[Resolved] Binary

Bah__Name

Can anyone provide the inverse of the following:

$var = Hexdec(Bin2Hex(strrev(fread($fp, 4))))

If I mis-spell a function name try not to pound me - my actual extract & convert code is working - I shall try and avoid being innaccurate in future 🙁

Your help would be appreciated.

Thanks,

Bah

laserlight

You'll probably need to use [man]pack/man, e.g.

$var = pack("i", $var);

Bah__Name

Thanks, I'll give it a shot.

Bah.

laserlight

Does it work?

Bah__Name

Will have to let you know. Will try later today (fingers crossed). I'm a little concerned by what is meant by 'Machine dependant size and byte order'.
Which machine? Server or client?
I will have to try and then see what format I end up with.

Weedpacket

Originally posted by Bah! Name
Which machine? Server or client?

The machine the script is running on, of course: that's the server.

Bah__Name

Thanks, yeah that has worked.

Now I have a new problem. <Sigh> One little chunk at a time....

I am getting problems from an otherwise successful technique

$var = hexdec(bin2hex(strrev(fread($fp, 4))));

except when I do

$var = hexdec(bin2hex(strrev(fread($fp, $SizeOfData))));

where strlen($SizeOfData) returns something like 300800.

Even if I do nothing to it but convert and reconvert pack via pack, I am getting #INF. If I do the exact same thing with much smaller byte lengths (variables), it completely works. Its purely on the big stuff.

Can anyone see a workaround or a fix for this?

Thanks

laserlight

If strlen($SizeOfData) returns 300800, then you're dealing with a pretty large amount of data.
For example, a googol (1e100), in decimal representation, would have a string length of 101.

Are you sure that you arent confusing the size of the data with the data itself?

Bah__Name

Thanks for helping me so far Laserlight (well, everyone also)

I was slightly wrong- strlen is returning 65000(ish).

Are you sure that you arent confusing the size of the data with the data itself?

God I am - I meant strlen($var) :rolleyes:

I'm fooling with waveform data :queasy:
I need to do some mathematics on this chunk.

my files are circa 65kb.
even if I split $var using sustr( ) into 25000 bytes (I think they're bytes), I get the following results

strlen($subString);  //25000
strlen(strrev($subString));     // 25000
strlen(bin2hex($subString)))  // 50000 (?)
strlen(hexdec(bin2hex(strrev($subString)))); // 6 --> #INF

My difficulties might stem from not understanding waveform data, as well as everything else. I am reading my PHP cookbook from the front when I can to help myself too.