Register integer as alias for foreign type int.

[clg] / glib / glib.lisp

diff --git a/glib/glib.lisp b/glib/glib.lisp
index 5a5fcb09de3eb1524570c2a3424cc9fcb4b35955..8eccedb96b473e75c29916be5680617b79f3a502 100644 (file)
--- a/glib/glib.lisp
+++ b/glib/glib.lisp
@@ -15,185 +15,578 @@
 ;; License along with this library; if not, write to the Free Software
 ;; Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
 ;; License along with this library; if not, write to the Free Software
 ;; Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 

-;; $Id: glib.lisp,v 1.6 2000-09-04 22:10:26 espen Exp $
+;; $Id: glib.lisp,v 1.27 2005-02-14 00:44:26 espen Exp $

 
 
 (in-package "GLIB")
 
 
 (in-package "GLIB")

+

 (use-prefix "g")
 
 
 ;;;; Memory management
 
 (use-prefix "g")
 
 
 ;;;; Memory management
 

-(define-foreign ("g_malloc0" allocate-memory) () pointer
+(defbinding (allocate-memory "g_malloc0") () pointer

   (size unsigned-long))
 
   (size unsigned-long))
 

-(define-foreign ("g_realloc" reallocate-memory) () pointer
+(defbinding (reallocate-memory "g_realloc") () pointer

   (address pointer)
   (size unsigned-long))
 
   (address pointer)
   (size unsigned-long))
 

-(define-foreign ("g_free" deallocate-memory) () nil
+(defbinding (deallocate-memory "g_free") () nil

   (address pointer))
   (address pointer))

+;; (defun deallocate-memory (address)
+;;   (declare (ignore address)))

 
 (defun copy-memory (from length &optional (to (allocate-memory length)))
 
 (defun copy-memory (from length &optional (to (allocate-memory length)))

-  (kernel:system-area-copy from 0 to 0 (* 8 length))
+  (;#+cmu kernel:system-area-copy 
+   ;#+sbcl sb-impl::system-area-copy 
+   system-area-copy from 0 to 0 (* 8 length))

   to)
 
 
   to)
 
 

+;;;; User data mechanism

 
 

-;;;; Quarks
+(internal *user-data* *user-data-count*)

 
 

-(deftype quark () 'unsigned)
+(defvar *user-data* (make-hash-table))
+(defvar *user-data-count* 0)

 
 

-;(define-foreign %quark-get-reserved () quark)
+(defun register-user-data (object &optional destroy-function)
+  (check-type destroy-function (or null symbol function))
+  (incf *user-data-count*)
+  (setf
+   (gethash *user-data-count* *user-data*)
+   (cons object destroy-function))
+  *user-data-count*)

 
 

-(define-foreign %quark-from-string () quark
-  (string string))
+(defun find-user-data (id)
+  (check-type id fixnum)
+  (multiple-value-bind (user-data p) (gethash id *user-data*)
+    (values (car user-data) p)))

 
 

-(defvar *string-counter* 0)
-
-(defun %quark-get-reserved ()
-  (%quark-from-string (format nil "CLG-~D" (incf *string-counter*))))
-
-(defvar *quark-from-object* (make-hash-table))
-(defvar *quark-to-object* (make-hash-table))
-
-(defun quark-from-object (object &key (test #'eq))
-  (let ((hash-code (sxhash object)))
-    (or
-     (assoc-ref object (gethash hash-code *quark-from-object*) :test test)
-     (let ((quark (%quark-get-reserved)))
-       (setf
-       (gethash hash-code *quark-from-object*)
-       (append
-        (gethash hash-code *quark-from-object*)
-        (list (cons object quark))))
-       (setf (gethash quark *quark-to-object*) object)
-       quark))))
-
-(defun quark-to-object (quark) 
-  (gethash quark *quark-to-object*))
-  
-(defun remove-quark (quark)
-  (let* ((object (gethash quark *quark-to-object*))
-        (hash-code (sxhash object)))
-    (remhash quark *quark-to-object*)
-    (unless (setf
-            (gethash hash-code *quark-from-object*)
-            (assoc-delete object (gethash hash-code *quark-from-object*)))
-      (remhash hash-code *quark-from-object*))))
+(defun user-data-exists-p (id)
+  (nth-value 1 (find-user-data id)))

 
 

