--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dwtx/ui/forms/widgets/LayoutCache.d	Sat May 24 05:11:16 2008 +0200
@@ -0,0 +1,126 @@
+/*******************************************************************************
+ * Copyright (c) 2004, 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.ui.forms.widgets.LayoutCache;
+
+import dwtx.ui.forms.widgets.SizeCache;
+
+import dwt.graphics.Point;
+import dwt.widgets.Control;
+
+import dwt.dwthelper.utils;
+
+/**
+ * Caches the preferred sizes of an array of controls
+ *
+ * @since 3.0
+ */
+public class LayoutCache {
+    private SizeCache[] caches;
+
+    /**
+     * Creates an empty layout cache
+     */
+    public this() {
+    }
+
+    /**
+     * Creates a cache for the given array of controls
+     *
+     * @param controls
+     */
+    public this(Control[] controls) {
+        rebuildCache(controls);
+    }
+
+    /**
+     * Returns the size cache for the given control
+     *
+     * @param idx
+     * @return the size cache for the given control
+     */
+    public SizeCache getCache(int idx) {
+        return caches[idx];
+    }
+
+    /**
+     * Sets the controls that are being cached here. If these are the same
+     * controls that were used last time, this method does nothing. Otherwise,
+     * the cache is flushed and a new cache is created for the new controls.
+     *
+     * @param controls
+     */
+    public void setControls(Control[] controls) {
+        // If the number of controls has changed, discard the entire cache
+        if (controls.length !is caches.length) {
+            rebuildCache(controls);
+            return;
+        }
+
+        for (int idx = 0; idx < controls.length; idx++) {
+            caches[idx].setControl(controls[idx]);
+        }
+    }
+
+    /**
+     * Creates a new size cache for the given set of controls, discarding any
+     * existing cache.
+     *
+     * @param controls the controls whose size is being cached
+     */
+    private void rebuildCache(Control[] controls) {
+        SizeCache[] newCache = new SizeCache[controls.length];
+
+        for (int idx = 0; idx < controls.length; idx++) {
+            // Try to reuse existing caches if possible
+            if (idx < caches.length) {
+                newCache[idx] = caches[idx];
+                newCache[idx].setControl(controls[idx]);
+            } else {
+                newCache[idx] = new SizeCache(controls[idx]);
+            }
+        }
+
+        caches = newCache;
+    }
+
+    /**
+     * Computes the preferred size of the nth control
+     *
+     * @param controlIndex index of the control whose size will be computed
+     * @param widthHint width of the control (or DWT.DEFAULT if unknown)
+     * @param heightHint height of the control (or DWT.DEFAULT if unknown)
+     * @return the preferred size of the control
+     */
+    public Point computeSize(int controlIndex, int widthHint, int heightHint) {
+        return caches[controlIndex].computeSize(widthHint, heightHint);
+    }
+
+    /**
+     * Flushes the cache for the given control. This should be called if exactly
+     * one of the controls has changed but the remaining controls remain unmodified
+     *
+     * @param controlIndex
+     */
+    public void flush(int controlIndex) {
+        caches[controlIndex].flush();
+    }
+
+    /**
+     * Flushes the cache.
+     */
+    public void flush() {
+        for (int idx = 0; idx < caches.length; idx++) {
+            caches[idx].flush();
+        }
+    }
+}