/src/dng_sdk/source/dng_auto_ptr.h

Source
/*****************************************************************************/
// Copyright 2006 Adobe Systems Incorporated
// All Rights Reserved.
//
// NOTICE:  Adobe permits you to use, modify, and distribute this file in
// accordance with the terms of the Adobe license agreement accompanying it.
/*****************************************************************************/

/* $Id: //mondo/dng_sdk_1_4/dng_sdk/source/dng_auto_ptr.h#2 $ */ 
/* $DateTime: 2012/07/11 10:36:56 $ */
/* $Change: 838485 $ */
/* $Author: tknoll $ */

/** \file
 * Class to implement std::auto_ptr like functionality even on platforms which do not
 * have a full Standard C++ library.
 */

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

#ifndef __dng_auto_ptr__
#define __dng_auto_ptr__

#include "dng_memory.h"

#include <memory>
#include <stddef.h>
#include <stdlib.h>

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

// The following template has similar functionality to the STL auto_ptr, without
// requiring all the weight of STL.

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

/// \brief A class intended to be used in stack scope to hold a pointer from new. The
/// held pointer will be deleted automatically if the scope is left without calling
/// Release on the AutoPtr first.

template<class T>
class AutoPtr
  {
  
  private:
  
    T *p_;
    
  public:

    /// Construct an AutoPtr with no referent.

    AutoPtr () : p_ (0) { }
  
    /// Construct an AutoPtr which owns the argument pointer.
    /// \param p pointer which constructed AutoPtr takes ownership of. p will be
    /// deleted on destruction or Reset unless Release is called first.

    explicit AutoPtr (T *p) :  p_( p ) { }

    /// Reset is called on destruction.

    ~AutoPtr ();

    /// Call Reset with a pointer from new. Uses T's default constructor.

    void Alloc ();

    /// Return the owned pointer of this AutoPtr, NULL if none. No change in
    /// ownership or other effects occur.

    T *Get () const { return p_; }

    /// Return the owned pointer of this AutoPtr, NULL if none. The AutoPtr gives
    /// up ownership and takes NULL as its value.

    T *Release ();

    /// If a pointer is owned, it is deleted. Ownership is taken of passed in
    /// pointer.
    /// \param p pointer which constructed AutoPtr takes ownership of. p will be
    /// deleted on destruction or Reset unless Release is called first.

    void Reset (T *p);

    /// If a pointer is owned, it is deleted and the AutoPtr takes NULL as its
    /// value.

    void Reset ();

    /// Allows members of the owned pointer to be accessed directly. It is an
    /// error to call this if the AutoPtr has NULL as its value.

    T *operator-> () const { return p_; }

    /// Returns a reference to the object that the owned pointer points to. It is
    /// an error to call this if the AutoPtr has NULL as its value.

    T &operator* () const { return *p_; }
    
    /// Swap with another auto ptr.
    
    friend inline void Swap (AutoPtr< T > &x, AutoPtr< T > &y)
      {
      T* temp = x.p_;
      x.p_ = y.p_;
      y.p_ = temp;
      }
    
  private:
  
    // Hidden copy constructor and assignment operator. I don't think the STL
    // "feature" of grabbing ownership of the pointer is a good idea.
  
    AutoPtr (AutoPtr<T> &rhs);

    AutoPtr<T> & operator= (AutoPtr<T> &rhs);
    
  };

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

template<class T>
AutoPtr<T>::~AutoPtr ()
  {
  
  delete p_;
  p_ = 0;
  
  }

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

template<class T>
T *AutoPtr<T>::Release ()
  {
  T *result = p_;
  p_ = 0;
  return result;
  }

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

template<class T>
void AutoPtr<T>::Reset (T *p)
  {
  
  if (p_ != p)
    {
    if (p_ != 0)
      delete p_;
    p_ = p;
    }
  
  }

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

template<class T>
void AutoPtr<T>::Reset ()
  {
  
  if (p_ != 0)
    {
    delete p_;
    p_ = 0;
    }
  
  }

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

template<class T>
void AutoPtr<T>::Alloc ()
  {
  this->Reset (new T);
  }

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

/// \brief A class that provides a variable-length array that automatically
/// deletes the underlying memory on scope exit.
///
/// T is not required to be movable. The class is implemented using
/// dng_std_vector but purposely does not use any member functions that require
/// T to be movable.

template<typename T>
class AutoArray
  {

  public:
    /// Construct an AutoArray that refers to a null pointer.

    AutoArray () { }
    
    /// Construct an AutoArray containing 'count' elements, which are
    /// default-constructed. If an out-of-memory condition occurs, a
    /// dng_exception with error code dng_error_memory is thrown.

    explicit AutoArray (size_t count)
      : vector_(new dng_std_vector<T>(count))
      {
      }

    /// Changes the size of the AutoArray to 'count' elements. The new
    /// elements are default-constructed. The previously existing elements
    /// of the array are destroyed. If an out-of-memory condition occurs, a
    /// dng_exception with error code dng_error_memory is thrown.

    void Reset (size_t count)
      {
      vector_.reset(new dng_std_vector<T>(count));
      }

    /// Allows indexing into the AutoArray. The index 'i' must be
    /// non-negative and smaller than size of the array (the value that was
    /// passed to the constructor or to Reset()).

    T &operator[] (ptrdiff_t i)
      {
      return (*vector_) [i];
      }
    const T &operator[] (ptrdiff_t i) const
      {
      return (*vector_) [i];
      }

    /// Return a pointer to the beginning of the array.

    T *Get ()
      {
      if (vector_)
        return vector_->data();
      else
        return nullptr;
      }
    const T *Get () const
      {
      if (vector_)
        return vector_->data();
      else
        return nullptr;
      }

  private:

    // Hidden copy constructor and assignment operator.

    AutoArray (const AutoArray &);

    const AutoArray & operator= (const AutoArray &);

  private:

    std::unique_ptr<dng_std_vector<T> > vector_;

  };

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

#endif

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

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Created: 2026-04-01 06:23