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

package org.eclipse.swt.ole.win32;

/*
 * Licensed Materials - Property of IBM,
 * WebSphere Studio Workbench
 * (c) Copyright IBM Corp 2000
 */
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
{
	// A variant always takes up 16 bytes, no matter what you 
	// store in it. Objects, strings, and arrays are not physically 
	// stored in the Variant; in these cases, four bytes of the 
	// Variant are used to hold either an object reference, or a 
	// pointer to the string or array. The actual data are stored elsewhere.
	public static final int sizeof = 16;

	private short type; // OLE.VT_* type
	
	private boolean booleanData;
	private float   floatData;
	private int     intData;
	private short   shortData;
	private String  stringData;
	private int     byRefPtr;
	private OleAutomation dispatchData;
	private IUnknown unknownData;
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 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 <code>short byRefType = OLE.VT_BSTR | OLE.VT_BYREF</code>).
 *
 * @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 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 = automation;
}
/**
 * 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 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;
}
/**
 * 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.
 *
 * @return the OleAutomation object represented by this Variant
 *
 * @exception SWTError
 *		ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into an OleAutomation object
 */
public OleAutomation getAutomation() {
	if (type == COM.VT_DISPATCH)
		return dispatchData;

	// try to coerce the value to the desired type
	int oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int 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 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 SWTError
 * <ul><li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into a boolean</ul>
 *
 */
public boolean getBoolean() {
	if (type == COM.VT_BOOL)
		return booleanData;

	// try to coerce the value to the desired type
	int oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int 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 getByRef() {
	if ((type & COM.VT_BYREF)== COM.VT_BYREF)
		return byRefPtr;
		
	return 0;
}
void getData(int pData){
	if (pData == 0) OLE.error(OLE.ERROR_OUT_OF_MEMORY);
	
	COM.VariantInit(pData);

	if ((type & COM.VT_BYREF) == COM.VT_BYREF) {
		COM.MoveMemory(pData, new short[] {type}, 2);
		COM.MoveMemory(pData + 8, new int[]{byRefPtr}, 4);
		return;
	}

	switch (type) {
		case COM.VT_EMPTY :
			break;
		case COM.VT_BOOL :
			COM.MoveMemory(pData, new short[] {type}, 2);
			COM.MoveMemory(pData + 8, new short[]{(short)((booleanData) ? 1 : 0)}, 2);
			break;
		case COM.VT_R4 :
			COM.MoveMemory(pData, new short[] {type}, 2);
			COM.MoveMemory(pData + 8, new float[]{floatData}, 4);
			break;
		case COM.VT_I4 :
			COM.MoveMemory(pData, new short[] {type}, 2);
			COM.MoveMemory(pData + 8, new int[]{intData}, 4);
			break;
		case COM.VT_DISPATCH :
			IDispatch dispatch = new IDispatch(dispatchData.getAddress());
			dispatch.AddRef();
			COM.MoveMemory(pData, new short[] {type}, 2);
			COM.MoveMemory(pData + 8, new int[]{dispatch.getAddress()}, 4);
			break;
		case COM.VT_UNKNOWN :
			unknownData.AddRef();
			COM.MoveMemory(pData, new short[] {type}, 2);
			COM.MoveMemory(pData + 8, new int[]{unknownData.getAddress()}, 4);
			break;
		case COM.VT_I2 :
			COM.MoveMemory(pData, new short[] {type}, 2);
			COM.MoveMemory(pData + 8, new short[]{shortData}, 2);
			break;
		case COM.VT_BSTR :
			COM.MoveMemory(pData, new short[] {type}, 2);
			char[] data = (stringData+"\0").toCharArray();
			int ptr = COM.SysAllocString(data);
			COM.MoveMemory(pData + 8, new int[] {ptr}, 4);
			break;
	
		default :
			OLE.error(SWT.ERROR_NOT_IMPLEMENTED);
	}
}
/**
 * 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 SWTError
 * <ul><li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into a float</ul>
 */
public float getFloat() {
	if (type == COM.VT_R4)
		return floatData;

	// try to coerce the value to the desired type
	int oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int 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 SWTError
 * <ul><li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into a int</ul>
 */
public int getInt() {
	if (type == COM.VT_I4)
		return intData;
		
	// try to coerce the value to the desired type
	int oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int 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 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 SWTError
 * <ul><li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into a short</ul>
 */
public short getShort() {
	if (type == COM.VT_I2)
		return shortData;
		
	// try to coerce the value to the desired type
	int oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int 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 SWTError
 * <ul><li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into a String</ul>
 */
public String getString() {
	if (type == COM.VT_BSTR)
		return stringData;

	// try to coerce the value to the desired type
	int oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int 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);
	}
}
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 SWTError
 * <ul><li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant can not be coerced into 
 *			an IUnknown object</ul>
 */
public IUnknown getUnknown() {
	if (type == COM.VT_UNKNOWN)
		return unknownData;

	// try to coerce the value to the desired type
	int oldPtr = OS.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, sizeof);
	int 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);
	}
}
void setData(int pData){
	if (pData == 0) OLE.error(OLE.ERROR_INVALID_ARGUMENT);

	short[] dataType = new short[1];
	COM.MoveMemory(dataType, pData, 2);
	type = dataType[0];

	if ((type & COM.VT_BYREF) == COM.VT_BYREF) {
		int[] newByRefPtr = new int[1];
		OS.MoveMemory(newByRefPtr, pData + 8, 4);
		byRefPtr = newByRefPtr[0];
		return;
	}
	
	switch (type) {
		case COM.VT_EMPTY :
			break;
		case COM.VT_BOOL :
			short[] newBooleanData = new short[1];
			COM.MoveMemory(newBooleanData, pData + 8, 2);
			booleanData = (newBooleanData[0] != 0);
			break;
		case COM.VT_R4 :
			float[] newFloatData = new float[1];
			COM.MoveMemory(newFloatData, pData + 8, 4);
			floatData = newFloatData[0];
			break;
		case COM.VT_I4 :
			int[] newIntData = new int[1];
			OS.MoveMemory(newIntData, pData + 8, 4);
			intData = newIntData[0];
			break;
		case COM.VT_DISPATCH :
			int[] newDispatchData = new int[1];
			OS.MoveMemory(newDispatchData, pData + 8, 4);
			dispatchData = new OleAutomation(newDispatchData[0]);
			break;
		case COM.VT_UNKNOWN :
			int[] newUnknownData = new int[1];
			OS.MoveMemory(newUnknownData, pData + 8, 4);
			unknownData = new IUnknown(newUnknownData[0]);
			unknownData.AddRef();
			break;
		case COM.VT_I2 :
			short[] newShortData = new short[1];
			COM.MoveMemory(newShortData, pData + 8, 2);
			shortData = newShortData[0];
			break;
		case COM.VT_BSTR :
			// get the address of the memory in which the string resides
			int[] hMem = new int[1];
			OS.MoveMemory(hMem, pData + 8, 4);

			// 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);
			}
			break;
	
		default :
			// try coercing it into one of the known forms
			int newPData = OS.GlobalAlloc(OS.GMEM_FIXED | OS.GMEM_ZEROINIT, Variant.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;
	}
}
}