--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/druntime/src/compiler/dmd/arraycat.d	Tue Nov 11 01:52:37 2008 +0100
@@ -0,0 +1,61 @@
+/**
+ * Part of the D programming language runtime library.
+ */
+
+/*
+ *  Copyright (C) 2004-2007 by Digital Mars, www.digitalmars.com
+ *  Written by Walter Bright
+ *
+ *  This software is provided 'as-is', without any express or implied
+ *  warranty. In no event will the authors be held liable for any damages
+ *  arising from the use of this software.
+ *
+ *  Permission is granted to anyone to use this software for any purpose,
+ *  including commercial applications, and to alter it and redistribute it
+ *  freely, in both source and binary form, subject to the following
+ *  restrictions:
+ *
+ *  o  The origin of this software must not be misrepresented; you must not
+ *     claim that you wrote the original software. If you use this software
+ *     in a product, an acknowledgment in the product documentation would be
+ *     appreciated but is not required.
+ *  o  Altered source versions must be plainly marked as such, and must not
+ *     be misrepresented as being the original software.
+ *  o  This notice may not be removed or altered from any source
+ *     distribution.
+ */
+
+/*
+ *  Modified by Sean Kelly for use with the D Runtime Project
+ */
+
+module rt.arraycat;
+
+private
+{
+    import stdc.string;
+    debug import stdc.stdio;
+}
+
+extern (C):
+
+byte[] _d_arraycopy(size_t size, byte[] from, byte[] to)
+{
+    debug printf("f = %p,%d, t = %p,%d, size = %d\n",
+                 from.ptr, from.length, to.ptr, to.length, size);
+
+    if (to.length != from.length)
+    {
+        throw new Exception("lengths don't match for array copy");
+    }
+    else if (to.ptr + to.length * size <= from.ptr ||
+             from.ptr + from.length * size <= to.ptr)
+    {
+        memcpy(to.ptr, from.ptr, to.length * size);
+    }
+    else
+    {
+        throw new Exception("overlapping array copy");
+    }
+    return to;
+}