factor/extra/random/random.factor

56 lines
1.5 KiB
Factor
Executable File

! Copyright (C) 2008 Doug Coleman.
! See http://factorcode.org/license.txt for BSD license.
USING: alien.c-types kernel math namespaces sequences
io.backend io.binary combinators system vocabs.loader
summary ;
IN: random
SYMBOL: system-random-generator
SYMBOL: secure-random-generator
SYMBOL: random-generator
GENERIC: seed-random ( tuple seed -- )
GENERIC: random-32* ( tuple -- r )
GENERIC: random-bytes* ( n tuple -- byte-array )
M: object random-bytes* ( n tuple -- byte-array )
swap [ drop random-32* ] with map >c-uint-array ;
M: object random-32* ( tuple -- r ) 4 random-bytes* le> ;
ERROR: no-random-number-generator ;
M: no-random-number-generator summary
drop "Random number generator is not defined." ;
M: f random-bytes* ( n obj -- * ) no-random-number-generator ;
M: f random-32* ( obj -- * ) no-random-number-generator ;
: random-bytes ( n -- byte-array )
[
dup 4 rem zero? [ 1+ ] unless
random-generator get random-bytes*
] keep head ;
: random ( seq -- elt )
dup empty? [
drop f
] [
[
length dup log2 7 + 8 /i
random-bytes byte-array>bignum swap mod
] keep nth
] if ;
: random-bits ( n -- r ) 2^ random ;
: with-random ( tuple quot -- )
random-generator swap with-variable ; inline
: with-system-random ( quot -- )
system-random-generator get swap with-random ; inline
: with-secure-random ( quot -- )
secure-random-generator get swap with-random ; inline