while(<FILE>) { # this reads through $FILE, line by line
       chomp;       # remove end of line character
        my $j = 0;
        my $contents = $_;
        next unless ($contents =~ /^INSERT /); # process only lines wh
+ich start with INSERT
        my ($junk1, $sql, $junk) = split(/\(|\)/, $contents); # get th
+e values from what could be an SQL INSERT statement?!
        my ($zoom, $x, $y, $flags, $length, $data) = split(/\,/, $sql)
+; # get the columns
        $data =~ s/^X'//; # remove X' at start
        $data =~ s/'$//; # remove single quote at end
        my $filename = "./maptiles-output/$x,$y\@$zoom.png";
        next if int(length($data))<128; # skip bogus data?

        # Write what appears to be hex-encoded data to a PNG file?!
        print $filename . "\n";
        open(OUT, ">$filename") || die "$filename: $!";
        print int(length($data)) . "\n";
        while($j < length($data)) {
            my $hex = "0x" . substr($data, $j, 2);
            print OUT chr(hex($hex));
            $j += 2;
        }
        close(OUT);
    }

[download]

Maybe you want a look at SQL::Parser for parsing the SQL?

In reply to Re: help figuring out what a section of script does by Corion
in thread help figuring out what a section of script does by michaelsingleton

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