Making zo-marshal more like C and not with large byte strings

collects/compiler/zo-marshal.rkt

@@ -1,5 +1,6 @@
 #lang scheme/base
 (require compiler/zo-structs
+         unstable/byte-counting-port
          scheme/match
          scheme/contract
          scheme/local
@@ -41,34 +42,37 @@
                  (when (closure? v)
                    (hash-set! shared v (add1 (hash-count shared))))
                  #t))))
-     (parameterize ([current-wrapped-ht wrapped])
+     (define (v-skipping v)
-       (traverse-prefix prefix visit)
+       (define skip? #t)
-       (traverse-form form visit))
-     (let* ([s (open-output-bytes)]
-            [out (make-out s (lambda (v) (hash-ref shared v #f)) wrapped)]
-            [offsets
-             (map (lambda (k*v)
-                    (define v (cdr k*v))
-                    (begin0
-                      (file-position s)
-                      (out-anything v (make-out
-                                       s
-                                       (let ([skip? #t])
        (lambda (v2)
          (if (and skip? (eq? v v2))
              (begin
                (set! skip? #f)
                #f)
              (hash-ref shared v2 #f))))
-                                       wrapped))))
+     (parameterize ([current-wrapped-ht wrapped])
+       (traverse-prefix prefix visit)
+       (traverse-form form visit))
+     (local [(define in-order-shareds 
                (sort (hash-map shared (lambda (k v) (cons v k)))
                      <
-                        #:key car))]
+                     #:key car))
-            [post-shared (file-position s)]
+             (define (write-all outp)
-            [all-short? (post-shared . < . #xFFFF)]
+               (define offsets
-            [version-bs (string->bytes/latin-1 (version))])
+                 (for/list ([k*v (in-list in-order-shareds)])
-       (out-data (list* max-let-depth prefix (protect-quote form)) out)
+                   (define v (cdr k*v))
-       (let ([res (get-output-bytes s)])
+                   (begin0
+                     (file-position outp)
+                     (out-anything v (make-out outp (v-skipping v) wrapped)))))
+               (define post-shared (file-position outp))
+               (out-data (list* max-let-depth prefix (protect-quote form)) 
+                         (make-out outp (lambda (v) (hash-ref shared v #f)) wrapped))
+               (values offsets post-shared (file-position outp)))
+             (define counting-p (make-byte-counting-port))
+             (define-values (offsets post-shared all-forms-length)
+               (write-all counting-p))
+             (define all-short? (post-shared . < . #xFFFF))
+             (define version-bs (string->bytes/latin-1 (version)))]
        (write-bytes #"#~" outp)
        (write-bytes (bytes (bytes-length version-bs)) outp)
        (write-bytes version-bs outp)
@@ -77,8 +81,9 @@
        (for ([o (in-list offsets)])
          (write-bytes (integer->integer-bytes o (if all-short? 2 4) #f #f) outp))
        (write-bytes (int->bytes post-shared) outp)
-         (write-bytes (int->bytes (bytes-length res)) outp)
+       (write-bytes (int->bytes all-forms-length) outp)
-         (write-bytes res outp)))]))
+       (write-all outp)
+       (void))]))
 
 ;; ----------------------------------------