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;;; binary.ftype - foreign types and foreign objects
;;;
;;; Copyright (c) 2011-2014 Shiro Kawai <shiro@acm.org>
;;;
;;; Redistribution and use in source and binary forms, with or without
;;; modification, are permitted provided that the following conditions
;;; are met:
;;;
;;; 1. Redistributions of source code must retain the above copyright
;;; notice, this list of conditions and the following disclaimer.
;;;
;;; 2. Redistributions in binary form must reproduce the above copyright
;;; notice, this list of conditions and the following disclaimer in the
;;; documentation and/or other materials provided with the distribution.
;;;
;;; 3. Neither the name of the authors nor the names of its contributors
;;; may be used to endorse or promote products derived from this
;;; software without specific prior written permission.
;;;
;;; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
;;; "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
;;; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
;;; A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
;;; OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
;;; SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
;;; TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
;;; PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
;;; LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
;;; NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
;;; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
;;;
;; This module provides means to define and manipulate
;; structured binary data.
;;
;; Foreign types and foreign objects
;;
;; A @emph{foreign type}, or @code{ftype}, refers to a way of representing
;; external data used outside the Scheme world. Ftypes are first-class
;; objects in Gauche. It can be used to extract or construct structured data
;; from/in a plain bytevector (@code{u8vector}).
;;
;; A @emph{foreign object} , or @code{fobject}, is a Scheme object
;; that packages a chunk of binary data (@emph{storage}) with ftype.
;; It behaves like a Scheme record---it can have slots and you can
;; get and set values.
;; However, it is possible to share storage among different Scheme objects.
;; For example, you can read binary data (e.g. image file content)
;; into an u8vector, then extract a part of it (e.g. image header)
;; as an fobject. When you do so, the extracted fobject shares its storage
;; with the original u8vector; you can modify the header of the image
;; content through the extracted fobject.
(define-module binary.ftype
(use gauche.uvector)
(use gauche.record)
(use srfi-1)
(use srfi-13)
(use binary.io)
(export
;; predefined primitive ftypes
ftype:schar ftype:uchar ftype:short ftype:ushort ftype:int ftype:uint
ftype:long ftype:ulong ftype:longlong ftype:ulonglong
ftype:int8 ftype:uint8 ftype:int16 ftype:uint16 ftype:int32 ftype:uint32
ftype:int64 ftype:uint64
ftype:float ftype:double
;; type metainformation
ftype ftype-name ftype-size ftype-alignment ftype-endian
ftype-getter ftype-putter
ftype:struct ftype:struct-slots
ftype:slot ftype:slot-name ftype:slot-type ftype:slot-position
make-fstruct-type
define-fstruct-type
fobject fobject? fobject-type fobject-storage fobject-offset
make-fobject
fobject-copy fobject-copy!/uv fobject-copy!
get-fobject put-fobject!
read-fobject!/uv read-fobject write-fobject/uv write-fobject
fobject-ref fobject-set! fobject-ref/uv fobject-set!/uv
describe-fstruct-type
))
(select-module binary.ftype)
;; Metainformation of foreign type.
;;
;; ftype base class and predefined primitive types
;; +-- ftype:struct user-defined struct
;; +-- ftype:array uniform array of ftype instances.
;; +-- ftype:bitfield integer with limited width
;; (+-- ftype:pointer maybe, if we support ffi through this.)
;; (+-- ftype:function maybe, if we support ffi through this.)
;;
;; The base class. The constructor is private, since the user code
;; never needs to call it.
(define-record-type ftype %make-ftype #t
name ; for diagnostics
size ; size in bytes
alignment ; natrual alignment of this type. can be overridden.
endian ; #f to obey context. symbol to enfoce specific endian.
getter ; uvector pos endian -> value ; pos is aligned
putter ; uvector pos value endian -> void ; pos is aligned
)
;; NB: this may not be needed if we have standard printer for structs.
(define-method write-object ((ftd ftype) port)
(format port "#<ftype ~a>" (ftype-name ftd)))
(define-record-type (ftype:struct ftype) %make-ftype:struct #t
slots ; an assoc list of name and ftype:slot
)
(define-record-type (ftype:array ftype) %make-ftype:array #t
(element-type ftype-element-type) ; ftype
(num-elements ftype-num-elements) ; count
(element-alignment ftype-element-alignment) ; default to natural alignment
; of element-type, can be
; overridden.
)
(define-record-type (ftype:bitfield ftype) %make-ftype:bitfield #t
type ; ftype
bit-position ; start bit position
bit-width ; width
)
;; Auxiliary structure to keep each slot's info of ftype:struct.
;; This isn't a subtype of ftype.
(define-record-type ftype:slot #t #t
name ; slot name
type ; ftype
position ; byte offset
)
;;
;; Foreign object instance.
