--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwtx/jface/internal/text/NonDeletingPositionUpdater.d	Sat Aug 23 19:10:48 2008 +0200
@@ -0,0 +1,111 @@
+/*******************************************************************************
+ * Copyright (c) 2005 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
+ * Port to the D programming language:
+ *     Frank Benoit <benoit@tionex.de>
+ *******************************************************************************/
+module dwtx.jface.internal.text.NonDeletingPositionUpdater;
+
+import dwt.dwthelper.utils;
+
+import dwtx.jface.text.BadPositionCategoryException;
+import dwtx.jface.text.DocumentEvent;
+import dwtx.jface.text.IPositionUpdater;
+import dwtx.jface.text.Position;
+
+
+/**
+ * A position updater that never deletes a position. If the region containing
+ * the position is deleted, the position is moved to the beginning/end (falling
+ * together) of the change. If the region containing the position is replaced,
+ * the position is placed at the same location inside the replacement text, but
+ * always inside the replacement text.
+ *
+ * @since 3.1
+ */
+public final class NonDeletingPositionUpdater : IPositionUpdater {
+    /** The position category. */
+    private final String fCategory;
+
+    /**
+     * Creates a new updater for the given <code>category</code>.
+     *
+     * @param category the new category.
+     */
+    public NonDeletingPositionUpdater(String category) {
+        fCategory= category;
+    }
+
+    /*
+     * @see dwtx.jface.text.IPositionUpdater#update(dwtx.jface.text.DocumentEvent)
+     */
+    public void update(DocumentEvent event) {
+
+        int eventOffset= event.getOffset();
+        int eventOldEndOffset= eventOffset + event.getLength();
+        int eventNewLength= event.getText() is null ? 0 : event.getText().length();
+        int eventNewEndOffset= eventOffset + eventNewLength;
+        int deltaLength= eventNewLength - event.getLength();
+
+        try {
+            Position[] positions= event.getDocument().getPositions(fCategory);
+
+            for (int i= 0; i !is positions.length; i++) {
+
+                Position position= positions[i];
+
+                if (position.isDeleted())
+                    continue;
+
+                int offset= position.getOffset();
+                int length= position.getLength();
+                int end= offset + length;
+
+                if (offset > eventOldEndOffset) {
+                    // position comes way after change - shift
+                    position.setOffset(offset + deltaLength);
+                } else if (end < eventOffset) {
+                    // position comes way before change - leave alone
+                } else if (offset <= eventOffset && end >= eventOldEndOffset) {
+                    // event completely internal to the position - adjust length
+                    position.setLength(length + deltaLength);
+                } else if (offset < eventOffset) {
+                    // event extends over end of position - include the
+                    // replacement text into the position
+                    position.setLength(eventNewEndOffset - offset);
+                } else if (end > eventOldEndOffset) {
+                    // event extends from before position into it - adjust
+                    // offset and length, including the replacement text into
+                    // the position
+                    position.setOffset(eventOffset);
+                    int deleted= eventOldEndOffset - offset;
+                    position.setLength(length - deleted + eventNewLength);
+                } else {
+                    // event comprises the position - keep it at the same
+                    // position, but always inside the replacement text
+                    int newOffset= Math.min(offset, eventNewEndOffset);
+                    int newEndOffset= Math.min(end, eventNewEndOffset);
+                    position.setOffset(newOffset);
+                    position.setLength(newEndOffset - newOffset);
+                }
+            }
+        } catch (BadPositionCategoryException e) {
+            // ignore and return
+        }
+    }
+
+    /**
+     * Returns the position category.
+     *
+     * @return the position category
+     */
+    public String getCategory() {
+        return fCategory;
+    }
+}