val) {
	type = COM.VT_I8;
	longData = val;
}
/**
 * Create a Variant object which represents a Java String as a VT_BSTR.
 *
 * @param string the Java String value that this Variant represents
 *
 */
public Variant(String string) {
	type = COM.VT_BSTR;
	stringData = string;
}
/**
 * Create a Variant object which represents a Java short as a VT_I2.
 *
 * @param val the Java short value that this Variant represents
 *
 */
public Variant(short val) {
	type = COM.VT_I2;
	shortData = val;
}
/**
 * Create a Variant object which represents a Java boolean as a VT_BOOL.
 *
 * @param val the Java boolean value that this Variant represents
 *
 */
public Variant(boolean val) {
	type = COM.VT_BOOL;
	booleanData = val;
}

/**
 * Calling dispose will release resources associated with this Variant.
 * If the resource is an IDispatch or IUnknown interface, Release will be called.
 * If the resource is a ByRef pointer, nothing is released.
 * 
 * @since 2.1
 */
public void dispose() {
	if ((type & COM.VT_BYREF) == COM.VT_BYREF) {
		return;
	}
		
	switch (type) {
		case COM.VT_DISPATCH :
			dispatchData.Release();
			break;
		case COM.VT_UNKNOWN :
			unknownData.Release();
			break;
	}
	
}
/**
 * Returns the OleAutomation object represented by this Variant.
 *
 * <p>If this Variant does not contain an OleAutomation object, an attempt is made to
 * coerce the Variant type into an OleAutomation object.  If this fails, an error is
 * thrown.  Note that OleAutomation objects must be disposed when no longer
 * needed.
 *
 * @return the OleAutomation object represented by this Variant
 *
 * @exception SWTException <ul>
 *     <li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into an OleAutomation object</li>
 * </ul>
 */
public OleAutomation getAutomation() {
	if (type == COM.VT_EMPTY) {
		OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, -1);
	}
	if (type == COM.VT_DISPATCH) {
		return new OleAutomation(dispatchData);
	}
	// try to coerce the value to the desired type
	int /*long*/ oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int /*long*/ newPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	try {
		getData(oldPtr);
		int result = COM.VariantChangeType(newPtr, oldPtr, (short) 0, COM.VT_DISPATCH);
		if (result != COM.S_OK)
			OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, result);
		Variant autoVar = new Variant();
		autoVar.setData(newPtr);
		return autoVar.getAutomation();
	} finally {
		COM.VariantClear(oldPtr);
		OS.GlobalFree(oldPtr);
		COM.VariantClear(newPtr); // Note: This must absolutely be done AFTER the 
		                          // OleAutomation object is created as Variant Clear 
		                          // will result in a Release being performed on the 
		                          // Dispatch object
		OS.GlobalFree(newPtr);
	}
}
/**
 * Returns the IDispatch object represented by this Variant.
 *
 * <p>If this Variant does not contain an IDispatch object, an attempt is made to
 * coerce the Variant type into an IDIspatch object.  If this fails, an error is
 * thrown.
 *
 * @since 2.0
 * 
 * @return the IDispatch object represented by this Variant
 *
 * @exception SWTException <ul>
 *     <li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into an IDispatch object</li>
 * </ul>
 */
public IDispatch getDispatch() {
	if (type == COM.VT_EMPTY) {
		OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, -1);
	}
	if (type == COM.VT_DISPATCH) {
		return dispatchData;
	}
	// try to coerce the value to the desired type
	int /*long*/ oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int /*long*/ newPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	try {
		getData(oldPtr);
		int result = COM.VariantChangeType(newPtr, oldPtr, (short) 0, COM.VT_DISPATCH);
		if (result != COM.S_OK)
			OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, result);
		Variant autoVar = new Variant();
		autoVar.setData(newPtr);
		return autoVar.getDispatch();
	} finally {
		COM.VariantClear(oldPtr);
		OS.GlobalFree(oldPtr);
		COM.VariantClear(newPtr); // Note: This must absolutely be done AFTER the 
		                          // OleAutomation object is created as Variant Clear 
		                          // will result in a Release being performed on the 
		                          // Dispatch object
		OS.GlobalFree(newPtr);
	}
}
/**
 * Returns the Java boolean represented by this Variant.
 *
 * <p>If this Variant does not contain a Java boolean, an attempt is made to
 * coerce the Variant type into a Java boolean.  If this fails, an error is thrown.
 *
 * @return the Java boolean represented by this Variant
 *
 * @exception SWTException <ul>
 *     <li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into a boolean</li>
 * </ul>
 *
 */
public boolean getBoolean() {
	if (type == COM.VT_EMPTY) {
		OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, -1);
	}
	if (type == COM.VT_BOOL) {
		return booleanData;
	}