+(defun update-user-data (id object)
+  (check-type id fixnum)
+  (multiple-value-bind (user-data exists-p) (gethash id *user-data*)
+    (cond
+     ((not exists-p) (error "User data id ~A does not exist" id))
+     (t 
+      (when (cdr user-data)
+       (funcall (cdr user-data) (car user-data)))
+      (setf (car user-data) object)))))

 
 

+(defun destroy-user-data (id)
+  (check-type id fixnum)
+  (let ((user-data (gethash id *user-data*)))
+    (when (cdr user-data)
+      (funcall (cdr user-data) (car user-data))))
+  (remhash id *user-data*))

 
 

-;;;; Linked list

 
 

-(deftype glist () 'pointer)
-(deftype double-list (type) `(or (null (cons ,type list))))
+;;;; Quarks

 
 

+(deftype quark () 'unsigned)

 
 

-(define-foreign ("g_list_append" %glist-append) () glist
-  (glist glist)
-  (data unsigned))
+(defbinding %quark-from-string () quark
+  (string string))

 
 

-(defmacro glist-append (glist value type-spec)
-  (ecase (first (mklist (translate-type-spec type-spec)))
-    (unsigned `(%glist-append ,glist ,value))
-;    (signed `(%glist-append ,glist (signed-to-unsigned ,value)))
-    (system-area-pointer `(%glist-append ,glist (system:sap-int ,value)))))
+(defun quark-intern (object)
+  (etypecase object
+    (quark object)
+    (string (%quark-from-string object))
+    (symbol (%quark-from-string (format nil "clg-~A:~A" 
+                                (package-name (symbol-package object)) 
+                                object)))))

 
 

+(defbinding quark-to-string () (copy-of string)
+  (quark quark))

 
 

-(defmacro glist-data (glist type-spec)
-  (ecase (first (mklist (translate-type-spec type-spec)))
-    (unsigned `(sap-ref-unsigned ,glist 0))
-    (signed `(sap-ref-signed ,glist 0))
-    (system-area-pointer `(sap-ref-sap ,glist 0))))

 
 

+;;;; Linked list (GList)
+
+(deftype glist (type) 
+  `(or (null (cons ,type list))))
+
+(defbinding (%glist-append "g_list_append") () pointer
+  (glist pointer)
+  (nil null))
+
+(defun make-glist (type list)
+  (loop
+   with writer = (writer-function type)
+   for element in list
+   as glist = (%glist-append (or glist (make-pointer 0)))
+   do (funcall writer element glist)
+   finally (return glist)))

 
 (defun glist-next (glist)
   (unless (null-pointer-p glist)
 
 (defun glist-next (glist)
   (unless (null-pointer-p glist)

-    (sap-ref-sap glist +size-of-sap+)))
- 
+    (sap-ref-sap glist +size-of-pointer+)))

   
   

-(define-foreign ("g_list_free" glist-free) () nil
+;; Also used for gslists
+(defun map-glist (seqtype function glist element-type)
+  (let ((reader (reader-function element-type)))
+    (case seqtype 
+     ((nil)
+      (loop
+       as tmp = glist then (glist-next tmp)
+       until (null-pointer-p tmp)
+       do (funcall function (funcall reader tmp))))
+     (list
+      (loop
+       as tmp = glist then (glist-next tmp)
+       until (null-pointer-p tmp)
+       collect (funcall function (funcall reader tmp))))
+     (t
+      (coerce 
+       (loop
+       as tmp = glist then (glist-next tmp)
+       until (null-pointer-p tmp)
+       collect (funcall function (funcall reader tmp)))
+       seqtype)))))
+
+(defbinding (glist-free "g_list_free") () nil

   (glist pointer))
 
   (glist pointer))
 

+(defun destroy-glist (glist element-type)
+  (loop
+   with destroy = (destroy-function element-type)
+   as tmp = glist then (glist-next tmp)
+   until (null-pointer-p tmp)
+   do (funcall destroy tmp 0))
+  (glist-free glist))

 
 

-(deftype-method translate-type-spec double-list (type-spec)
-  (declare (ignore type-spec))
-  (translate-type-spec 'pointer))
+(defmethod alien-type ((type (eql 'glist)) &rest args)
+  (declare (ignore type args))
+  (alien-type 'pointer))

 
 

-(deftype-method size-of double-list (type-spec)
-  (declare (ignore type-spec))
+(defmethod size-of ((type (eql 'glist)) &rest args)
+  (declare (ignore type args))

