// Ceres Solver - A fast non-linear least squares minimizer

// Copyright 2015 Google Inc. All rights reserved.

// http://ceres-solver.org/

//

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are met:

//

// * Redistributions of source code must retain the above copyright notice,

//   this list of conditions and the following disclaimer.

// * Redistributions in binary form must reproduce the above copyright notice,

//   this list of conditions and the following disclaimer in the documentation

//   and/or other materials provided with the distribution.

// * Neither the name of Google Inc. nor the names of its contributors may be

//   used to endorse or promote products derived from this software without

//   specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE

// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR

// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

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// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

// POSSIBILITY OF SUCH DAMAGE.

//

// Author: jorg@google.com (Jorg Brown)

//

// This is an implementation designed to match the anticipated future TR2

// implementation of the scoped_ptr class, and its closely-related brethren,

// scoped_array, scoped_ptr_malloc, and make_scoped_ptr.

#ifndef CERES_PUBLIC_INTERNAL_SCOPED_PTR_H_

#define CERES_PUBLIC_INTERNAL_SCOPED_PTR_H_

#include <assert.h>

#include <stdlib.h>

#include <cstddef>

#include <algorithm>

namespace ceres {

namespace internal {

template <class C> class scoped_ptr;

template <class C, class Free> class scoped_ptr_malloc;

template <class C> class scoped_array;

template <class C>

scoped_ptr<C> make_scoped_ptr(C *);

// A scoped_ptr<T> is like a T*, except that the destructor of

// scoped_ptr<T> automatically deletes the pointer it holds (if

// any). That is, scoped_ptr<T> owns the T object that it points

// to. Like a T*, a scoped_ptr<T> may hold either NULL or a pointer to

// a T object. Also like T*, scoped_ptr<T> is thread-compatible, and

// once you dereference it, you get the threadsafety guarantees of T.

//

// The size of a scoped_ptr is small: sizeof(scoped_ptr<C>) == sizeof(C*)

template <class C>

class scoped_ptr {

 public:

  // The element type

  typedef C element_type;

  // Constructor.  Defaults to intializing with NULL.

  // There is no way to create an uninitialized scoped_ptr.

  // The input parameter must be allocated with new.

  explicit scoped_ptr(C* p = NULL) : ptr_(p) { }

  // Destructor.  If there is a C object, delete it.

  // We don't need to test ptr_ == NULL because C++ does that for us.

  ~scoped_ptr() {

    enum { type_must_be_complete = sizeof(C) };

    delete ptr_;

  }

  // Reset.  Deletes the current owned object, if any.

  // Then takes ownership of a new object, if given.

  // this->reset(this->get()) works.

  void reset(C* p = NULL) {

    if (p != ptr_) {

      enum { type_must_be_complete = sizeof(C) };

      delete ptr_;

      ptr_ = p;

    }

  }

  // Accessors to get the owned object.

  // operator* and operator-> will assert() if there is no current object.

  C& operator*() const {

    assert(ptr_ != NULL);

    return *ptr_;

  }

  C* operator->() const  {

    assert(ptr_ != NULL);

    return ptr_;

  }

  C* get() const { return ptr_; }

  // Comparison operators.

  // These return whether a scoped_ptr and a raw pointer refer to

  // the same object, not just to two different but equal objects.

  bool operator==(const C* p) const { return ptr_ == p; }

  bool operator!=(const C* p) const { return ptr_ != p; }

  // Swap two scoped pointers.

  void swap(scoped_ptr& p2) {

    C* tmp = ptr_;

    ptr_ = p2.ptr_;

    p2.ptr_ = tmp;

  }

  // Release a pointer.

  // The return value is the current pointer held by this object.

  // If this object holds a NULL pointer, the return value is NULL.

  // After this operation, this object will hold a NULL pointer,

  // and will not own the object any more.

  C* release() {

    C* retVal = ptr_;

    ptr_ = NULL;

    return retVal;

  }

 private:

  C* ptr_;

  // google3 friend class that can access copy ctor (although if it actually

  // calls a copy ctor, there will be a problem) see below

  friend scoped_ptr<C> make_scoped_ptr<C>(C *p);

  // Forbid comparison of scoped_ptr types.  If C2 != C, it totally doesn't

  // make sense, and if C2 == C, it still doesn't make sense because you should

  // never have the same object owned by two different scoped_ptrs.

  template <class C2> bool operator==(scoped_ptr<C2> const& p2) const;

  template <class C2> bool operator!=(scoped_ptr<C2> const& p2) const;

  // Disallow evil constructors

  scoped_ptr(const scoped_ptr&);

  void operator=(const scoped_ptr&);

};

// Free functions

template <class C>

inline void swap(scoped_ptr<C>& p1, scoped_ptr<C>& p2) {

  p1.swap(p2);

}

template <class C>

inline bool operator==(const C* p1, const scoped_ptr<C>& p2) {

  return p1 == p2.get();

