[Summary view]

   1  <?php
   2  /**
   3   * Simple interface for tracking memory consumption.
   4   *
   5   * <code>
   6   *  $t = new Horde_Support_Memory;
   7   *  $t->push();
   8   *  $used = $t->pop();
   9   * </code>
  10   *
  11   * Do not expect too much of this memory tracker. Profiling memory is not
  12   * trivial as your placement of the measurements may obscure important
  13   * information. As a trivial example: Assuming that your script used 20 MB of
  14   * memory befory you call push() the information you get when calling pop()
  15   * might only tell you that there was less than 20 MB of memory consumed in
  16   * between the two calls. Take the changes to internal memory handling of PHP in
  17   * between the different versions into account
  18   * (http://de3.php.net/manual/en/features.gc.performance-considerations.php) and
  19   * you should get an idea about why you might be cautious about the values you
  20   * get from this memory tracker.
  21   *
  22   * Copyright 2011-2017 Horde LLC (http://www.horde.org/)
  23   *
  24   * @category   Horde
  25   * @package    Support
  26   * @license    http://www.horde.org/licenses/bsd
  27   */
  28  class Horde_Support_Memory
  29  {
  30      /**
  31       * Holds the starting memory consumption.
  32       *
  33       * @var array
  34       */
  35      protected $_start = array();
  36  
  37      /**
  38       * Current index for stacked trackers.
  39       *
  40       * @var integer
  41       */
  42      protected $_idx = 0;
  43  
  44      /**
  45       * Push a new tracker on the stack.
  46       */
  47      public function push()
  48      {
  49          $start = $this->_start[$this->_idx++] = array(
  50              memory_get_usage(),
  51              memory_get_peak_usage(),
  52              memory_get_usage(true),
  53              memory_get_peak_usage(true)
  54          );
  55          return $start;
  56      }
  57  
  58      /**
  59       * Pop the latest tracker and return the difference with the current
  60       * memory situation.
  61       *
  62       * @return array The change in memory allocated via emalloc() in between the
  63       *               push() and the pop() call. The array holds four values: the
  64       *               first one indicates the change in current usage of memory
  65       *               while the second value indicates any changes in the peak
  66       *               amount of memory used. The third and fourth value show
  67       *               current and peak usage as well but indicate the real memory
  68       *               usage and not just the part allocated via emalloc(),
  69       */
  70      public function pop()
  71      {
  72          if (! ($this->_idx > 0)) {
  73              throw new Exception('No timers have been started');
  74          }
  75          $start = $this->_start[--$this->_idx];
  76          return array(
  77              memory_get_usage() - $start[0],
  78              memory_get_peak_usage() - $start[1],
  79              memory_get_usage(true) - $start[2],
  80              memory_get_peak_usage(true) - $start[3]
  81          );
  82      }
  83  
  84  }