X-Git-Url: https://git.distorted.org.uk/~mdw/clg/blobdiff_plain/310da1d592f5c9d2f906e1c6defb9ef8747c7a11..1dc849d71672aa3b250e852965d3b13b65f4e0f4:/glib/ffi.lisp

diff --git a/glib/ffi.lisp b/glib/ffi.lisp
index 6fe93a5..7fe85ab 100644
--- a/glib/ffi.lisp
+++ b/glib/ffi.lisp
@@ -1,236 +1,29 @@
-;; Common Lisp bindings for GTK+ v2.0
-;; Copyright (C) 1999-2001 Espen S. Johnsen <esj@stud.cs.uit.no>
+;; Common Lisp bindings for GTK+ v2.x
+;; Copyright 1999-2005 Espen S. Johnsen <espen@users.sf.net>
 ;;
-;; 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 of the License, or (at your option) any later version.
+;; Permission is hereby granted, free of charge, to any person obtaining
+;; a copy of this software and associated documentation files (the
+;; "Software"), to deal in the Software without restriction, including
+;; without limitation the rights to use, copy, modify, merge, publish,
+;; distribute, sublicense, and/or sell copies of the Software, and to
+;; permit persons to whom the Software is furnished to do so, subject to
+;; the following conditions:
 ;;
-;; 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.
+;; The above copyright notice and this permission notice shall be
+;; included in all copies or substantial portions of the Software.
 ;;
-;; 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
+;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+;; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+;; MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+;; IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+;; CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+;; TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+;; SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-;; $Id: ffi.lisp,v 1.1 2004-10-27 14:46:01 espen Exp $
+;; $Id: ffi.lisp,v 1.30 2006-03-03 20:31:24 espen Exp $
 
 (in-package "GLIB")
 
-;;;; Type methods
-
-(defvar *type-methods* (make-hash-table))
-
-(defun ensure-type-method-fun (fname)
-  (unless (fboundp fname)
-    (setf
-     (symbol-function fname)
-     #'(lambda (type-spec &rest args)
-	 (apply
-	  (find-applicable-type-method type-spec fname) type-spec args)))))
-
-(defmacro define-type-method-fun (fname lambda-list)
-  (declare (ignore lambda-list))
-  `(defun ,fname (type-spec &rest args)
-     (apply
-      (find-applicable-type-method type-spec ',fname) type-spec args)))
-
-
-(defun ensure-type-name (type)
-  (etypecase type
-    (symbol type)
-    (pcl::class (class-name type))))
-
-(defun add-type-method (type fname function)
-  (push
-   (cons fname function)
-   (gethash (ensure-type-name type) *type-methods*)))
-
-(defun find-type-method (type fname)
-  (cdr (assoc fname (gethash (ensure-type-name type) *type-methods*))))
-
-(defun find-applicable-type-method (type-spec fname &optional (error t))
-  (flet ((find-superclass-method (class)
-	   (when (and class (class-finalized-p class))
-;  	     (unless (class-finalized-p class)
-;	       (finalize-inheritance class))
-	     (dolist (super (cdr (pcl::class-precedence-list class)))
-	       (return-if (find-type-method super fname)))))
-	 (find-expanded-type-method (type-spec)
-	   (multiple-value-bind (expanded-type-spec expanded-p)
-	       (type-expand-1 type-spec)
-	     (cond
-	      (expanded-p 
-	       (find-applicable-type-method expanded-type-spec fname nil))
-	      ((neq type-spec t)
-	       (find-applicable-type-method t fname nil))))))
-
-    (or
-     (typecase type-spec
-       (pcl::class
-	(or
-	 (find-type-method type-spec fname)
-	 (find-superclass-method type-spec)))
-       (symbol
-	(or
-	 (find-type-method type-spec fname)
-	 (find-expanded-type-method type-spec)
-	 (find-superclass-method (find-class type-spec nil))))
-       (cons
-	(or
-	 (find-type-method (first type-spec) fname)
-	 (find-expanded-type-method type-spec)))
-       (t
-	(error "Invalid type specifier ~A" type-spec)))
-     (and
-      error
-      (error
-       "No applicable method for ~A when called with type specifier ~A"
-       fname type-spec)))))
-
-(defmacro deftype-method (fname type lambda-list &body body)
-  `(progn
-     (ensure-type-method-fun ',fname)
-     (add-type-method ',type ',fname #'(lambda ,lambda-list ,@body))
-     ',fname))
-  
-;; To make the compiler happy
-(eval-when (:compile-toplevel :load-toplevel :execute)
-  (define-type-method-fun translate-type-spec (type-spec))
-  (define-type-method-fun size-of (type-spec))
-  (define-type-method-fun translate-to-alien (type-spec expr &optional weak-ref))
-  (define-type-method-fun translate-from-alien (type-spec expr &optional weak-ref))
-  (define-type-method-fun cleanup-alien (type-spec sap &otional weak-ref))
-  (define-type-method-fun unreference-alien (type-spec sap)))
-
-
-;;;; 
-
-(defvar *type-function-cache* (make-hash-table :test #'equal))
-
-(defun get-cached-function (type-spec fname)
-  (cdr (assoc fname (gethash type-spec *type-function-cache*))))
-
-(defun set-cached-function (type-spec fname function)
-  (push (cons fname function) (gethash type-spec *type-function-cache*))
-  function)
-  
-
-(defun intern-argument-translator (type-spec)
-  (or
-   (get-cached-function type-spec 'argument-translator)
-   (set-cached-function type-spec 'argument-translator
-    (compile
-     nil
-     `(lambda (object)
-	(declare (ignorable object))
-	,(translate-to-alien type-spec 'object t))))))
-
-(defun intern-return-value-translator (type-spec)
-  (or
-   (get-cached-function type-spec 'return-value-translator)
-   (set-cached-function type-spec 'return-value-translator
-    (compile
-     nil
-     `(lambda (alien)
-	(declare (ignorable alien))
-	,(translate-from-alien type-spec 'alien nil))))))
-
-(defun intern-cleanup-function (type-spec)
-  (or
-   (get-cached-function type-spec 'cleanup-function)
-   (set-cached-function type-spec 'cleanup-function
-    (compile
-     nil
-     `(lambda (alien)
-	(declare (ignorable alien))
-	,(cleanup-alien type-spec 'alien t))))))
-
-
-
-;; Returns a function to write an object of the specified type
-;; to a memory location
-(defun intern-writer-function (type-spec)
-  (or
-   (get-cached-function type-spec 'writer-function)
-   (set-cached-function type-spec 'writer-function
-    (compile
-     nil
-     `(lambda (value sap offset)
-	(declare (ignorable value sap offset))
-	(setf
-	 (,(sap-ref-fname type-spec) sap offset)
-	 ,(translate-to-alien type-spec 'value nil)))))))
-
-;; Returns a function to read an object of the specified type
-;; from a memory location
-(defun intern-reader-function (type-spec)
-  (or
-   (get-cached-function type-spec 'reader-function)
-   (set-cached-function type-spec 'reader-function
-    (compile
-     nil
-     `(lambda (sap offset)	 
-	(declare (ignorable sap offset))
-	,(translate-from-alien
-	  type-spec `(,(sap-ref-fname type-spec) sap offset) t))))))
-
-(defun intern-destroy-function (type-spec)
-  (if (atomic-type-p type-spec)
-      #'(lambda (sap offset)	 
-	  (declare (ignore sap offset)))
-    (or
-     (get-cached-function type-spec 'destroy-function)
-     (set-cached-function type-spec 'destroy-function
-       (compile
-	nil
-	`(lambda (sap offset)	 
-	   (declare (ignorable sap offset))
-	   ,(unreference-alien
-	     type-spec `(,(sap-ref-fname type-spec) sap offset))))))))
-
-
-
-;;;;
-
-(defconstant +bits-per-unit+ 8
-  "Number of bits in an addressable unit (byte)")
-
-;; Sizes of fundamental C types in addressable units
-(defconstant +size-of-short+ 2)
-(defconstant +size-of-int+ 4)
-(defconstant +size-of-long+ 4)
-(defconstant +size-of-sap+ 4)
-(defconstant +size-of-float+ 4)
-(defconstant +size-of-double+ 8)
-
-(defun sap-ref-unsigned (sap offset)
-  (sap-ref-32 sap offset))
-
-(defun sap-ref-signed (sap offset)
-  (signed-sap-ref-32 sap offset))
-
-(defun sap-ref-fname (type-spec)
-  (let ((alien-type-spec (mklist (translate-type-spec type-spec))))
-    (ecase (first alien-type-spec)
-      (unsigned
-       (ecase (second alien-type-spec)
-	 (8 'sap-ref-8)
-	 (16 'sap-ref-16)
-	 (32 'sap-ref-32)
-	 (64 'sap-ref-64)))
-      (signed
-       (ecase (second alien-type-spec)
-	 (8 'signed-sap-ref-8)
-	 (16 'signed-sap-ref-16)
-	 (32 'signed-sap-ref-32)
-	 (64 'signed-sap-ref-64)))
-      (system-area-pointer 'sap-ref-sap)
-      (single-float 'sap-ref-single)
-      (double-float 'sap-ref-double))))
-
 
