Mini Shell

#!/usr/bin/perl
# encoding: utf-8
#
# author: Kyle Yetter
#

package IMH::Bytes;

use strict;
use warnings;

require Exporter;

our @ISA = qw(Exporter);


our %EXPORT_TAGS = ( 'all' => [ qw(
  byte_format parse_bytes %BYTE_UNIT_PRECISION %BYTE_UNIT_ORDER @BYTE_UNITS
) ] );

our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );

our @EXPORT = qw( byte_format parse_bytes );

our $VERSION = '0.01';

our @BYTE_UNITS      = qw( TB GB MB KB B );
our %BYTE_UNIT_ORDER = ();

foreach ( 0 .. $#BYTE_UNITS ) {
  $BYTE_UNIT_ORDER{ $BYTE_UNITS[ $_ ] } = 2 ** ( 10 * ( $#BYTE_UNITS - $_ ) );
}

our %BYTE_UNIT_PRECISION = (
  TB => 2,  GB => 2,  MB => 1,
  KB => 0,  B  => 0
);

sub parse_bytes($) {
  my $byte_string = uc( shift );
  if ( $byte_string =~ /^\s*(\d+)\s*([TKGM]?B)/ ) {
    return ( $1 + 0 ) * $BYTE_UNIT_ORDER{ $2 };
  }
  return $byte_string + 0;
}

sub byte_format($) {
  my $bytes = shift;
  my $size  = $bytes / ( 1024.0 ** $#BYTE_UNITS );

  foreach my $unit ( @BYTE_UNITS ) {
    if ( $size >= 1 ) {
      my $precision = $BYTE_UNIT_PRECISION{ $unit };
      return sprintf( "%.${precision}f %2s", $size, $unit );
    }
    $size *= 1024;
  }

  return "$bytes  B";
}

1;