smartptr.h

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// smartptr.h - originally written and placed in the public domain by Wei Dai
 
/// \file smartptr.h
/// \brief Classes for automatic resource management
 
#ifndef CRYPTOPP_SMARTPTR_H
#define CRYPTOPP_SMARTPTR_H
 
#include "config.h"
#include "stdcpp.h"
 
NAMESPACE_BEGIN(CryptoPP)
 
/// \brief Manages resources for a single object
/// \tparam T class or type
/// \details \p simple_ptr is used frequently in the library to manage resources and
///   ensure cleanup under the RAII pattern (Resource Acquisition Is Initialization).
template <class T> class simple_ptr
{
public:
    simple_ptr(T *p = NULLPTR) : m_p(p) {}
    ~simple_ptr()
    {
        delete m_p;
        m_p = NULLPTR;
    }
 
    T *m_p;
};
 
/// \brief Pointer that overloads operator ->
/// \tparam T class or type
/// \details member_ptr is used frequently in the library to avoid the issues related to
///  std::auto_ptr in C++11 (deprecated) and std::unique_ptr in C++03 (non-existent).
/// \bug <a href="http://github.com/weidai11/cryptopp/issues/48">Issue 48: "Use of auto_ptr
///  causes dirty compile under C++11"</a>
template <class T> class member_ptr
{
public:
    explicit member_ptr(T *p = NULLPTR) : m_p(p) {}
 
    ~member_ptr();
 
    const T& operator*() const { return *m_p; }
    T& operator*() { return *m_p; }
 
    const T* operator->() const { return m_p; }
    T* operator->() { return m_p; }
 
    const T* get() const { return m_p; }
    T* get() { return m_p; }
 
    T* release()
    {
        T *old_p = m_p;
        m_p = NULLPTR;
        return old_p;
    }
 
    void reset(T *p = NULLPTR);
 
protected:
    member_ptr(const member_ptr<T>& rhs);       // copy not allowed
    void operator=(const member_ptr<T>& rhs);   // assignment not allowed
 
    T *m_p;
};
 
template <class T> member_ptr<T>::~member_ptr() {delete m_p;}
template <class T> void member_ptr<T>::reset(T *p) {delete m_p; m_p = p;}
 
// ********************************************************
 
/// \brief Value pointer
/// \tparam T class or type
template<class T> class value_ptr : public member_ptr<T>
{
public:
    value_ptr(const T &obj) : member_ptr<T>(new T(obj)) {}
    value_ptr(T *p = NULLPTR) : member_ptr<T>(p) {}
    value_ptr(const value_ptr<T>& rhs)
        : member_ptr<T>(rhs.m_p ? new T(*rhs.m_p) : NULLPTR) {}
 
    value_ptr<T>& operator=(const value_ptr<T>& rhs);
    bool operator==(const value_ptr<T>& rhs)
    {
        return (!this->m_p && !rhs.m_p) || (this->m_p && rhs.m_p && *this->m_p == *rhs.m_p);
    }
};
 
template <class T> value_ptr<T>& value_ptr<T>::operator=(const value_ptr<T>& rhs)
{
    T *old_p = this->m_p;
    this->m_p = rhs.m_p ? new T(*rhs.m_p) : NULLPTR;
    delete old_p;
    return *this;
}
 
// ********************************************************
 
/// \brief A pointer which can be copied and cloned
/// \tparam T class or type
/// \details \p T should adhere to the \p Clonable interface
template<class T> class clonable_ptr : public member_ptr<T>
{
public:
    clonable_ptr(const T &obj) : member_ptr<T>(obj.Clone()) {}
    clonable_ptr(T *p = NULLPTR) : member_ptr<T>(p) {}
    clonable_ptr(const clonable_ptr<T>& rhs)
        : member_ptr<T>(rhs.m_p ? rhs.m_p->Clone() : NULLPTR) {}
 
    clonable_ptr<T>& operator=(const clonable_ptr<T>& rhs);
};
 
template <class T> clonable_ptr<T>& clonable_ptr<T>::operator=(const clonable_ptr<T>& rhs)
{
    T *old_p = this->m_p;
    this->m_p = rhs.m_p ? rhs.m_p->Clone() : NULLPTR;
    delete old_p;
    return *this;
}
 
