feature request

newdep · Post by **newdep** » Mon May 30, 2005 3:27 pm

Hi Lutz,

Is CRC16 and CRC32 an option to have included in newlisp? (On a file and or string...)
Im missing it sometimes and perhpas others do too?
Would be a "nice to have" function for 8.5.10 though ;-)

Regards, Norman.

Sammo · Post by **Sammo** » Mon May 30, 2005 3:39 pm

Until Lutz gets around to it, here is crc32 code that seems to work (i.e., passes standard tests). It is based on Emerson's public domain work.

Can anyone point me to a standard crc16 implementation? I've got one I use at work to generate CRCs for EEPROMs, but I think the algorithm is, shall we say, non-standard.

Code: Select all

;;	crc32
;;	adapted from CMUCL code written by R. Matthew Emerson
;;	<rme@acm.org> in August 1999 and placed in the public domain
;;
;;	examples and test cases
;;	(format "%08X" (crc "ABC")) --> A3830348
;;	(format "%08X" (crc "abc")) --> 352441C2
;;	(format "%08X" (crc "123456789")) --> CBF43926
;;
(define (crc32 buf)
	(update-crc32 0 buf) )

(define (update-crc32 crc buf , i)
	(set 'crc (^ crc 0xFFFFFFFF))
	(dotimes (n (length buf))
		(set 'i (& 0xFF (^ crc (char buf n))))
		(set 'crc (^ (nth i CRC32-TABLE) (>> (& 0x7FFFFFFF (>> crc 1)) 7))) )
	(^ crc 0xFFFFFFFF) )