;;
;; An instance of fobject.
(define-record-type fobject %make-fobject fobject?
type ; ftype:struct
storage ; u8vector. NB: The storage may be shared.
offset ; byte offset within <storage>
)
;; NB: this may not be needed if we have standard printer for structs.
(define-method write-object ((fst fobject) port)
(format port "#<fobject ~a>"
(ftype-name (fobject-type fst))))
;;========================================================================
;; Primitive ftypes.
;;
(define *%primtype-info* (with-module binary.io (%primitive-type-info)))
(define (%primtype-size prim-name) (cadr (assq prim-name *%primtype-info*)))
(define (%primtype-align prim-name) (caddr (assq prim-name *%primtype-info*)))
(define (%primtype name get put!)
(let* ([sname (x->string name)]
[prim-name (cond [(string-prefix? "u" sname)
(string->symbol (string-drop sname 1))]
[(eq? 'schar name) 'char] ;special case
[else name])])
(%make-ftype name
(%primtype-size prim-name)
(%primtype-align prim-name)
#f get put!)))
(define (%intproc name n)
(let1 procs `((1 ,get-s8 ,get-u8 ,put-s8! ,put-u8!)
(2 ,get-s16 ,get-u16 ,put-s16! ,put-u16!)
(4 ,get-s32 ,get-u32 ,put-s32! ,put-u32!)
(8 ,get-s64 ,get-u64 ,put-s64! ,put-u64!))
(list-ref (assq (%primtype-size name) procs) n)))
(define get-schar get-s8)
(define get-uchar get-u8)
(define get-short (%intproc 'short 1))
(define get-ushort (%intproc 'short 2))
(define get-int (%intproc 'int 1))
(define get-uint (%intproc 'int 2))
(define get-long (%intproc 'long 1))
(define get-ulong (%intproc 'long 2))
(define get-longlong (%intproc 'longlong 1))
(define get-ulonglong (%intproc 'longlong 2))
(define get-float get-f32)
(define get-double get-f64)
(define put-schar! put-s8!)
(define put-uchar! put-u8!)
(define put-short! (%intproc 'short 3))
(define put-ushort! (%intproc 'short 4))
(define put-int! (%intproc 'int 3))
(define put-uint! (%intproc 'int 4))
(define put-long! (%intproc 'long 3))
(define put-ulong! (%intproc 'long 4))
(define put-longlong! (%intproc 'longlong 3))
(define put-ulonglong!(%intproc 'longlong 4))
(define put-float! put-f32!)
(define put-double! put-f64!)
(define ftype:schar (%primtype 'schar get-schar put-schar!))
(define ftype:uchar (%primtype 'uchar get-uchar put-uchar!))
(define ftype:short (%primtype 'short get-short put-short!))
(define ftype:ushort (%primtype 'ushort get-ushort put-ushort!))
(define ftype:int (%primtype 'int get-int put-int!))
(define ftype:uint (%primtype 'uint get-uint put-uint!))
(define ftype:long (%primtype 'long get-long put-long!))
(define ftype:ulong (%primtype 'ulong get-ulong put-ulong!))
(define ftype:longlong (%primtype 'longlong get-longlong put-longlong!))
(define ftype:ulonglong (%primtype 'ulonglong get-ulonglong put-ulonglong!))
(define ftype:float (%primtype 'float get-float put-float!))
(define ftype:double (%primtype 'double get-double put-double!))
(define ftype:int8 (%primtype 'int8 get-s8 put-s8!))
(define ftype:uint8 (%primtype 'uint8 get-u8 put-u8!))
(define ftype:int16 (%primtype 'int16 get-s16 put-s16!))
(define ftype:uint16 (%primtype 'uint16 get-u16 put-u16!))
(define ftype:int32 (%primtype 'int32 get-s32 put-s32!))
(define ftype:uint32 (%primtype 'uint32 get-u32 put-u32!))
(define ftype:int64 (%primtype 'int64 get-s64 put-s64!))
(define ftype:uint64 (%primtype 'uint64 get-u64 put-u64!))
;;
;; Utilities
;;
(define-inline (%round val align) ;assumes align is power of 2.
(if (or (= val 0) (= align 0))
val
(logand (+ val (- align 1)) (lognot (- align 1)))))
(define (%check-size ftype uvector pos which)
(when (< (- (uvector-size uvector) pos) (ftype-size ftype))
(case which
[(src) (errorf "source uvector too short to extract \
fobject of type ~s" ftype)]
[(dest) (errorf "destination uvector too small to put \
fobject of type ~s" ftype)]
[else (error "[internal] invalid which argument:" which)])))
(define (%adjust-pos ftype uvector pos alignment)
(let1 align (or alignment (ftype-alignment ftype))
(rlet1 pos (%round pos align)
(%check-size ftype uvector pos 'src))))
(define (%get-slot-desc ftd slot)
(let1 s (assq slot (ftype:struct-slots ftd))
(unless s (errorf "ftype ~a does't have such slot: ~s" ftd slot))
(cdr s)))
;;========================================================================
;; foreign struct building blocks
;;
;; slots :: ((name type) ...)