}

template <class C>

inline bool operator==(const C* p1, const scoped_ptr<const C>& p2) {

  return p1 == p2.get();

}

template <class C>

inline bool operator!=(const C* p1, const scoped_ptr<C>& p2) {

  return p1 != p2.get();

}

template <class C>

inline bool operator!=(const C* p1, const scoped_ptr<const C>& p2) {

  return p1 != p2.get();

}

template <class C>

scoped_ptr<C> make_scoped_ptr(C *p) {

  // This does nothing but to return a scoped_ptr of the type that the passed

  // pointer is of.  (This eliminates the need to specify the name of T when

  // making a scoped_ptr that is used anonymously/temporarily.)  From an

  // access control point of view, we construct an unnamed scoped_ptr here

  // which we return and thus copy-construct.  Hence, we need to have access

  // to scoped_ptr::scoped_ptr(scoped_ptr const &).  However, it is guaranteed

  // that we never actually call the copy constructor, which is a good thing

  // as we would call the temporary's object destructor (and thus delete p)

  // if we actually did copy some object, here.

  return scoped_ptr<C>(p);

}

// scoped_array<C> is like scoped_ptr<C>, except that the caller must allocate

// with new [] and the destructor deletes objects with delete [].

//

// As with scoped_ptr<C>, a scoped_array<C> either points to an object

// or is NULL.  A scoped_array<C> owns the object that it points to.

// scoped_array<T> is thread-compatible, and once you index into it,

// the returned objects have only the threadsafety guarantees of T.

//

// Size: sizeof(scoped_array<C>) == sizeof(C*)

template <class C>

class scoped_array {

 public:

  // The element type

  typedef C element_type;

  // Constructor.  Defaults to intializing with NULL.

  // There is no way to create an uninitialized scoped_array.

  // The input parameter must be allocated with new [].

  explicit scoped_array(C* p = NULL) : array_(p) { }

  // Destructor.  If there is a C object, delete it.

  // We don't need to test ptr_ == NULL because C++ does that for us.

  ~scoped_array() {

    enum { type_must_be_complete = sizeof(C) };

    delete[] array_;

  }

  // Reset. Deletes the current owned object, if any.

  // Then takes ownership of a new object, if given.

  // this->reset(this->get()) works.

  void reset(C* p = NULL) {

    if (p != array_) {

      enum { type_must_be_complete = sizeof(C) };

      delete[] array_;

      array_ = p;

    }

  }

  // Get one element of the current object.

  // Will assert() if there is no current object, or index i is negative.

  C& operator[](std::ptrdiff_t i) const {

    assert(i >= 0);

    assert(array_ != NULL);

    return array_[i];

  }

  // Get a pointer to the zeroth element of the current object.

  // If there is no current object, return NULL.

  C* get() const {

    return array_;

  }

  // Comparison operators.

  // These return whether a scoped_array and a raw pointer refer to

  // the same array, not just to two different but equal arrays.

  bool operator==(const C* p) const { return array_ == p; }

  bool operator!=(const C* p) const { return array_ != p; }

  // Swap two scoped arrays.

  void swap(scoped_array& p2) {

    C* tmp = array_;

    array_ = p2.array_;

    p2.array_ = tmp;

  }

  // Release an array.

  // The return value is the current pointer held by this object.

  // If this object holds a NULL pointer, the return value is NULL.

  // After this operation, this object will hold a NULL pointer,

  // and will not own the object any more.

  C* release() {

    C* retVal = array_;

    array_ = NULL;

    return retVal;

  }

 private:

  C* array_;

  // Forbid comparison of different scoped_array types.

  template <class C2> bool operator==(scoped_array<C2> const& p2) const;

  template <class C2> bool operator!=(scoped_array<C2> const& p2) const;

  // Disallow evil constructors

  scoped_array(const scoped_array&);

  void operator=(const scoped_array&);

};

// Free functions

template <class C>

inline void swap(scoped_array<C>& p1, scoped_array<C>& p2) {

  p1.swap(p2);

}

template <class C>

inline bool operator==(const C* p1, const scoped_array<C>& p2) {

  return p1 == p2.get();

}

template <class C>

inline bool operator==(const C* p1, const scoped_array<const C>& p2) {

  return p1 == p2.get();

}

template <class C>

inline bool operator!=(const C* p1, const scoped_array<C>& p2) {

  return p1 != p2.get();

}

template <class C>

inline bool operator!=(const C* p1, const scoped_array<const C>& p2) {

  return p1 != p2.get();

}

// This class wraps the c library function free() in a class that can be

// passed as a template argument to scoped_ptr_malloc below.

class ScopedPtrMallocFree {

 public:

  inline void operator()(void* x) const {

    free(x);

  }

};

}  // namespace internal

}  // namespace ceres

#endif  // CERES_PUBLIC_INTERNAL_SCOPED_PTR_H_