interface/modules/zend_modules/library/Zend/Memory/Value.php

   1 <?php
   2 /**
   3  * Zend Framework (http://framework.zend.com/)
   4  *
   5  * @link      http://github.com/zendframework/zf2 for the canonical source repository
   6  * @copyright Copyright (c) 2005-2013 Zend Technologies USA Inc. (http://www.zend.com)
   7  * @license   http://framework.zend.com/license/new-bsd New BSD License
   8  */
   9
  10 namespace Zend\Memory;
  11
  12 use ArrayAccess;
  13 use Countable;
  14
  15 /**
  16  * String value object
  17  *
  18  * It's an OO string wrapper.
  19  * Used to intercept string updates.
  20  */
  21 class Value implements ArrayAccess, Countable
  22 {
  23     /**
  24      * Value
  25      *
  26      * @var string
  27      */
  28     private $value;
  29
  30     /**
  31      * Container
  32      *
  33      * @var Container\Movable
  34      */
  35     private $container;
  36
  37     /**
  38      * Boolean flag which signals to trace value modifications
  39      *
  40      * @var bool
  41      */
  42     private $trace;
  43
  44
  45     /**
  46      * Object constructor
  47      *
  48      * @param string $value
  49      * @param \Zend\Memory\Container\Movable $container
  50      */
  51     public function __construct($value, Container\Movable $container)
  52     {
  53         $this->container = $container;
  54
  55         $this->value = (string) $value;
  56
  57         /**
  58          * Object is marked as just modified by memory manager
  59          * So we don't need to trace followed object modifications and
  60          * object is processed (and marked as traced) when another
  61          * memory object is modified.
  62          *
  63          * It reduces overall number of calls necessary to modification trace
  64          */
  65         $this->trace = false;
  66     }
  67
  68     /**
  69      * Countable
  70      *
  71      * @return int
  72      */
  73     public function count()
  74     {
  75         return strlen($this->value);
  76     }
  77
  78     /**
  79      * ArrayAccess interface method
  80      * returns true if string offset exists
  81      *
  82      * @param int $offset
  83      * @return bool
  84      */
  85     public function offsetExists($offset)
  86     {
  87         return $offset >= 0 && $offset < strlen($this->value);
  88     }
  89
  90     /**
  91      * ArrayAccess interface method
  92      * Get character at $offset position
  93      *
  94      * @param int $offset
  95      * @return string
  96      */
  97     public function offsetGet($offset)
  98     {
  99         return $this->value[$offset];
 100     }
 101
 102     /**
 103      * ArrayAccess interface method
 104      * Set character at $offset position
 105      *
 106      * @param int $offset
 107      * @param string $char
 108      */
 109     public function offsetSet($offset, $char)
 110     {
 111         $this->value[$offset] = $char;
 112
 113         if ($this->trace) {
 114             $this->trace = false;
 115             $this->container->processUpdate();
 116         }
 117     }
 118
 119     /**
 120      * ArrayAccess interface method
 121      * Unset character at $offset position
 122      *
 123      * @param int $offset
 124      */
 125     public function offsetUnset($offset)
 126     {
 127         unset($this->value[$offset]);
 128
 129         if ($this->trace) {
 130             $this->trace = false;
 131             $this->container->processUpdate();
 132         }
 133     }
 134
 135
 136     /**
 137      * To string conversion
 138      *
 139      * @return string
 140      */
 141     public function __toString()
 142     {
 143         return $this->value;
 144     }
 145
 146
 147     /**
 148      * Get string value reference
 149      *
 150      * _Must_ be used for value access before PHP v 5.2
 151      * or _may_ be used for performance considerations
 152      *
 153      * @internal
 154      * @return string
 155      */
 156     public function &getRef()
 157     {
 158         return $this->value;
 159     }
 160
 161     /**
 162      * Start modifications trace
 163      *
 164      * _Must_ be used for value access before PHP v 5.2
 165      * or _may_ be used for performance considerations
 166      *
 167      * @internal
 168      */
 169     public function startTrace()
 170     {
 171         $this->trace = true;
 172     }
 173 }