(define (make-fstruct-type name slots endian alignment)
(receive (size slot-descriptors) (compute-fstruct-slots slots alignment)
(rec ftype
(%make-ftype:struct name size
(or alignment (compute-fstruct-alignment slots))
endian
(rec (fobject-get uv pos endian)
(%check-size ftype uv pos 'src)
(%make-fobject ftype uv pos))
(rec (fobject-put! uv pos val endian)
(%check-size ftype uv pos 'dest)
(let1 off (fobject-offset val)
(uvector-copy! uv pos
(fobject-storage val)
off
(+ off size))))
slot-descriptors))))
(define (compute-fstruct-alignment slots)
(apply max (map (^p (ftype-alignment (cadr p))) slots)))
(define (compute-fstruct-slots slots alignment)
(let loop ([slots slots]
[pos 0]
[descs '()])
(if (null? slots)
(values pos (reverse descs))
(let* ([name (caar slots)]
[type (cadar slots)]
[align (if alignment
(min alignment (ftype-alignment type))
(ftype-alignment type))]
[pos (%round pos align)])
(loop (cdr slots)
(+ pos (ftype-size type))
(acons name (make-ftype:slot name type pos) descs))))))
;;
;; Generic accessors.
;;
(define (get-fobject ftype uvector pos :optional (endian #f) (alignment #f))
(let1 pos (%adjust-pos ftype uvector pos alignment)
((ftype-getter ftype)
uvector pos (or endian (ftype-endian ftype)))))
(define (put-fobject! ftype uvector pos val
:optional (endian #f) (alignment #f))
(let1 pos (%adjust-pos ftype uvector pos alignment)
((ftype-putter ftype)
uvector pos val (or endian (ftype-endian ftype)))))
;; NB: If we allow variable fields, we need to interpret the content.
;; It may also be an option to allow specifying endian and/or alignment
;; which is different from the internal representation, and let this
;; procedure to do the conversion. Still not sure if it is worth.
(define (read-fobject!/uv ftype uvector pos
:optional (port (current-input-port)))
(check-arg u8vector? uvector)
(%check-size ftype uvector pos 'dest)
(let* ([size (ftype-size ftype)]
[end (+ pos size)])
(let loop ([pos pos]
[nread 0])
(let1 nread (+ nread (read-block! uvector port pos end))
(if (< nread size)
(loop (+ pos nread) nread)
nread)))))
(define (read-fobject ftype :optional (port (current-input-port)))
(let1 v (make-u8vector (ftype-size ftype) 0)
(read-fobject!/uv ftype v 0 port)
(get-fobject ftype v 0)))
(define (write-fobject/uv ftype uvector pos
:optional (port (current-output-port)))
(check-arg u8vector? uvector)
(%check-size ftype uvector pos 'src)
(write-block uvector port pos (+ pos (ftype-size ftype))))
(define (write-fobject fobject :optional (port (current-output-port)))
(write-fobject/uv (fobject-type fobject)
(fobject-storage fobject)
(fobject-offset fobject)
port))
;; NB: support endian switch
(define (fobject-ref/uv ftd slot uvector pos)
(let1 s (%get-slot-desc ftd slot)
((ftype-getter (ftype:slot-type s))
uvector (+ pos (ftype:slot-position s)))))
(define (fobject-set!/uv ftd slot uvector pos val)
(let1 s (%get-slot-desc ftd slot)
((ftype-putter (ftype:slot-type s))
uvector (+ pos (ftype:slot-position s)) val)))
(define (fobject-ref obj slot)
(fobject-ref/uv (fobject-type obj) slot
(fobject-storage obj) (fobject-offset obj)))
(define (fobject-set! obj slot val)
(fobject-set!/uv (fobject-type obj) slot
(fobject-storage obj) (fobject-offset obj) val))
;; Initializes byte vector v, returns fobject of type ftype.
;; TODO: allow constructing fobjects other than fstructs.