 ;;;; Foreign function call interface
 
@@ -238,7 +31,7 @@
 
 (defun set-package-prefix (prefix &optional (package *package*))
   (let ((package (find-package package)))
-    (delete-if #'(lambda (assoc) (eq (car assoc) package)) *package-prefix*)
+    (setq *package-prefix* (delete package *package-prefix* :key #'car))
     (push (cons package prefix) *package-prefix*))
   prefix)
 
@@ -259,15 +52,22 @@
 
 
 (defun default-alien-fname (lisp-name)
-  (let* ((lisp-name-string
-	  (if (char= (char (the simple-string (string lisp-name)) 0) #\%)
-	      (subseq (the simple-string (string lisp-name)) 1)
-	    (string lisp-name)))
-	 (prefix (package-prefix *package*))
-	 (name (substitute #\_ #\- (string-downcase lisp-name-string))))
+  (let* ((name (substitute #\_ #\- (string-downcase lisp-name)))
+	 (stripped-name
+	  (cond
+	   ((and 
+	     (char= (char name 0) #\%)
+	     (string= "_p" name :start2 (- (length name) 2)))
+	    (subseq name 1 (- (length name) 2)))
+	   ((char= (char name 0) #\%)
+	    (subseq name 1))
+	   ((string= "_p" name :start2 (- (length name) 2))
+	    (subseq name 0 (- (length name) 2)))
+	   (name)))
+	 (prefix (package-prefix *package*)))
     (if (or (not prefix) (string= prefix ""))
-	name
-      (format nil "~A_~A" prefix name))))
+	stripped-name
+      (format nil "~A_~A" prefix stripped-name))))
 
 (defun default-alien-type-name (type-name)
   (let ((prefix (package-prefix *package*)))
@@ -288,7 +88,7 @@
       (rest parts) #\-) (find-prefix-package (first parts)))))
     
 	 
-(defmacro defbinding (name lambda-list return-type-spec &rest docs/args)
+(defmacro defbinding (name lambda-list return-type &rest docs/args)
   (multiple-value-bind (lisp-name c-name)
       (if (atom name)
  	  (values name (default-alien-fname name))
@@ -302,461 +102,974 @@
 	    (push doc/arg docs)
 	  (progn
 	    (destructuring-bind (expr type &optional (style :in)) doc/arg
-	      (unless (member style '(:in :out :in-out))
+	      (unless (member style '(:in :out :in-out :return))
 		(error "Bogus argument style ~S in ~S." style doc/arg))
 	      (when (and
 		     (not supplied-lambda-list)
-		     (namep expr) (member style '(:in :in-out)))
+		     (namep expr) (member style '(:in :in-out :return)))
 		(push expr lambda-list))
-	      (push
-	       (list (if (namep expr) (make-symbol (string expr)) (gensym)) expr type style) args)))))
+	      (push (list (cond 
+			   ((and (namep expr) (eq style :out)) expr)
+			   ((namep expr) (make-symbol (string expr)))
+			   ((gensym)))
+			  expr type style) args)))))
       
       (%defbinding
        c-name lisp-name (or supplied-lambda-list (nreverse lambda-list))
-       return-type-spec (reverse docs) (reverse args)))))
+       return-type (reverse docs) (reverse args)))))
 
-#+cmu
-(defun %defbinding (foreign-name lisp-name lambda-list
-		    return-type-spec docs args)
-  (ext:collect ((alien-types) (alien-bindings) (alien-parameters)
-		(alien-values) (alien-deallocators))
+#+(or cmu sbcl)
+(defun %defbinding (foreign-name lisp-name lambda-list return-type docs args)
+  (collect ((alien-types) (alien-bindings) (alien-parameters) 
+	    (return-values) (cleanup-forms))
     (dolist (arg args)
-      (destructuring-bind (var expr type-spec style) arg
-	(let ((declaration (translate-type-spec type-spec))
-	      (deallocation (cleanup-alien type-spec var t)))
+      (destructuring-bind (var expr type style) arg
+	(let ((declaration (alien-type type))
+	      (cleanup (cleanup-form type var)))
+
 	  (cond
-	   ((member style '(:out :in-out))
-	    (alien-types `(* ,declaration))
-	    (alien-parameters `(addr ,var))
-	    (alien-bindings
-	     `(,var ,declaration
-	       ,@(when (eq style :in-out)
-		   (list (translate-to-alien type-spec expr t)))))
-	    (alien-values (translate-from-alien type-spec var nil)))
-	  (deallocation
-	   (alien-types declaration)
-	   (alien-bindings
-	    `(,var ,declaration ,(translate-to-alien type-spec expr t)))
-	   (alien-parameters var)
-	   (alien-deallocators deallocation))
-	  (t
-	   (alien-types declaration)
-	   (alien-parameters (translate-to-alien type-spec expr t)))))))
+	    ((member style '(:out :in-out))
+	     (alien-types `(* ,declaration))
+	     (alien-parameters `(addr ,var))
+	     (alien-bindings
+	      `(,var ,declaration
+		,@(cond 
+		   ((eq style :in-out) (list (to-alien-form type expr)))
+		   ((eq declaration 'system-area-pointer) 
+		    (list '(make-pointer 0))))))
+	     (return-values (from-alien-form type var)))
+	    ((eq style :return)
+	     (alien-types declaration)
+	     (alien-bindings
+	      `(,var ,declaration ,(to-alien-form type expr)))
+	     (alien-parameters var)
+	     (return-values (from-alien-form type var)))
+	    (cleanup
+	     (alien-types declaration)
+	     (alien-bindings
+	      `(,var ,declaration ,(to-alien-form type expr)))
+	     (alien-parameters var)
+	     (cleanup-forms cleanup))
+	    (t
+	     (alien-types declaration)
+	     (alien-parameters (to-alien-form type expr)))))))
 
     (let* ((alien-name (make-symbol (string lisp-name)))
 	   (alien-funcall `(alien-funcall ,alien-name ,@(alien-parameters))))
       `(defun ,lisp-name ,lambda-list
 	 ,@docs
-	 (declare (optimize (ext:inhibit-warnings 3)))
+	 #+cmu(declare (optimize (inhibit-warnings 3)))
+	 #+sbcl(declare (muffle-conditions compiler-note))
 	 (with-alien ((,alien-name
 		       (function
-			,(translate-type-spec return-type-spec)
+			,(alien-type return-type)
 			,@(alien-types))
 		       :extern ,foreign-name)
 		      ,@(alien-bindings))
-	   ,(if return-type-spec
-		`(let ((result
-			,(translate-from-alien return-type-spec alien-funcall nil)))
-		   ,@(alien-deallocators)
-		   (values result ,@(alien-values)))
+	   ,(if return-type
+		`(values
+		  (unwind-protect 
+		      ,(from-alien-form return-type alien-funcall)
+		    ,@(cleanup-forms))
+		  ,@(return-values))
 	      `(progn
-		 ,alien-funcall
-		 ,@(alien-deallocators)
-		 (values ,@(alien-values)))))))))
+		(unwind-protect 
+		     ,alien-funcall
+		  ,@(cleanup-forms))
+		(values ,@(return-values)))))))))
 
