foreign-c/foreign/c/struct.scm

167 lines
7.3 KiB
Scheme

#;(define-record-type <c-struct>
(c-struct-make c-type size pointer members)
c-struct?
(c-type c-struct:type)
(size c-struct:size)
(pointer c-struct:pointer)
(members c-struct:members))
(define round-to-next-modulo-of
(lambda (to-round roundee)
(if (= (modulo to-round roundee) 0)
to-round
(round-to-next-modulo-of (+ to-round 1) roundee))))
(define calculate-struct-members
(lambda (members)
(let*
((size 0)
(largest-member-size 0)
(data (map (lambda (member)
(let* ((name (list-ref member 0))
(type (list-ref member 1))
(accessor (list-ref member 2))
(type-alignment (c-type-align type)))
(when (> (size-of-type type) largest-member-size)
(set! largest-member-size (size-of-type type)))
(if (or (= size 0)
(= (modulo size type-alignment) 0))
(begin
(set! size (+ size type-alignment))
(list name type (- size type-alignment) accessor))
(let ((next-alignment
(round-to-next-modulo-of size type-alignment)))
(set! size (+ next-alignment type-alignment))
(list name type next-alignment accessor)))))
members)))
data)))
(define-syntax define-c-struct
(syntax-rules ()
((_ name members struct-pointer (field-name field-type accessor modifier) ...)
(begin
(define accessor
(lambda (c-bytevector)
(let ((offset (let ((offset 0)
(before? #t))
(for-each
(lambda (member)
(when (equal? (list-ref member 0) 'field-name)
(set! before? #f))
(when before?
(set! offset
(+ offset
(c-type-align (list-ref member 1))))))
members)
offset)))
(cond
((equal? 'pointer field-type)
(c-bytevector-pointer-ref c-bytevector offset))
((c-type-signed? field-type)
(c-bytevector-sint-ref c-bytevector
offset
(native-endianness)
(c-type-size field-type)))
(else
(c-bytevector-uint-ref c-bytevector
offset
(native-endianness)
(c-type-size field-type)))))))
...
(define modifier
(lambda (c-bytevector value)
(let ((offset (let ((offset 0)
(before? #t))
(for-each
(lambda (member)
(when (equal? (list-ref member 0) 'field-name)
(set! before? #f))
(when before?
(set! offset
(+ offset
(c-type-align (list-ref member 1))))))
members)
offset)))
(cond
((equal? 'pointer field-type)
(c-bytevector-pointer-set! c-bytevector offset value))
((c-type-signed? field-type)
(c-bytevector-sint-set! c-bytevector
offset
value
(native-endianness)
(c-type-size field-type)))
(else
(c-bytevector-uint-set! c-bytevector
offset
value
(native-endianness)
(c-type-size field-type)))))))
...
(define members (calculate-struct-members
(list (list 'field-name field-type accessor) ...)))
(define name
(if (c-null? struct-pointer)
(make-c-bytevector (+ (c-type-size field-type) ...))
struct-pointer))))))
(define c-struct->alist
(lambda (struct-c-bytevector struct-members)
(map (lambda (member)
(cons (list-ref member 0)
(apply (list-ref member 3) (list struct-c-bytevector))))
struct-members)))
#;(define-syntax define-c-struct
(syntax-rules ()
((_ name constructor pred field ...)
(define name
(lambda arguments
(let* ((size-and-offsets (calculate-struct-size-and-offsets members))
(size (cdr (assoc 'size size-and-offsets)))
(offsets (cdr (assoc 'offsets size-and-offsets)))
(pointer (if (and (not (null? arguments))
(c-bytevector? (car arguments)))
(car arguments)
(make-c-bytevector size)))
(c-type-string (if (string? c-type) c-type (symbol->string c-type))))
(c-struct-make c-type-string size pointer offsets)))))))
#;(define pffi-struct-make
(lambda (c-type members . pointer)
(for-each
(lambda (member)
(when (not (pair? member))
(error "All struct members must be pairs" (list c-type member)))
(when (not (symbol? (car member)))
(error "All struct member types must be symbols" (list c-type member)))
(when (not (symbol? (cdr member)))
(error "All struct member names must be symbols" (list c-type member))))
members)
(let* ((size-and-offsets (calculate-struct-size-and-offsets members))
(size (cdr (assoc 'size size-and-offsets)))
(offsets (cdr (assoc 'offsets size-and-offsets)))
(pointer (if (null? pointer) (make-c-bytevector size) (car pointer)))
(c-type (if (string? c-type) c-type (symbol->string c-type))))
(struct-make c-type size pointer offsets))))
#;(define (pffi-struct-offset-get struct member-name)
(when (not (assoc member-name (pffi-struct-members struct)))
(error "Struct has no such member" (list struct member-name)))
(car (cdr (cdr (assoc member-name (pffi-struct-members struct))))))
#;(define (pffi-struct-get struct member-name)
(when (not (assoc member-name (pffi-struct-members struct)))
(error "Struct has no such member" (list struct member-name)))
(let ((type (car (cdr (assoc member-name (pffi-struct-members struct)))))
(offset (car (cdr (cdr (assoc member-name (pffi-struct-members struct)))))))
(pffi-pointer-get (pffi-struct-pointer struct) type offset)))
#;(define (pffi-struct-set! struct member-name value)
(when (not (assoc member-name (pffi-struct-members struct)))
(error "Struct has no such member" (list struct member-name)))
(let ((type (car (cdr (assoc member-name (pffi-struct-members struct)))))
(offset (car (cdr (cdr (assoc member-name (pffi-struct-members struct)))))))
(pffi-pointer-set! (pffi-struct-pointer struct) type offset value)))