(define (init-fobject! ftype v pos . initargs)
(let loop ([args initargs])
(cond [(null? args) (%make-fobject ftype v 0)]
[(null? (cdr args)) (error "odd number of initargs:" initargs)]
[(not (keyword? (car args)))
(error "keyword required for initarg, but got:" (car args))]
[else (let1 slot (string->symbol (keyword->string (car args)))
(fobject-set!/uv ftype slot v pos (cadr args)))
(loop (cddr args))])))
(define (make-fobject ftype . initargs)
(let1 v (make-u8vector (ftype-size ftype) 0)
(apply init-fobject! ftype v 0 initargs)))
(define (fobject-copy obj)
(let ([type (fobject-type obj)]
[off (fobject-offset obj)])
(%make-fobject type
(u8vector-copy (fobject-storage obj)
off (+ off (ftype-size type)))
0)))
;; TODO: Should it be a bytewise copy, or should adjust endian, padding etc?
;; Should it check types, or just blindly copy the vector?
(define (fobject-copy!/uv dest-uvector pos src)
(%check-size (fobject-type src) dest-uvector pos 'dest)
(uvector-copy! dest-uvector pos
(fobject-storage src)
(fobject-offset src)))
(define (fobject-copy! dest src)
;; TODO: check type compatibility?
(let ([dest-vec (fobject-storage dest)]
[dest-off (fobject-offset dest)])
(%check-size (fobject-type src) dest-vec dest-off 'dest)
(uvector-copy! dest-vec dest-off
(fobject-storage src)
(fobject-offset src))
dest))
;;========================================================================
;; farray
;;
;;========================================================================
;; High-level macro
;;
;; define-fstruct-type name ctor-name pred-name (slot-spec ...) options ...
;; Creates ftype:struct, and defines the following procedures.
;;
;; Constructor & filler
;;
;; make-NAME . initargs => fstruct
;; init-NAME! uvector pos . initargs
;;
;; Accessors and modifiers
;;
;; NAME-SLOT fstruct => object
;; NAME-SLOT-set! fstruct val => void
;; get-NAME-SLOT uvector pos :optional endian => object
;; put-NAME-SLOT! uvector pos val :optional endian
;;
;; NAME is bound to a newly created fstruct-type
;;
;; <slot-spec> := (slot-name ftype-expr) ;FTYPE-EXPR is evaluated.
;;
(define-macro (define-fstruct-type name ctor-name pred-name slots . options)
(let* ([yname (unwrap-syntax name)]
[maker (cond
[(or (symbol? ctor-name) (identifier? ctor-name)) ctor-name]
[(eq? ctor-name #t) (string->symbol #`"make-,yname")]
[(eq? ctor-name #f) #f]
;; TODO: support inheritance like define-record-type
[else (error "invalid define-fstruct-type: ctor-name \
must be a symbol or a boolean, but got:"
ctor-name)])]
[pred (cond
[(or (symbol? pred-name) (identifier? pred-name)) pred-name]
[(eq? pred-name #t) (string->symbol #`",|yname|?")]
[(eq? pred-name #f) #f]
[else (error "invalid define-fstruct-type: pred-name \
must be a symbol or a boolean, but got:"
pred-name)])]
[initializer (string->symbol #`"init-,|yname|!")])
;; Kludge to get hygienity
(define (->id x) ((with-module gauche.internal make-identifier) x
(find-module 'binary.ftype) '()))
(define (make-slot-procs sname type)
(let ([.ref (string->symbol #`",|yname|-,|sname|")]
[.set! (string->symbol #`",|yname|-,|sname|-set!")]
[.get (string->symbol #`"get-,|yname|-,|sname|")]
[.put! (string->symbol #`"put-,|yname|-,|sname|!")])
`(begin
(define (,.ref obj)
(,(->id 'fobject-ref) obj ',sname))
(define (,.set! obj val)
(,(->id 'fobject-set!) obj ',sname val))
(define (,.get vec pos)
(,(->id 'fobject-ref/uv) ,name ',sname vec pos))
(define (,.put! vec pos val)
(,(->id 'fobject-set!/uv) ,name ',sname vec pos val)))))
`(begin
(define ,name (,(->id 'make-fstruct-type) ',yname
(list
,@(map (^s `(list ',(unwrap-syntax (car s)) ,(cadr s)))
slots))
#f #f))
,(if maker
`(define (,maker . initargs)
(apply ,(->id 'make-fobject) ,name initargs))
'(begin))
,(if pred
`(define (,pred obj)
(and (fobject? obj)
(eq? (fobject-type obj) ,name)))
'(begin))
(define (,initializer v pos . initargs)
(apply ,(->id 'init-fobject!) ,name v pos initargs))
,@(map (^s (make-slot-procs (unwrap-syntax (car s)) (cadr s))) slots)
)))
;;
;; Debugging aid
;;
(define (describe-fstruct-type fd)
(print "fstruct slots:")
(dolist [slot (ftype:struct-slots fd)]
(format #t " ~3d ~10a::~a~%"
(ftype:slot-position (cdr slot))
(car slot)
(ftype-name (ftype:slot-type (cdr slot))))))
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