00001 // This is oxl/mvl/mvl_modify_handle.h 00002 #ifndef mvl_modify_handle_h_ 00003 #define mvl_modify_handle_h_ 00004 #ifdef VCL_NEEDS_PRAGMA_INTERFACE 00005 #pragma interface 00006 #endif 00007 //: 00008 // \file 00009 // \brief Temporarily modify a value, restoring on end-of-block 00010 // 00011 // Take a pointer to some type, and when the mvl_modify_handle goes out 00012 // of scope, restore the old value. 00013 // 00014 // \author 00015 // Andrew W. Fitzgibbon, Oxford RRG, 03 Aug 96 00016 // 00017 //----------------------------------------------------------------------------- 00018 00019 template <class T> 00020 class mvl_modify_handle 00021 { 00022 T _oldvalue; 00023 T* _place; 00024 public: 00025 mvl_modify_handle(T* place) { _place = place; _oldvalue = *place; } 00026 ~mvl_modify_handle() { *_place = _oldvalue; } 00027 operator T* () { return _place; } 00028 T& operator*() { return *_place; } 00029 }; 00030 00031 #endif // mvl_modify_handle_h_
1.7.5.1