Re: fast serialization of huge bit vectors?

just in case somebody wants a quick hack for now. Something like this
should work:

(define-module bitvector-io
  (use gauche.bitvector)
  (use binary.io)
  (use runtime-compile)
  (export read-bitvector
          write-bitvector))

(select-module bitvector-io)

(compile-and-load
 `((inline-stub
    (define-cproc read-bitvector-bits (v::<bitvector> p::<input-port>)
      (let* ((bytes::ScmSize (* (+ (/ (SCM_BITVECTOR_SIZE v) SCM_WORD_BITS)
                                   (!= (% (SCM_BITVECTOR_SIZE v) SCM_WORD_BITS) 0))
                                (/ SCM_WORD_BITS 8)))
             (r::ScmSize (Scm_Getz (cast (char *) (SCM_BITVECTOR_BITS v)) bytes p)))
        (return (SCM_MAKE_BOOL (== bytes r)))))
    (define-cproc write-bitvector-bits (v::<bitvector> p::<output-port>)
      (Scm_Putz (cast (char *) (SCM_BITVECTOR_BITS v))
                (* (+ (/ (SCM_BITVECTOR_SIZE v) SCM_WORD_BITS)
                      (!= (% (SCM_BITVECTOR_SIZE v) SCM_WORD_BITS) 0))
                   (/ SCM_WORD_BITS 8))
                p)
      (return SCM_UNDEFINED))))
 '(read-bitvector-bits write-bitvector-bits))

(define (read-bitvector)
  (let1 len (read-u64)
    (rlet1 r (make-bitvector len)
           (when (not (read-bitvector-bits r (current-input-port)))
             (error "read-bitvector: read failure")))))

(define (write-bitvector v)
  (write-u64 (bitvector-length v))
  (write-bitvector-bits v (current-output-port)))

;; (let1 v #*11111111111111111111111111111111111111111111111111111111111111111 (with-output-to-file "/tmp/v" (lambda() (write-bitvector v))) (equal? v (with-input-from-file "/tmp/v" (lambda() (read-bitvector)))))