+(deftype flags (&rest args)
+ `(or (member ,@(%map-flags args :symbols)) list))
+
+(defmethod alien-type ((type (eql 'flags)) &rest args)
+ (declare (ignore type args))
+ (alien-type 'unsigned))
+
+(defmethod size-of ((type (eql 'flags)) &rest args)
+ (declare (ignore type args))
+ (size-of 'unsigned))
+
+(defmethod to-alien-form (flags (type (eql 'flags)) &rest args)
+ `(reduce #'logior (mklist ,flags)
+ :key #'(lambda (flag)
+ (case flag
+ ,@(%map-flags args :symbol-int)
+ (t (error 'type-error :datum ,flags
+ :expected-type '(,type ,@args)))))))
+
+(defmethod from-alien-form (int (type (eql 'flags)) &rest args)
+ (declare (ignore type))
+ `(loop
+ for mapping in ',(%map-flags args :int-symbol)
+ unless (zerop (logand ,int (first mapping)))
+ collect (second mapping)))
+
+(defmethod to-alien-function ((type (eql 'flags)) &rest args)
+ (declare (ignore type))
+ (let ((mappings (%map-flags args :symbol-int)))
+ #'(lambda (flags)
+ (reduce #'logior (mklist flags)
+ :key #'(lambda (flag)
+ (or
+ (second (assoc flag mappings))
+ (error 'type-error :datum flags
+ :expected-type (cons 'flags args))))))))
+
+(defmethod from-alien-function ((type (eql 'flags)) &rest args)
+ (declare (ignore type))
+ (let ((mappings (%map-flags args :int-symbol)))
+ #'(lambda (int)
+ (loop
+ for mapping in mappings
+ unless (zerop (logand int (first mapping)))
+ collect (second mapping)))))
+
+(defmethod writer-function ((type (eql 'flags)) &rest args)
+ (declare (ignore type))
+ (let ((writer (writer-function 'unsigned))
+ (function (apply #'to-alien-function 'flags args)))
+ #'(lambda (flags location &optional (offset 0))
+ (funcall writer (funcall function flags) location offset))))
+
+(defmethod reader-function ((type (eql 'flags)) &rest args)
+ (declare (ignore type))
+ (let ((reader (reader-function 'unsigned))
+ (function (apply #'from-alien-function 'flags args)))
+ #'(lambda (location &optional (offset 0))
+ (funcall function (funcall reader location offset)))))
+
+
+;;;; Named flags types
+
+(defmacro define-flags-type (name &rest args)
+ (let ((flags-int (intern (format nil "~A-TO-INT" name)))
+ (int-flags (intern (format nil "INT-TO-~A" name)))
+ (satisfies (intern (format nil "~A-P" name))))
+ `(progn
+ (deftype ,name () '(satisfies ,satisfies))
+ (defun ,satisfies (object)
+ (flet ((valid-p (ob)
+ (find ob ',(%map-flags args :symbols))))
+ (typecase object
+ (symbol (valid-p object))
+ (list (every #'valid-p object)))))
+ (defun ,flags-int (flags)
+ (reduce #'logior (mklist flags)
+ :key #'(lambda (flag)
+ (case flag
+ ,@(%map-flags args :symbol-int)
+ (t (error 'type-error :datum flags
+ :expected-type ',name))))))
+ (defun ,int-flags (value)
+ (loop
+ for mapping in ',(%map-flags args :int-symbol)
+ unless (zerop (logand value (first mapping)))
+ collect (second mapping)))
+ (defmethod alien-type ((type (eql ',name)) &rest args)
+ (declare (ignore type args))
+ (alien-type 'flags))
+ (defmethod size-of ((type (eql ',name)) &rest args)
+ (declare (ignore type args))
+ (size-of 'flags))
+ (defmethod to-alien-form (form (type (eql ',name)) &rest args)
+ (declare (ignore type args))
+ (list ',flags-int form))
+ (defmethod from-alien-form (form (type (eql ',name)) &rest args)
+ (declare (ignore type args))
+ (list ',int-flags form))
+ (defmethod to-alien-function ((type (eql ',name)) &rest args)
+ (declare (ignore type args))
+ #',flags-int)
+ (defmethod from-alien-function ((type (eql ',name)) &rest args)
+ (declare (ignore type args))
+ #',int-flags)
+ (defmethod writer-function ((type (eql ',name)) &rest args)
+ (declare (ignore type args))
+ (let ((writer (writer-function 'signed)))
+ #'(lambda (flags location &optional (offset 0))
+ (funcall writer (,flags-int flags) location offset))))
+ (defmethod reader-function ((type (eql ',name)) &rest args)
+ (declare (ignore type args))
+ (let ((reader (reader-function 'signed)))
+ #'(lambda (location &optional (offset 0))
+ (,int-flags (funcall reader location offset))))))))
+
+
+
+;;;; Type definition by introspection