   (size-of 'pointer))
 
   (size-of 'pointer))
 

-(deftype-method translate-to-alien double-list (type-spec list &optional copy)
-  (declare (ignore copy))
-  (let* ((element-type-spec (second (type-expand-to 'double-list type-spec)))
-        (to-alien (translate-to-alien element-type-spec 'element t)))
-    `(let ((glist (make-pointer 0))) 
-       (dolist (element ,list glist)
-        (setq glist (glist-append glist ,to-alien ,element-type-spec))))))
-
-(deftype-method
-    translate-from-alien
-    double-list (type-spec glist &optional (alloc :reference))
-  (let ((element-type-spec (second (type-expand-to 'double-list type-spec))))
-    `(let ((glist ,glist)
-          (list nil))
-       (do ((tmp glist (glist-next tmp)))
-          ((null-pointer-p tmp))
-        (push
-         ,(translate-from-alien
-           element-type-spec `(glist-data tmp ,element-type-spec) alloc)
-         list))
-       ,(when (eq alloc :reference)
-         '(glist-free glist))
-       (nreverse list))))
-
-(deftype-method cleanup-alien double-list (type-spec glist &optional copied)
-  (declare (ignore copied))
-  (let* ((element-type-spec (second (type-expand-to 'double-list type-spec)))
-        (alien-type-spec (translate-type-spec element-type-spec)))
+(defmethod to-alien-form (list (type (eql 'glist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args    
+    `(make-glist ',element-type ,list)))
+
+(defmethod to-alien-function ((type (eql 'glist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args    
+    #'(lambda (list)
+       (make-glist element-type list))))
+
+(defmethod from-alien-form (glist (type (eql 'glist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args

     `(let ((glist ,glist))
     `(let ((glist ,glist))

-       (unless (null-pointer-p glist)
-        ,(when (eq alien-type-spec 'system-area-pointer)
-           `(do ((tmp glist (glist-next tmp)))
-                ((null-pointer-p tmp))
-              ,(cleanup-alien
-                element-type-spec `(glist-data tmp ,element-type-spec) t)))
-        (glist-free glist)))))
+      (unwind-protect
+          (map-glist 'list #'identity glist ',element-type)
+       (destroy-glist glist ',element-type)))))
+
+(defmethod from-alien-function ((type (eql 'glist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    #'(lambda (glist)
+       (unwind-protect
+            (map-glist 'list #'identity glist element-type)
+         (destroy-glist glist element-type)))))
+
+(defmethod copy-from-alien-form (glist (type (eql 'glist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    `(map-glist 'list #'identity ,glist ',element-type)))
+
+(defmethod copy-from-alien-function ((type (eql 'glist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    #'(lambda (glist)
+       (map-glist 'list #'identity glist element-type))))
+
+(defmethod cleanup-form (glist (type (eql 'glist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    `(destroy-glist ,glist ',element-type)))
+
+(defmethod cleanup-function ((type (eql 'glist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    #'(lambda (glist)
+       (destroy-glist glist element-type))))
+
+(defmethod writer-function ((type (eql 'glist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    #'(lambda (list location &optional (offset 0))
+       (setf 
+        (sap-ref-sap location offset)
+        (make-glist element-type list)))))
+
+(defmethod reader-function ((type (eql 'glist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    #'(lambda (location &optional (offset 0))
+       (unless (null-pointer-p (sap-ref-sap location offset))
+         (map-glist 'list #'identity (sap-ref-sap location offset) element-type)))))
+
+(defmethod destroy-function ((type (eql 'glist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    #'(lambda (location &optional (offset 0))
+       (unless (null-pointer-p (sap-ref-sap location offset))
+         (destroy-glist (sap-ref-sap location offset) element-type)
+         (setf (sap-ref-sap location offset) (make-pointer 0))))))
+
+
+
+;;;; Single linked list (GSList)
+
+(deftype gslist (type) `(or (null (cons ,type list))))
+
+(defbinding (%gslist-prepend "g_slist_prepend") () pointer
+  (gslist pointer)
+  (nil null))
+
+(defun make-gslist (type list)
+  (loop
+   with writer = (writer-function type)
+   for element in (reverse list)
+   as gslist = (%gslist-prepend (or gslist (make-pointer 0)))
+   do (funcall writer element gslist)
+   finally (return gslist)))
+
+(defbinding (gslist-free "g_slist_free") () nil
+  (gslist pointer))
+
+(defun destroy-gslist (gslist element-type)
+  (loop
+   with destroy = (destroy-function element-type)
+   as tmp = gslist then (glist-next tmp)
+   until (null-pointer-p tmp)
+   do (funcall destroy tmp 0))
+  (gslist-free gslist))
+
+(defmethod alien-type ((type (eql 'gslist)) &rest args)
+  (declare (ignore type args))
+  (alien-type 'pointer))
+
+(defmethod size-of ((type (eql 'gslist)) &rest args)
+  (declare (ignore type args))
+  (size-of 'pointer))

