finding length of encrypted(binary) string

linuxfan has asked for the wisdom of the Perl Monks concerning the following question:

Hi, My perl script reads an encrypted string from a server. It then calculates the length of this string and sends this number along with the string back to the server. I am using:

$str = read_str_from_server($args);
$len = length $str;
send_str_to_server($str,$len);

Based on the server response, I think that the above method fails for certain values of $str and $len. Is there an alternate function to count the nubmer of "bytes" in the encrypted string?

Thanks!

Comment on finding length of encrypted(binary) string

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Re: finding length of encrypted(binary) string by bart (Canon) on Dec 03, 2004 at 22:49 UTC
You can enforce the string to be treated as pure bytes, by pushing it through an incantation of pack. Then, length will work. `my $bytes_string = pack 'C0a*', $string; my $bytecount = length $bytes_string;` [download]	[reply] [d/l]
Re: finding length of encrypted(binary) string by BrowserUk (Patriarch) on Dec 03, 2004 at 22:29 UTC
Sounds like your binary data is being mistaken for unicode data. Using the bytes pragma, optionally localised around the call to length should fix the problem. `$s = "\x{200}\x{400}\x{301}"; print length $s; 3 print do{ use bytes; length $s }; 6` [download] Examine what is said, not who speaks. "But you should never overestimate the ingenuity of the sceptics to come up with a counter-argument." -Myles Allen "Think for yourself!" - Abigail "Time is a poor substitute for thought"--theorbtwo "Efficiency is intelligent laziness." -David Dunham "Memory, processor, disk in that order on the hardware side. Algorithm, algorithm, algorithm on the code side." - tachyon	[reply] [d/l]
Re^2: finding length of encrypted(binary) string by linuxfan (Beadle) on Dec 07, 2004 at 23:55 UTC
Thanks for your reply. I realized I was not using the use bytes pragma in a different place in the program while extracting the encrypted text, and this was causing my program to fail. My program works like a charm now!	[reply]
Re: finding length of encrypted(binary) string by Zed_Lopez (Chaplain) on Dec 03, 2004 at 22:23 UTC
Use the bytes pragma.	[reply]