diff --git a/server/class.c b/server/class.c
new file mode 100644
index 0000000..13d9d5c
--- /dev/null
+++ b/server/class.c
@@ -0,0 +1,204 @@
+/*
+ * Server-side window class management
+ *
+ * Copyright (C) 2002 Mike McCormack
+ * Copyright (C) 2003 Alexandre Julliard
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include "config.h"
+#include "wine/port.h"
+
+#include <assert.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "wine/list.h"
+
+#include "request.h"
+#include "object.h"
+#include "process.h"
+#include "user.h"
+
+struct window_class
+{
+    struct list     entry;           /* entry in process list */
+    struct process *process;         /* process owning the class */
+    int             count;           /* reference count */
+    int             local;           /* local class? */
+    atom_t          atom;            /* class atom */
+    void           *instance;        /* module instance */
+    unsigned int    style;           /* class style */
+    int             win_extra;       /* number of window extra bytes */
+    int             nb_extra_bytes;  /* number of extra bytes */
+    char            extra_bytes[1];  /* extra bytes storage */
+};
+
+static struct window_class *create_class( struct process *process, int extra_bytes, int local )
+{
+    struct window_class *class;
+
+    if (!(class = mem_alloc( sizeof(*class) + extra_bytes - 1 ))) return NULL;
+
+    class->process = (struct process *)grab_object( process );
+    class->count = 0;
+    class->local = local;
+    class->nb_extra_bytes = extra_bytes;
+    memset( class->extra_bytes, 0, extra_bytes );
+    /* other fields are initialized by caller */
+
+    /* local classes have priority so we put them first in the list */
+    if (local) list_add_head( &process->classes, &class->entry );
+    else list_add_tail( &process->classes, &class->entry );
+    return class;
+}
+
+static void destroy_class( struct window_class *class )
+{
+    list_remove( &class->entry );
+    release_object( class->process );
+    free( class );
+}
+
+void destroy_process_classes( struct process *process )
+{
+    struct list *ptr;
+
+    while ((ptr = list_head( &process->classes )))
+    {
+        struct window_class *class = LIST_ENTRY( ptr, struct window_class, entry );
+        destroy_class( class );
+    }
+}
+
+static struct window_class *find_class( struct process *process, atom_t atom, void *instance )
+{
+    struct list *ptr;
+
+    LIST_FOR_EACH( ptr, &process->classes )
+    {
+        struct window_class *class = LIST_ENTRY( ptr, struct window_class, entry );
+        if (class->atom != atom) continue;
+        if (!instance || !class->local || class->instance == instance) return class;
+    }
+    return NULL;
+}
+
+struct window_class *grab_class( struct process *process, atom_t atom, void *instance )
+{
+    struct window_class *class = find_class( process, atom, instance );
+    if (class) class->count++;
+    else set_error( STATUS_INVALID_HANDLE );
+    return class;
+}
+
+void release_class( struct window_class *class )
+{
+    assert( class->count > 0 );
+    class->count--;
+}
+
+atom_t get_class_atom( struct window_class *class )
+{
+    return class->atom;
+}
+
+/* create a window class */
+DECL_HANDLER(create_class)
+{
+    struct window_class *class = find_class( current->process, req->atom, req->instance );
+
+    if (class && !class->local == !req->local)
+    {
+        set_win32_error( ERROR_CLASS_ALREADY_EXISTS );
+        return;
+    }
+    if (req->extra < 0 || req->extra > 4096)  /* don't allow stupid values here */
+    {
+        set_error( STATUS_INVALID_PARAMETER );
+        return;
+    }
+    if (!grab_global_atom( req->atom )) return;
+
+    if (!(class = create_class( current->process, req->extra, req->local )))
+    {
+        release_global_atom( req->atom );
+        return;
+    }
+    class->atom      = req->atom;
+    class->instance  = req->instance;
+    class->style     = req->style;
+    class->win_extra = req->win_extra;
+}
+
+/* destroy a window class */
+DECL_HANDLER(destroy_class)
+{
+    struct window_class *class = find_class( current->process, req->atom, req->instance );
+
+    if (!class)
+        set_error( STATUS_INVALID_HANDLE );
+    else if (class->count)
+        set_win32_error( ERROR_CLASS_HAS_WINDOWS );
+    else
+        destroy_class( class );
+}
+
+
+/* set some information in a class */
+DECL_HANDLER(set_class_info)
+{
+    struct window_class *class = get_window_class( req->window );
+
+    if (!class) return;
+
+    if (req->extra_size > sizeof(req->extra_value) ||
+        req->extra_offset < -1 ||
+        req->extra_offset > class->nb_extra_bytes - (int)req->extra_size)
+    {
+        set_win32_error( ERROR_INVALID_INDEX );
+        return;
+    }
+    if (req->extra_offset != -1)
+    {
+        memcpy( &reply->old_extra_value, class->extra_bytes + req->extra_offset, req->extra_size );
+    }
+    else if (req->flags & SET_CLASS_EXTRA)
+    {
+        set_win32_error( ERROR_INVALID_INDEX );
+        return;
+    }
+
+    reply->old_atom      = class->atom;
+    reply->old_style     = class->style;
+    reply->old_extra     = class->nb_extra_bytes;
+    reply->old_win_extra = class->win_extra;
+    reply->old_instance  = class->instance;
+
+    if (req->flags & SET_CLASS_ATOM)
+    {
+        if (!grab_global_atom( req->atom )) return;
+        release_global_atom( class->atom );
+        class->atom = req->atom;
+    }
+    if (req->flags & SET_CLASS_STYLE) class->style = req->style;
+    if (req->flags & SET_CLASS_WINEXTRA) class->win_extra = req->win_extra;
+    if (req->flags & SET_CLASS_INSTANCE) class->instance = req->instance;
+    if (req->flags & SET_CLASS_EXTRA) memcpy( class->extra_bytes + req->extra_offset,
+                                              &req->extra_value, req->extra_size );
+}
+