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Convert Perl Code in PHP

Hi Every one,

I have a perl script which uses the following code to decode the username saved in a cookie. I want to parse that cookie in php for adding some more features in the application. The source application in perl but I don't know any thing about perl. Here is the code ...

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  1. @table = (('A' .. 'Z'), ('a' .. 'z'), ('0' .. '9'), '+', '/', '|');
  2. for ($_ = 0; $_ <= $#table; $_++) {
  3. $decode_table[ord($table[$_])] = $_;
  4. }
  5. local $_ = $_[0];
  6. s/./unpack('B6', chr($decode_table[ord($&)] << 2))/eg;
  7. pack('B' . (int(length($_) / 8) * 8), $_);
Can any one help me to convert this code in PHP?

Thanks in advance
Jun 24 '08 #1
9 4876
3,503 Expert Mod 2GB
Sure, if this were the PHP forum . Unfortunately, it is not and I know that I do not know any PHP. What I can do though, is move this to the PHP forum where hopefully they can help you.

Please know that you might have to specify what your requirements are for the script to do and also write code (these are learning forums).

On the other hand, if you are looking for someone to write this for you, then you can certainly post this to the Jobs forum and offer to pay someone. The choice is up to you.


Jun 30 '08 #2
5,821 Expert 4TB
Heya, aliusman.

I'm no Perl guru, but I dabble from time to time in the dark arts. Let's see if we can run through this and generate a suitable translation.

And if I happen to get anything wrong, perhaps numberwhun would be wiling to step in and assist... *AHEM*.


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  1. @table = (('A' .. 'Z'), ('a' .. 'z'), ('0' .. '9'), '+', '/', '|');
This line creates a big 'ol table with all the letters and numbers, and a few symbols to boot.

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  1. for ($_ = 0; $_ <= $#table; $_++) {
  2. $decode_table[ord($table[$_])] = $_;
  3. }
Now we're looping through the table array that we created and generating a new hash called #decode_table (in Perl, hashes start with the '#' character, but you reference individual elements in the hash using '$'). The keys of this table are the ordinal values of @table and the values start with 0 and increase by 1 each time.

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  1. local $_ = $_[0];
This creates a local variable $_ and sets it equal to the first index in the special $_ variable (rough equivalent in PHP is probably $_GET or $_COOKIE).

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  1. s/./unpack('B6', chr($decode_table[ord($&)] << 2))/eg;
  2. pack('B' . (int(length($_) / 8) * 8), $_);
Got no idea here. Perhaps numberwhun could be of some assistance as to the purpose of these lines. *AHEM*
Jul 2 '08 #3
6,050 Expert 4TB

Sounds like you need some cough medicine, Josh.
Jul 2 '08 #4
5,821 Expert 4TB
Ooh, cherry-flavored.

Alrightey. After further consultation with our Perl forum leader, we (well, he) determined that the code you provided is not adequate to determine what's going on.

He checked it out, and here are the errors it generates:

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  1. Useless use of pack in void context at C:/coding/Eclipse_Workspace/Perl_Testing_Area/test4.pl line 15.
  2. Use of uninitialized value $_ in substitution (s///) at C:/coding/Eclipse_Workspace/Perl_Testing_Area/test4.pl line 13.
  3. Use of uninitialized value $_ in length at C:/coding/Eclipse_Workspace/Perl_Testing_Area/test4.pl line 15.
  4. Use of uninitialized value $_ in pack at C:/coding/Eclipse_Workspace/Perl_Testing_Area/test4.pl line 15.
If you can, please post the rest of the code. If that's all you have, we'll need some more info on where the code came from.
Jul 3 '08 #5
13,262 8TB
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  1. s/./unpack('B6', chr($decode_table[ord($&)] << 2))/eg;
  2. pack('B' . (int(length($_) / 8) * 8), $_);
Got no idea here. Perhaps numberwhun could be of some assistance as to the purpose of these lines. *AHEM*
That's probably intended to be the encoding/decoding part.
The pack converts a string into some machine level representation and the unpack does the opposite. The OP might just want to explain what their algorithm is for the decode and then we could suggest the php equivalence of that.
Jul 3 '08 #6
5,821 Expert 4TB
Unfortunately, PHP's pack() function takes a slightly different syntax than Perl's (http://php.net/pack), so I'm afraid that this is beyond my ken.

I will go ahead and move this thread back to the Perl forum so that the OP might be able to get a better idea of what's going on. Once we have that, then we can tackle how to translate it.
Jul 4 '08 #7
4,059 Expert 2GB
it would be nice to see what the value of $_ is from this line of the code:

local $_ = $_[0];

without knowing what the input is trying to figure out the correct output is going to be useless. But I have a feeling this thread has been abandoned anyway.
Jul 4 '08 #8
$decoded_string = base64_decode($thestring);

echo $decoded_string;

Mar 7 '09 #9
3,503 Expert Mod 2GB
This thread has not been posted to for about 8 months. It is quite possible that the OP has either forgotten about this issue, solved i t or moved on.

While it is commendable to provide answers, please keep these things in mind in the future.


Mar 8 '09 #10

This discussion thread is closed

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