	// try to coerce the value to the desired type
	int /*long*/ oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int /*long*/ newPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	try {
		getData(oldPtr);
		int result = COM.VariantChangeType(newPtr, oldPtr, (short) 0, COM.VT_BOOL);
		if (result != COM.S_OK)
			OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, result);
		Variant boolVar = new Variant();
		boolVar.setData(newPtr);
		return boolVar.getBoolean();
	} finally {
		COM.VariantClear(oldPtr);
		OS.GlobalFree(oldPtr);
		COM.VariantClear(newPtr);
		OS.GlobalFree(newPtr);
	}
}
/**
 * Returns a pointer to the referenced data represented by this Variant.
 *
 * <p>If this Variant does not contain a reference to data, zero is returned.
 *
 * @return a pointer to the referenced data represented by this Variant or 0
 *
 */
public int /*long*/ getByRef() {
	if (type == COM.VT_EMPTY) {
		OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, -1);
	}
	if ((type & COM.VT_BYREF)== COM.VT_BYREF) {
		return byRefPtr;
	}
		
	return 0;
}
/**
 * Returns the Java byte represented by this Variant.
 *
 * <p>If this Variant does not contain a Java byte, an attempt is made to
 * coerce the Variant type into a Java byte.  If this fails, an error is thrown.
 *
 * @return the Java byte represented by this Variant
 *
 * @exception SWTException <ul>
 *     <li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into a byte</li>
 * </ul>
 * 
 * @since 3.3
 */
public byte getByte() {
	if (type == COM.VT_EMPTY) {
		OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, -1);
	}
	if (type == COM.VT_I1) {
		return byteData;
	}
		
	// try to coerce the value to the desired type
	int /*long*/ oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int /*long*/ newPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	try {
		getData(oldPtr);
		int result = COM.VariantChangeType(newPtr, oldPtr, (short) 0, COM.VT_I1);
		if (result != COM.S_OK)
			OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, result);
		Variant byteVar = new Variant();
		byteVar.setData(newPtr);
		return byteVar.getByte();
	} finally {
		COM.VariantClear(oldPtr);
		OS.GlobalFree(oldPtr);
		COM.VariantClear(newPtr);
		OS.GlobalFree(newPtr);
	}
}
/**
 * Returns the Java char represented by this Variant.
 *
 * <p>If this Variant does not contain a Java char, an attempt is made to
 * coerce the Variant type into a Java char.  If this fails, an error is thrown.
 *
 * @return the Java char represented by this Variant
 *
 * @exception SWTException <ul>
 *     <li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into a char</li>
 * </ul>
 * 
 * @since 3.3
 */
public char getChar() {
	if (type == COM.VT_EMPTY) {
		OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, -1);
	}
	if (type == COM.VT_UI2) {
		return charData;
	}
		
	// try to coerce the value to the desired type
	int /*long*/ oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int /*long*/ newPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	try {
		getData(oldPtr);
		int result = COM.VariantChangeType(newPtr, oldPtr, (short) 0, COM.VT_UI2);
		if (result != COM.S_OK)
			OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, result);
		Variant charVar = new Variant();
		charVar.setData(newPtr);
		return charVar.getChar();
	} finally {
		COM.VariantClear(oldPtr);
		OS.GlobalFree(oldPtr);
		COM.VariantClear(newPtr);
		OS.GlobalFree(newPtr);
	}
}
void getData(int /*long*/ pData){
	if (pData == 0) OLE.error(OLE.ERROR_OUT_OF_MEMORY);
	