 
 

+(defmethod to-alien-form (list (type (eql 'gslist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args    
+    `(make-sglist ',element-type ,list)))
+
+(defmethod to-alien-function ((type (eql 'gslist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args    
+    #'(lambda (list)
+       (make-gslist element-type list))))
+
+(defmethod from-alien-form (gslist (type (eql 'gslist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    `(let ((gslist ,gslist))
+      (unwind-protect
+          (map-glist 'list #'identity gslist ',element-type)
+       (destroy-gslist gslist ',element-type)))))
+
+(defmethod from-alien-function ((type (eql 'gslist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    #'(lambda (gslist)
+       (unwind-protect
+            (map-glist 'list #'identity gslist element-type)
+         (destroy-gslist gslist element-type)))))
+
+(defmethod copy-from-alien-form (gslist (type (eql 'gslist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    `(map-glist 'list #'identity ,gslist ',element-type)))
+
+(defmethod copy-from-alien-function ((type (eql 'gslist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    #'(lambda (gslist)
+       (map-glist 'list #'identity gslist element-type))))
+
+(defmethod cleanup-form (gslist (type (eql 'gslist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    `(destroy-gslist ,gslist ',element-type)))
+
+(defmethod cleanup-function ((type (eql 'gslist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    #'(lambda (gslist)
+       (destroy-gslist gslist element-type))))
+
+(defmethod writer-function ((type (eql 'gslist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    #'(lambda (list location &optional (offset 0))
+       (setf 
+        (sap-ref-sap location offset)
+        (make-gslist element-type list)))))
+
+(defmethod reader-function ((type (eql 'gslist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    #'(lambda (location &optional (offset 0))
+       (unless (null-pointer-p (sap-ref-sap location offset))
+         (map-glist 'list #'identity (sap-ref-sap location offset) element-type)))))
+
+(defmethod destroy-function ((type (eql 'gslist)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    #'(lambda (location &optional (offset 0))
+       (unless (null-pointer-p (sap-ref-sap location offset))
+         (destroy-gslist (sap-ref-sap location offset) element-type)
+         (setf (sap-ref-sap location offset) (make-pointer 0))))))

 
 
 ;;; Vector
 
 
 
 ;;; Vector
 

-(deftype-method translate-type-spec vector (type-spec)
-  (declare (ignore type-spec))
-  (translate-type-spec 'pointer))
-
-(deftype-method size-of vector (type-spec)
-  (declare (ignore type-spec))
+(defun make-c-vector (type length &optional content location)
+  (let* ((size-of-type (size-of type))
+        (location (or location (allocate-memory (* size-of-type length))))
+        (writer (writer-function type)))
+    (etypecase content
+      (vector
+       (loop
+       for element across content
+       for i from 0 below length
+       as offset = 0 then (+ offset size-of-type)
+       do (funcall writer element location offset)))
+      (list
+       (loop
+       for element in content
+       for i from 0 below length
+       as offset = 0 then (+ offset size-of-type)
+       do (funcall writer element location offset))))
+    location))
+
+
+(defun map-c-vector (seqtype function location element-type length)
+  (let ((reader (reader-function element-type))
+       (size-of-element (size-of element-type)))
+    (case seqtype 
+     ((nil)
+      (loop
+       for i from 0 below length
+       as offset = 0 then (+ offset size-of-element)
+       do (funcall function (funcall reader location offset))))
+     (list
+      (loop
+       for i from 0 below length
+       as offset = 0 then (+ offset size-of-element)
+       collect (funcall function (funcall reader location offset))))
+     (t
+      (loop
+       with sequence = (make-sequence seqtype length)
+       for i from 0 below length
+       as offset = 0 then (+ offset size-of-element)
+       do (setf 
+          (elt sequence i)
+          (funcall function (funcall reader location offset)))
+       finally (return sequence))))))
+
+
+(defun destroy-c-vector (location element-type length)
+  (loop
+   with destroy = (destroy-function element-type)
+   with element-size = (size-of element-type)
+   for i from 0 below length
+   as offset = 0 then (+ offset element-size)
+   do (funcall destroy location offset))
+  (deallocate-memory location))
+
+
+(defmethod alien-type ((type (eql 'vector)) &rest args)
+  (declare (ignore type args))
+  (alien-type 'pointer))
+
+(defmethod size-of ((type (eql 'vector)) &rest args)
+  (declare (ignore type args))

