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copied!<p>Have a look at this article: <a href="http://www.bearcave.com/software/c++_mem.html" rel="nofollow noreferrer">Overloading New in C++ </a>. You could overload the <code>new</code> operator for <code>ObjectBase</code> so that it takes your allocator as a parameter and does the rest of the job:</p> <pre><code>void *ObjectBase::operator new(size_t size, Allocator *allocator) { void *ptr = allocator->allocate(size); // Hack to pre-initialize member before constructor is called ObjectBase *obj = static_cast<ObjectBase *>(ptr); obj->setAllocator(allocator); return ptr; } </code></pre> <p>Normally, the operator is supposed to just return a pointer to the allocated memory, but since you need access to the new object to call your <code>setAllocator</code> method, I've included a hack that should (but may not) work. Note that the actual <code>ObjectBase</code> constructor is called after the above function returns, so you should make sure that your constructor does not re-initialize the allocator member.</p> <p>And then a similar overload for <code>delete</code>:</p> <pre><code>void ObjectBase::operator delete(void *ptr) { ObjectBase *obj = static_cast<ObjectBase *>(ptr); obj->getAllocator()->free(ptr); } </code></pre> <p>You would then create objects by calling <code>new (allocator) SomeClass(...)</code> where <code>SomeClass</code> derives from <code>ObjectBase</code>.</p> <p><strong>Edit:</strong> One potential problem with this is that you cannot allocate objects on the stack any more, because there is no way to initialize the allocator to <code>NULL</code> without affecting the how the overloaded <code>new</code> works.</p> <p><strong>Update:</strong> There is one last (dirty) hack to get it working with both stack and dynamic allocation. You can make <code>new</code> set a global variable (a class static member would work as well) pointing to the current allocator and the constructor could consume this and reset it to <code>NULL</code>. At all other times, this global will already be <code>NULL</code> so an object constructed on the stack will get a <code>NULL</code> allocator.</p> <pre><code>Allocator *currentAllocator = NULL; void *ObjectBase::operator new(size_t size, Allocator *allocator) { currentAllocator = allocator; return allocator->allocate(size); } ObjectBase::ObjectBase() { setAllocator(currentAllocator); currentAllocator = NULL; } </code></pre>

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