localpointer.h

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/*
*******************************************************************************
*
*   Copyright (C) 2009-2012, International Business Machines
*   Corporation and others.  All Rights Reserved.
*
*******************************************************************************
*   file name:  localpointer.h
*   encoding:   US-ASCII
*   tab size:   8 (not used)
*   indentation:4
*
*   created on: 2009nov13
*   created by: Markus W. Scherer
*/
 
#ifndef __LOCALPOINTER_H__
#define __LOCALPOINTER_H__

 
#include "unicode/utypes.h"
 
#if U_SHOW_CPLUSPLUS_API
 
U_NAMESPACE_BEGIN

template<typename T>
class LocalPointerBase {
public:
    explicit LocalPointerBase(T *p=NULL) : ptr(p) {}
    ~LocalPointerBase() { /* delete ptr; */ }
    UBool isNull() const { return ptr==NULL; }
    UBool isValid() const { return ptr!=NULL; }
    bool operator==(const T *other) const { return ptr==other; }
    bool operator!=(const T *other) const { return ptr!=other; }
    T *getAlias() const { return ptr; }
    T &operator*() const { return *ptr; }
    T *operator->() const { return ptr; }
    T *orphan() {
        T *p=ptr;
        ptr=NULL;
        return p;
    }

    void adoptInstead(T *p) {
        // delete ptr;
        ptr=p;
    }
protected:
    T *ptr;
private:
    // No comparison operators with other LocalPointerBases.
    bool operator==(const LocalPointerBase &other);
    bool operator!=(const LocalPointerBase &other);
    // No ownership transfer: No copy constructor, no assignment operator.
    LocalPointerBase(const LocalPointerBase &other);
    void operator=(const LocalPointerBase &other);
    // No heap allocation. Use only on the stack.
    static void * U_EXPORT2 operator new(size_t size);
    static void * U_EXPORT2 operator new[](size_t size);
#if U_HAVE_PLACEMENT_NEW
    static void * U_EXPORT2 operator new(size_t, void *ptr);
#endif
};

template<typename T>
class LocalPointer : public LocalPointerBase<T> {
public:
    explicit LocalPointer(T *p=NULL) : LocalPointerBase<T>(p) {}
    ~LocalPointer() {
        delete LocalPointerBase<T>::ptr;
    }

    void adoptInstead(T *p) {
        delete LocalPointerBase<T>::ptr;
        LocalPointerBase<T>::ptr=p;
    }
};

template<typename T>
class LocalArray : public LocalPointerBase<T> {
public:
    explicit LocalArray(T *p=NULL) : LocalPointerBase<T>(p) {}
    ~LocalArray() {
        delete[] LocalPointerBase<T>::ptr;
    }

    void adoptInstead(T *p) {
        delete[] LocalPointerBase<T>::ptr;
        LocalPointerBase<T>::ptr=p;
    }

    T &operator[](ptrdiff_t i) const { return LocalPointerBase<T>::ptr[i]; }
};

#define U_DEFINE_LOCAL_OPEN_POINTER(LocalPointerClassName, Type, closeFunction) \
    class LocalPointerClassName : public LocalPointerBase<Type> { \
    public: \
        explicit LocalPointerClassName(Type *p=NULL) : LocalPointerBase<Type>(p) {} \
        ~LocalPointerClassName() { closeFunction(ptr); } \
        void adoptInstead(Type *p) { \
            closeFunction(ptr); \
            ptr=p; \
        } \
    }
 
U_NAMESPACE_END
 
#endif  /* U_SHOW_CPLUSPLUS_API */
#endif  /* __LOCALPOINTER_H__ */