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Hi,
Here's my problem:

I read encrypted data from a server and save it in a variable. Now, I need
to send this back to the server along with a number that tells how many
bytes long the binary data is.

I've tried
$x = read_data_from_server($args);
$y = length $x;
send_data_to_server($x,$y);

I am not sure if the length function is the right way to count the number
of bytes in the string $x. Can someone please show me how to do this?

Thanks a lot!

Quoth Perl User <>:
> Hi,
> Here's my problem:
>
> I read encrypted data from a server and save it in a variable. Now, I need
> to send this back to the server along with a number that tells how many
> bytes long the binary data is.
>
> I've tried
> $x = read_data_from_server($args);
> $y = length $x;
> send_data_to_server($x,$y);
>
> I am not sure if the length function is the right way to count the number
> of bytes in the string $x. Can someone please show me how to do this?

It is, provided you've told perl that your data is binary not textual.
Make sure you use binmode on the socket filehandle.

Ben

--
If you put all the prophets, | You'd have so much more reason
Mystics and saints | Than ever was born
In one room together, | Out of all of the conflicts of time.
The Levellers, 'Believers'

Perl User wrote:

> I read encrypted data from a server and save it in a variable. Now, I
> need to send this back to the server along with a number that tells how
> many bytes long the binary data is.
>
> I've tried
> $x = read_data_from_server($args);
> $y = length $x;
> send_data_to_server($x,$y);
>
> I am not sure if the length function is the right way to count the
> number of bytes in the string $x.

It is right since you say it's a binary string. If it were a text
string then length() would return the number of characters.

If you want to force length() to count bytes even in text strings:

use bytes;

Perl User wrote:

> I am not sure if the length function is the right way to count the
> number of bytes in the string $x.

The length() function returns the number of characters in the string.
If you're not using Unicode, the number of bytes is the same as
the number of characters.
-Joe

Joe Smith wrote:
> The length() function returns the number of characters in the string.
> If you're not using Unicode, the number of bytes is the same as
> the number of characters.
> -Joe

If you are using Perl 5.8+ and the string is is_utf8 (see perldoc
Encode) the length returns the number of characters, not the number of
bytes.

--- Shawn

#!/usr/bin/perl

use strict;
use warnings;

my $s = "\x{2022}"; # Unicode for a bullet character

print length($s), "\n";

__END__

Joe Smith wrote:
> Perl User wrote:
>
>> I am not sure if the length function is the right way to count the
>> number of bytes in the string $x.
>
> The length() function returns the number of characters in the string.
> If you're not using Unicode, the number of bytes is the same as
> the number of characters.

That's wrong. Any MBCS or DBCS uses more than one byte for a single
character.

jue

Jürgen Exner wrote:
> Joe Smith wrote:
>
>>Perl User wrote:
>>
>>
>>>I am not sure if the length function is the right way to count the
>>>number of bytes in the string $x.
>>
>>The length() function returns the number of characters in the string.
>>If you're not using Unicode, the number of bytes is the same as
>>the number of characters.
>
>
> That's wrong. Any MBCS or DBCS uses more than one byte for a single
> character.

I was not aware of any non-Unicode version of perl that does
multibyte character sets.
-Joe

Joe Smith wrote:
> Jürgen Exner wrote:
>> Joe Smith wrote:
>>> Perl User wrote:
>>>> I am not sure if the length function is the right way to count the
>>>> number of bytes in the string $x.
>>>
>>> The length() function returns the number of characters in the
>>> string. If you're not using Unicode, the number of bytes is the
>>> same as the number of characters.
>>
>>
>> That's wrong. Any MBCS or DBCS uses more than one byte for a single
>> character.
>
> I was not aware of any non-Unicode version of perl that does
> multibyte character sets.

I am not sure what a "unicode version of perl" would be, but if the OP sends
lets say Japanese characters in Windows-932 back to the server, then he is
using a DBCS where each character is two bytes long and which has nothing to
do with Unicode.

jue

On Sat, 4 Dec 2004, Jürgen Exner wrote:

> Joe Smith wrote:
> > Jürgen Exner wrote:
> >>
> >> That's wrong. Any MBCS or DBCS uses more than one byte for a single
> >> character.
> >
> > I was not aware of any non-Unicode version of perl that does
> > multibyte character sets.
>
> I am not sure what a "unicode version of perl" would be,

Presumably one of the recent versions which have native Unicode
support... (5.6 or later, whatever)

> but if the OP sends lets say Japanese characters in Windows-932 back
> to the server, then he is using a DBCS where each character is two
> bytes long and which has nothing to do with Unicode.

But then Perl itself has no concept of "character" in such a piece
of data, and cannot meaningfully be asked to count "characters".

It has to be up to the programmer to count their own characters, if
the only definition of "characters" is some specification external to
Perl.

Or else they use an encode layer, or explicit encoding function, to
convert the external character encoding into native Perl (unicode)
characters, and use Perl's own functions on the result.

Doesn't that seem reasonable?

Alan J. Flavell wrote:
[Very reasonable arguments snipped]

> Doesn't that seem reasonable?

Absolutely.

However it misses the point. Joe wrote:
>>If you're not using Unicode, the number of bytes is the same as
>>the number of characters.

And this is the statement I still don't agree with.

jue