	COM.VariantInit(pData);

	if ((type & COM.VT_BYREF) == COM.VT_BYREF) {
		//TODO - use VARIANT structure
		COM.MoveMemory(pData, new short[] {type}, 2);
		COM.MoveMemory(pData + 8, new int /*long*/[]{byRefPtr}, OS.PTR_SIZEOF);
		return;
	}

	switch (type) {
		case COM.VT_EMPTY :
		case COM.VT_NULL :
            COM.MoveMemory(pData, new short[] {type}, 2);
			break;
		case COM.VT_BOOL :
			COM.MoveMemory(pData, new short[] {type}, 2);
			COM.MoveMemory(pData + 8, new short[]{(booleanData) ? COM.VARIANT_TRUE : COM.VARIANT_FALSE}, 2);
			break;
		case COM.VT_I1 :
			COM.MoveMemory(pData, new short[] {type}, 2);
			COM.MoveMemory(pData + 8, new byte[]{byteData}, 1);
			break;
		case COM.VT_I2 :
			COM.MoveMemory(pData, new short[] {type}, 2);
			COM.MoveMemory(pData + 8, new short[]{shortData}, 2);
			break;
		case COM.VT_UI2 :
			COM.MoveMemory(pData, new short[] {type}, 2);
			COM.MoveMemory(pData + 8, new char[]{charData}, 2);
			break;
		case COM.VT_I4 :
			COM.MoveMemory(pData, new short[] {type}, 2);
			COM.MoveMemory(pData + 8, new int[]{intData}, 4);
			break;
		case COM.VT_I8 :
			COM.MoveMemory(pData, new short[] {type}, 2);
			COM.MoveMemory(pData + 8, new long[]{longData}, 8);
			break;
		case COM.VT_R4 :
			COM.MoveMemory(pData, new short[] {type}, 2);
			COM.MoveMemory(pData + 8, new float[]{floatData}, 4);
			break;
		case COM.VT_R8 :
			COM.MoveMemory(pData, new short[] {type}, 2);
			COM.MoveMemory(pData + 8, new double[]{doubleData}, 8);
			break;
		case COM.VT_DISPATCH :
			dispatchData.AddRef();
			COM.MoveMemory(pData, new short[] {type}, 2);
			COM.MoveMemory(pData + 8, new int /*long*/[]{dispatchData.getAddress()}, OS.PTR_SIZEOF);
			break;
		case COM.VT_UNKNOWN :
			unknownData.AddRef();
			COM.MoveMemory(pData, new short[] {type}, 2);
			COM.MoveMemory(pData + 8, new int /*long*/[]{unknownData.getAddress()}, OS.PTR_SIZEOF);
			break;
		case COM.VT_BSTR :
			COM.MoveMemory(pData, new short[] {type}, 2);
			char[] data = (stringData+"\0").toCharArray();
			int /*long*/ ptr = COM.SysAllocString(data);
			COM.MoveMemory(pData + 8, new int /*long*/[] {ptr}, OS.PTR_SIZEOF);
			break;
	
		default :
			OLE.error(SWT.ERROR_NOT_IMPLEMENTED);
	}
}
/**
 * Returns the Java double represented by this Variant.
 *
 * <p>If this Variant does not contain a Java double, an attempt is made to
 * coerce the Variant type into a Java double.  If this fails, an error is thrown.
 *
 * @return the Java double represented by this Variant
 *
 * @exception SWTException <ul>
 *     <li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into a double</li>
 * </ul>
 * 
 * @since 3.2
 */
public double getDouble() {
    if (type == COM.VT_EMPTY) {
        OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, -1);
    }
    if (type == COM.VT_R8) {
        return doubleData;
    }
    
