63 lines
2.5 KiB
Scheme
63 lines
2.5 KiB
Scheme
(define-record-type <pffi-struct>
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(pffi-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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(begin
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(set! size (+ (round-to-next-modulo-of size type-alignment)
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type-alignment))
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(list name
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type
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(round-to-next-modulo-of size type-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-word-size
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(cond-expand
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(larceny 4) ; 32-bit system
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(else 8))) ; 64-bit system
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(define (pffi-struct-allocate name 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 (pffi-pointer-allocate size)))
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(write size-and-offsets)
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(newline)
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(pffi-struct-make name size pointer members)))
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