pad

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#! /usr/bin/perl

# Pad a file with zero bytes to make its length
# an even multiple of some value.

# $Revision: 1.1 $

use strict qw(refs vars);
use FileHandle;

if ( scalar(@ARGV) != 2 ) {
    print STDERR "usage: pad <filename> <multiple>\n";
    exit 1;
}

my $filename = shift @ARGV;
my $multiple = shift @ARGV;

my $size = (-s $filename);
die "Couldn't get size of $filename: $!" if ( !defined $size );

my $num_pad = ($multiple - ($size % $multiple)) % $multiple;

my $buf = chr(0) x $num_pad;

my $fh = new FileHandle(">>$filename");
die "Couldn't open $filename: $!" if ( !defined $fh );
binmode $fh;
syswrite $fh, $buf, $num_pad, 0;
$fh->close();