 
+;;; Creates bindings at runtime
 (defun mkbinding (name return-type &rest arg-types)
-   (declare (optimize (ext:inhibit-warnings 3)))
-   (let* ((ftype
-	   `(function
-	     ,@(mapcar #'translate-type-spec (cons return-type arg-types))))
+  #+cmu(declare (optimize (inhibit-warnings 3)))
+  #+sbcl(declare (muffle-conditions compiler-note))
+  (let* ((ftype 
+	  `(function ,@(mapcar #'alien-type (cons return-type arg-types))))
 	 (alien
-	  (alien::%heap-alien
-	   (alien::make-heap-alien-info
-	    :type (alien::parse-alien-type ftype)
-	    :sap-form (system:foreign-symbol-address name :flavor :code))))
-	 (translate-arguments
-	  (mapcar #'intern-argument-translator arg-types))
-	 (translate-return-value (intern-return-value-translator return-type))
-	 (cleanup-arguments (mapcar #'intern-cleanup-function arg-types)))
-	 
+	  (%heap-alien
+	   (make-heap-alien-info
+	    :type (parse-alien-type ftype #+sbcl nil)
+	    :sap-form (let ((address (foreign-symbol-address name)))
+			(etypecase address
+			  (integer (int-sap address))
+			  (system-area-pointer address))))))
+	 (translate-arguments (mapcar #'to-alien-function arg-types))
+	 (translate-return-value (from-alien-function return-type))
+	 (cleanup-arguments (mapcar #'cleanup-function arg-types)))
+        
     #'(lambda (&rest args)
 	(map-into args #'funcall translate-arguments args)
 	(prog1
-	    (funcall
-	     translate-return-value (apply #'alien:alien-funcall alien args))
+	    (funcall translate-return-value 
+	     (apply #'alien-funcall alien args))
 	  (mapc #'funcall cleanup-arguments args)))))
 
 
-(defun type-translateable-p (type-spec)
-  (find-applicable-type-method type-spec 'translate-type-spec nil))
-
-(defun every-type-translateable-p (type-specs)
-  (every #'type-translateable-p type-specs))
-
-(defun mkbinding-late (name return-type &rest arg-types)
-  (if (every-type-translateable-p (cons return-type arg-types))
-      (apply #'mkbinding name return-type arg-types)
-    (let ((binding nil))
-      #'(lambda (&rest args)
-	  (cond
-	   (binding (apply binding args))
-	   ((every-type-translateable-p (cons return-type arg-types))
-	    (setq binding (apply #'mkbinding name return-type arg-types))
-	    (apply binding args))
-	   (t
-	    (dolist (type-spec (cons return-type arg-types))
-	      (unless (type-translateable-p type-spec)
-		(error "Can't translate type ~A" type-spec)))))))))
-
-  
-
-;;;; Definitons and translations of fundamental types
 
