variant.java

源码为Eclipse开源开发平台桌面开发工具SWT的源代码,

}
/**
 * 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_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 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_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 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_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 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_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 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);
	}
}
/**
 * Returns the ytpe 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 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_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 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);
	}
}
/**
 * Update the by reference value of this variant with a new boolean value.
 * 
 * @param val the new boolean value
 * 
 * @exception SWTError
 * <ul><li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant is not 
 *			a (VT_BYREF | VT_BOOL) object</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 SWTError
 * <ul><li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant is not 
 *			a (VT_BYREF | VT_R4) object</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 SWTError
 * <ul><li>ERROR_CANNOT_CHANGE_VARIANT_TYPE when type of Variant is not 
 *			a (VT_BYREF | VT_I4) object</ul>
 *
 * @since 2.1
 */
public void setByRef(int 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[]{val}, 4);
}
/**
 * Update the by reference value of this variant with a new short value.
 * 
 * @param val the new short value
 * 
 * @exception SWTError
 * <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 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] != COM.VARIANT_FALSE);
			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[] ppvObject = new int[1];
			OS.MoveMemory(ppvObject, pData + 8, 4);
			if (ppvObject[0] == 0) {
				type = COM.VT_EMPTY;
				break;
			}
			dispatchData = new IDispatch(ppvObject[0]);
			dispatchData.AddRef();
			break;
		}
		case COM.VT_UNKNOWN : {
			int[] ppvObject = new int[1];
			OS.MoveMemory(ppvObject, pData + 8, 4);
			if (ppvObject[0] == 0) {
				type = COM.VT_EMPTY;
				break;
			}
			unknownData = new IUnknown(ppvObject[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);
			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 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;
	}
}
}