40 lines
896 B
Factor
Executable File
40 lines
896 B
Factor
Executable File
! Copyright (C) 2006 Doug Coleman
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! See http://factorcode.org/license.txt for BSD license.
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USING: kernel math sequences sequences.private namespaces
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words io io.binary io.files io.streams.string quotations
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definitions checksums ;
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IN: checksums.crc32
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: crc32-polynomial HEX: edb88320 ; inline
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: crc32-table V{ } ; inline
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256 [
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8 [
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dup even? >r 2/ r> [ crc32-polynomial bitxor ] unless
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] times >bignum
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] map 0 crc32-table copy
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: (crc32) ( crc ch -- crc )
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>bignum dupd bitxor
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mask-byte crc32-table nth-unsafe >bignum
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swap -8 shift bitxor ; inline
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SINGLETON: crc32
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INSTANCE: crc32 checksum
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: init-crc32 drop >r HEX: ffffffff dup r> ; inline
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: finish-crc32 bitxor 4 >be ; inline
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M: crc32 checksum-bytes
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init-crc32
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[ (crc32) ] each
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finish-crc32 ;
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M: crc32 checksum-lines
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init-crc32
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[ [ (crc32) ] each CHAR: \n (crc32) ] each
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finish-crc32 ;
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