-(deftype long (&optional (min '*) (max '*)) `(integer ,min ,max))
-(deftype unsigned-long (&optional (min '*) (max '*)) `(integer ,min ,max))
-(deftype int (&optional (min '*) (max '*)) `(long ,min ,max))
-(deftype unsigned-int (&optional (min '*) (max '*)) `(unsigned-long ,min ,max))
-(deftype short (&optional (min '*) (max '*)) `(int ,min ,max))
-(deftype unsigned-short (&optional (min '*) (max '*)) `(unsigned-int ,min ,max))
+;;;; C callbacks
+
+(defmacro define-callback (name return-type args &body body)
+  (let ((define-callback 
+	  #+cmu'alien:def-callback 	              
+	  #+(and sbcl alien-callbacks)'sb-alien::define-alien-callback
+	  #+(and sbcl (not alien-callbacks))'sb-alien:define-alien-function))
+    (multiple-value-bind (doc declaration body)
+	(cond
+	 ((and (stringp (first body)) (eq (cadr body) 'declare))
+	  (values (first body) (second body) (cddr body)))
+	 ((stringp (first body))
+	  (values (first body) nil (rest body)))
+	 ((eq (caar body) 'declare)
+	  (values nil (first body) (rest body)))
+	 (t (values nil nil body)))
+      `(progn
+	 #+cmu(defparameter ,name nil)
+	 (,define-callback ,name 
+	   #+(and sbcl alien-callbacks),(alien-type return-type) 
+	   (#+(or cmu (and sbcl (not alien-callbacks))),(alien-type return-type)
+	   ,@(mapcar #'(lambda (arg)
+			 (destructuring-bind (name type) arg
+			   `(,name ,(alien-type type))))
+		     args))
+	   ,@(when doc (list doc))
+	   ,(to-alien-form return-type
+	     `(let (,@(loop
+		       for (name type) in args
+		       as from-alien-form = (callback-from-alien-form type name)
+		       collect `(,name ,from-alien-form)))
+		,@(when declaration (list declaration))
+		(unwind-protect
+		    (progn ,@body)
+		  ,@(loop 
+		     for (name type) in args
+		     do (callback-cleanup-form type name))))))))))
+
+(defun callback-address (callback)
+  #+cmu(alien::callback-trampoline callback)
+  #+(and sbcl (not alien-callbacks))(sb-alien:alien-function-sap callback)
+  #+(and sbcl alien-callbacks)(sb-alien:alien-sap callback))
+
+#+sbcl
+(deftype callback () 
+  #-alien-callbacks'sb-alien:alien-function
+  #+alien-callbacks'sb-alien:alien)
+
+
+;;; These are for backward compatibility
+
+(defmacro defcallback (name (return-type &rest args) &body body)
+  `(define-callback ,name ,return-type ,args ,@body))
+
+#-cmu
+(defun callback (callback)
+  (callback-address callback))
+
+
+
+;;;; The "type method" system
+
+(defun find-applicable-type-method (name type-spec &optional (error-p t))
+  (let ((type-methods (get name 'type-methods)))
+    (labels ((search-method-in-cpl-order (classes)
+	       (when classes
+		 (or 
+		  (gethash (class-name (first classes)) type-methods)
+		  (search-method-in-cpl-order (rest classes)))))
+	     (lookup-method (type-spec)
+	       (if (and (symbolp type-spec) (find-class type-spec nil))
+		   (search-method-in-cpl-order
+		    (class-precedence-list (find-class type-spec)))
+		 (or 
+		  (let ((specifier (etypecase type-spec
+				     (symbol type-spec)
+				     (list (first type-spec)))))
+		    (gethash specifier type-methods))
+		  (multiple-value-bind (expanded-type expanded-p) 
+		      (type-expand-1 type-spec)
+		    (when expanded-p
+		      (lookup-method expanded-type))))))
+	     (search-built-in-type-hierarchy (sub-tree)
+               (when (subtypep type-spec (first sub-tree))
+		 (or
+		  (search-nodes (cddr sub-tree))
+		  (second sub-tree))))
+	     (search-nodes (nodes)
+	       (loop
+		for node in nodes
+		as function = (search-built-in-type-hierarchy node)
+		until function
+		finally (return function))))
+    (or 
+     (lookup-method type-spec)
+     ;; This is to handle unexpandable types whichs doesn't name a class
+     (unless (and (symbolp type-spec) (find-class type-spec nil))
+       (search-nodes (get name 'built-in-type-hierarchy)))
+     (and 
+      error-p
+      (error "No applicable type method for ~A when call width type specifier ~A" name type-spec))))))
+
+
+(defun insert-type-in-hierarchy (specifier function nodes)
+  (cond
+   ((let ((node (find specifier nodes :key #'first)))
+      (when node
+	(setf (second node) function)
+	nodes)))
+   ((let ((node
+	   (find-if 
+	    #'(lambda (node)
+		(subtypep specifier (first node)))
+	    nodes)))
+      (when node
+	(setf (cddr node) 
+	 (insert-type-in-hierarchy specifier function (cddr node)))
+	nodes)))
+   ((let ((sub-nodes (remove-if-not 
+		      #'(lambda (node)
+			  (subtypep (first node) specifier))
+		      nodes)))
+      (cons
+       (list* specifier function sub-nodes)
+       (nset-difference nodes sub-nodes))))))
+
+
+(defun add-type-method (name specifier function)
+  (setf (gethash specifier (get name 'type-methods)) function)
+  (when (typep (find-class specifier nil) 'built-in-class)
+    (setf (get name 'built-in-type-hierarchy)
+     (insert-type-in-hierarchy specifier function 
+      (get name 'built-in-type-hierarchy)))))
+
+
+;; TODO: handle optional, key and rest arguments
+(defmacro define-type-generic (name lambda-list &optional documentation)
+  (if (or 
+       (not lambda-list) 
+       (find (first lambda-list) '(&optional &key &rest &allow-other-keys)))
+      (error "A type generic needs at least one required argument")
+    `(progn 
+       (unless (get ',name 'type-methods)
+	 (setf (get ',name 'type-methods) (make-hash-table))
+	 (setf (get ',name 'built-in-type-hierarchy) ()))
+       (defun ,name ,lambda-list
+	 ,documentation
+	 (funcall 
+	  (find-applicable-type-method ',name ,(first lambda-list))
+	  ,@lambda-list)))))
+
+
+(defmacro define-type-method (name lambda-list &body body)
+  (let ((specifier (cadar lambda-list))
+	(args (cons (caar lambda-list) (rest lambda-list))))
+    `(progn
+       (add-type-method ',name ',specifier #'(lambda ,args ,@body))
+       ',name)))
+
+
+
+;;;; Definitons and translations of fundamental types    
+
+(define-type-generic alien-type (type-spec))
+(define-type-generic size-of (type-spec))
+(define-type-generic to-alien-form (type-spec form))
+(define-type-generic from-alien-form (type-spec form))
+(define-type-generic cleanup-form (type-spec form)
+  "Creates a form to clean up after the alien call has finished.")
+(define-type-generic callback-from-alien-form (type-spec form))
+(define-type-generic callback-cleanup-form (type-spec form))
+
+(define-type-generic to-alien-function (type-spec))
+(define-type-generic from-alien-function (type-spec))
+(define-type-generic cleanup-function (type-spec))
+
+(define-type-generic copy-to-alien-form (type-spec form))
+(define-type-generic copy-to-alien-function (type-spec))
+(define-type-generic copy-from-alien-form (type-spec form))
+(define-type-generic copy-from-alien-function (type-spec))
+(define-type-generic writer-function (type-spec))
+(define-type-generic reader-function (type-spec))
+(define-type-generic destroy-function (type-spec))
+
+(define-type-generic unbound-value (type-spec)
+  "Returns a value which should be intepreted as unbound for slots with virtual allocation")
+
+
+#+sbcl
+(eval-when (:compile-toplevel :load-toplevel :execute)
+  (defun sb-sizeof-bits (type)
+    (sb-alien-internals:alien-type-bits
+     (sb-alien-internals:parse-alien-type type nil)))
+
+  (defun sb-sizeof (type)
+    (/ (sb-sizeof-bits type) 8)))
+
+
+;; Sizes of fundamental C types in bytes (8 bits)
+(defconstant +size-of-short+
+  #+sbcl (sb-sizeof 'sb-alien:short)
+  #-sbcl 2)
+(defconstant +size-of-int+
+  #+sbcl (sb-sizeof 'sb-alien:int)
+  #-sbcl 4)
+(defconstant +size-of-long+
+  #+sbcl (sb-sizeof 'sb-alien:long)
+  #-sbcl 4)
+(defconstant +size-of-pointer+
+  #+sbcl (sb-sizeof 'sb-alien:system-area-pointer)
+  #-sbcl 4)
+(defconstant +size-of-float+
+  #+sbcl (sb-sizeof 'sb-alien:float)
+  #-sbcl 4)
+(defconstant +size-of-double+
+  #+sbcl (sb-sizeof 'sb-alien:double)
+  #-sbcl 8)
+
+
+;; Sizes of fundamental C types in bits
+(defconstant +bits-of-byte+ 8)
+(defconstant +bits-of-short+
+  #+sbcl (sb-sizeof-bits 'sb-alien:short)
+  #-sbcl 16)
+(defconstant +bits-of-int+
+  #+sbcl (sb-sizeof-bits 'sb-alien:int)
+  #-sbcl 32)
+(defconstant +bits-of-long+
+  #+sbcl (sb-sizeof-bits 'sb-alien:long)
+  #-sbcl 32)
+
+
+(deftype int () '(signed-byte #.+bits-of-int+))
+(deftype unsigned-int () '(unsigned-byte #.+bits-of-int+))
+(deftype long () '(signed-byte #.+bits-of-long+))
+(deftype unsigned-long () '(unsigned-byte #.+bits-of-long+))
+(deftype short () '(signed-byte #.+bits-of-short+))
+(deftype unsigned-short () '(unsigned-byte #.+bits-of-short+))
 (deftype signed (&optional (size '*)) `(signed-byte ,size))
-(deftype unsigned (&optional (size '*)) `(signed-byte ,size))
+(deftype unsigned (&optional (size '*)) `(unsigned-byte ,size))
 (deftype char () 'base-char)
 (deftype pointer () 'system-area-pointer)
-(deftype boolean (&optional (size '*))
-  (declare (ignore size))
-  `(member t nil))
-(deftype invalid () nil)
+(deftype boolean (&optional (size '*)) (declare (ignore size)) t)
+(deftype copy-of (type) type)
 
-(defun atomic-type-p (type-spec)
-  (or
-   (eq type-spec 'pointer)
-   (not (eq (translate-type-spec type-spec) 'system-area-pointer))))
+(define-type-method alien-type ((type t))
+  (error "No alien type corresponding to the type specifier ~A" type))
 
+(define-type-method to-alien-form ((type t) form)
+  (declare (ignore form))
+  (error "Not a valid type specifier for arguments: ~A" type))
 
-(deftype-method cleanup-alien t (type-spec sap &optional weak-ref)
-  (declare (ignore type-spec sap weak-ref))
-  nil)
+(define-type-method to-alien-function ((type t))
+  (error "Not a valid type specifier for arguments: ~A" type))
 
+(define-type-method from-alien-form ((type t) form)
+  (declare (ignore form))
+  (error "Not a valid type specifier for return values: ~A" type))
 
-(deftype-method translate-to-alien integer (type-spec number &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  number)
+(define-type-method from-alien-function ((type t))
+  (error "Not a valid type specifier for return values: ~A" type))
+ 
+(define-type-method cleanup-form ((type t) form)
+  (declare (ignore form type))
+  nil)
 
-(deftype-method translate-from-alien integer (type-spec number &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  number)
+(define-type-method cleanup-function ((type t))
+  (declare (ignore type))
+  #'identity)
 
+(define-type-method callback-from-alien-form ((type t) form)
+  (copy-from-alien-form type form))
 
-(deftype-method translate-type-spec fixnum (type-spec)
-  (declare (ignore type-spec))
-  (translate-type-spec 'signed))
+(define-type-method callback-cleanup-form ((type t) form)
+  (declare (ignore form type))
+  nil)
 
