/******************************************************************************* * Copyright (c) 2000, 2003 IBM Corporation and others. * All rights reserved. This program and the accompanying materials  * are made available under the terms of the Common Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/cpl-v10.html *  * Contributors: *     IBM Corporation - initial API and implementation *******************************************************************************/package org.eclipse.swt.dnd;import org.eclipse.swt.internal.ole.win32.*;import org.eclipse.swt.internal.win32.*;/** * The class <code>ByteArrayTransfer</code> provides a platform specific  * mechanism for converting a java <code>byte[]</code> to a platform  * specific representation of the byte array and vice versa.  See  * <code>Transfer</code> for additional information. * * <p><code>ByteArrayTransfer</code> is never used directly but is sub-classed  * by transfer agents that convert between data in a java format such as a * <code>String</code> and a platform specific byte array. *  * <p>If the data you are converting <b>does not</b> map to a  * <code>byte[]</code>, you should sub-class <code>Transfer</code> directly  * and do your own mapping to a platform data type.</p> *  * <p>The following snippet shows a sublcass of ByteArrayTransfer that transfers * data defined by the class <code>MyType</code>.</p> *  * <pre><code> * public class MyType { *	public String fileName; *	public long fileLength; *	public long lastModified; * } * </code></pre> *  * <code><pre> * public class MyTypeTransfer extends ByteArrayTransfer { *	 *	private static final String MYTYPENAME = "my_type_name"; *	private static final int MYTYPEID = registerType(MYTYPENAME); *	private static MyTypeTransfer _instance = new MyTypeTransfer(); *  * private MyTypeTransfer() {} *  * public static MyTypeTransfer getInstance () { * 	return _instance; * } * public void javaToNative (Object object, TransferData transferData) { * 	if (object == null || !(object instanceof MyType[])) return; * 	 * 	if (isSupportedType(transferData)) { * 		MyType[] myTypes = (MyType[]) object;	 * 		try { * 			// write data to a byte array and then ask super to convert to pMedium * 			ByteArrayOutputStream out = new ByteArrayOutputStream(); * 			DataOutputStream writeOut = new DataOutputStream(out); * 			for (int i = 0, length = myTypes.length; i &lt length;  i++){ * 				byte[] buffer = myTypes[i].fileName.getBytes(); * 				writeOut.writeInt(buffer.length); * 				writeOut.write(buffer); * 				writeOut.writeLong(myTypes[i].fileLength); * 				writeOut.writeLong(myTypes[i].lastModified); * 			} * 			byte[] buffer = out.toByteArray(); * 			writeOut.close(); *  * 			super.javaToNative(buffer, transferData); * 			 * 		} catch (IOException e) { * 		} * 	} * } * public Object nativeToJava(TransferData transferData){	 *  * 	if (isSupportedType(transferData)) { * 		 * 		byte[] buffer = (byte[])super.nativeToJava(transferData); * 		if (buffer == null) return null; * 		 * 		MyType[] myData = new MyType[0]; * 		try { * 			ByteArrayInputStream in = new ByteArrayInputStream(buffer); * 			DataInputStream readIn = new DataInputStream(in); * 			while(readIn.available() > 20) { * 				MyType datum = new MyType(); * 				int size = readIn.readInt(); * 				byte[] name = new byte[size]; * 				readIn.read(name); * 				datum.fileName = new String(name); * 				datum.fileLength = readIn.readLong(); * 				datum.lastModified = readIn.readLong(); * 				MyType[] newMyData = new MyType[myData.length + 1]; * 				System.arraycopy(myData, 0, newMyData, 0, myData.length); * 				newMyData[myData.length] = datum; * 				myData = newMyData; * 			} * 			readIn.close(); * 		} catch (IOException ex) { * 			return null; * 		} * 		return myData; * 	} *  * 	return null; * } * protected String[] getTypeNames(){ * 	return new String[]{MYTYPENAME}; * } * protected int[] getTypeIds(){ * 	return new int[] {MYTYPEID}; * } * } */public abstract class ByteArrayTransfer extends Transfer {public TransferData[] getSupportedTypes() {	int[] types = getTypeIds();	TransferData[] data = new TransferData[types.length];	for (int i = 0; i < types.length; i++) {		data[i] = new TransferData();		data[i].type = types[i];		data[i].formatetc = new FORMATETC();		data[i].formatetc.cfFormat = types[i];		data[i].formatetc.dwAspect = COM.DVASPECT_CONTENT;		data[i].formatetc.lindex = -1;		data[i].formatetc.tymed = COM.TYMED_HGLOBAL;		}	return data;}public boolean isSupportedType(TransferData transferData){	if (transferData == null) return false;	int[] types = getTypeIds();	for (int i = 0; i < types.length; i++) {		FORMATETC format = transferData.formatetc;		if (format.cfFormat == types[i] &&		    (format.dwAspect & COM.DVASPECT_CONTENT) == COM.DVASPECT_CONTENT && 		    (format.tymed & COM.TYMED_HGLOBAL) == COM.TYMED_HGLOBAL  )		    return true;	}	return false;}/** * This implementation of <code>javaToNative</code> converts a java  * <code>byte[]</code> to a platform specific representation.  For additional * information see <code>Transfer#javaToNative</code>. *  * @see Transfer#javaToNative *  * @param object a java <code>byte[]</code> containing the data to be converted * @param transferData an empty <code>TransferData</code> object; this *  object will be filled in on return with the platform specific format of the data */protected void javaToNative (Object object, TransferData transferData) {	transferData.result = COM.E_FAIL;	if (object == null || !(object instanceof byte[])) return;	if (!isSupportedType(transferData)) {		// did not match the TYMED		transferData.stgmedium = new STGMEDIUM();		transferData.result = COM.DV_E_TYMED;		return;	}	// Allocate the memory because the caller (DropTarget) has not handed it in	// The caller of this method must release the data when it is done with it.	byte[] data = (byte[])object;	int size = data.length;	int newPtr = OS.GlobalAlloc(OS.GMEM_FIXED | OS.GMEM_ZEROINIT, size);	OS.MoveMemory(newPtr, data, size);		transferData.stgmedium = new STGMEDIUM();	transferData.stgmedium.tymed = COM.TYMED_HGLOBAL;	transferData.stgmedium.unionField = newPtr;	transferData.stgmedium.pUnkForRelease = 0;	transferData.result = COM.S_OK;}/** * This implementation of <code>nativeToJava</code> converts a platform specific  * representation of a byte array to a java <code>byte[]</code>.    * For additional information see <code>Transfer#nativeToJava</code>. *  * @see Transfer#nativeToJava *  * @param transferData the platform specific representation of the data to be  * been converted * @return a java <code>byte[]</code> containing the converted data if the  * conversion was successful; otherwise null */protected Object nativeToJava(TransferData transferData) {	if (!isSupportedType(transferData) || transferData.pIDataObject == 0)  return null;		IDataObject data = new IDataObject(transferData.pIDataObject);	data.AddRef();	FORMATETC formatetc = transferData.formatetc;	STGMEDIUM stgmedium = new STGMEDIUM();	stgmedium.tymed = COM.TYMED_HGLOBAL;		transferData.result = data.GetData(formatetc, stgmedium);	data.Release();	if (transferData.result != COM.S_OK) return null;	int hMem = stgmedium.unionField;	int size = OS.GlobalSize(hMem);	byte[] buffer = new byte[size];	int ptr = OS.GlobalLock(hMem);	OS.MoveMemory(buffer, ptr, size);	OS.GlobalUnlock(hMem);		OS.GlobalFree(hMem);	return buffer;}}