diff options
| -rw-r--r-- | guix/serialization.scm | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/guix/serialization.scm b/guix/serialization.scm index 9452303730..836ad06caf 100644 --- a/guix/serialization.scm +++ b/guix/serialization.scm @@ -27,6 +27,7 @@ #:use-module ((ice-9 rdelim) #:prefix rdelim:) #:use-module (ice-9 match) #:use-module (ice-9 ftw) + #:use-module (system foreign) #:export (write-int read-int write-long-long read-long-long write-padding @@ -80,6 +81,17 @@ (port port))))) bv)) +(define (sub-bytevector bv len) + "Return a bytevector that aliases the first LEN bytes of BV." + (define max (bytevector-length bv)) + (cond ((= len max) bv) + ((< len max) + ;; Yes, this is safe because the result of each conversion procedure + ;; has its life cycle synchronized with that of its argument. + (pointer->bytevector (bytevector->pointer bv) len)) + (else + (error "sub-bytevector called to get a super bytevector")))) + (define (write-int n p) (let ((b (make-bytevector 8 0))) (bytevector-u32-set! b 0 n (endianness little)) @@ -119,10 +131,9 @@ (define (read-byte-string p) (let* ((len (read-int p)) (m (modulo len 8)) - (bv (get-bytevector-n* p len))) - (or (zero? m) - (get-bytevector-n* p (- 8 m))) - bv)) + (pad (if (zero? m) 0 (- 8 m))) + (bv (get-bytevector-n* p (+ len pad)))) + (sub-bytevector bv len))) (define (read-string p) (utf8->string (read-byte-string p))) |