/*******************************************************************************
 * Copyright (c) 2000, 2007 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
 *******************************************************************************/
module dwt.dnd;

import dwt.internal.carbon.CFRange;
import dwt.internal.carbon.OS;
 
/**
 * 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.
 * 
 * <p>An example of a java <code>String</code> containing plain text is shown 
 * below:</p>
 * 
 * <code><pre>
 *     String textData = "Hello World";
 * </code></pre>
 * 
 * @see Transfer
 */
public class TextTransfer : ByteArrayTransfer {

    static TextTransfer _instance = new TextTransfer();
    static final String TEXT = "TEXT"; //$NON-NLS-1$
    static final String UTEXT = "utxt"; //$NON-NLS-1$
    static final int TEXTID = OS.kScrapFlavorTypeText;
    static final int UTEXTID = OS.kScrapFlavorTypeUnicode;

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.
 * 
 * @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
 *  
 * @see Transfer#javaToNative
 */
public void javaToNative (Object object, TransferData transferData) {
    if (!checkText(object) || !isSupportedType(transferData)) {
        DND.error(DND.ERROR_INVALID_DATA);
    }
    String String = (String)object;
    char[] chars = new char[String.length()];
    String.getChars (0, chars.length, chars, 0);
    transferData.result = -1;
    switch (transferData.type) {
        case TEXTID: {
            int cfString = OS.CFStringCreateWithCharacters(OS.kCFAllocatorDefault, chars, chars.length);
            if (cfString is 0) return;
            byte[] buffer = null;
            try {
                CFRange range = new CFRange();
                range.length = chars.length;
                int encoding = OS.CFStringGetSystemEncoding();
                int[] size = new int[1];
                int numChars = OS.CFStringGetBytes(cfString, range, encoding, (byte)'?', true, null, 0, size);
                if (numChars is 0) return;
                buffer = new byte[size[0]];
                numChars = OS.CFStringGetBytes(cfString, range, encoding, (byte)'?', true, buffer, size [0], size);
                if (numChars is 0) return;
            } finally {
                OS.CFRelease(cfString);
            }
            transferData.data = new byte[1][];
            transferData.data[0] = buffer;
            transferData.result = OS.noErr;
            break;
        }
        case UTEXTID: {
            byte[] buffer = new byte[chars.length * 2];
            OS.memmove(buffer, chars, buffer.length);
            transferData.data = new byte[1][];
            transferData.data[0] = buffer;
            transferData.result = OS.noErr;
            break;
        }
    }
}

/**
 * This implementation of <code>nativeToJava</code> converts a platform specific 
 * representation of plain text to a java <code>String</code>.
 * 
 * @param transferData the platform specific representation of the data to be converted
 * @return a java <code>String</code> containing text if the conversion was successful; otherwise null
 * 
 * @see Transfer#nativeToJava
 */
public Object nativeToJava(TransferData transferData){
    if (!isSupportedType(transferData) || transferData.data is null) return null;
    if (transferData.data.length is 0 || transferData.data[0].length is 0) return null;
    byte[] buffer = transferData.data[0];
    switch (transferData.type) {
        case TEXTID: {
            int encoding = OS.CFStringGetSystemEncoding();
            int cfString = OS.CFStringCreateWithBytes(OS.kCFAllocatorDefault, buffer, buffer.length, encoding, true);
            if (cfString is 0) return null;
            try {
                int length = OS.CFStringGetLength(cfString);
                if (length is 0) return null;
                char[] chars = new char[length];
                CFRange range = new CFRange();
                range.length = length;
                OS.CFStringGetCharacters(cfString, range, chars);
                return new String(chars);
            } finally {
                OS.CFRelease(cfString);
            }
        }
        case UTEXTID: {
            char[] chars = new char[(buffer.length + 1) / 2];
            OS.memmove(chars, buffer, buffer.length);
            return new String(chars);
        }
    }
    return null;
}

protected int[] getTypeIds() {
    return new int[] {UTEXTID, TEXTID};
}

protected String[] getTypeNames() {
    return new String[] {UTEXT, TEXT};
}

bool checkText(Object object) {
    return (object !is null && object instanceof String && ((String)object).length() > 0);
}
protected bool validate(Object object) {
    return checkText(object);
}
}