Floats to Bytes and back again

David N. Smith dnsmith at watson.ibm.com
Mon Nov 2 16:33:41 UTC 1998


At 1:59 -0500 10/31/98, Travis or Kerrin Griggs wrote:
>I'm trying to create a typed FloatArray. There's not a lot in the system
>for converting floats to bytes, so I hacked up something where I use
>basicAt: to extract the first and second dwords, and then strip the
>dwords down a byte at a time (a bit more complex then VW where
>changeClassToThatOf: #[] works handily). But now that I've got it ripped
>down into 8 bytes, I can't figure out how to get the float back again. I
>put the 4 byte chunks back together (via bitShift: and +), but can't use
>basicAt:put: on an instance of a float. Feature, bug,...? Is there a
>better way to do this anyway?
>
>Travis Griggs

Look at Float>>asTrueFraction; it tears apart a float and builds a fraction
out of the same bits. Reverse conversion is done by sending #asFloat to the
fraction; an identical float is produced.
_______________________________
David N. Smith
IBM T J Watson Research Center
Hawthorne, NY
_______________________________
Any opinions or recommendations
herein are those of the author
and not of his employer.





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