Utilities for representing arbitrary byte-lengths in a human-readable way.

Format.cs

using System;

public static class Format
{
	public static string HumanSize( int size, int places = 2, bool lower = false )
	{
		return Format.HumanSize( Convert.ToDecimal( size ), places, lower );
	}
	
	public static string HumanSize( long size, int places = 2, bool lower = false )
	{
		return Format.HumanSize( Convert.ToDecimal( size ), places, lower );
	}
	
	public static string HumanSize( float size, int places = 2, bool lower = false )
	{
		return Format.HumanSize( Convert.ToDecimal( size ), places, lower );
	}
	
	public static string HumanSize( double size, int places = 2, bool lower = false )
	{
		return Format.HumanSize( Convert.ToDecimal( size ), places, lower );
	}
	
	public static string HumanSize( decimal size, int places = 2, bool lower = false )
	{
		string[] units = { "B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" };
		int index = 0;
		decimal newSize = size;
		
		while( newSize >= 1024.0m )
		{
			newSize /= 1024.0m;
			++index;
		}
		
		string unit = lower ? units[index].ToLower() : units[index];
		newSize = Decimal.Round( newSize, places, MidpointRounding.AwayFromZero );
		return String.Format( "{0:0." + new String( '0', 2 ) + "}{1}", newSize, unit );
	}
}

human_size.rb

module HumanSize
    def human_size( places = 2, lower = false )
        units = [ "B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" ]
        i = 0
        newSize = self + 0.0
        
        until i >= units.length - 2 or newSize < 1024.0
            newSize /= 1024.0
            i += 1
        end
        
        fmt  = "%.0" + places.to_s + "f%s"
        unit = lower ? units[i].downcase : units[i]
        sprintf fmt, newSize, unit
    end
end

class Fixnum
    include HumanSize
end

class Bignum
    include HumanSize
end

class Integer
    include HumanSize
end

class Float
    include HumanSize
end

class Rational
    include HumanSize
end

humanSize.coffee

#Prototype version
Number::humanSize = ( places = 2, lower = false ) ->
	units = [ "B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" ]
	newSize = @ * 1.0
	index = 0
	
	while newSize > 1024.0
		newSize /= 1024.0
		++index
	
	unit = if lower then units[index].toLowerCase() else units[index]
	return "#{+newSize.toFixed( places ).toString()}#{unit}"

#Non-prototype
humanSize = ( size, places = 2, lower = false ) ->
	units = [ "B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" ]
	newSize = size * 1.0
	index = 0
	
	while newSize > 1024.0
		newSize /= 1024.0
		++index
	
	unit = if lower then units[index].toLowerCase() else units[index]
	return "#{+newSize.toFixed( places )}#{unit}"

humanSize.d

module humanSize;

private import std.traits : isNumeric;
private import std.string : toLower, format;

string humanSize( T )( T size, bool lower = false ) if( isNumeric!T )
{
	string[] units = [ "B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" ];
	real newSize = cast( real )size;
	int index = 0;
	
	while( newSize >= 1024.0 )
	{
		newSize /= 1024.0;
		++index;
	}
	
	string unit = lower ? units[index].toLower : units[index];
	return "%0.2f%s".format( newSize, unit );
}

humanSize.js

//Prototype version
Number.prototype.humanSize = function( places, lower ) {
	if( places == null )
		places = 2;
	
	if( lower == null )
		lower = false;
	
	var units = [ "B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" ];
	var newSize = this * 1.0;
	var index = 0;
	
	while( newSize >= 1024.0 )
	{
		newSize /= 1024.0;
		++index;
	}
	
	var unit = lower ? units[index].toLowerCase() : units[index];
	return ( +newSize.toFixed( places ) ).toString() + unit;
};

//Non-prototype
function humanSize( size, places, lower )
{
	if( places == null )
		places = 2;
	
	if( lower == null )
		lower = false;
	
	var units = [ "B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" ];
	var newSize = size * 1.0;
	var index = 0;
	
	while( newSize >= 1024.0 )
	{
		newSize /= 1024.0;
		++index;
	}
	
	var unit = lower ? units[index].toLowerCase() : units[index];
	return ( +newSize.toFixed( places ) ).toString() + unit;
}

humanSize.php

<?php

//For PHP ≥ 5.4.x
function humanSize( $size, $decimalPlaces = 2, $lower = false )
{
	$units = [ "B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" ];
	$index = 0;
	$newSize = (double)$size;
	
	while( $newSize >= 1024.0 )
	{
		$newSize /= 1024.0;
		++$index;
	}
	
	$unit = $lower ? strtolower( $units[$index] ) : $units[$index];
	$newSize = number_format( round( $newSize, $decimalPlaces ), $decimalPlaces );
	return sprintf( "%0.2f%s", $newSize, $unit );
}

//For PHP ≥ 5.x
function humanSize( $size, $decimalPlaces = 2, $lower = false )
{
	$units = array( "B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" );
	$index = 0;
	$newSize = (double)$size;
	
	while( $newSize >= 1024.0 )
	{
		$newSize /= 1024.0;
		++$index;
	}
	
	$unit = $lower ? strtolower( $units[$index] ) : $units[$index];
	$newSize = number_format( round( $newSize, $decimalPlaces ), $decimalPlaces );
	return sprintf( "%0.2f%s", $newSize, $unit );
}

humanSize.py

def humanSize( size, places = 2, lower = False ):
	units = ( "B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" )
	index = 0
	newSize = float( size )
	
	while newSize >= 1024.0:
		newSize /= 1024.0
		index += 1
	
	unit = units[index].lower() if lower is True else units[index]
	newSize = round( newSize, places )
	return "%0.2f%s" % ( newSize, unit )