-(deftype-method size-of fixnum (type-spec)
-  (declare (ignore type-spec))
-  (size-of 'signed))
+(define-type-method destroy-function ((type t))
+  (declare (ignore type))
+  #'(lambda (location &optional offset)
+      (declare (ignore location offset))))
 
-(deftype-method translate-to-alien fixnum (type-spec number &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  number)
+(define-type-method copy-to-alien-form ((type t) form)
+  (to-alien-form type form))
 
-(deftype-method translate-from-alien fixnum (type-spec number &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  number)
+(define-type-method copy-to-alien-function ((type t))
+  (to-alien-function type))
 
+(define-type-method copy-from-alien-form ((type t) form)
+  (from-alien-form type  form))
 
-(deftype-method translate-type-spec long (type-spec)
-  (declare (ignore type-spec))
-  `(signed ,(* +bits-per-unit+ +size-of-long+)))
+(define-type-method copy-from-alien-function ((type t))
+  (from-alien-function type))
 
-(deftype-method size-of long (type-spec)
-  (declare (ignore type-spec))
-  +size-of-long+)
 
+(define-type-method to-alien-form ((type real) form)
+  (declare (ignore type))
+  form)
 
-(deftype-method translate-type-spec unsigned-long (type-spec)
-  (declare (ignore type-spec))
-  `(unsigned ,(* +bits-per-unit+ +size-of-long+)))
+(define-type-method to-alien-function ((type real))
+  (declare (ignore type))
+  #'identity)
 
-(deftype-method size-of unsigned-long (type-spec)
-  (declare (ignore type-spec))
-  +size-of-long+)
+(define-type-method from-alien-form ((type real) form)
+  (declare (ignore type))
+  form)
 
+(define-type-method from-alien-function ((type real))
+  (declare (ignore type))
+  #'identity)
 
-(deftype-method translate-type-spec int (type-spec)
-  (declare (ignore type-spec))
-  `(signed ,(* +bits-per-unit+ +size-of-int+)))
 
-(deftype-method size-of int (type-spec)
-  (declare (ignore type-spec))
-  +size-of-int+)
+(define-type-method alien-type ((type integer))
+  (declare (ignore type))
+  (alien-type 'signed-byte))
 
+(define-type-method size-of ((type integer))
+  (declare (ignore type))
+  (size-of 'signed-byte))
 
-(deftype-method translate-type-spec unsigned-int (type-spec)
-  (declare (ignore type-spec))
-  `(unsigned ,(* +bits-per-unit+ +size-of-int+)))
+(define-type-method writer-function ((type integer))
+  (declare (ignore type))
+  (writer-function 'signed-byte))
 
-(deftype-method size-of unsigned-int (type-spec)
-  (declare (ignore type-spec))
-  +size-of-int+)
+(define-type-method reader-function ((type integer))
+  (declare (ignore type))
+  (reader-function 'signed-byte))
 
+  
+(define-type-method alien-type ((type signed-byte))
+  (destructuring-bind (&optional (size '*)) 
+      (rest (mklist (type-expand-to 'signed-byte type)))
+    (ecase size
+      (#.+bits-of-byte+ #+cmu'(alien:signed 8) #+sbcl'(sb-alien:signed 8))
+      (#.+bits-of-short+ #+cmu 'c-call:short #+sbcl 'sb-alien:short)
+      ((* #.+bits-of-int+) #+cmu 'c-call:int #+sbcl 'sb-alien:int)
+      (#.+bits-of-long+ #+cmu 'c-call:long #+sbcl 'sb-alien:long))))
+
+(define-type-method size-of ((type signed-byte))
+  (destructuring-bind (&optional (size '*))
+      (rest (mklist (type-expand-to 'signed-byte type)))
+    (ecase size
+      (#.+bits-of-byte+ 1)
+      (#.+bits-of-short+ +size-of-short+)
+      ((* #.+bits-of-int+) +size-of-int+)
+      (#.+bits-of-long+ +size-of-long+))))
+
+(define-type-method writer-function ((type signed-byte))
+  (destructuring-bind (&optional (size '*))
+      (rest (mklist (type-expand-to 'signed-byte type)))
+    (let ((size (if (eq size '*) +bits-of-int+ size)))
+      (ecase size
+	(8 #'(lambda (value location &optional (offset 0))
+	       (setf (signed-sap-ref-8 location offset) value)))
+	(16 #'(lambda (value location &optional (offset 0))
+		(setf (signed-sap-ref-16 location offset) value)))
+	(32 #'(lambda (value location &optional (offset 0))
+		(setf (signed-sap-ref-32 location offset) value)))
+	(64 #'(lambda (value location &optional (offset 0))
+		(setf (signed-sap-ref-64 location offset) value)))))))
+  
+(define-type-method reader-function ((type signed-byte))
+  (destructuring-bind (&optional (size '*))
+      (rest (mklist (type-expand-to 'signed-byte type)))
+    (let ((size (if (eq size '*) +bits-of-int+ size)))
+      (ecase size
+	(8 #'(lambda (sap &optional (offset 0) weak-p) 
+	       (declare (ignore weak-p))
+	       (signed-sap-ref-8 sap offset)))
+	(16 #'(lambda (sap &optional (offset 0) weak-p)
+		(declare (ignore weak-p))
+		(signed-sap-ref-16 sap offset)))
+	(32 #'(lambda (sap &optional (offset 0) weak-p) 
+		(declare (ignore weak-p)) 
+		(signed-sap-ref-32 sap offset)))
+	(64 #'(lambda (sap &optional (offset 0) weak-p) 
+		(declare (ignore weak-p))
+		(signed-sap-ref-64 sap offset)))))))
+
+
+(define-type-method alien-type ((type unsigned-byte))
+  (destructuring-bind (&optional (size '*))
+      (rest (mklist (type-expand-to 'unsigned-byte type)))
+    (ecase size
+      (#.+bits-of-byte+ #+cmu'(alien:unsigned 8) #+sbcl'(sb-alien:unsigned 8))
+      (#.+bits-of-short+ #+cmu 'c-call:unsigned-short 
+			 #+sbcl 'sb-alien:unsigned-short)
+      ((* #.+bits-of-int+) #+cmu 'c-call:unsigned-int 
+                           #+sbcl 'sb-alien:unsigned-int)
+      (#.+bits-of-long+ #+cmu 'c-call:unsigned-long 
+			#+sbcl 'sb-alien:unsigned-long))))
+
+
+(define-type-method size-of ((type unsigned-byte))
+  (destructuring-bind (&optional (size '*))
+      (rest (mklist (type-expand-to 'unsigned-byte type)))
+  (size-of `(signed ,size))))
+
+(define-type-method writer-function ((type unsigned-byte))
+  (destructuring-bind (&optional (size '*))
+      (rest (mklist (type-expand-to 'unsigned-byte type)))
+    (let ((size (if (eq size '*) +bits-of-int+ size)))
+      (ecase size
+	(8 #'(lambda (value location &optional (offset 0))
+	       (setf (sap-ref-8 location offset) value)))
+	(16 #'(lambda (value location &optional (offset 0))
+		(setf (sap-ref-16 location offset) value)))
+	(32 #'(lambda (value location &optional (offset 0))
+		(setf (sap-ref-32 location offset) value)))
+	(64 #'(lambda (value location &optional (offset 0))
+		(setf (sap-ref-64 location offset) value)))))))
+      
+(define-type-method reader-function ((type unsigned-byte))
+  (destructuring-bind (&optional (size '*))
+      (rest (mklist (type-expand-to 'unsigned-byte type)))
+    (let ((size (if (eq size '*) +bits-of-int+ size)))
+      (ecase size
+	(8 #'(lambda (sap &optional (offset 0) weak-p)
+	       (declare (ignore weak-p))
+	       (sap-ref-8 sap offset)))
+	(16 #'(lambda (sap &optional (offset 0) weak-p)
+		(declare (ignore weak-p)) 
+		(sap-ref-16 sap offset)))
+	(32 #'(lambda (sap &optional (offset 0) weak-p)
+		(declare (ignore weak-p)) 
+		(sap-ref-32 sap offset)))
+	(64 #'(lambda (sap &optional (offset 0) weak-p)
+		(declare (ignore weak-p))
+		(sap-ref-64 sap offset)))))))
+
+(define-type-method alien-type ((type single-float))
+  (declare (ignore type))
+  #+cmu 'alien:single-float #+sbcl 'sb-alien:single-float)
+
+(define-type-method size-of ((type single-float))
+  (declare (ignore type))
+  +size-of-float+)
 