   (size-of 'pointer))
 
   (size-of 'pointer))
 

-(deftype-method translate-to-alien vector (type-spec vector &optional copy)
-  (declare (ignore copy))
-  (destructuring-bind (element-type &optional (length '*))
-      (cdr (type-expand-to 'vector type-spec))
-    (let ((element-to-alien (translate-to-alien element-type 'element :copy))
-         (element-size (size-of element-type)))
-      `(let ((vector ,vector))
-        (let ((c-vector
-               (allocate-memory
-                ,(if (eq length '*)
-                     `(* ,element-size (length vector))
-                   (* element-size length)))))
-          (dotimes (i ,(if (eq length '*) '(length vector) length) c-vector)
-            (setf
-             (,(sap-ref-fname element-type) c-vector (* i ,element-size))
-             ,(translate-to-alien element-type '(svref vector i) :copy))))))))
-
-(deftype-method cleanup-alien vector (type-spec sap &optional copied)
-  (declare (ignore type-spec copied))
-  ;; The individual elements also have to be cleaned up to avoid memory leaks,
-  ;; but this is currently not possible because we can't always tell the
-  ;; length of the vector
-  `(deallocate-memory ,sap))
+(defmethod to-alien-form (vector (type (eql 'vector)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type &optional (length '*)) args
+    (if (eq length '*)
+       `(let* ((vector ,vector)
+               (location (sap+
+                          (allocate-memory (+ ,+size-of-int+ 
+                                              (* ,(size-of element-type) 
+                                                 (length vector))))
+                          ,+size-of-int+)))
+         (make-c-vector ',element-type (length vector) vector location)
+         (setf (sap-ref-32 location ,(- +size-of-int+)) (length vector))
+         location)       
+      `(make-c-vector ',element-type ,length ,vector))))
+
+(defmethod from-alien-form (c-vector (type (eql 'vector)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type &optional (length '*)) args
+    (if (eq length '*)
+       (error "Can't use vector of variable size as return type")
+      `(let ((c-vector ,c-vector))
+       (prog1
+           (map-c-vector 'vector #'identity c-vector ',element-type ,length)
+         (destroy-c-vector c-vector ',element-type ,length))))))
+
+(defmethod copy-from-alien-form (c-vector (type (eql 'vector)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type &optional (length '*)) args
+    (if (eq length '*)
+       (error "Can't use vector of variable size as return type")
+      `(map-c-vector 'vector #'identity ,c-vector ',element-type ',length))))
+
+(defmethod cleanup-form (location (type (eql 'vector)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type &optional (length '*)) args
+    `(let* ((location ,location)
+           (length ,(if (eq length '*)
+                        `(sap-ref-32 location ,(- +size-of-int+))
+                        length)))
+      (loop
+       with destroy = (destroy-function ',element-type)
+       for i from 0 below length
+       as offset = 0 then (+ offset ,(size-of element-type))
+       do (funcall destroy location offset))
+      (deallocate-memory ,(if (eq length '*) 
+                             `(sap+ location  ,(- +size-of-int+))
+                           'location)))))
+
+(defmethod writer-function ((type (eql 'vector)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type &optional (length '*)) args
+    #'(lambda (vector location &optional (offset 0))
+       (setf 
+        (sap-ref-sap location offset)
+        (make-c-vector element-type length vector)))))
+
+(defmethod reader-function ((type (eql 'vector)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type &optional (length '*)) args
+    (if (eq length '*)
+       (error "Can't create reader function for vector of variable size")
+      #'(lambda (location &optional (offset 0))
+         (unless (null-pointer-p (sap-ref-sap location offset))
+           (map-c-vector 'vector #'identity (sap-ref-sap location offset) 
+            element-type length))))))
+
+(defmethod destroy-function ((type (eql 'vector)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type &optional (length '*)) args