    // try to coerce the value to the desired type
    int /*long*/ oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
    int /*long*/ newPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
    try {
        getData(oldPtr);
        int result = COM.VariantChangeType(newPtr, oldPtr, (short) 0, COM.VT_R8);
        if (result != COM.S_OK)
            OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, result);
        Variant doubleVar = new Variant();
        doubleVar.setData(newPtr);
        return doubleVar.getDouble();
    } finally {
        COM.VariantClear(oldPtr);
        OS.GlobalFree(oldPtr);
        COM.VariantClear(newPtr);
        OS.GlobalFree(newPtr);
    } 
}

/**
 * Returns the Java float represented by this Variant.
 *
 * <p>If this Variant does not contain a Java float, an attempt is made to
 * coerce the Variant type into a Java float.  If this fails, an error is thrown.
 *
 * @return the Java float represented by this Variant
 *
 * @exception SWTException <ul>
 *     <li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into a float</li>
 * </ul>
 */
public float getFloat() {
	if (type == COM.VT_EMPTY) {
		OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, -1);
	}
	if (type == COM.VT_R4) {
		return floatData;
	}

	// try to coerce the value to the desired type
	int /*long*/ oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int /*long*/ newPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	try {
		getData(oldPtr);
		int result = COM.VariantChangeType(newPtr, oldPtr, (short) 0, COM.VT_R4);
		if (result != COM.S_OK)
			OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, result);
		Variant floatVar = new Variant();
		floatVar.setData(newPtr);
		return floatVar.getFloat();
	} finally {
		COM.VariantClear(oldPtr);
		OS.GlobalFree(oldPtr);
		COM.VariantClear(newPtr);
		OS.GlobalFree(newPtr);
	}
	
}
/**
 * Returns the Java int represented by this Variant.
 *
 * <p>If this Variant does not contain a Java int, an attempt is made to
 * coerce the Variant type into a Java int.  If this fails, an error is thrown.
 *
 * @return the Java int represented by this Variant
 *
 * @exception SWTException <ul>
 *     <li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into a int</li>
 * </ul>
 */
public int getInt() {
	if (type == COM.VT_EMPTY) {
		OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, -1);
	}
	if (type == COM.VT_I4) {
		return intData;
	}
		
	// try to coerce the value to the desired type
	int /*long*/ oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int /*long*/ newPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	try {
		getData(oldPtr);
		int result = COM.VariantChangeType(newPtr, oldPtr, (short) 0, COM.VT_I4);
		if (result != COM.S_OK)
			OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, result);
		Variant intVar = new Variant();
		intVar.setData(newPtr);
		return intVar.getInt();
	} finally {
		COM.VariantClear(oldPtr);
		OS.GlobalFree(oldPtr);
		COM.VariantClear(newPtr);
		OS.GlobalFree(newPtr);
	}
}
/**
 * Returns the Java long represented by this Variant.
 *
 * <p>If this Variant does not contain a Java long, an attempt is made to
 * coerce the Variant type into a Java long.  If this fails, an error is thrown.
 *
 * @return the Java long represented by this Variant
 *
 * @exception SWTException <ul>
 *     <li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into a long</li>
 * </ul>
 *
 * @since 3.2
 */
public long getLong() {
	if (type == COM.VT_EMPTY) {
		OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, -1);
	}
	if (type == COM.VT_I8) {
		return longData;
	}
		
	// try to coerce the value to the desired type
	int /*long*/ oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int /*long*/ newPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	try {
		getData(oldPtr);
		int result = COM.VariantChangeType(newPtr, oldPtr, (short) 0, COM.VT_I8);
		if (result != COM.S_OK)
			OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, result);
		Variant longVar = new Variant();
		longVar.setData(newPtr);
		return longVar.getLong();
	} finally {
		COM.VariantClear(oldPtr);
		OS.GlobalFree(oldPtr);
		COM.VariantClear(newPtr);
		OS.GlobalFree(newPtr);
	}
}
/**
 * Returns the Java short represented by this Variant.
 *
 * <p>If this Variant does not contain a Java short, an attempt is made to
 * coerce the Variant type into a Java short.  If this fails, an error is thrown.
 *
 * @return the Java short represented by this Variant
 *
 * @exception SWTException <ul>
 *     <li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into a short</li>
 * </ul>
 */
public short getShort() {
	if (type == COM.VT_EMPTY) {
		OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, -1);
	}
	if (type == COM.VT_I2) {
		return shortData;
	}
		
