56 lines
		
	
	
		
			1.5 KiB
		
	
	
	
		
			Factor
		
	
	
		
			Executable File
		
	
			
		
		
	
	
			56 lines
		
	
	
		
			1.5 KiB
		
	
	
	
		
			Factor
		
	
	
		
			Executable File
		
	
! 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 ;
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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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    swap [ drop random-32* ] with map >c-uint-array ;
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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 4 rem zero? [ 1+ ] unless
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        random-generator get random-bytes*
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    ] keep head ;
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: random ( seq -- elt )
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    dup empty? [
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        drop f
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    ] [
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        [
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            length dup log2 7 + 8 /i
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            random-bytes byte-array>bignum swap mod
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        ] keep nth
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    ] if ;
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: random-bits ( n -- r ) 2^ random ;
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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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