+(define-syntax define-conversion-type
+ (lambda (x)
+ (define (mk-string . args)
+ (string-concatenate
+ (map (lambda (a)
+ (if (string? a)
+ a
+ (symbol->string (syntax->datum a))))
+ args)))
+ (define (mk-symbol . args)
+ (datum->syntax x
+ (string->symbol
+ (apply mk-string args))))
+ (syntax-case x (->)
+ ((_ parser -> name (field-name field-proc) ...)
+ (with-syntax ((type? (mk-symbol #'name "?"))
+ (wrap-type (mk-symbol "wrap-" #'name))
+ (unwrap-type (mk-symbol "unwrap-" #'name))
+ (output-string (mk-string "#<" #'name " ~x>"))
+ (type-contents (mk-symbol #'name "-contents"))
+ (type-parse (mk-symbol #'name "-parse"))
+ ((field-reader ...) (map (lambda (f) (mk-symbol #'name "-" (car f))) #'((field-name field-proc) ...))))
+ #'(begin
+ (define-wrapped-pointer-type name
+ type?
+ wrap-type unwrap-type
+ (lambda (x p)
+ (format p output-string
+ (pointer-address (unwrap-type x)))))
+ (define (type-parse wrapped)
+ (let ((unwrapped (unwrap-type wrapped)))
+ (cond ((= (pointer-address unwrapped) 0)
+ '())
+ (else
+ (parser unwrapped)))))
+ (define (type-contents wrapped)
+ (let ((alist (type-parse wrapped)))
+ (list (cons 'field-name (field-proc alist))
+ ...)))
+ (define (field-reader wrapped)
+ (let ((alist (type-parse wrapped)))
+ (field-proc alist)))
+ ...))))))
+
+(define (field name)
+ (lambda (alist)
+ (assoc-ref alist name)))
+
+(define (get-element-address root-pointer offset)
+ (make-pointer (+ (pointer-address root-pointer) offset)))
+
+(define* (array size-tag root-tag #:key (element-size 4) (element-proc bv-uint-ref))
+ (lambda (alist)
+ (let ((size (assoc-ref alist size-tag))
+ (root (assoc-ref alist root-tag)))
+ (cond ((= (pointer-address root) 0)
+ '())
+ (else
+ (let loop ((i 0))
+ (cond ((= i size)
+ '())
+ (else
+ (cons (element-proc root (* element-size i))
+ (loop (+ i 1)))))))))))
+
+(define (wrap proc wrap-proc)
+ (define (make-wrap element)
+ (let ((pointer
+ (cond ((pointer? element)
+ (if (= (pointer-address element) 0)
+ #f
+ element))
+ ((= element 0)
+ #f)
+ (else
+ (make-pointer element)))))
+ (cond (pointer
+ (wrap-proc pointer))
+ (else
+ #f))))
+ (lambda (alist)
+ (let ((res (proc alist)))
+ (cond ((list? res)
+ (map make-wrap res))
+ (else
+ (make-wrap res))))))
+
+(define (sized-string string-tag)
+ (lambda (alist)
+ (let ((s (assoc-ref alist string-tag)))
+ (cond (s
+ (bytevector->string
+ (u8-list->bytevector (list-head (cadr s) (car s)))
+ (fluid-ref %default-port-encoding)))
+ (else
+ #f)))))
+
+