#!/usr/bin/perl 
# -------------------------------------

use strict;
use Compress::Zlib;

# -------------------------------------
# -------------------------------------

my $content1 = "<p>This is content part1</p>";
my $content2 = "<p>This is content part2</p>";
my $content3 = "<p>This is content part3</p>";




#my $apply_encoding_type	= 'deflate';
my $apply_encoding_type	= 'gzip';

my $this_line_break 	= "\r\n";
my $status;




# -------------------------------------
# compress and prepare '$content1'
# -------------------------------------

my $compressed_content1 = '';
$status = &compress_content($apply_encoding_type,\$content1,\$compressed_content1);
	
	unless($status eq 'ok'){
	print "Content-type: text/html\n\n";
	print "<p>Problem-1: $status </p>";
	exit;
	}


my $hexadecimal_length_compressed_content1 = sprintf("%X", length($compressed_content1));

# -------------------------------------
# output compressed '$content1' chunk !
# -------------------------------------

		# First HTTP Response Headers
	
	print "Cache-Control: private, max-age=0, must-revalidate",$this_line_break;
	print "Vary: Accept-Encoding",$this_line_break;
	print "Content-Encoding: $apply_encoding_type",$this_line_break;
	print "Transfer-Encoding: chunked",$this_line_break;
	print "Content-type: text/html; charset=UTF-8",$this_line_break,$this_line_break;

	
		# Now, output compressed '$content_part1'
	
	print $hexadecimal_length_compressed_content1,$this_line_break;
	print $compressed_content1,$this_line_break;



# ... do something else ...
# ... do something else ...
# ... do something else ...


# ... do something else ...
# ... do something else ...
# ... do something else ...



# -------------------------------------
# compress and prepare '$content2'
# -------------------------------------

my $compressed_content2 = '';
$status = &compress_content($apply_encoding_type,\$content2,\$compressed_content2);

	unless($status eq 'ok'){
	print "Content-type: text/html\n\n";
	print "<p>Problem-2: $status </p>";
	exit;
	}

my $hexadecimal_length_compressed_content2 = sprintf("%X", length($compressed_content2));

# -------------------------------------
# output compressed '$content2' chunk !
# -------------------------------------
	
	print $hexadecimal_length_compressed_content2,$this_line_break;
	print $compressed_content2,$this_line_break;


# .
# . 
# .

# Now, do the same for the final '$content3'
# -------------------------------------
# compress and prepare '$content3'
# -------------------------------------

my $compressed_content3 = '';
$status = &compress_content($apply_encoding_type,\$content3,\$compressed_content3);

	unless($status eq 'ok'){
	print "Content-type: text/html\n\n";
	print "<p>Problem-3: $status </p>";
	exit;
	}

my $hexadecimal_length_compressed_content3 = sprintf("%X", length($compressed_content3));

# -------------------------------------
# output compressed '$content3' chunk !
# -------------------------------------
	
	print $hexadecimal_length_compressed_content3,$this_line_break;
	print $compressed_content3,$this_line_break;




# -------------------------------------------------
# Now, finish with the final (zero length) header/s
# -------------------------------------------------

print "0", $this_line_break, $this_line_break;
exit;

###########################################
# END OF MAIN SCRIPT !
###########################################



sub compress_content{

#my($apply_encoding_type,$content_ref,$compressed_content_ref,$end_of_stream) = @_;
my($apply_encoding_type,$content_ref,$compressed_content_ref) = @_;

$apply_encoding_type = $apply_encoding_type || 'gzip';

my($d, $out1, $out2, $status);

# -------------------------------------

if($apply_encoding_type eq 'gzip'){

	($d,$status) = deflateInit(
	
	-WindowBits => 16 + &MAX_WBITS()
	
	);

}
else{
	# ------------
	# 'deflate' ?
	# ------------
	($d,$status) = deflateInit();

}
# -------------------------------------


	
# -------------------------------------
unless(defined($d)){

	my $err_msg = $status;
	print "Content-type: text/html\n\n";
	print "<P>DEFLATE-INIT ERROR: $err_msg (\$apply_encoding_type: $apply_encoding_type)<P>";
	exit;
	
	#return "fail-1 ($err_msg);
}
# -------------------------------------



# -------------------------------------
($out1, $status) = $d->deflate($content_ref);

unless($status == Z_OK){

	my $err_msg = $d->msg();
	#my $err_msg = $status;
	
	print "Content-type: text/html\n\n";
	print "<P>COMPRESS-ERROR: $err_msg (\$apply_encoding_type: $apply_encoding_type)<P>";
	
	exit;
	#return "fail-2 ($err_msg);

}
# -------------------------------------
	

# -------------------------------------
if($apply_encoding_type eq 'gzip'){

	
	#if($end_of_stream){
	#	($out2, $status) = $d->flush(Z_FINISH);
	#}
	#else{
	#	($out2, $status) = $d->flush(Z_SYNC_FLUSH);
	#}

	($out2, $status) = $d->flush(Z_SYNC_FLUSH);
	
}
else{

	# ------------
	# 'deflate' ?
	# ------------
	($out2, $status) = $d->flush(Z_SYNC_FLUSH);

}
# -------------------------------------


# -------------------------------------
unless($status == Z_OK){

	my $err_msg = $d->msg();
	#my $err_msg = $status;
	print "Content-type: text/html\n\n";
	print "<P>DEFLATE-FINISH ERROR: $err_msg (\$apply_encoding_type: $apply_encoding_type)<P>";
	
	exit;
	#return "fail-3 (error: $err_msg, status: $status)";
}
# -------------------------------------



# Finally, add 'flush' output data to the initially deflated data '$out1') !!!

if(defined($out2)){
	
	$out1 .= $out2;
}
# -------------------------------------


$$compressed_content_ref = $out1;

return 'ok';
}



############################################
# END OF EVERYTHING !!!
############################################