Re: Problem with reading 4-byte floats from file on Intel
Re: Problem with reading 4-byte floats from file on Intel
- Subject: Re: Problem with reading 4-byte floats from file on Intel
- From: email@hidden
- Date: Wed, 05 Dec 2007 08:12:35 -0500
Hi jj,
The purpose of my script was to test a binary file that contains 4-byte
floats (aka "small real") in a known format to see if the file was
big-endian or little-endian.
The fact that the script ran fine on your Intel Mac but not on mine
tells that might be a problem with reading lots of objects from a binary
file. When I reduced the number of bytes I tried to read from 512 bytes
(128 floats) to (for example) 128 bytes, everything was fine even on my
Intel Mac. So I could certainly read and process one float at a time,
if I could figure out how to do it. In AppleScript I'm not sure how to
read 4 bytes, swap them (but only on Intel Mac to simulate a little
endian file read), coerce to "small real", and then test. Or maybe
there's a better way.
Thanks again for all of your time,
- Rick
On 12/5/2007 7:57 AM, jj wrote:
Well, you could swap bytes before attempting to read (if that is the real
issue)... But noone of the methods I know may be faster than your C tool...
jj
* BTW, I never read a specific binary file known to contain numbers. I used
in my test a random text file, but I guess it's the same: it will just read
double-bytes and interpret them as small reals.
Hello jj,
I was reporting my experiences with Mac OS X 10.4, not 10.5. But it is
good to know that my future testing with 10.5 would also fail.
Having found out on a non-Apple web page that (apparently) AppleScript
is always reading binary files in big-endian mode, I have abandoned this
script. I wrote a C command line tool in just a few minutes that did
exactly what I wanted.
Thanks for your help, everybody. If there is more information on how to
do this in AppleScript, I am still interested!
- Rick
On 12/4/2007 7:35 PM, jj wrote:
First, running Leopard I do reiterate I get an error.
Ooops! I didn't read before this issue was Leopard-related. I thot it was
only Intel-related.
I can only confirm that reading small reals works fine in my machine, OS X
10.4.11 ;-)
jj
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