-(deftype-method translate-type-spec short (type-spec)
-  (declare (ignore type-spec))
-  `(signed ,(* +bits-per-unit+ +size-of-short+)))
+(define-type-method to-alien-form ((type single-float) form)
+  (declare (ignore type))
+  `(coerce ,form 'single-float))
 
-(deftype-method size-of short (type-spec)
-  (declare (ignore type-spec))
-  +size-of-short+)
+(define-type-method to-alien-function ((type single-float))
+  (declare (ignore type))
+  #'(lambda (number)
+      (coerce number 'single-float)))
 
+(define-type-method writer-function ((type single-float))
+  (declare (ignore type))
+  #'(lambda (value location &optional (offset 0))
+      (setf (sap-ref-single location offset) (coerce value 'single-float))))
 
-(deftype-method translate-type-spec unsigned-short (type-spec)
-  (declare (ignore type-spec))
-  `(unsigned ,(* +bits-per-unit+ +size-of-short+)))
+(define-type-method reader-function ((type single-float))
+  (declare (ignore type))
+  #'(lambda (sap &optional (offset 0) weak-p)
+      (declare (ignore weak-p))
+      (sap-ref-single sap offset)))
 
-(deftype-method size-of unsigned-short (type-spec)
-  (declare (ignore type-spec))
-  +size-of-short+)
 
+(define-type-method alien-type ((type double-float))
+  (declare (ignore type))
+  #+cmu 'alien:double-float #+sbcl 'sb-alien:double-float)
 
-(deftype-method translate-type-spec signed-byte (type-spec)
-  (let ((size (second (mklist (type-expand-to 'signed-byte type-spec)))))
-    `(signed
-      ,(cond
-	((member size '(nil *)) (* +bits-per-unit+ +size-of-int+))
-	(t size)))))
+(define-type-method size-of ((type double-float))
+  (declare (ignore type))
+  +size-of-double+)
 
-(deftype-method size-of signed-byte (type-spec)
-  (let ((size (second (mklist (type-expand-to 'signed-byte type-spec)))))
-    (cond
-     ((member size '(nil *)) +size-of-int+)
-     (t (/ size +bits-per-unit+)))))
+(define-type-method to-alien-form ((type double-float) form)
+  (declare (ignore type))
+  `(coerce ,form 'double-float))
 
-(deftype-method translate-to-alien signed-byte (type-spec number &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  number)
+(define-type-method to-alien-function ((type double-float))
+  (declare (ignore type))
+  #'(lambda (number)
+      (coerce number 'double-float)))
 
-(deftype-method translate-from-alien signed-byte
-    (type-spec number &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  number)
+(define-type-method writer-function ((type double-float))
+  (declare (ignore type))
+  #'(lambda (value location &optional (offset 0))
+      (setf (sap-ref-double location offset) (coerce value 'double-float))))
 
+(define-type-method reader-function ((type double-float))
+  (declare (ignore type))
+  #'(lambda (sap &optional (offset 0) weak-p)
+      (declare (ignore weak-p))
+      (sap-ref-double sap offset)))
 
-(deftype-method translate-type-spec unsigned-byte (type-spec)
-  (let ((size (second (mklist (type-expand-to 'unsigned-byte type-spec)))))
-    `(signed
-      ,(cond
-	((member size '(nil *)) (* +bits-per-unit+ +size-of-int+))
-	(t size)))))
 
-(deftype-method size-of unsigned-byte (type-spec)
-  (let ((size (second (mklist (type-expand-to 'unsigned-byte type-spec)))))
-    (cond
-     ((member size '(nil *)) +size-of-int+)
-     (t (/ size +bits-per-unit+)))))
+(define-type-method alien-type ((type base-char))
+  (declare (ignore type))
+  #+cmu 'c-call:char #+sbcl 'sb-alien:char)
 
-(deftype-method translate-to-alien unsigned-byte (type-spec number &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  number)
+(define-type-method size-of ((type base-char))
+  (declare (ignore type))
+  1)
 
-(deftype-method translate-from-alien unsigned-byte
-    (type-spec number &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  number)
+(define-type-method to-alien-form ((type base-char) form)
+  (declare (ignore type))
+  form)
 
+(define-type-method to-alien-function ((type base-char))
+  (declare (ignore type))
+  #'identity)
 
-(deftype-method translate-type-spec single-float (type-spec)
-  (declare (ignore type-spec))
-  'single-float)
+(define-type-method from-alien-form ((type base-char) form)
+  (declare (ignore type))
+  form)
 
-(deftype-method size-of single-float (type-spec)
-  (declare (ignore type-spec))
-  +size-of-float+)
+(define-type-method from-alien-function ((type base-char))
+  (declare (ignore type))
+  #'identity)
 
-(deftype-method translate-to-alien single-float (type-spec number &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  number)
+(define-type-method writer-function ((type base-char))
+  (declare (ignore type))
+  #'(lambda (char location &optional (offset 0))
+      (setf (sap-ref-8 location offset) (char-code char))))
 
-(deftype-method translate-from-alien single-float
-    (type-spec number &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  number)
+(define-type-method reader-function ((type base-char))
+  (declare (ignore type))
+  #'(lambda (location &optional (offset 0) weak-p)
+      (declare (ignore weak-p))
+      (code-char (sap-ref-8 location offset))))
 
 
-(deftype-method translate-type-spec double-float (type-spec)
-  (declare (ignore type-spec))
-  'double-float)
+(define-type-method alien-type ((type string))
+  (declare (ignore type))
+  (alien-type 'pointer))
 
-(deftype-method size-of double-float (type-spec)
-  (declare (ignore type-spec))
-  +size-of-double+)
+(define-type-method size-of ((type string))
+  (declare (ignore type))
+  (size-of 'pointer))
 
-(deftype-method translate-to-alien double-float (type-spec number &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  `(coerce ,number 'double-float))
+(define-type-method to-alien-form ((type string) string)
+  (declare (ignore type))
+  `(let ((string ,string))
+     ;; Always copy strings to prevent seg fault due to GC
+     #+cmu
+     (copy-memory
+      (vector-sap (coerce string 'simple-base-string))
+      (1+ (length string)))
+     #+sbcl
+     (let ((utf8 (%deport-utf8-string string)))
+       (copy-memory (vector-sap utf8) (length utf8)))))
+  
+(define-type-method to-alien-function ((type string))
+  (declare (ignore type))
+  #'(lambda (string)
+      #+cmu
+      (copy-memory
+       (vector-sap (coerce string 'simple-base-string))
+       (1+ (length string)))
+      #+sbcl
+      (let ((utf8 (%deport-utf8-string string)))
+	(copy-memory (vector-sap utf8) (length utf8)))))
+
+(define-type-method from-alien-form ((type string) string)
+  (declare (ignore type))
+  `(let ((string ,string))
+    (unless (null-pointer-p string)
+      (prog1
+	  #+cmu(%naturalize-c-string string)
+	  #+sbcl(%naturalize-utf8-string string)
+	(deallocate-memory string)))))
+
+(define-type-method from-alien-function ((type string))
+  (declare (ignore type))
+  #'(lambda (string)
+      (unless (null-pointer-p string)
+	(prog1
+	    #+cmu(%naturalize-c-string string)
+	    #+sbcl(%naturalize-utf8-string string)
+	  (deallocate-memory string)))))
 
