Did you see the examples in the Compress::Zlib docs? They have some examples of using gzopen, gzwrite, gzread, etc.

use Compress::Zlib;


 my $outlog=gzopen($fn,"a");
 
....

   $outlog->gzwrite($line."\n");

....

 $outlog->gzclose();
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I was going to post my own SoPW on my troubles at getting Compress::Zlib to work, and Super Search pointed me here. Based on the code samples here, I was able to get my test case (a line-oriented zip/unzip) to work correctly.

Specifically, my problem was that I was creating a $gz handle using deflateInit(). So here's my code for future readers in the same predicament:

#! /usr/bin/perl -w

use strict;
use Compress::Zlib;

my $file = shift || 'testdata.gz';
my $gz   = gzopen( $file, 'wb' ) or die "Cannot open $file for gzwrite
+: $gzerrno\n";
my $line;

while( defined($line = <DATA>) ) {
    $gz->gzwrite( $line )
        or die "Could not write gzipped data to $file: $gzerrno\n";
}
$gz->gzclose();

$gz = gzopen( $file, 'rb' ) or die "Cannot open $file for gzread: $gze
+rrno\n";
while( $gz->gzreadline($line) > 0 ) {
    print $line;
}
die "Error reading from $file: [$gzerrno]\n" unless Z_STREAM_END == $g
+zerrno;
$gz->gzclose();

__DATA__
foo
bar
Judge my vow, sphinx of black quartz
__END__
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I think it's pretty self-explanatory...

This does leave me with one question, however, and that is, how can I specify the that the writer uses different compression strategies, à la Z_BEST_SPEED and Z_BEST_COMPRESSION?

update: in reply to idnopheq's suggestion, despite have 512Mb RAM, I'd rather not have this hanging around in RAM, I actually want to dump it straight out onto tape. I initially used a deflateInit approach and wrote the output to a file myself, but I was unable to successfully read it back using gzopen on the resulting file.

g r i n d e r

If you go with the in-memory compression/decompression odel, you have more flexibility. From the perldoc for the deflateInit call:

-Level Defines the compression level. Valid values are 1 through 9, Z_BEST_SPEED, Z_BEST_COMPRESSION, and Z_DEFAULT_COMPRESSION. The default is -Level =>Z_DEFAULT_COMPRESSION.

So then:

deflateInit( -Bufsize => 300, 
                 -Level => Z_BEST_SPEED  ) ;
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Then IIRC write the buffer to disk.

HTH
--
idnopheq
Apply yourself to new problems without preparation, develop confidence in your ability to to meet situations as they arrise.

~ Shunryu Suzuki

##################################################

mostly stylistic (and hopefully constructive) suggestions re "Simple WebServer Scanner"

#!/usr/bin/perl -w

# swesc.pl

use strict;
use warnings;
use Socket;

my $remote = shift;
my $port   = 80;

Usage() unless($remote);

if ($port  =~ /\D/) { $port = getservbyname($port, 'tcp') }
my $iaddr  = inet_aton($remote)         or die "Error with inet_aton: 
+$!";
my $paddr  = sockaddr_in($port, $iaddr) or die "Error with sockaddr_in
+: $!";
my $proto  = getprotobyname('tcp')      or die "Error with getprotobyn
+ame: $!";
my $submit = "HEAD / HTTP/1.0\r\n\r\n";

socket(SOCK, PF_INET, SOCK_STREAM, $proto) or die "Error with socket: 
+$!";
connect(SOCK, $paddr) or die "cannot connect to $remote: $!";
send(SOCK,$submit,0);
while(<SOCK>) {
   if($_ =~ /Server: (.*)/) {
      print "\n$_";
      }
   }
close(SOCK);

######################################################################
+####

sub Usage {
   print "\nUsage : $0 <remote host>\n";
   exit();
   }

######################################################################
+####

=head1 Mostly stylistic suggestions, hopefully constructive:

 X -w on shebang line or use warnings;
 X use strict;
   unless ($remote... instead of if ($ARGV[0]...
   Don't need die "no port specified"... line
   Rename "affichage" to "Usage"
   Mixed-case subroutine names
   Use "or" instead of "||" in die statements
   Use $! in all die messages
   Consistant die messages
   my $remote = shift;

=head1 good monk Asmo's original code:
 
 #!/usr/bin/perl
 
 use Socket;
 use Strict;
 use warnings;
 
 my $remote = $ARGV[0];
 my $port=80;
 
 if ($ARGV[0] eq "") {
 affichage();
 }
 
 sub affichage
 {
         print "\n\nUsage : $0 <remote host>\n";
 exit();
 }

 $submit = "HEAD / HTTP/1.0\r\n\r\n";
 if($port =~ /\D/) { $port = getservbyname($port, 'tcp') }
 die "no port specified" unless $port;
 my $iaddr = inet_aton($remote) || die "$remote";
 my $paddr = sockaddr_in($port, $iaddr) || die "Caca !!";
 my $proto = getprotobyname('tcp') || die "protocol !!";
 
 socket(SOCK, PF_INET, SOCK_STREAM, $proto) || die "cannot open socket
+ : $!";
 connect(SOCK, $paddr) || die "cannot connect to $remote: $!";
 send(SOCK,$submit,0);
 while(<SOCK>)
 {
 if($_ =~ /Server: (.*)/) {
         print $_;
 }
 
 }
 close(SOCK);

=cut
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