91 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			Scheme
		
	
	
	
			
		
		
	
	
			91 lines
		
	
	
		
			4.1 KiB
		
	
	
	
		
			Scheme
		
	
	
	
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(define-record-type <pffi-struct>
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  (struct-make name size pointer members)
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  pffi-struct?
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  (name pffi-struct-name)
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  (size pffi-struct-size)
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  (pointer pffi-struct-pointer)
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  (members pffi-struct-members))
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(define pffi-align-of
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  (lambda (type)
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    (cond-expand
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      ;(guile (alignof (pffi-type->native-type type)))
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      (else (pffi-size-of type)))))
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(define (round-to-next-modulo-of to-round roundee)
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  (if (= (floor-remainder to-round roundee) 0)
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    to-round
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    (round-to-next-modulo-of (+ to-round 1) roundee)))
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(define (calculate-struct-size-and-offsets members)
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  (let* ((size 0)
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         (largest-member-size 0)
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         (offsets (map (lambda (member)
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                         (let* ((name (cdr member))
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                                (type (car member))
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                                (type-alignment (pffi-align-of type)))
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                           (when (> (pffi-size-of type) largest-member-size)
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                             (set! largest-member-size (pffi-size-of type)))
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                           (if (or (= size 0)
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                                   (= (floor-remainder size type-alignment) 0))
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                             (begin
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                               (set! size (+ size type-alignment))
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                               (list name type (- size type-alignment)))
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                             (let ((next-alignment (round-to-next-modulo-of size type-alignment)))
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                               (set! size (+ next-alignment type-alignment))
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                               (list name
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                                     type
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                                     next-alignment)))))
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                       members)))
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    (list (cons 'size
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                (cond-expand
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                  ;(guile (sizeof (map pffi-type->native-type (map car members))))
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                  (else
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                    (if (= (modulo size largest-member-size) 0)
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                      size
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                      (round-to-next-modulo-of size largest-member-size)))))
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          (cons 'offsets offsets))))
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(define (pffi-struct-make name members . pointer)
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  (for-each
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    (lambda (member)
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      (write member)
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      (newline)
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      (when (not (pair? member))
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        (error "All struct members must be pairs" (list name member)))
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      (when (not (symbol? (car member)))
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        (error "All struct member types must be symbols" (list name member)))
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      (when (not (symbol? (cdr member)))
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        (error "All struct member names must be symbols" (list name member))))
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    members)
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  (let* ((size-and-offsets (calculate-struct-size-and-offsets members))
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         (size (cdr (assoc 'size size-and-offsets)))
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         (offsets (cdr (assoc 'offsets size-and-offsets)))
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         (pointer (if (null? pointer) (pffi-pointer-allocate size) (car pointer)))
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         (name (if (string? name) name (symbol->string name))))
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    (struct-make name size pointer offsets)))
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(define (pffi-struct-offset-get struct member-name)
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  (when (not (assoc member-name (pffi-struct-members struct)))
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    (error "Struct has no such member" (list struct member-name)))
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  (car (cdr (cdr (assoc member-name (pffi-struct-members struct))))))
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(define (pffi-struct-get struct member-name)
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  (when (not (assoc member-name (pffi-struct-members struct)))
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    (error "Struct has no such member" (list struct member-name)))
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  (let ((type (car (cdr (assoc member-name (pffi-struct-members struct)))))
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        (offset (car (cdr (cdr (assoc member-name (pffi-struct-members struct)))))))
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    (map display (list "type: " type
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                       ", offset: " offset
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                       ", value: " (pffi-pointer-get (pffi-struct-pointer struct) type offset)
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                       #\newline))
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    (pffi-pointer-get (pffi-struct-pointer struct) type offset)))
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(define (pffi-struct-set! struct member-name value)
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  (when (not (assoc member-name (pffi-struct-members struct)))
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    (error "Struct has no such member" (list struct member-name)))
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  (let ((type (car (cdr (assoc member-name (pffi-struct-members struct)))))
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        (offset (car (cdr (cdr (assoc member-name (pffi-struct-members struct)))))))
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    (pffi-pointer-set! (pffi-struct-pointer struct) type offset value)))
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