	// try to coerce the value to the desired type
	int /*long*/ oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int /*long*/ newPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	try {
		getData(oldPtr);
		int result = COM.VariantChangeType(newPtr, oldPtr, (short) 0, COM.VT_I2);
		if (result != COM.S_OK)
			OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, result);
		Variant shortVar = new Variant();
		shortVar.setData(newPtr);
		return shortVar.getShort();
	} finally {
		COM.VariantClear(oldPtr);
		OS.GlobalFree(oldPtr);
		COM.VariantClear(newPtr);
		OS.GlobalFree(newPtr);
	}
	
}
/**
 * Returns the Java String represented by this Variant.
 *
 * <p>If this Variant does not contain a Java String, an attempt is made to
 * coerce the Variant type into a Java String.  If this fails, an error is thrown.
 *
 * @return the Java String represented by this Variant
 *
 * @exception SWTException <ul>
 *     <li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into a String</li>
 * </ul>
 */
public String getString() {
	if (type == COM.VT_EMPTY) {
		OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, -1);
	}
	if (type == COM.VT_BSTR) {
		return stringData;
	}

	// try to coerce the value to the desired type
	int /*long*/ oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int /*long*/ newPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	try {
		getData(oldPtr);
		int result = COM.VariantChangeType(newPtr, oldPtr, (short) 0, COM.VT_BSTR);
		if (result != COM.S_OK)
			OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, result);

		Variant stringVar = new Variant();
		stringVar.setData(newPtr);
		return stringVar.getString();
			
	} finally {
		COM.VariantClear(oldPtr);
		OS.GlobalFree(oldPtr);
		COM.VariantClear(newPtr);
		OS.GlobalFree(newPtr);
	}
}
/**
 * Returns the type of the variant type.  This will be an OLE.VT_* value or
 * a bitwise combination of OLE.VT_* values as in the case of 
 * OLE.VT_BSTR | OLE.VT_BYREF.
 * 
 * @return the type of the variant data
 * 
 * @since 2.0
 */
public short getType() {
	return type;
}
/**
 * Returns the IUnknown object represented by this Variant.
 *
 * <p>If this Variant does not contain an IUnknown object, an attempt is made to
 * coerce the Variant type into an IUnknown object.  If this fails, an error is
 * thrown.
 *
 * @return the IUnknown object represented by this Variant
 *
 * @exception SWTException <ul>
 *     <li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into 
 *			an IUnknown object</li>
 * </ul>
 */
public IUnknown getUnknown() {
	if (type == COM.VT_EMPTY) {
		OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, -1);
	}
	if (type == COM.VT_UNKNOWN) {
		return unknownData;
	}

