hphp/runtime/base/string_offset.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010- Facebook, Inc. (http://www.facebook.com)         |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16
  17 #ifndef incl_HPHP_STRING_OFFSET_H_
  18 #define incl_HPHP_STRING_OFFSET_H_
  19
  20 #include "hphp/runtime/base/types.h"
  21 #include "hphp/runtime/base/string_data.h"
  22 #include "hphp/runtime/base/util/exceptions.h"
  23
  24 namespace HPHP {
  25 ///////////////////////////////////////////////////////////////////////////////
  26
  27 /**
  28  * Handles sub-string expressions. This class should delegate all real work to
  29  * StringData.
  30  */
  31 class StringOffset {
  32  public:
  33   /**
  34    * Constructor. "offset" is where we are at in the string.
  35    */
  36   StringOffset(StringData *data, int offset)
  37     : m_data(data), m_offset(offset) {
  38     assert(m_data);
  39   }
  40
  41   /**
  42    * Get r-value of this offset object.
  43    */
  44   operator String() const;
  45
  46   /**
  47    * Get l-value of this offset object. Well, not quite, since this is illegal.
  48    */
  49   String &lval() const {
  50     throw InvalidOperandException("taking l-value of a string offset");
  51   }
  52
  53   /**
  54    * Assignement operator. Almost the whole purpose for having this offset
  55    * class.
  56    */
  57   StringOffset &operator=(CVarRef v);
  58
  59  private:
  60   StringData *m_data;
  61   int m_offset;
  62 };
  63
  64 ///////////////////////////////////////////////////////////////////////////////
  65 }
  66
  67 #endif // incl_HPHP_STRING_OFFSET_H_