source: git/src-cryptopp/smartptr.h

// smartptr.h - written and placed in the public domain by Wei Dai

//! \file
//! \headerfile 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)

//! \class simple_ptr
//! \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 = NULL) : m_p(p) {}
        ~simple_ptr()
        {
                delete m_p;
                *((volatile T**)&m_p) = NULL;
        }

        T *m_p;
};

//! \class member_ptr
//! \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 = NULL) : 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;
                *((volatile T**)&m_p) = NULL;
                return old_p;
        }

        void reset(T *p = 0);

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;}

// ********************************************************

//! \class value_ptr
//! \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 = NULL) : member_ptr<T>(p) {}
        value_ptr(const value_ptr<T>& rhs)
                : member_ptr<T>(rhs.m_p ? new T(*rhs.m_p) : NULL) {}

        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) : NULL;
        delete old_p;
        return *this;
}

// ********************************************************

//! \class clonable_ptr
//! \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 = NULL) : member_ptr<T>(p) {}
        clonable_ptr(const clonable_ptr<T>& rhs)
                : member_ptr<T>(rhs.m_p ? rhs.m_p->Clone() : NULL) {}

        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() : NULL;
        delete old_p;
        return *this;
}

// ********************************************************

//! \class counted_ptr
//! \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 = 0);
        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;
}

// ********************************************************

//! \class vector_ptr
//! \brief Manages resources for an array of objects
//! \tparam T class or type
//! \details \p vector_ptr is used frequently in the library to avoid large stack allocations,
//!   and manage resources and ensure cleanup under the RAII pattern (Resource Acquisition
//!   Is Initialization).
template <class T> class vector_ptr
{
public:
        //! Construct an arry 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_ptr(size_t size=0)
                : m_size(size), m_ptr(new T[m_size]) {}
        ~vector_ptr()
                {delete [] m_ptr;}

        T& operator[](size_t index)
                {CRYPTOPP_ASSERT(m_size && index<this->m_size); return this->m_ptr[index];}
        const T& operator[](size_t index) const
                {CRYPTOPP_ASSERT(m_size && index<this->m_size); return this->m_ptr[index];}

        size_t size() const {return this->m_size;}
        void resize(size_t newSize)
        {
                T *newPtr = new T[newSize];
                for (size_t i=0; i<this->m_size && i<newSize; i++)
                        newPtr[i] = m_ptr[i];
                delete [] this->m_ptr;
                this->m_size = newSize;
                this->m_ptr = newPtr;
        }

#ifdef __BORLANDC__
        operator T *() const
                {return (T*)m_ptr;}
#else
        operator const void *() const
                {return m_ptr;}
        operator void *()
                {return m_ptr;}

        operator const T *() const
                {return m_ptr;}
        operator T *()
                {return m_ptr;}
#endif

private:
        vector_ptr(const vector_ptr<T> &c);     // copy not allowed
        void operator=(const vector_ptr<T> &x);         // assignment not allowed

        size_t m_size;
        T *m_ptr;
};

// ********************************************************

//! \class vector_member_ptrs
//! \brief Manages resources for an array of objects
//! \tparam T class or type
template <class T> class vector_member_ptrs
{
public:
        //! Construct an arry 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