shared_ptr.h

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/** @file
 *  @author Bram de Greve (bram@cocamware.com)
 *  @author Tom De Muer (tom@cocamware.com)
 *
 *  *** BEGIN LICENSE INFORMATION ***
 *  
 *  The contents of this file are subject to the Common Public Attribution License 
 *  Version 1.0 (the "License"); you may not use this file except in compliance with 
 *  the License. You may obtain a copy of the License at 
 *  http://lass.sourceforge.net/cpal-license. The License is based on the 
 *  Mozilla Public License Version 1.1 but Sections 14 and 15 have been added to cover 
 *  use of software over a computer network and provide for limited attribution for 
 *  the Original Developer. In addition, Exhibit A has been modified to be consistent 
 *  with Exhibit B.
 *  
 *  Software distributed under the License is distributed on an "AS IS" basis, WITHOUT 
 *  WARRANTY OF ANY KIND, either express or implied. See the License for the specific 
 *  language governing rights and limitations under the License.
 *  
 *  The Original Code is LASS - Library of Assembled Shared Sources.
 *  
 *  The Initial Developer of the Original Code is Bram de Greve and Tom De Muer.
 *  The Original Developer is the Initial Developer.
 *  
 *  All portions of the code written by the Initial Developer are:
 *  Copyright (C) 2004-2023 the Initial Developer.
 *  All Rights Reserved.
 *  
 *  Contributor(s):
 *
 *  Alternatively, the contents of this file may be used under the terms of the 
 *  GNU General Public License Version 2 or later (the GPL), in which case the 
 *  provisions of GPL are applicable instead of those above.  If you wish to allow use
 *  of your version of this file only under the terms of the GPL and not to allow 
 *  others to use your version of this file under the CPAL, indicate your decision by 
 *  deleting the provisions above and replace them with the notice and other 
 *  provisions required by the GPL License. If you do not delete the provisions above,
 *  a recipient may use your version of this file under either the CPAL or the GPL.
 *  
 *  *** END LICENSE INFORMATION ***
 */
 
#ifndef LASS_GUARDIAN_OF_INCLUSION_UTIL_SHARED_PTR_H
#define LASS_GUARDIAN_OF_INCLUSION_UTIL_SHARED_PTR_H
 
#include "util_common.h"
#include "smart_ptr_policies.h"
 
namespace lass
{
namespace util
{
 
template
<
    typename T,
    template <typename, typename> class StoragePolicy = ObjectStorage,
    typename CounterPolicy = DefaultCounter
>
class SharedPtr: public StoragePolicy<T, CounterPolicy>
{
public:
 
    typedef T TPointee;
    typedef StoragePolicy<T, CounterPolicy> TStoragePolicy;
    typedef CounterPolicy TCounterPolicy;
    typedef typename TStoragePolicy::TStorage TStorage;
    typedef typename TStoragePolicy::TPointer TPointer;
    typedef typename TStoragePolicy::TReference TReference;
    typedef typename TCounterPolicy::TCount TCount;
 
    template <typename U> struct Rebind
    {
        typedef SharedPtr<U, StoragePolicy, CounterPolicy> Type;
    };
 
    SharedPtr():
        TStoragePolicy()
    {
    }
    explicit SharedPtr(TPointer p):
        TStoragePolicy(p)
    {
        if (!isEmpty())
        {
            CounterPolicy::init(TStoragePolicy::storage());
        }
    }
    SharedPtr(const SharedPtr& other):
        TStoragePolicy(other)
    {
        if (!isEmpty())
        {
            CounterPolicy::increment(TStoragePolicy::storage());
        }
    }
 
    SharedPtr(SharedPtr&& other) noexcept:
        TStoragePolicy(std::move(other))
    {
        LASS_ASSERT(other.isEmpty());
    }
 
    template <typename U> SharedPtr(const SharedPtr<U, StoragePolicy, CounterPolicy>& other):
        TStoragePolicy(other)
    {
        if (!isEmpty())
        {
            CounterPolicy::increment(TStoragePolicy::storage());
        }
    }
 
    ~SharedPtr()
    {
        if (!isEmpty() && CounterPolicy::decrement(TStoragePolicy::storage()))
        {
            CounterPolicy::dispose(TStoragePolicy::storage());
            TStoragePolicy::dispose();
        }
    }
 
