scoped_ptr.h

// Ceres Solver - A fast non-linear least squares minimizer
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// 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 PALLAS_SCOPED_PTR_H
#define  PALLAS_SCOPED_PTR_H

#include <assert.h>
#include <stdlib.h>
#include <cstddef>
#include <algorithm>

namespace pallas {

    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 *);
    template <class C>
    class scoped_ptr {
    public:
        typedef C element_type;
        explicit scoped_ptr(C* p = NULL) : ptr_(p) { }

        ~scoped_ptr() {
            enum { type_must_be_complete = sizeof(C) };
            delete ptr_;
        }
  
        void reset(C* p = NULL) {
            if (p != ptr_) {
                enum { type_must_be_complete = sizeof(C) };
                delete ptr_;
                ptr_ = p;
            }
        }


        C& operator*() const {
            assert(ptr_ != NULL);
            return *ptr_;
        }
        
        C* operator->() const  {
            assert(ptr_ != NULL);
            return ptr_;
        }

        C* get() const { return ptr_; }

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

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

        void swap(scoped_ptr& p2) {
            C* tmp = ptr_;
            ptr_ = p2.ptr_;
            p2.ptr_ = tmp;
        }

        C* release() {
            C* retVal = ptr_;
            ptr_ = NULL;
            return retVal;
        }

    private:
        C* ptr_;

        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) {
        return scoped_ptr<C>(p);
    }

    template <class C>
    class scoped_array {
    public:
        typedef C element_type;
        explicit scoped_array(C* p = NULL) : array_(p) { }
 
        ~scoped_array() {
            enum { type_must_be_complete = sizeof(C) };
            delete[] array_;
        }

        void reset(C* p = NULL) {
            if (p != array_) {
                enum { type_must_be_complete = sizeof(C) };
                delete[] array_;
                array_ = p;
            }
        }
 
        C& operator[](std::ptrdiff_t i) const {
            assert(i >= 0);
            assert(array_ != NULL);
            return array_[i];
        }
 
        C* get() const {
            return array_;
        }

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

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

        void swap(scoped_array& p2) {
            C* tmp = array_;
            array_ = p2.array_;
            p2.array_ = tmp;
        }

        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();
    }

    class ScopedPtrMallocFree {
    public:
        inline void operator()(void* x) const {
            free(x);
        }
    };

}  // namespace pallas

#endif  // PALLAS_SCOPED_PTR_H