Source for file ByteSize.class.php

<?php
 
/**
 * @since 7/14/05
 * @package harmoni.primitives.numbers
 * 
 * @copyright Copyright &copy; 2005, Middlebury College
 * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License (GPL)
 *
 * @version $Id: ByteSize.class.php,v 1.5 2007/09/04 20:25:28 adamfranco Exp $
 */ 
 
require_once(dirname(__FILE__)."/Integer.class.php");
 
/**
 * A representation of a Byte size. Provides easy conversion between B, KB, MB, etc
 * as well as a pretty string reprentation
 *
 * @package harmoni.primitives.numbers
 * 
 * @copyright Copyright &copy; 2005, Middlebury College
 * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License (GPL)
 *
 * @version $Id: ByteSize.class.php,v 1.5 2007/09/04 20:25:28 adamfranco Exp $
 */
class ByteSize 
    extends Integer
{
 
/*******************************************************
 * Class Methods
 *********************************************************/
 
    
    /**
     * Answer the string suffix for the desired muliple of 2^10 bytes
     * i.e. 0 -> B, 10 -> kB, 20 -> MB, 30 -> GB, etc.
     * 
     * @param integer $power A multiple of 10; Range, 0-80
     * @return string 
     * @access public
     * @since 10/11/05
     */
    function suffixForPower ($power) {
        $multiple = intval($power/10);
        if ($multiple < 0 || $multiple > 8)
            throwError(new Error("Invalid power, $power. Valid values are multiples of ten, 0-80.",
                "ByteSize", true));
        
        $suffixes = array("B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB");
        return $suffixes[$multiple];
    }
    
/*******************************************************
 * Class Methods - Instance Creation
 *********************************************************/
 
 
    /**
     * Answer a new object with the string value specified.
     * 
     * @param string $stringValue String representation of the size
     * @param optional string $class The class to instantiate. Do NOT use outside
     *         of this package.
     * @return object ByteSize 
     * @access public
     * @since 7/14/05
     */
    function fromString ( $stringValue, $class = 'ByteSize') {
        if (preg_match("/([0-9\.]+)\s*(B|kB|MB|GB|TB|PB|EB|ZB|YB)/i", 
            $stringValue, $matches)) 
        {
            $suffixes = array("B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB");
            $bytes = $matches[1] * pow(2, 
                (10 * array_search(strtoupper($matches[2]), $suffixes)));
        } else if (preg_match("/^[0-9]+$/", $stringValue)) {
            $bytes = intval($stringValue);
        } else {
            print "not found, going with 0";
            $bytes = 0;
        }
        
        eval('$result = '.$class.'::withValue($bytes, $class);');
        return $result;
    }
    
    /**
     * Answer a new object with the value specified
     * 
     * @param integer $value Integer number of Bytes
     * @param optional string $class The class to instantiate. Do NOT use outside
     *         of this package.
     * @return object ByteSize 
     * @access public
     * @since 7/14/05
     */
    function withValue ( $value, $class = 'ByteSize') {
        return parent::withValue($value, $class);
    }
    
    /**
     * Answer a new object with the value zero
     * 
     * @param optional string $class The class to instantiate. Do NOT use outside
     *         of this package.
     * @return object ByteSize 
     * @access public
     * @since 7/14/05
     */
    function zero ( $class = 'ByteSize') {
        return parent::zero($class);
    }
    
/*******************************************************
 * Instance Methods - Printing
 *********************************************************/
 
    
    /**
      * Answer a String whose characters are a description of the receiver.
      * Override this method as needed to provide a better representation
      * 
      * @return string 
      * @access public
      * @since 7/11/05
      */
     function printableString () {
        for ($i = 0; $i <= 80; $i = $i + 10) {
            if ($this->value() < pow(2, ($i + 10)))
                break;
        }
        
        if ($i == 0)
            $numString = $this->multipleOfPowerOf2($i);
        else
            $numString = sprintf("%01.2f", $this->multipleOfPowerOf2($i));
            
        return $numString." ".$this->suffixForPower($i);
    }
    
    /**
     * Answer the string in kilo bytes (kB)
     * 
     * @return string 
     * @access public
     * @since 10/11/05
     */
    function asKBString () {
        return round($this->multipleOfPowerOf2(10), 2).$this->suffixForPower(10);
    }
    
    /**
     * Answer the string in mega bytes (MB)
     * 
     * @return string 
     * @access public
     * @since 10/11/05
     */
    function asMBString () {
        return round($this->multipleOfPowerOf2(20), 2).$this->suffixForPower(20);
    }
 
/*******************************************************
 * Instance Methods - Accessing
 *********************************************************/
 
     
     /**
     * Answer the PHP primitive value of the reciever.
     * We need to store our internal representation as a float to allow for
     * very large integers, but we never want to return a decimal number of
     * bytes.
     * 
     * @return integer 
     * @access public
     * @since 7/14/05
     */
    function value () {
        return round($this->_value, 0);
    }
     
     /**
      * Answer the value as a multiple of 2^$power.
      * Ex: for the number in kilo bytes (in computer-terms), $power = 10;
      * 
      * @param integer $power 0 for bytes, 10 for kilobyes, 20 for megabytes, etc.
      * @return float 
      * @access public
      * @since 10/11/05
      */
     function multipleOfPowerOf2 ( $power ) {
         return $this->value() / pow(2, $power);
     }
 
     /**
      * Answer the value in Kilo Bytes KB
      * 
      * @return integer 
      * @access public
      * @since 10/11/05
      */
     function kiloBytes () {
         return $this->multipleOfPowerOf2(10);
     }
 
     /**
      * Answer the value in Mega Bytes (MB)
      * 
      * @return integer 
      * @access public
      * @since 10/11/05
      */
     function megaBytes () {
         return $this->multipleOfPowerOf2(20);
     }
     
/*******************************************************
 * Instance Methods - Private
 *********************************************************/
 
    
    /**
     * Set the internal value to a PHP primitive.
     * 
     * @param mixed $value 
     * @return void 
     * @access private
     * @since 7/14/05
     */
    function _setValue ( $value ) {
        $this->_value = $value;
    }
     
}