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

G'day.
I've just stepped into the, erm, wonderful world of Win32 programming. I have a dll which is needed to translate a password in an application we use. I've been given the specs of the dll as follows:

Function: bgfnTextDecrypt
    Description:
    Export Ordinal: 0
    Returns
        Boolean: BOOL
    Parameters
        String: LPSTR
        Receive String: LPSTR

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I'm trying to translate this into either a Win32::API or Win32::API::Prototype programme.
I have tried the following pieces of code:
#!perl
use strict;
use Win32::API;

my $bgfnTextDecrypt = new Win32::API('eq_handy', 'bgfnTextDecrypt','PP
+','P');
if(not defined $bgfnTextDecrypt) {
    die "Can't import API bgfnTextDecrypt: $!\n";
    }
print "Eerk\n";
my $lpBuffer = " " x 80;
print "Eerk2\n";
my $return = $bgfnTextDecrypt->Call('password-crypt', $lpBuffer);
print "Eerk3\n";
my $decrypt = substr($lpBuffer, 0, $return);
print "$decrypt\n";

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and 
#!perl
use strict;
use Win32::API::Prototype;
ApiLink( 'eq_handy.dll', 'BOOL bgfnTextDecrypt( LPSTRING  lpString, LP
+STRING, lpBuffer )' ) || die;
my $lpString="password-crypt";
my $lpBuffer = pack( "L*", $lpString);
    
bgfnTextDecrypt($lpString);
    
my $pass = unpack( "L*", $lpBuffer );
print( "The pass is: $pass\n";

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As I have never coded in Win32 before, I'm a little lost.
Is there anyone who can point me in the right direction? Even a similar MS dll as an example would be wonderful.

Thanks.
Neil

EDIT: Changed the dll name in the second example.

Replies are listed 'Best First'.
Re: Win32::API and ::Prototype assistance
by neilh (Pilgrim) on Jul 29, 2005 at 12:20 UTC
    Some potentially working code : 

    #!perl
#use strict;
use Win32::API::Prototype;
ApiLink( 'eq_handy.dll', 'BOOL bgfnTextDecrypt( LPSTR  lpString, LPSTR
+, lpBuffer )' ) || die ($!);
my $passphrase="encrypt-phrase";

my $lpString = pack( "L2", $passphrase,0);
   
print "Hi there\n";
$nBufferLength = 256;
$lpBuffer = NewString( $nBufferLength );
if (bgfnTextDecrypt($lpString,$lpBuffer, $nBufferLength)) {
        print "It worked!\n"; }
   

my $pass = unpack( "L*", $lpBuffer );
print "The pass is:",$pass,"\n";

    [download]
    Output is: 
    Hi there
It worked!
The pass is:189

    [download]
    The actual pass is bluemean.
    I think my unpack is wrong.. any suggestions?
    Neil
[reply]
[d/l]
[select]
      Well I got it to work. It turned out that my pack and unpack were wrong.
      Thanks to the Pack/Unpack Tutorial (aka How the System Stores Data) for the ideas.

      #!perl
use strict;
use Win32::API::Prototype;
ApiLink( 'eq_handy.dll', 'BOOL bgfnTextDecrypt( LPTSTR  lpString, LPTS
+TR, lpBuffer )' ) || die ($!);
my $passphrase="encrypt-pass";

my $lpString = pack( "A*", $passphrase,0);
   
print "Hi there\n";
my $nBufferLength = 256;
my $lpBuffer = NewString( $nBufferLength );
if (bgfnTextDecrypt($lpString,$lpBuffer, $nBufferLength)) {
        print "It worked!\n"; }
   

my $pass = unpack( "A*", $lpBuffer );
print "The pass is:",$pass,"\n";

      [download]
      Back to my box.

      Neil

[reply]
[d/l]

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