Add a null driver that does absolutely nothing.

caca/Makefile.am

@@ -62,6 +62,7 @@ codec_source = \
 driver_source = \
 	driver/conio.c \
 	driver/ncurses.c \
+	driver/null.c \
 	driver/raw.c \
 	driver/slang.c \
 	driver/vga.c \

caca/caca.c

@@ -178,6 +178,7 @@ char const * const * caca_get_display_driver_list(void)
 #endif
 #if !defined(__KERNEL__)
         "raw", "raw libcaca output",
+        "null", "null driver",
 #endif
         NULL, NULL
     };
@@ -388,6 +389,9 @@ static int caca_select_driver(caca_display_t *dp, char const *driver)
 #endif
 #if defined(USE_VGA)
         if(!strcasecmp(var, "vga")) return vga_install(dp);
+#endif
+#if !defined(__KERNEL__)
+        if(!strcasecmp(var, "null")) return null_install(dp);
 #endif
         return -1;
     }
@@ -419,6 +423,8 @@ static int caca_select_driver(caca_display_t *dp, char const *driver)
 #if defined(USE_SLANG)
     if(slang_install(dp) == 0) return 0;
 #endif
+    /* Of course we don't try "raw" or "null" if the user did not
+     * specifically ask for them. */
 
     return -1;
 }

caca/caca_internals.h

@@ -1,6 +1,6 @@
 /*
  *  libcaca       Colour ASCII-Art library
- *  Copyright (c) 2002-2006 Sam Hocevar <sam@zoy.org>
+ *  Copyright (c) 2002-2006 Sam Hocevar <sam@hocevar.net>
  *                All Rights Reserved
  *
  *  $Id$
@@ -80,7 +80,7 @@ struct caca_canvas
 /* Graphics driver */
 enum caca_driver
 {
-    CACA_DRIVER_NONE = 0,
+    CACA_DRIVER_NULL = 0,
     CACA_DRIVER_RAW = 1,
 #if defined(USE_COCOA)
     CACA_DRIVER_COCOA = 2,
@@ -121,6 +121,7 @@ int gl_install(caca_display_t *);
 #if defined(USE_NCURSES)
 int ncurses_install(caca_display_t *);
 #endif
+int null_install(caca_display_t *);
 int raw_install(caca_display_t *);
 #if defined(USE_SLANG)
 int slang_install(caca_display_t *);

caca/driver/null.c

@@ -0,0 +1,90 @@
+/*
+ *  libcaca       Colour ASCII-Art library
+ *  Copyright (c) 2002-2009 Sam Hocevar <sam@hocevar.net>
+ *                All Rights Reserved
+ *
+ *  $Id$
+ *
+ *  This library is free software. It comes without any warranty, to
+ *  the extent permitted by applicable law. You can redistribute it
+ *  and/or modify it under the terms of the Do What The Fuck You Want
+ *  To Public License, Version 2, as published by Sam Hocevar. See
+ *  http://sam.zoy.org/wtfpl/COPYING for more details.
+ */
+
+/*
+ *  This file contains a null libcaca input and output driver
+ */
+
+#include "config.h"
+
+#if !defined(__KERNEL__)
+
+#include "caca.h"
+#include "caca_internals.h"
+
+static int null_init_graphics(caca_display_t *dp)
+{
+    return 0;
+}
+
+static int null_end_graphics(caca_display_t *dp)
+{
+    return 0;
+}
+
+static int null_set_display_title(caca_display_t *dp, char const *title)
+{
+    return -1;
+}
+
+static int null_get_display_width(caca_display_t const *dp)
+{
+    return 0;
+}
+
+static int null_get_display_height(caca_display_t const *dp)
+{
+    return 0;
+}
+
+static void null_display(caca_display_t *dp)
+{
+    ;
+}
+
+static void null_handle_resize(caca_display_t *dp)
+{
+    ;
+}
+
+static int null_get_event(caca_display_t *dp, caca_privevent_t *ev)
+{
+    ev->type = CACA_EVENT_NONE;
+    return 0;
+}
+
+/*
+ * Driver initialisation
+ */
+
+int null_install(caca_display_t *dp)
+{
+    dp->drv.id = CACA_DRIVER_NULL;
+    dp->drv.driver = "null";
+
+    dp->drv.init_graphics = null_init_graphics;
+    dp->drv.end_graphics = null_end_graphics;
+    dp->drv.set_display_title = null_set_display_title;
+    dp->drv.get_display_width = null_get_display_width;
+    dp->drv.get_display_height = null_get_display_height;
+    dp->drv.display = null_display;
+    dp->drv.handle_resize = null_handle_resize;
+    dp->drv.get_event = null_get_event;
+    dp->drv.set_mouse = NULL;
+    dp->drv.set_cursor = NULL;
+
+    return 0;
+}
+
+#endif /* !__KERNEL__ */