() steve tell <[email protected]>
() Wed, 9 Jun 2010 00:04:41 -0400 (EDT)
But is there any way to copy the contents of bitvector a to another
bitvector b of the same size, short of iterating over the elements?
You can use ‘bit-set*!’, something like:
(define (copy-bit-vector orig)
(let ((copy (make-uniform-vector (uniform-vector-length orig) #t)))
(bit-invert! copy)
(bit-set*! copy orig #t)
copy))
(write-line (copy-bit-vector #*111111111111111))
#*111111111111111
This uses Guile 1.4.x-isms for constructing the bit vector; YMMV.
Here is a more elegant variant that does not work under Guile 1.4.1.118,
even though it should (a bug):
(define (copy-bit-vector orig)
(let ((copy (make-uniform-vector (uniform-vector-length orig) #t)))
(bit-set*! copy orig #f)
copy))
The first variant creates all-1s, "manually" inverts, then does a logical OR.
The second creates all-1s, then does a logical AND-NOT.
BTW, to answer the previous question (re shift), you can avoid shifting by
specifying a non-bitvec uniform vector as the second arg to ‘bit-set*!’.
thi