-(deftype-method translate-from-alien double-float
-    (type-spec number &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  number)
+(define-type-method cleanup-form ((type string) string)
+  (declare (ignore type))
+  `(let ((string ,string))
+    (unless (null-pointer-p string)
+      (deallocate-memory string))))
 
+(define-type-method cleanup-function ((type string))
+  (declare (ignore type))
+  #'(lambda (string)
+      (unless (null-pointer-p string)
+	(deallocate-memory string))))
 
-(deftype-method translate-type-spec base-char (type-spec)
-  (declare (ignore type-spec))
-  `(unsigned ,+bits-per-unit+))
+(define-type-method copy-from-alien-form ((type string) string)
+  (declare (ignore type))
+  `(let ((string ,string))
+    (unless (null-pointer-p string)
+      #+cmu(%naturalize-c-string string)
+      #+sbcl(%naturalize-utf8-string string))))
+
+(define-type-method copy-from-alien-function ((type string))
+  (declare (ignore type))
+  #'(lambda (string)
+      (unless (null-pointer-p string)
+	#+cmu(%naturalize-c-string string)
+	#+sbcl(%naturalize-utf8-string string))))
+
+(define-type-method writer-function ((type string))
+  (declare (ignore type))
+  #'(lambda (string location &optional (offset 0))
+      (assert (null-pointer-p (sap-ref-sap location offset)))
+      (setf (sap-ref-sap location offset)
+       #+cmu
+       (copy-memory
+	(vector-sap (coerce string 'simple-base-string))
+	(1+ (length string)))
+       #+sbcl
+       (let ((utf8 (%deport-utf8-string string)))
+	 (copy-memory (vector-sap utf8) (length utf8))))))
+
+(define-type-method reader-function ((type string))
+  (declare (ignore type))
+  #'(lambda (location &optional (offset 0) weak-p)
+      (declare (ignore weak-p))
+      (unless (null-pointer-p (sap-ref-sap location offset))
+	#+cmu(%naturalize-c-string (sap-ref-sap location offset))
+	#+sbcl(%naturalize-utf8-string (sap-ref-sap location offset)))))
+
+(define-type-method destroy-function ((type string))
+  (declare (ignore type))
+  #'(lambda (location &optional (offset 0))
+      (unless (null-pointer-p (sap-ref-sap location offset))
+	(deallocate-memory (sap-ref-sap location offset))
+	(setf (sap-ref-sap location offset) (make-pointer 0)))))
+
+(define-type-method unbound-value ((type string))
+  (declare (ignore type))
+  nil)
 
-(deftype-method size-of base-char (type-spec)
-  (declare (ignore type-spec))
-  1)
 
-(deftype-method translate-to-alien base-char (type-spec char &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  `(char-code ,char))
+(define-type-method alien-type ((type pathname))
+  (declare (ignore type))
+  (alien-type 'string))
 
-(deftype-method translate-from-alien base-char (type-spec code &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  `(code-char ,code))
+(define-type-method size-of ((type pathname))
+  (declare (ignore type))
+  (size-of 'string))
 
+(define-type-method to-alien-form ((type pathname) path)
+  (declare (ignore type))
+  (to-alien-form 'string `(namestring (translate-logical-pathname ,path))))
+
+(define-type-method to-alien-function ((type pathname))
+  (declare (ignore type))
+  (let ((string-function (to-alien-function 'string)))
+    #'(lambda (path)
+	(funcall string-function (namestring path)))))
+
+(define-type-method from-alien-form ((type pathname) string)
+  (declare (ignore type))
+  `(parse-namestring ,(from-alien-form 'string string)))
+
+(define-type-method from-alien-function ((type pathname))
+  (declare (ignore type))
+  (let ((string-function (from-alien-function 'string)))
+    #'(lambda (string)
+	(parse-namestring (funcall string-function string)))))
+
+(define-type-method cleanup-form ((type pathnanme) string)
+  (declare (ignore type))
+  (cleanup-form 'string string))
+
+(define-type-method cleanup-function ((type pathnanme))
+  (declare (ignore type))
+  (cleanup-function 'string))
+
+(define-type-method writer-function ((type pathname))
+  (declare (ignore type))
+  (let ((string-writer (writer-function 'string)))
+    #'(lambda (path location &optional (offset 0))
+	(funcall string-writer (namestring path) location offset))))
+
+(define-type-method reader-function ((type pathname))
+  (declare (ignore type))
+  (let ((string-reader (reader-function 'string)))
+  #'(lambda (location &optional (offset 0) weak-p)
+      (declare (ignore weak-p))
+      (let ((string (funcall string-reader location offset)))
+	(when string
+	  (parse-namestring string))))))
+
+(define-type-method destroy-function ((type pathname))
+  (declare (ignore type))
+  (destroy-function 'string))
+
+(define-type-method unbound-value ((type pathname))
+  (declare (ignore type))
+  (unbound-value 'string))
+
+
+(define-type-method alien-type ((type boolean))
+  (destructuring-bind (&optional (size '*))
+      (rest (mklist (type-expand-to 'boolean type)))
+    (alien-type `(signed-byte ,size))))
+
+(define-type-method size-of ((type boolean))
+  (destructuring-bind (&optional (size '*))
+      (rest (mklist (type-expand-to 'boolean type)))
+    (size-of `(signed-byte ,size))))
+
+(define-type-method to-alien-form ((type boolean) boolean)
+  (declare (ignore type))
+  `(if ,boolean 1 0))
+
+(define-type-method to-alien-function ((type boolean))
+  (declare (ignore type))
+  #'(lambda (boolean)
+      (if boolean 1 0)))
+
+(define-type-method from-alien-form ((type boolean) boolean)
+  (declare (ignore type))
+  `(not (zerop ,boolean)))
+
+(define-type-method from-alien-function ((type boolean))
+  (declare (ignore type))
+  #'(lambda (boolean)
+      (not (zerop boolean))))
+
+(define-type-method writer-function ((type boolean))
+  (destructuring-bind (&optional (size '*))
+      (rest (mklist (type-expand-to 'boolean type)))
+    (let ((writer (writer-function `(signed-byte ,size))))
+      #'(lambda (boolean location &optional (offset 0))
+	  (funcall writer (if boolean 1 0) location offset)))))
+
+(define-type-method reader-function ((type boolean))
+  (destructuring-bind (&optional (size '*))
+      (rest (mklist (type-expand-to 'boolean type)))
+    (let ((reader (reader-function `(signed-byte ,size))))
+      #'(lambda (location &optional (offset 0) weak-p)
+	  (declare (ignore weak-p))
+	  (not (zerop (funcall reader location offset)))))))
+
+
+(define-type-method alien-type ((type or))
+  (let* ((expanded-type (type-expand-to 'or type))
+	 (alien-type (alien-type (second expanded-type))))
+    (unless (every #'(lambda (type)
+		       (eq alien-type (alien-type type)))
+		   (cddr expanded-type))
+      (error "No common alien type specifier for union type: ~A" type))
+    alien-type))
 
-(deftype-method translate-type-spec string (type-spec)
-  (declare (ignore type-spec))
+(define-type-method size-of ((type or))
+  (size-of (second (type-expand-to 'or type))))
+
+(define-type-method to-alien-form ((type or) form)
+  `(let ((value ,form))
+     (etypecase value
+       ,@(mapcar	 
+	  #'(lambda (type)
+	      `(,type ,(to-alien-form type 'value)))
+	  (rest (type-expand-to 'or type))))))
+
+(define-type-method to-alien-function ((type or))
+  (let* ((expanded-type (type-expand-to 'or type))
+	 (functions (mapcar #'to-alien-function (rest expanded-type))))
+    #'(lambda (value)
+	(loop
+	 for function in functions
+	 for alt-type in (rest expanded-type)
+	 when (typep value alt-type)
+	 do (return (funcall function value))
+	 finally (error "~S is not of type ~A" value type)))))
+
+
+(define-type-method alien-type ((type pointer))
+  (declare (ignore type))
   'system-area-pointer)
 
