/******************************************************************************* * 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.COM;import org.eclipse.swt.internal.win32.TCHAR;import org.eclipse.swt.internal.ole.win32.STGMEDIUM;import org.eclipse.swt.internal.ole.win32.FORMATETC;import org.eclipse.swt.internal.ole.win32.IDataObject;/** * The class <code>TextTransfer</code> provides a platform specific mechanism  * for converting plain text represented as a java <code>String</code>  * to a platform specific representation of the data and vice versa.  See  * <code>Transfer</code> for additional information. *  * <p>An example of a java <code>String</code> containing plain text is shown  * below:</p> *  * <code><pre> *     String textData = "Hello World"; * </code></pre> */public class TextTransfer extends ByteArrayTransfer {	private static TextTransfer _instance = new TextTransfer();	private static final String CF_UNICODETEXT = "CF_UNICODETEXT";	private static final String CF_TEXT = "CF_TEXT";	private static final int CF_UNICODETEXTID = COM.CF_UNICODETEXT;	private static final int CF_TEXTID = COM.CF_TEXT;	private static int CodePage = COM.GetACP();	private TextTransfer() {}/** * Returns the singleton instance of the TextTransfer class. * * @return the singleton instance of the TextTransfer class */public static TextTransfer getInstance () {	return _instance;}/** * This implementation of <code>javaToNative</code> converts plain text * represented by a java <code>String</code> to a platform specific representation. * For additional information see <code>Transfer#javaToNative</code>. *  * @param object a java <code>String</code> containing text * @param transferData an empty <code>TransferData</code> object; this *  object will be filled in on return with the platform specific format of the data */public void javaToNative (Object object, TransferData transferData){	transferData.result = COM.E_FAIL;	if (object == null || !(object instanceof String)) return;	String string = (String)object;	if (string.length() == 0) return;	if (!isSupportedType(transferData)) {		// did not match the TYMED		transferData.stgmedium = new STGMEDIUM();		transferData.result = COM.DV_E_TYMED;		return;	}	switch (transferData.type) {		case COM.CF_UNICODETEXT: {			TCHAR buffer = new TCHAR(0, string, true);			int byteCount = buffer.length() * TCHAR.sizeof;			int newPtr = COM.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, byteCount);			COM.MoveMemory(newPtr, buffer, byteCount);				transferData.stgmedium = new STGMEDIUM();			transferData.stgmedium.tymed = COM.TYMED_HGLOBAL;			transferData.stgmedium.unionField = newPtr;			transferData.stgmedium.pUnkForRelease = 0;			transferData.result = COM.S_OK;			break;		}		case COM.CF_TEXT: {			int count = string.length();			char[] chars = new char[count + 1];			string.getChars(0, count, chars, 0);			int cchMultiByte = COM.WideCharToMultiByte(CodePage, 0, chars, -1, null, 0, null, null);			if (cchMultiByte == 0) {				transferData.stgmedium = new STGMEDIUM();				transferData.result = COM.DV_E_STGMEDIUM;				return;			}			int lpMultiByteStr = COM.GlobalAlloc(COM.GMEM_FIXED | COM.GMEM_ZEROINIT, cchMultiByte);			COM.WideCharToMultiByte(CodePage, 0, chars, -1, lpMultiByteStr, cchMultiByte, null, null);			transferData.stgmedium = new STGMEDIUM();			transferData.stgmedium.tymed = COM.TYMED_HGLOBAL;			transferData.stgmedium.unionField = lpMultiByteStr;			transferData.stgmedium.pUnkForRelease = 0;			transferData.result = COM.S_OK;			break;		}	}	return;}/** * This implementation of <code>nativeToJava</code> converts a platform specific  * representation of plain text to a java <code>String</code>. * For additional information see <code>Transfer#nativeToJava</code>. *  * @param transferData the platform specific representation of the data to be  * been converted * @return a java <code>String</code> containing text if the  * conversion was successful; otherwise null */public 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;	try {		switch (transferData.type) {			case CF_UNICODETEXTID: {				/* Ensure byteCount is a multiple of 2 bytes on UNICODE platforms */				int size = COM.GlobalSize(hMem) / TCHAR.sizeof * TCHAR.sizeof;				if (size == 0) return null;				TCHAR buffer = new TCHAR(0, size / TCHAR.sizeof);				int ptr = COM.GlobalLock(hMem);				if (ptr == 0) return null;				try {					COM.MoveMemory(buffer, ptr, size);					return buffer.toString(0, buffer.strlen());				} finally {					COM.GlobalUnlock(hMem);					}			}			case CF_TEXTID: {				int lpMultiByteStr = COM.GlobalLock(hMem);				if (lpMultiByteStr == 0) return null;				try {					int cchWideChar = COM.MultiByteToWideChar (CodePage, COM.MB_PRECOMPOSED, lpMultiByteStr, -1, null, 0);					if (cchWideChar == 0) return null;					char[] lpWideCharStr = new char [cchWideChar - 1];					COM.MultiByteToWideChar (CodePage, COM.MB_PRECOMPOSED, lpMultiByteStr, -1, lpWideCharStr, lpWideCharStr.length);					return new String(lpWideCharStr);				} finally {					COM.GlobalUnlock(hMem);				}			}		}	} finally {		COM.GlobalFree(hMem);	}	return null;}protected int[] getTypeIds(){	return new int[] {CF_UNICODETEXTID, CF_TEXTID};}protected String[] getTypeNames(){	return new String[] {CF_UNICODETEXT, CF_TEXT};}}