    SharedPtr& operator=(const SharedPtr& other)
    {
        SharedPtr temp(other);
        swap(temp);
        return *this;
    }
 
    SharedPtr& operator=(SharedPtr&& other) noexcept
    {
        SharedPtr temp(std::forward<SharedPtr>(other));
        LASS_ASSERT(other.isEmpty());
        swap(temp);
        return *this;
    }
 
    void reset(TPointer p = 0)
    {
        SharedPtr temp(p);
        swap(temp);
    }
 
    template <typename U> SharedPtr(std::unique_ptr<U>&& p) :
        TStoragePolicy(p.get())
    {
        if (!isEmpty())
        {
            CounterPolicy::init(TStoragePolicy::storage());
        }
        p.release();
    }
    template <typename U> void reset(std::unique_ptr<U>&& p)
    {
        SharedPtr temp(std::forward<std::unique_ptr<U>>(p));
        LASS_ASSERT(!p);
        swap(temp);
    }
 
    void swap(SharedPtr& other)
    {
        TStoragePolicy::swap(other);
    }
 
    TPointer get() const
    {
        return TStoragePolicy::pointer();
    }
    TPointer operator->() const
    {
        LASS_ASSERT(get());
        return get();
    }
    TReference operator*() const
    {
        LASS_ASSERT(get());
        return *get();
    }
    TReference operator[](size_t i) const
    {
        LASS_ASSERT(get());
        return TStoragePolicy::at(i);
    }
 
    const TCount count() const
    {
        return isEmpty() ? 0 : TCounterPolicy::count(TStoragePolicy::storage());
    }
    bool isEmpty() const
    {
        return TStoragePolicy::isNull();
    }
    bool operator!() const
    {
        return isEmpty();
    }
    explicit operator bool() const
    {
        return !isEmpty();
    }
 
    /** returns reference to storage pointer */
    const TStorage& storage() const
    {
        return TStoragePolicy::storage();
    }
    /** returns reference to storage pointer */
    TStorage& storage()
    {
        return TStoragePolicy::storage();
    }
 
    template <typename U>
    const SharedPtr<U, StoragePolicy, CounterPolicy> staticCast() const
    {
        return SharedPtr<U, StoragePolicy, CounterPolicy>(TStoragePolicy::template staticCast<U>());
    }
 
    template <typename U>
    const SharedPtr<U, StoragePolicy, CounterPolicy> dynamicCast() const
    {
        return SharedPtr<U, StoragePolicy, CounterPolicy>(TStoragePolicy::template dynamicCast<U>());
    }
 
    template <typename U>
    const SharedPtr<U, StoragePolicy, CounterPolicy> constCast() const
    {
        return SharedPtr<U, StoragePolicy, CounterPolicy>(TStoragePolicy::template constCast<U>());
    }
 
private:
 
    template <typename U, template <typename, typename> class S, typename C> friend class SharedPtr;
 
    SharedPtr(const TStoragePolicy& storage): 
        TStoragePolicy(storage)
    {
        if (!isEmpty())
        {
            CounterPolicy::increment(TStoragePolicy::storage());
        }
    }   
};
 
template <typename T1, template <typename, typename> class S1, typename C1, typename T2, template <typename, typename> class S2, typename C2>
bool operator==(const SharedPtr<T1, S1, C1>& a, const SharedPtr<T2, S2, C2>& b)
{
    return a.get() == b.get();
}
 
template <typename T1, template <typename, typename> class S1, typename C1, typename T2, template <typename, typename> class S2, typename C2>
bool operator!=(const SharedPtr<T1, S1, C1>& a, const SharedPtr<T2, S2, C2>& b)
{
    return !(a == b);
}
 
template <typename T, template <typename, typename> class S, typename C>
bool operator==(const SharedPtr<T, S, C>& a, std::nullptr_t)
{
    return !a;
}
 
template <typename T, template <typename, typename> class S, typename C>
bool operator!=(const SharedPtr<T, S, C>& a, std::nullptr_t)
{
    return static_cast<bool>(a);
}
 
template <typename T, template <typename, typename> class S, typename C>
bool operator==(std::nullptr_t, const SharedPtr<T, S, C>& b)
{
    return !b;
}
 
template <typename T, template <typename, typename> class S, typename C>
bool operator!=(std::nullptr_t, const SharedPtr<T, S, C>& b)
{
    return static_cast<bool>(b);
}
 
}
}
 
#endif
 
// EOF