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Re: Problem with reading 4-byte floats from file on Intel
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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: Tue, 04 Dec 2007 12:25:08 -0500

Hi folks,

More strange behavior...  sorry for the length of this message.

After more experimenting, I have come up with the following:

1. You may recall that this is my main line of code

set floatList to read file_alias from 0 for 512 as small real

Here is a complete short script:

on run
	set file_alias to choose file
	set floatList to read file_alias from 0 for 512 as small real
end run

If I compile this script as an application (or an application bundle) on my Intel Mac, I can click on the app and run it once. The 2nd time I try to run it, the following dialog is displayed "Could not run this script because of a numeric overflow in the script. -2702"

If I change the "512" to "256" in the script, all is well, and I can launch the app many times in a row. Is there some limitation that I need to be aware of for memory allocation? I am concerned that this might somehow be machine-dependent. Is it?

2. The "read as small real" operation seems to be byte swapped. So a file containing the bytes 01 02 03 04, read in as a small real in AppleScript, appears as 04 03 02 01. I assume that this means that the Script Editor runs its scripts through Rosetta??

With this small script:

on run
	set file_alias to choose file
	set floatList to read file_alias from 0 for 256 as small real
	display alert "first float is: " & (real 1 in floatList as text)
end run

compare the result of the first float to this in the Terminal app:

od -vf -N 16 your_file_name


By the way, this script is designed to be launched from inside a shell script inside an Installer. The files I need to test are 2GB each, but I only need to read the first 128 floats.


As always, any help is GREATLY appreciated.

           - Rick

On 12/4/2007 9:06 AM, email@hidden wrote:
Hello JJ,

I'll generate a small example and post.

How do you generate a list of scripting additions?

      - Rick

On 12/4/2007 4:05 AM, jj wrote:
Has anybody else had a successful experience reading 4-byte floats (aka
"small real") with AppleScript (especially on an Intel Mac)?

No errors here: Mac Mini Intel, OS X 10.4.11.

Tested in both Smile and Script Editor.

Maybe you can upload a sample file somewhere and post a list of scripting
additions in your OS?


jj

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