	// try to coerce the value to the desired type
	int /*long*/ oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int /*long*/ newPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	try {
		getData(oldPtr);
		int result = COM.VariantChangeType(newPtr, oldPtr, (short) 0, COM.VT_UNKNOWN);
		if (result != COM.S_OK)
			OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE, result);
		Variant unknownVar = new Variant();
		unknownVar.setData(newPtr);
		return unknownVar.getUnknown();
	} finally {
		COM.VariantClear(oldPtr);
		OS.GlobalFree(oldPtr);
		COM.VariantClear(newPtr); // Note: This must absolutely be done AFTER the 
		                          // IUnknown object is created as Variant Clear 
		                          // will result in a Release being performed on the 
		                          // Dispatch object
		OS.GlobalFree(newPtr);
	}
}
/**
 * Update the by reference value of this variant with a new boolean value.
 * 
 * @param val the new boolean value
 * 
 * @exception SWTException <ul>
 *     <li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant is not 
 *			a (VT_BYREF | VT_BOOL) object</li>
 * </ul>
 *
 * @since 2.1
 */
public void setByRef(boolean val) {
	if ((type & COM.VT_BYREF) == 0 || (type & COM.VT_BOOL) == 0) {
		OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE);
	}
	COM.MoveMemory(byRefPtr, new short[]{val ? COM.VARIANT_TRUE : COM.VARIANT_FALSE}, 2);
}
/**
 * Update the by reference value of this variant with a new float value.
 * 
 * @param val the new float value
 * 
 * @exception SWTException <ul>
 *     <li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant is not 
 *			a (VT_BYREF | VT_R4) object</li>
 * </ul>
 *
 * @since 2.1
 */
public void setByRef(float val) {
	if ((type & COM.VT_BYREF) == 0 || (type & COM.VT_R4) == 0) {
		OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE);
	}
	COM.MoveMemory(byRefPtr, new float[]{val}, 4);	
}
/**
 * Update the by reference value of this variant with a new integer value.
 * 
 * @param val the new integer value
 * 
 * @exception SWTException <ul>
 *     <li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant is not a (VT_BYREF | VT_I4) object</li>
 * </ul>
 *
 * @since 2.1
 */
public void setByRef(int /*long*/ val) {
	if ((type & COM.VT_BYREF) == 0 || (type & COM.VT_I4) == 0) {
		OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE);
	}
	COM.MoveMemory(byRefPtr, new int /*long*/[]{val}, OS.PTR_SIZEOF);
}
/**
 * Update the by reference value of this variant with a new short value.
 * 
 * @param val the new short value
 * 
 * @exception SWTException <ul>
 *     <li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant is not a (VT_BYREF | VT_I2) object
 * </ul>
 *
 * @since 2.1
 */
public void setByRef(short val) {
	if ((type & COM.VT_BYREF) == 0 || (type & COM.VT_I2) == 0) {
		OLE.error(OLE.ERROR_CANNOT_CHANGE_VARIANT_TYPE);
	}
	COM.MoveMemory(byRefPtr, new short[]{val}, 2);
}
void setData(int /*long*/ pData){
	if (pData == 0) OLE.error(OLE.ERROR_INVALID_ARGUMENT);

	//TODO - use VARIANT structure
	short[] dataType = new short[1];
	COM.MoveMemory(dataType, pData, 2);
	type = dataType[0];

	if ((type & COM.VT_BYREF) == COM.VT_BYREF) {
		int /*long*/[] newByRefPtr = new int /*long*/[1];
		OS.MoveMemory(newByRefPtr, pData + 8, OS.PTR_SIZEOF);
		byRefPtr = newByRefPtr[0];
		return;
	}
	