+    (if (eq length '*)
+       (error "Can't create destroy function for vector of variable size")
+      #'(lambda (location &optional (offset 0))
+         (unless (null-pointer-p (sap-ref-sap location offset))
+           (destroy-c-vector 
+            (sap-ref-sap location offset) element-type length)
+           (setf (sap-ref-sap location offset) (make-pointer 0)))))))
+
+
+;;;; Null terminated vector
+
+(defun make-0-vector (type content &optional location)
+  (let* ((size-of-type (size-of type))
+        (location (or 
+                   location 
+                   (allocate-memory (* size-of-type (1+ (length content))))))
+        (writer (writer-function type)))
+    (etypecase content
+      (vector
+       (loop
+       for element across content
+       as offset = 0 then (+ offset size-of-type)
+       do (funcall writer element location offset)
+       finally (setf (sap-ref-sap location offset) (make-pointer 0))))
+      (list
+       (loop
+       for element in content
+       as offset = 0 then (+ offset size-of-type)
+       do (funcall writer element location offset)
+       finally (setf (sap-ref-sap location (+ offset size-of-type)) (make-pointer 0)))))
+    location))
+
+
+(defun map-0-vector (seqtype function location element-type)
+  (let ((reader (reader-function element-type))
+       (size-of-element (size-of element-type)))
+    (case seqtype 
+     ((nil)
+      (loop
+       as offset = 0 then (+ offset size-of-element)
+       until (null-pointer-p (sap-ref-sap location offset))
+       do (funcall function (funcall reader location offset))))
+     (list
+      (loop
+       as offset = 0 then (+ offset size-of-element)
+       until (null-pointer-p (sap-ref-sap location offset))
+       collect (funcall function (funcall reader location offset))))
+     (t
+      (coerce 
+       (loop
+       as offset = 0 then (+ offset size-of-element)
+       until (null-pointer-p (sap-ref-sap location offset))
+       collect (funcall function (funcall reader location offset)))
+       seqtype)))))
+
+
+(defun destroy-0-vector (location element-type)
+  (loop
+   with destroy = (destroy-function element-type)
+   with element-size = (size-of element-type)
+   as offset = 0 then (+ offset element-size)
+   until (null-pointer-p (sap-ref-sap location offset))
+   do (funcall destroy location offset))
+  (deallocate-memory location))
+
+
+(defmethod alien-type ((type (eql 'null-terminated-vector)) &rest args)
+  (declare (ignore type args))
+  (alien-type 'pointer))
+
+(defmethod size-of ((type (eql 'null-terminated-vector)) &rest args)
+  (declare (ignore type args))
+  (alien-type 'pointer))
+
+(defmethod writer-function ((type (eql 'null-terminated-vector)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    (unless (eq (alien-type element-type) (alien-type 'pointer))
+      (error "Elements in null-terminated vectors need to be of pointer types"))
+    #'(lambda (vector location &optional (offset 0))
+       (setf 
+        (sap-ref-sap location offset)
+        (make-0-vector element-type vector)))))
+
+(defmethod reader-function ((type (eql 'null-terminated-vector)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    (unless (eq (alien-type element-type) (alien-type 'pointer))
+      (error "Elements in null-terminated vectors need to be of pointer types"))
+    #'(lambda (location &optional (offset 0))
+       (unless (null-pointer-p (sap-ref-sap location offset))
+         (map-0-vector 'vector #'identity (sap-ref-sap location offset) 
+          element-type)))))
+
+(defmethod destroy-function ((type (eql 'null-terminated-vector)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (element-type) args
+    (unless (eq (alien-type element-type) (alien-type 'pointer))
+      (error "Elements in null-terminated vectors need to be of pointer types"))
+    #'(lambda (location &optional (offset 0))
+         (unless (null-pointer-p (sap-ref-sap location offset))
+           (destroy-0-vector 
+            (sap-ref-sap location offset) element-type)
+           (setf (sap-ref-sap location offset) (make-pointer 0))))))
+
+(defmethod unbound-value ((type (eql 'null-terminated-vector)) &rest args)
+  (declare (ignore type args))
+  (values t nil))