system/classes/uuid.php

<?php
namespace Habari;
class UUID
{
  private $uuid = array();
  
  public function __construct( $version = 4 )
  {
    $uuid = array();
    for ( $i = 0; $i < 16; $i++ ) {
      $uuid[] = mt_rand( 0, 255 );
    }
    // variant (bit 6 = 1, bit 7 = 0)
    $uuid[8] = ( $uuid[8] & 0x3f ) | 0x80;
    /* // weird byte orders make my head hurt!
    // version (bits 4-7 = 0100);
    $uuid[7] = ( $uuid[7] & 0x0f ) | 0x40;
    */
    // version (bits 12-15 = 0100)
    $uuid[6] = ( $uuid[6] & 0x0f ) | 0x40;
    
    $this->uuid = $uuid;
  }
  
  public function __toString()
  {
    return $this->get_hex();
  }
  
  public function get_array()
  {
    return $this->uuid;
  }
  
  public function get_raw()
  {
    return implode( '', array_map( 'chr', $this->uuid ) );
  }
  
  public function get_hex()
  {
    $uuid_hex = '';
    for ( $i = 0; $i < 16; $i++ ) {
      if ( 4==$i || 6==$i || 8==$i || 10==$i ) {
        $uuid_hex.= '-';
      }
      $uuid_hex.= sprintf( '%02x', $this->uuid[$i] );
    }
    
    return $uuid_hex;
  }
  
  public static function get()
  {
    $uuid = new UUID();
    return $uuid->get_hex();
  }
  
}

?>