// ********************************************************
 
/// \brief Reference counted pointer
/// \tparam T class or type
/// \details users should declare \p m_referenceCount as <tt>std::atomic<unsigned></tt>
///   (or similar) under C++ 11
template<class T> class counted_ptr
{
public:
    explicit counted_ptr(T *p = NULLPTR);
    counted_ptr(const T &r) : m_p(0) {attach(r);}
    counted_ptr(const counted_ptr<T>& rhs);
 
    ~counted_ptr();
 
    const T& operator*() const { return *m_p; }
    T& operator*() { return *m_p; }
 
    const T* operator->() const { return m_p; }
    T* operator->() { return get(); }
 
    const T* get() const { return m_p; }
    T* get();
 
    void attach(const T &p);
 
    counted_ptr<T> & operator=(const counted_ptr<T>& rhs);
 
private:
    T *m_p;
};
 
template <class T> counted_ptr<T>::counted_ptr(T *p)
    : m_p(p)
{
    if (m_p)
        m_p->m_referenceCount = 1;
}
 
template <class T> counted_ptr<T>::counted_ptr(const counted_ptr<T>& rhs)
    : m_p(rhs.m_p)
{
    if (m_p)
        m_p->m_referenceCount++;
}
 
template <class T> counted_ptr<T>::~counted_ptr()
{
    if (m_p && --m_p->m_referenceCount == 0)
        delete m_p;
}
 
template <class T> void counted_ptr<T>::attach(const T &r)
{
    if (m_p && --m_p->m_referenceCount == 0)
        delete m_p;
    if (r.m_referenceCount == 0)
    {
        m_p = r.clone();
        m_p->m_referenceCount = 1;
    }
    else
    {
        m_p = const_cast<T *>(&r);
        m_p->m_referenceCount++;
    }
}
 
template <class T> T* counted_ptr<T>::get()
{
    if (m_p && m_p->m_referenceCount > 1)
    {
        T *temp = m_p->clone();
        m_p->m_referenceCount--;
        m_p = temp;
        m_p->m_referenceCount = 1;
    }
    return m_p;
}
 
template <class T> counted_ptr<T> & counted_ptr<T>::operator=(const counted_ptr<T>& rhs)
{
    if (m_p != rhs.m_p)
    {
        if (m_p && --m_p->m_referenceCount == 0)
            delete m_p;
        m_p = rhs.m_p;
        if (m_p)
            m_p->m_referenceCount++;
    }
    return *this;
}
 
// ********************************************************
 
/// \brief Manages resources for an array of objects
/// \tparam T class or type
template <class T> class vector_member_ptrs
{
public:
    /// Construct an array of \p T
    /// \param size the size of the array, in elements
    /// \details If \p T is a Plain Old Dataype (POD), then the array is uninitialized.
    vector_member_ptrs(size_t size=0)
        : m_size(size), m_ptr(new member_ptr<T>[size]) {}
    ~vector_member_ptrs()
        {delete [] this->m_ptr;}
 
    member_ptr<T>& operator[](size_t index)
        {CRYPTOPP_ASSERT(index<this->m_size); return this->m_ptr[index];}
    const member_ptr<T>& operator[](size_t index) const
        {CRYPTOPP_ASSERT(index<this->m_size); return this->m_ptr[index];}
 
    size_t size() const {return this->m_size;}
    void resize(size_t newSize)
    {
        member_ptr<T> *newPtr = new member_ptr<T>[newSize];
        for (size_t i=0; i<this->m_size && i<newSize; i++)
            newPtr[i].reset(this->m_ptr[i].release());
        delete [] this->m_ptr;
        this->m_size = newSize;
        this->m_ptr = newPtr;
    }
 
private:
    vector_member_ptrs(const vector_member_ptrs<T> &c); // copy not allowed
    void operator=(const vector_member_ptrs<T> &x);     // assignment not allowed
 
    size_t m_size;
    member_ptr<T> *m_ptr;
};
 
NAMESPACE_END
 
#endif