- ;; This thing is externally visible, so compiling meta-information
- ;; is more important than byte-compiling it; but it's otherwise
- ;; suitable for byte-compilation.
- ;;
- ;; (As long as the byte compiler isn't capable of compiling
- ;; meta-information such as the argument list required by functions
- ;; (as in sbcl-0.6.12, anyway), it's not suitable for compiling
- ;; externally visible things like CL:INSPECT even if their speed
- ;; requirements are small enough that it'd otherwise be OK. If some
- ;; later version of the byte compiler learns to compile such
- ;; meta-information, we'll probably change the implementation of
- ;; this idiom so that it causes byte compilation of the thing after
- ;; all.)
- (defvar *optimize-external-despite-byte-compilation*
- '(optimize (speed 1)
- ;; still might as well be as small as possible..
- (space 3))))
+;;; Constructing shortish strings one character at a time. More efficient then
+;;; a string-stream, as can directly use simple-base-strings when applicable,
+;;; and if the maximum size is know doesn't need to copy the result at all --
+;;; but if the result is going to be HUGE, string-streams will win.
+(defmacro with-push-char ((&key (element-type 'character) (initial-size 28)) &body body)
+ (with-unique-names (string size pointer)
+ `(let* ((,size ,initial-size)
+ (,string (make-array ,size :element-type ',element-type))
+ (,pointer 0))
+ (declare (type (integer 0 ,sb!xc:array-dimension-limit) ,size)
+ (type (integer 0 ,(1- sb!xc:array-dimension-limit)) ,pointer)
+ (type (simple-array ,element-type (*)) ,string))
+ (flet ((push-char (char)
+ (declare (optimize (sb!c::insert-array-bounds-checks 0)))
+ (when (= ,pointer ,size)
+ (let ((old ,string))
+ (setf ,size (* 2 (+ ,size 2))
+ ,string (make-array ,size :element-type ',element-type))
+ (replace ,string old)))
+ (setf (char ,string ,pointer) char)
+ (incf ,pointer))
+ (get-pushed-string ()
+ (let ((string ,string)
+ (size ,pointer))
+ (setf ,size 0
+ ,pointer 0
+ ,string ,(coerce "" `(simple-array ,element-type (*))))
+ ;; This is really local, so we can be destructive!
+ (%shrink-vector string size)
+ string)))
+ ,@body))))