(setq CRC32-TABLE
   '(0x00000000 0x77073096 0xEE0E612C 0x990951BA 0x076DC419 0x706AF48F
     0xE963A535 0x9E6495A3 0x0EDB8832 0x79DCB8A4 0xE0D5E91E 0x97D2D988
     0x09B64C2B 0x7EB17CBD 0xE7B82D07 0x90BF1D91 0x1DB71064 0x6AB020F2
     0xF3B97148 0x84BE41DE 0x1ADAD47D 0x6DDDE4EB 0xF4D4B551 0x83D385C7
     0x136C9856 0x646BA8C0 0xFD62F97A 0x8A65C9EC 0x14015C4F 0x63066CD9
     0xFA0F3D63 0x8D080DF5 0x3B6E20C8 0x4C69105E 0xD56041E4 0xA2677172
     0x3C03E4D1 0x4B04D447 0xD20D85FD 0xA50AB56B 0x35B5A8FA 0x42B2986C
     0xDBBBC9D6 0xACBCF940 0x32D86CE3 0x45DF5C75 0xDCD60DCF 0xABD13D59
     0x26D930AC 0x51DE003A 0xC8D75180 0xBFD06116 0x21B4F4B5 0x56B3C423
     0xCFBA9599 0xB8BDA50F 0x2802B89E 0x5F058808 0xC60CD9B2 0xB10BE924
     0x2F6F7C87 0x58684C11 0xC1611DAB 0xB6662D3D 0x76DC4190 0x01DB7106
     0x98D220BC 0xEFD5102A 0x71B18589 0x06B6B51F 0x9FBFE4A5 0xE8B8D433
     0x7807C9A2 0x0F00F934 0x9609A88E 0xE10E9818 0x7F6A0DBB 0x086D3D2D
     0x91646C97 0xE6635C01 0x6B6B51F4 0x1C6C6162 0x856530D8 0xF262004E
     0x6C0695ED 0x1B01A57B 0x8208F4C1 0xF50FC457 0x65B0D9C6 0x12B7E950
     0x8BBEB8EA 0xFCB9887C 0x62DD1DDF 0x15DA2D49 0x8CD37CF3 0xFBD44C65
     0x4DB26158 0x3AB551CE 0xA3BC0074 0xD4BB30E2 0x4ADFA541 0x3DD895D7
     0xA4D1C46D 0xD3D6F4FB 0x4369E96A 0x346ED9FC 0xAD678846 0xDA60B8D0
     0x44042D73 0x33031DE5 0xAA0A4C5F 0xDD0D7CC9 0x5005713C 0x270241AA
     0xBE0B1010 0xC90C2086 0x5768B525 0x206F85B3 0xB966D409 0xCE61E49F
     0x5EDEF90E 0x29D9C998 0xB0D09822 0xC7D7A8B4 0x59B33D17 0x2EB40D81
     0xB7BD5C3B 0xC0BA6CAD 0xEDB88320 0x9ABFB3B6 0x03B6E20C 0x74B1D29A
     0xEAD54739 0x9DD277AF 0x04DB2615 0x73DC1683 0xE3630B12 0x94643B84
     0x0D6D6A3E 0x7A6A5AA8 0xE40ECF0B 0x9309FF9D 0x0A00AE27 0x7D079EB1
     0xF00F9344 0x8708A3D2 0x1E01F268 0x6906C2FE 0xF762575D 0x806567CB
     0x196C3671 0x6E6B06E7 0xFED41B76 0x89D32BE0 0x10DA7A5A 0x67DD4ACC
     0xF9B9DF6F 0x8EBEEFF9 0x17B7BE43 0x60B08ED5 0xD6D6A3E8 0xA1D1937E
     0x38D8C2C4 0x4FDFF252 0xD1BB67F1 0xA6BC5767 0x3FB506DD 0x48B2364B
     0xD80D2BDA 0xAF0A1B4C 0x36034AF6 0x41047A60 0xDF60EFC3 0xA867DF55
     0x316E8EEF 0x4669BE79 0xCB61B38C 0xBC66831A 0x256FD2A0 0x5268E236
     0xCC0C7795 0xBB0B4703 0x220216B9 0x5505262F 0xC5BA3BBE 0xB2BD0B28
     0x2BB45A92 0x5CB36A04 0xC2D7FFA7 0xB5D0CF31 0x2CD99E8B 0x5BDEAE1D
     0x9B64C2B0 0xEC63F226 0x756AA39C 0x026D930A 0x9C0906A9 0xEB0E363F
     0x72076785 0x05005713 0x95BF4A82 0xE2B87A14 0x7BB12BAE 0x0CB61B38
     0x92D28E9B 0xE5D5BE0D 0x7CDCEFB7 0x0BDBDF21 0x86D3D2D4 0xF1D4E242
     0x68DDB3F8 0x1FDA836E 0x81BE16CD 0xF6B9265B 0x6FB077E1 0x18B74777
     0x88085AE6 0xFF0F6A70 0x66063BCA 0x11010B5C 0x8F659EFF 0xF862AE69
     0x616BFFD3 0x166CCF45 0xA00AE278 0xD70DD2EE 0x4E048354 0x3903B3C2
     0xA7672661 0xD06016F7 0x4969474D 0x3E6E77DB 0xAED16A4A 0xD9D65ADC
     0x40DF0B66 0x37D83BF0 0xA9BCAE53 0xDEBB9EC5 0x47B2CF7F 0x30B5FFE9
     0xBDBDF21C 0xCABAC28A 0x53B39330 0x24B4A3A6 0xBAD03605 0xCDD70693
     0x54DE5729 0x23D967BF 0xB3667A2E 0xC4614AB8 0x5D681B02 0x2A6F2B94
     0xB40BBE37 0xC30C8EA1 0x5A05DF1B 0x2D02EF8D))

newdep · Post by **newdep** » Mon May 30, 2005 4:25 pm

Thanks Sammo... ill try it right away ;-)

Norman.

newdep · Post by **newdep** » Mon May 30, 2005 4:32 pm

Last week i ran into a nice webpage that had all about compression and crc..
but i forgot it :(..

Thought the TCLlib has also crc32 and crc16 inside the source code is the
complete workout... IIRC ;-)

http://tcllib.sourceforge.net/doc/crc16.html

Norman.

newdep · Post by **newdep** » Mon May 30, 2005 4:40 pm

The crc32 works...thought its a little slow ;-)
A 650Kb file took 1807 ms -->

But it works ;-)

Norman..

Lutz · Post by **Lutz** » Mon May 30, 2005 6:20 pm

Does anybody know a really small implementation?

Lutz

newdep · Post by **newdep** » Mon May 30, 2005 6:41 pm

Hi Lutz,

Im not sure if its an option for NewLisp but perhpas
linking with the Zlib could extend in different way newlisp.

http://www.gzip.org/zlib/ (PS: I like that License ;o)

Norman.

Lutz · Post by **Lutz** » Mon May 30, 2005 11:41 pm

You can use 'import' to make gzip functionality available in newLISP.

Lutz