! :folding=indent:collapseFolds=0:

! $Id$
!
! Copyright (C) 2003, 2004 Slava Pestov.
! 
! Redistribution and use in source and binary forms, with or without
! modification, are permitted provided that the following conditions are met:
! 
! 1. Redistributions of source code must retain the above copyright notice,
!    this list of conditions and the following disclaimer.
! 
! 2. Redistributions in binary form must reproduce the above copyright notice,
!    this list of conditions and the following disclaimer in the documentation
!    and/or other materials provided with the distribution.
! 
! THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
! INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
! FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
! DEVELOPERS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
! SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
! PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
! OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
! WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
! OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
! ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

IN: random
USE: kernel
USE: lists
USE: math

: power-of-2? ( n -- ? )
    dup dup neg bitand = ;

: (random-int-0) ( n bits val -- n )
    3dup - + pred 0 < [
        2drop (random-int) 2dup swap mod (random-int-0)
    ] [
        nip nip
    ] ifte ;

: random-int-0 ( max -- n )
    succ dup power-of-2? [
        (random-int) * -31 shift
    ] [
        (random-int) 2dup swap mod (random-int-0)
    ] ifte ;

: random-int ( min max -- n )
    dupd swap - random-int-0 + ;

: random-boolean ( -- ? )
    0 1 random-int 0 = ;

: random-digit ( -- digit )
    0 9 random-int ;