90 lines
4.1 KiB
Scheme
90 lines
4.1 KiB
Scheme
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(define-record-type <pffi-struct>
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(struct-make c-type size pointer members)
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pffi-struct?
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(c-type pffi-struct-c-type)
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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 (size-of-type 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 (> (size-of-type type) largest-member-size)
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(set! largest-member-size (size-of-type 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
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(lambda (c-type members . pointer)
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(for-each
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(lambda (member)
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(when (not (pair? member))
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(error "All struct members must be pairs" (list c-type member)))
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(when (not (symbol? (car member)))
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(error "All struct member types must be symbols" (list c-type member)))
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(when (not (symbol? (cdr member)))
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(error "All struct member names must be symbols" (list c-type 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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(c-type (if (string? c-type) c-type (symbol->string c-type))))
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(struct-make c-type 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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