	switch (type) {
		case COM.VT_EMPTY :
		case COM.VT_NULL :
			break;
		case COM.VT_BOOL :
			short[] newBooleanData = new short[1];
			COM.MoveMemory(newBooleanData, pData + 8, 2);
			booleanData = (newBooleanData[0] != COM.VARIANT_FALSE);
			break;
		case COM.VT_I1 :
			byte[] newByteData = new byte[1];
			COM.MoveMemory(newByteData, pData + 8, 1);
			byteData = newByteData[0];
			break;
		case COM.VT_I2 :
			short[] newShortData = new short[1];
			COM.MoveMemory(newShortData, pData + 8, 2);
			shortData = newShortData[0];
			break;
		case COM.VT_UI2 :
			char[] newCharData = new char[1];
			COM.MoveMemory(newCharData, pData + 8, 2);
			charData = newCharData[0];
			break;
		case COM.VT_I4 :
			int[] newIntData = new int[1];
			OS.MoveMemory(newIntData, pData + 8, 4);
			intData = newIntData[0];
			break;
		case COM.VT_I8 :
			long[] newLongData = new long[1];
			OS.MoveMemory(newLongData, pData + 8, 8);
			longData = newLongData[0];
			break;
		case COM.VT_R4 :
			float[] newFloatData = new float[1];
			COM.MoveMemory(newFloatData, pData + 8, 4);
			floatData = newFloatData[0];
			break;
		case COM.VT_R8 :
			double[] newDoubleData = new double[1];
			COM.MoveMemory(newDoubleData, pData + 8, 8);
 			doubleData = newDoubleData[0];
			break;
		case COM.VT_DISPATCH : {
			int /*long*/[] ppvObject = new int /*long*/[1];
			OS.MoveMemory(ppvObject, pData + 8, OS.PTR_SIZEOF);
			if (ppvObject[0] == 0) {
				type = COM.VT_EMPTY;
				break;
			}
			dispatchData = new IDispatch(ppvObject[0]);
			dispatchData.AddRef();
			break;
		}
		case COM.VT_UNKNOWN : {
			int /*long*/[] ppvObject = new int /*long*/[1];
			OS.MoveMemory(ppvObject, pData + 8, OS.PTR_SIZEOF);
			if (ppvObject[0] == 0) {
				type = COM.VT_EMPTY;
				break;
			}
			unknownData = new IUnknown(ppvObject[0]);
			unknownData.AddRef();
			break;
		}
		case COM.VT_BSTR :
			// get the address of the memory in which the string resides
			int /*long*/[] hMem = new int /*long*/[1];
			OS.MoveMemory(hMem, pData + 8, OS.PTR_SIZEOF);
			if (hMem[0] == 0) {
				type = COM.VT_EMPTY;
				break;
			}
			// Get the size of the string from the OS - the size is expressed in number
			// of bytes - each unicode character is 2 bytes.
			int size = COM.SysStringByteLen(hMem[0]);
			if (size > 0){
				// get the unicode character array from the global memory and create a String
				char[] buffer = new char[(size + 1) /2]; // add one to avoid rounding errors
				COM.MoveMemory(buffer, hMem[0], size);
				stringData = new String(buffer);
			} else {
				stringData = ""; //$NON-NLS-1$
			}
			break;
	
		default :
			// try coercing it into one of the known forms
			int /*long*/ newPData = OS.GlobalAlloc(OS.GMEM_FIXED | OS.GMEM_ZEROINIT, sizeof);
			if (COM.VariantChangeType(newPData, pData, (short) 0, COM.VT_R4) == COM.S_OK) {
				setData(newPData);
			} else if (COM.VariantChangeType(newPData, pData, (short) 0, COM.VT_I4) == COM.S_OK) {
				setData(newPData);
			} else if (COM.VariantChangeType(newPData, pData, (short) 0, COM.VT_BSTR) == COM.S_OK) {
				setData(newPData);
			}
			COM.VariantClear(newPData);
			OS.GlobalFree(newPData);
			break;
	}
}
/**
 * Returns a string containing a concise, human-readable
 * description of the receiver.
 *
 * @return a string representation of the Variant
 */
public String toString () {
    switch (type) {
	    case COM.VT_BOOL :
	        return "VT_BOOL{"+booleanData+"}";
	    case COM.VT_I1 :
	        return "VT_I1{"+byteData+"}";
	    case COM.VT_I2 :
	        return "VT_I2{"+shortData+"}";
	    case COM.VT_UI2 :
	        return "VT_UI2{"+charData+"}";
	    case COM.VT_I4 :
	        return "VT_I4{"+intData+"}";
	    case COM.VT_I8 :
	        return "VT_I8{"+longData+"}";
	    case COM.VT_R4 :
	        return "VT_R4{"+floatData+"}";
   	    case COM.VT_R8 :
	        return "VT_R8{"+doubleData+"}";
	    case COM.VT_BSTR :
	        return "VT_BSTR{"+stringData+"}";
	    case COM.VT_DISPATCH :
	        return "VT_DISPATCH{"+(dispatchData == null ? 0 : dispatchData.getAddress())+"}";
	    case COM.VT_UNKNOWN :
	        return "VT_UNKNOWN{"+(unknownData == null ? 0 : unknownData.getAddress())+"}";
	    case COM.VT_EMPTY :
	        return "VT_EMPTY";
	    case COM.VT_NULL :
	        return "VT_NULL";
	 }
    if ((type & COM.VT_BYREF) != 0) {
        return "VT_BYREF|"+(type & ~COM.VT_BYREF)+"{"+byRefPtr+"}";
    }
    return "Unsupported Type "+type;
}
}