76 lines
1.9 KiB
Factor
76 lines
1.9 KiB
Factor
! Copyright (C) 2008 Doug Coleman.
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! See http://factorcode.org/license.txt for BSD license.
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USING: alien.c-types kernel math namespaces sequences
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io.backend io.binary combinators system vocabs.loader
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summary math.bitwise ;
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IN: random
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SYMBOL: system-random-generator
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SYMBOL: secure-random-generator
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SYMBOL: random-generator
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GENERIC: seed-random ( tuple seed -- )
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GENERIC: random-32* ( tuple -- r )
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GENERIC: random-bytes* ( n tuple -- byte-array )
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M: object random-bytes* ( n tuple -- byte-array )
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[ random-32* ] curry replicate [ 4 >le ] map concat ;
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M: object random-32* ( tuple -- r ) 4 random-bytes* le> ;
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ERROR: no-random-number-generator ;
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M: no-random-number-generator summary
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drop "Random number generator is not defined." ;
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M: f random-bytes* ( n obj -- * ) no-random-number-generator ;
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M: f random-32* ( obj -- * ) no-random-number-generator ;
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: random-bytes ( n -- byte-array )
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[
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dup 3 mask zero? [ 1+ ] unless
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random-generator get random-bytes*
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] keep head ;
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GENERIC: random ( obj -- elt )
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: random-bits ( n -- r ) 2^ random ;
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<PRIVATE
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: random-integer ( n -- n' )
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dup log2 7 + 8 /i 1+
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[ random-bytes byte-array>bignum ]
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[ 3 shift 2^ ] bi / * >integer ;
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PRIVATE>
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M: sequence random ( seq -- elt )
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[ f ] [
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[ length random-integer ] keep nth
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] if-empty ;
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ERROR: negative-random n ;
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M: integer random ( integer -- integer' )
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{
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{ [ dup 0 = ] [ ] }
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{ [ dup 0 < ] [ negative-random ] }
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[ random-integer ]
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} cond ;
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M: float random ( float -- elt )
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64 random-bits 64 2^ 1- / * ;
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: delete-random ( seq -- elt )
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[ length random-integer ] keep [ nth ] 2keep delete-nth ;
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: with-random ( tuple quot -- )
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random-generator swap with-variable ; inline
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: with-system-random ( quot -- )
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system-random-generator get swap with-random ; inline
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: with-secure-random ( quot -- )
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secure-random-generator get swap with-random ; inline
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