X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/clg/blobdiff_plain/0739b019015e56f8f9149d7a0e087b074651e58b..7af3f90b04993dbb4bf7c28ecbf3777d9d09b55e:/glib/glib.lisp

diff --git a/glib/glib.lisp b/glib/glib.lisp
index d5c6856..8bbda64 100644
--- a/glib/glib.lisp
+++ b/glib/glib.lisp
@@ -20,7 +20,7 @@
 ;; TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 ;; SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-;; $Id: glib.lisp,v 1.32 2006/02/06 18:12:19 espen Exp $
+;; $Id: glib.lisp,v 1.35 2006/02/19 22:34:28 espen Exp $
 
 
 (in-package "GLIB")
@@ -47,6 +47,23 @@ (defun copy-memory (from length &optional (to (allocate-memory length)))
   #+sbcl(system-area-ub8-copy from 0 to 0 length)
   to)
 
+(defun clear-memory (from length)
+  #+cmu(system-area-fill 0 0 from 0 (* 8 length))
+  #+sbcl(system-area-ub8-fill 0 from 0 length))
+
+(defmacro with-allocated-memory ((var size) &body body)
+  (if (constantp size)
+      (let ((alien (make-symbol "ALIEN"))
+	    (size (eval size)))
+	`(with-alien ((,alien (array #+sbcl(sb-alien:unsigned 8) #+cmu(alien:unsigned 8) ,size)))
+	   (let ((,var (alien-sap ,alien)))
+	     (clear-memory ,var ,size)
+	     ,@body)))
+    `(let ((,var (allocate-memory ,size)))
+       (unwind-protect
+	   (progn ,@body)
+	 (deallocate-memory ,var)))))
+
 
 ;;;; User data mechanism