-(deftype-method size-of string (type-spec)
-  (declare (ignore type-spec))
-  +size-of-sap+)
+(define-type-method size-of ((type pointer))
+  (declare (ignore type))
+  +size-of-pointer+)
 
-(deftype-method translate-to-alien string (type-spec string &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  `(let ((string ,string))
-     ;; Always copy strings to prevent seg fault due to GC
-     (copy-memory
-      (make-pointer (1+ (kernel:get-lisp-obj-address string)))
-      (1+ (length string)))))
-
-(deftype-method translate-from-alien string
-    (type-spec c-string &optional weak-ref)
-  (declare (ignore type-spec))
-  `(let ((c-string ,c-string))
-     (unless (null-pointer-p c-string)
-       (prog1
-	   (c-call::%naturalize-c-string c-string)
-	 ;,(unless weak-ref `(deallocate-memory c-string))
-	 ))))
-
-(deftype-method cleanup-alien string (type-spec c-string &optional weak-ref)
-  (when weak-ref
-    (unreference-alien type-spec c-string)))
-
-(deftype-method unreference-alien string (type-spec c-string)
-  (declare (ignore type-spec))
-  `(let ((c-string ,c-string))
-     (unless (null-pointer-p c-string)
-       (deallocate-memory c-string))))
-
-
-;;; Pathname
-
-(deftype-method translate-type-spec pathname (type-spec)
-  (declare (ignore type-spec))
-  (translate-type-spec 'string))
-
-(deftype-method size-of pathname (type-spec)
-  (declare (ignore type-spec))
-  (size-of 'string))
+(define-type-method to-alien-form ((type pointer) form)
+  (declare (ignore type))
+  form)
 
-(deftype-method translate-to-alien pathname (type-spec path &optional weak-ref)
-  (declare (ignore type-spec))
-  (translate-to-alien 'string 
-   `(namestring (translate-logical-pathname ,path)) weak-ref))
+(define-type-method to-alien-function ((type pointer))
+  (declare (ignore type))
+  #'identity)
 
-(deftype-method translate-from-alien pathname (type-spec c-string &optional weak-ref)
-  (declare (ignore type-spec))
-  `(parse-namestring ,(translate-from-alien 'string c-string weak-ref)))
+(define-type-method from-alien-form ((type pointer) form)
+  (declare (ignore type))
+  form)
 
-(deftype-method cleanup-alien pathname (type-spec c-string &optional weak-ref)
-  (declare (ignore type-spec))
-  (cleanup-alien 'string c-string weak-ref))
+(define-type-method from-alien-function ((type pointer))
+  (declare (ignore type))
+  #'identity)
 
-(deftype-method unreference-alien pathname (type-spec c-string)
-  (declare (ignore type-spec))
-  (unreference-alien 'string c-string))
-  
+(define-type-method writer-function ((type pointer))
+  (declare (ignore type))
+  #'(lambda (sap location &optional (offset 0))
+      (setf (sap-ref-sap location offset) sap)))
 
-(deftype-method translate-type-spec boolean (type-spec)
-  (translate-type-spec
-   (cons 'unsigned (cdr (mklist (type-expand-to 'boolean type-spec))))))
+(define-type-method reader-function ((type pointer))
+  (declare (ignore type))
+  #'(lambda (location &optional (offset 0) weak-p)
+      (declare (ignore weak-p))
+      (sap-ref-sap location offset)))
 
-(deftype-method size-of boolean (type-spec)
-  (size-of
-   (cons 'unsigned (cdr (mklist (type-expand-to 'boolean type-spec))))))
 
-(deftype-method translate-to-alien boolean (type-spec boolean &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  `(if ,boolean 1 0))
+(define-type-method alien-type ((type null))
+  (declare (ignore type))
+  (alien-type 'pointer))
 
-(deftype-method translate-from-alien boolean (type-spec int &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  `(not (zerop ,int)))
+(define-type-method size-of ((type null))
+  (declare (ignore type))
+  (size-of 'pointer))
 
+(define-type-method to-alien-form ((type null) null)
+  (declare (ignore null type))
+  `(make-pointer 0))
 
-(deftype-method translate-type-spec or (union-type)
-  (let* ((member-types (cdr (type-expand-to 'or union-type)))
-	 (alien-type (translate-type-spec (first member-types))))
-    (dolist (type (cdr member-types))
-      (unless (eq alien-type (translate-type-spec type))
-	(error "No common alien type specifier for union type: ~A" union-type)))
-    alien-type))
+(define-type-method to-alien-function ((type null))
+  (declare (ignore type))
+  #'(lambda (null)
+      (declare (ignore null))
+      (make-pointer 0)))
 
-(deftype-method size-of or (union-type)
-  (size-of (first (cdr (type-expand-to 'or union-type)))))
 
-(deftype-method translate-to-alien or (union-type-spec expr &optional weak-ref)
-  (destructuring-bind (name &rest type-specs)
-      (type-expand-to 'or union-type-spec)
-    (declare (ignore name))
-    `(let ((value ,expr))
-       (etypecase value
-	 ,@(map
-	    'list
-	      #'(lambda (type-spec)
-		  (list type-spec (translate-to-alien type-spec 'value weak-ref)))
-	      type-specs)))))
+(define-type-method alien-type ((type nil))
+  (declare (ignore type))
+  'void)
 
+(define-type-method from-alien-function ((type nil))
+  (declare (ignore type))
+  #'(lambda (value)
+      (declare (ignore value))
+      (values)))
 
-(deftype-method translate-type-spec system-area-pointer (type-spec)
-  (declare (ignore type-spec))
-  'system-area-pointer)
+(define-type-method to-alien-form ((type nil) form)
+  (declare (ignore type))
+  form)
 
-(deftype-method size-of system-area-pointer (type-spec)
-  (declare (ignore type-spec))
-  +size-of-sap+)
 
-(deftype-method translate-to-alien system-area-pointer (type-spec sap &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  sap)
+(define-type-method to-alien-form ((type copy-of) form)
+  (copy-to-alien-form (second (type-expand-to 'copy-of type)) form))
 
-(deftype-method translate-from-alien system-area-pointer
-    (type-spec sap &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  sap)
+(define-type-method to-alien-function ((type copy-of))
+  (copy-to-alien-function (second (type-expand-to 'copy-of type))))
 
+(define-type-method from-alien-form ((type copy-of) form)
+  (copy-from-alien-form (second (type-expand-to 'copy-of type)) form))
 
-(deftype-method translate-type-spec null (type-spec)
-  (declare (ignore type-spec))
-  'system-area-pointer)
+(define-type-method from-alien-function ((type copy-of))
+  (copy-from-alien-function (second (type-expand-to 'copy-of type))))
 
-(deftype-method translate-to-alien null (type-spec expr &optional weak-ref)
-  (declare (ignore type-spec expr weak-ref))
-  `(make-pointer 0))
+(define-type-method cleanup-function ((type copy-of))
+  (declare (ignore type))
+  #'identity)
 
+(define-type-method destroy-function ((type copy-of))
+  (declare (ignore type))
+  #'(lambda (location &optional offset)
+      (declare (ignore location offset))))
 
-(deftype-method translate-type-spec nil (type-spec)
-  (declare (ignore type-spec))
-  'void)
 
-(deftype-method translate-from-alien nil (type-spec expr &optional weak-ref)
-  (declare (ignore type-spec weak-ref))
-  `(progn
-     ,expr
-     (values)))
+(define-type-method alien-type ((type callback))
+  (declare (ignore type))
+  (alien-type 'pointer))
+
+(define-type-method to-alien-form ((type callback) callback)
+  (declare (ignore type ))
+  `(callback-address ,callback))