Re^3: reading packed unsigned long long

Rejected how? "Invalid type 'Q' in unpack"? Note the comment at the bottom of my previous post. Your Perl can't handle 64-bit numbers because your processor can't handle them natively. You could build a Perl that supports 64-bit numbers (even if your processor doesn't handle them natively), or you could use Math::BigInt to hold such a big number. I'll even code the solution if you tell me which byte ordering you want to use.

turns out that the last two fields are six bytes and eight bytes

There's no unpack specifier for reading 6-byte ints. j and J might be 6-bytes on your machine, but I'd be surprised. Nobody uses 6-byte ints. That's part of why I said your data is messed up.

You expect         To get that        What you have
----------------   ----------------   ----------------
0                  0000000000000000
5967*              000000000000174f   000000000000174f
74                 000000000000004a     0100000000004a
74                 000000000000004a   000000000000004a
[download]

* — You actually said 5976. I presume that's a typo.

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Re^4: reading packed unsigned long long by Spooky (Beadle) on Jul 15, 2009 at 15:32 UTC
Hi - ..I get "Invalid type in unpack: 'Q'" ..you're right, "J" & "j" don't cut it either... ...thanks for the offer, what's the standard byte order? I also want to look into "Math::BigInt" - I've never heard of this: is it a library of Perl functions?	[reply]
Re^5: reading packed unsigned long long by ikegami (Patriarch) on Jul 15, 2009 at 15:45 UTC
what's the standard byte order? There isn't one. You're either using your local machine's byte order (which happens to be big-endian) or you're using big-endian explicitly. The question was whether you want to use the local machine's byte order (whatever it might be) or to use big-endian explicitly. I also want to look into "Math::BigInt" - I've never heard of this: is it a library of Perl functions? Math::BigInt	[reply]
Re^6: reading packed unsigned long long by Spooky (Beadle) on Jul 21, 2009 at 13:59 UTC
It may not be the most efficient Perl but I was able to get the results I wanted using the following (not without some trial and error!) - $raw = '000000000000174f0100000000004a000000000000004a'; $x = hex(unpack("H",(substr($raw,9,6)))) ; $y = hex(unpack("H",(substr($raw,15,8)))) ; The output was the integer value of 74 in both cases which is what I was shooting for...	[reply]