(/show0 "host-c-call.lisp 12")
-(define-alien-type-class (c-string :include pointer :include-args (to)))
+(define-alien-type-class (c-string :include pointer :include-args (to))
+ (external-format :default :type keyword)
+ (element-type 'character :type (member character base-char)))
-(define-alien-type-translator c-string ()
+(define-alien-type-translator c-string
+ (&key (external-format :default)
+ (element-type 'character))
(make-alien-c-string-type
- :to (parse-alien-type 'char (sb!kernel:make-null-lexenv))))
+ :to (parse-alien-type 'char (sb!kernel:make-null-lexenv))
+ :element-type element-type
+ :external-format external-format))
+
+(defun c-string-external-format (type)
+ (let ((external-format (alien-c-string-type-external-format type)))
+ (if (eq external-format :default)
+ (default-c-string-external-format)
+ external-format)))
(define-alien-type-method (c-string :unparse) (type)
- (declare (ignore type))
- 'c-string)
+ (list 'c-string
+ :external-format (alien-c-string-type-external-format type)
+ :element-type (alien-c-string-type-element-type type)))
(define-alien-type-method (c-string :lisp-rep) (type)
(declare (ignore type))
'(or simple-string null (alien (* char))))
+(defun c-string-needs-conversion-p (type)
+ #+sb-xc-host
+ t
+ #-sb-xc-host
+ (let ((external-format (sb!impl::get-external-format
+ ;; Can't use C-STRING-EXTERNAL-FORMAT here,
+ ;; since the meaning of :DEFAULT can change
+ ;; when *DEFAULT-C-STRING-EXTERNAL-FORMAT*
+ ;; changes.
+ (alien-c-string-type-external-format type))))
+ (not (and external-format
+ (or (eq (caar external-format) :ascii)
+ ;; On non-SB-UNICODE all latin-1 codepoints will fit
+ ;; into a base-char, on SB-UNICODE they won't.
+ #!-sb-unicode
+ (eq (caar external-format) :latin-1))))))
+
(define-alien-type-method (c-string :naturalize-gen) (type alien)
- (declare (ignore type))
`(if (zerop (sap-int ,alien))
nil
- (%naturalize-c-string ,alien)))
+ ;; Check whether we need to do a full external-format
+ ;; conversion, or whether we can just do a cheap byte-by-byte
+ ;; copy of the c-string data.
+ ;;
+ ;; On SB-UNICODE we can never do the cheap copy, even if the
+ ;; external format and element-type are suitable, since
+ ;; simple-base-strings may not contain ISO-8859-1 characters.
+ ;; If we need to check for non-ascii data in the input, we
+ ;; might as well go through the usual external-format machinery
+ ;; instead of rewriting another version of it.
+ ,(if #!+sb-unicode t
+ #!-sb-unicode (c-string-needs-conversion-p type)
+ `(sb!alien::c-string-to-string ,alien
+ (c-string-external-format ,type)
+ (alien-c-string-type-element-type
+ ,type))
+ `(%naturalize-c-string ,alien))))
(define-alien-type-method (c-string :deport-gen) (type value)
- (declare (ignore type))
- `(etypecase ,value
- (null (int-sap 0))
- ((alien (* char)) (alien-sap ,value))
- (simple-base-string (vector-sap ,value))
- (simple-string (vector-sap (coerce ,value 'simple-base-string)))))
-
-(/show0 "host-c-call.lisp 42")
-
-(define-alien-type-class (utf8-string :include pointer :include-args (to)))
-
-(define-alien-type-translator utf8-string ()
- (make-alien-utf8-string-type
- :to (parse-alien-type 'char (sb!kernel:make-null-lexenv))))
-
-(define-alien-type-method (utf8-string :unparse) (type)
- (declare (ignore type))
- 'utf8-string)
-
-(define-alien-type-method (utf8-string :lisp-rep) (type)
- (declare (ignore type))
- '(or simple-string null (alien (* char))))
-
-(define-alien-type-method (utf8-string :naturalize-gen) (type alien)
- (declare (ignore type))
- `(if (zerop (sap-int ,alien))
- nil
- (%naturalize-utf8-string ,alien)))
-
-(define-alien-type-method (utf8-string :deport-gen) (type value)
- (declare (ignore type))
`(etypecase ,value
(null (int-sap 0))
((alien (* char)) (alien-sap ,value))
- (simple-base-string (vector-sap ,value))
- (simple-string (vector-sap (%deport-utf8-string ,value)))))
+ ;; FIXME: GC safety alert! These SAPs are not safe, since the
+ ;; Lisp string can move. This is not hard to arrange, for example
+ ;; the following will fail very quickly on a SB-UNICODE build:
+ ;;
+ ;; (setf (bytes-consed-between-gcs) 4096)
+ ;; (define-alien-routine "strcmp" int (s1 c-string) (s2 c-string))
+ ;;
+ ;; (loop
+ ;; (let ((string "hello, world"))
+ ;; (assert (zerop (strcmp string string)))))
+ ;;
+ ;; (This will appear to work on post-0.9.8.19 GENCGC, since
+ ;; the GC no longer zeroes memory immediately after releasing
+ ;; it after a minor GC. Either enabling the READ_PROTECT_FREE_PAGES
+ ;; #define in gencgc.c or modifying the example so that a major
+ ;; GC will occasionally be triggered would unmask the bug).
+ ;;
+ ;; The pure VECTOR-SAP branch for the SIMPLE-BASE-STRING case
+ ;; will generally be very hard to trigger on GENCGC (even when
+ ;; threaded) thanks to GC conservativeness. It's mostly a problem
+ ;; on cheneygc. -- JES, 2006-01-13
+ (simple-base-string
+ ,(if (c-string-needs-conversion-p type)
+ ;; If the alien type is not ascii-compatible (+SB-UNICODE)
+ ;; or latin-1-compatible (-SB-UNICODE), we need to do
+ ;; external format conversion.
+ `(vector-sap (string-to-c-string ,value
+ (c-string-external-format ,type)))
+ ;; Otherwise we can just pass it uncopied.
+ `(vector-sap ,value)))
+ ;; This case, on the other hand, will cause trouble on GENCGC, since
+ ;; we're taking the SAP of a immediately discarded temporary -> the
+ ;; conservativeness doesn't protect us.
+ ;; -- JES, 2006-01-13
+ (simple-string
+ (vector-sap (string-to-c-string ,value
+ (c-string-external-format ,type))))))
(/show0 "host-c-call.lisp end of file")
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