Re: reading an integer value from file?

[Mark Cohen]

Pablo,
Try one of the following subsubroutines. In the following example
the binary subroutine is called with the first 4 bytes. The key is to
understand how to use the unpack function.

            Regards Mark


$value = binary(substr($_record,0,4));



sub ib {  # A signed integer value.
    my $_buffer = $_[0];
    $ret = unpack("i*", $_buffer);
    return $ret;
}

sub IB { # An unsigned integer value
    my $_buffer = $_[0];
    $ret = unpack("I*", $_buffer);
    return $ret;
}

sub char { # An char value
    my $_buffer = $_[0];
    $ret = unpack("C*", $_buffer);
    return $ret;
}

sub pk {  # A packed.
    my $_buffer = $_[0];
    $ret = unpack("p*", $_buffer);
    return $ret;
}
sub binary {
    my $_buffer = $_[0];
    $ret = hex(unpack("H*", $_buffer));
    return $ret;
}


sub packed {
    my $_buffer = $_[0];
    $ret = unpack("H*", $_buffer);
    return $ret;
}


sub binary8 {
 my $hex = unpack("H*", $_[0]);
 my $vec = Bit::Vector->new_Hex(64,$hex);
 my $ret = $vec->to_Dec();
 return ($ret);
}

----- Original Message -----
From: "pablo wablo" <[EMAIL PROTECTED]>
To: <beginners@perl.org>
Sent: Sunday, February 06, 2005 8:11 AM
Subject: reading an integer value from file?


> I'm trying to parse an avi header and I'm having
> problems getting the actual values of the integer data
> in the file.
>
>
> Here's what I do:
>
> open(INHANDLE, "tesmovie.avi.mp3") || die("can't open
> file");
>
> my $line = <INHANDLE>;
>
> my $datarate = substr($line, 4, 4) - 0;
> print "$datarate\n";
>
> What I'm trying to do here is read the data rate,
> which is a 4 byte integer into $datarate... but I
> always get 0... How do I treat a string and convert
> it's actual bit value to a long integer?
>
> Thanks hope you can help me
>
>
>
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