Reading Binary Data in Little Endian Format

[Dave]

Hi Mark,

Great! Thanks a lot. I think it would be good to have an Endian  
Converter built into RunRev - would save a lot of mucking about.

One more thing (isn't there always?!). Is there anyway to read back  
the current position of the file?

Thanks again
All the Best
Dave

On 8 Jan 2008, at 13:23, Mark Smith wrote:

> That's right - the initialization figures out the endianness of the  
> system it's running on. It's necessary to know the endianness of  
> the system it's running on so that it does the right thing with  
> it's inputs.
>
> For instance, in your case,  the input is little-endian whatever  
> kind of system you're running, so if your system is also little- 
> endian, it doesn't need to reverse the bytes before decoding,  
> whereas if your system is big-endian, it knows it has to reverse  
> the bytes before decoding.
> The bug (now fixed in 2.9 beta) was with the 'n' and 'N' binary  
> decode specifiers, which aren't used in the library, so weren't a  
> factor.
>
> Assuming your case is unsigned, little-endian integers, you'd use  
> getUIntLE().
>
> Best,
>
> Mark
>
>
>
> On 8 Jan 2008, at 12:00, Dave wrote:
>
>> Hi Mark,
>>
>> Thanks a bunch! I was just playing binaryEncode/Decode when you  
>> mail popped up. I've downloaded the stack. One quick question  
>> though. In the Initialization you set the the endian flag, is this  
>> is based on the type of system you are running on? e.g. (Big or  
>> Little Endian?). If so is this because of the bug you mentioned in  
>> the readme file?
>>
>>  Thanks again and All the Best
>> Dave
>>
>> On 8 Jan 2008, at 11:34, Mark Smith wrote:
>>
>>> Dave, you can download a small library I wrote for exactly this  
>>> sort of thing:
>>> go to  http://www.futility.co.uk/futsoft/revolutionstuff.html
>>>
>>> and download libBinConvert.
>>>
>>> If you don't want to have to use yet another library, you can  
>>> just copy the appropriate function ( getIntLE() or getUIntLE() )  
>>> out of the library.
>>>
>>> Best,
>>>
>>> Mark
>>>
>>> On 8 Jan 2008, at 11:19, Dave wrote:
>>>
>>>> Hi,
>>>>
>>>> I've tried a few things, such as:
>>>>
>>>> put empty into myData
>>>> repeat 4 times
>>>> read from file myFile for 1 char
>>>> put it before myData
>>>> end repeat
>>>>
>>>> But this doesn't work - just returns 0.
>>>>
>>>> Not sure how to go about this in RunRev, although in C it was be  
>>>> sooooooooooooooooooooo simple!
>>>>
>>>> All the Best
>>>> Dave
>>>>
>>>> On 8 Jan 2008, at 11:13, Mark Schonewille wrote:
>>>>
>>>>> Hi Dave,
>>>>>
>>>>> You need to write a function to revert the numbers manually.  
>>>>> I'd say that's an easy task to do.
>>>>>
>>>>> Best regards,
>>>>>
>>>>> Mark Schonewille
>>>>>
>>>>> --
>>>>>
>>>>> Economy-x-Talk Consulting and Software Engineering
>>>>> http://economy-x-talk.com
>>>>> http://www.salery.biz
>>>>>
>>>>> Quickly extract data from your HyperCard stacks with  
>>>>> DIFfersifier. http://differsifier.economy-x-talk.com
>>>>>
>>>>>
>>>>> Op 8-jan-2008, om 12:08 heeft Dave het volgende geschreven:
>>>>>
>>>>>> Happy New Year to All!
>>>>>>
>>>>>> Does anyone know of an easy way to read a 4 bytes (32 bit)  
>>>>>> little endian number from a file?
>>>>>>
>>>>>> I am running on a Mac and the file I am trying to process  
>>>>>> *always* is stored in Little Endian Format, for instance:
>>>>>>
>>>>>> The number 0x00000000BC   (188) is stored in the file as:
>>>>>>
>>>>>> 0xBC000000 (a VERY large number!)
>>>>>>
>>>>>> I want to get 188 when I read these four bytes.
>>>>>>
>>>>>> Any ideas???
>>>>>>
>>>>>> Thanks a lot
>>>>>> All the Best
>>>>>> Dave
>>>>>>
>>>>>>
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