Method remove_duplicates

lib/pugixml/src/pugixml.cpp:8967–9003

		}

		void remove_duplicates(xpath_allocator* alloc)
		{
			if (_type == xpath_node_set::type_unsorted && _end - _begin > 2)
			{
				xpath_allocator_capture cr(alloc);

				size_t size_ = static_cast<size_t>(_end - _begin);

				size_t hash_size = 1;
				while (hash_size < size_ + size_ / 2) hash_size *= 2;

				const void** hash_data = static_cast<const void**>(alloc->allocate(hash_size * sizeof(void**)));
				if (!hash_data) return;

				memset(hash_data, 0, hash_size * sizeof(const void**));

				xpath_node* write = _begin;

				for (xpath_node* it = _begin; it != _end; ++it)
				{
					const void* attr = it->attribute().internal_object();
					const void* node = it->node().internal_object();
					const void* key = attr ? attr : node;

					if (key && hash_insert(hash_data, hash_size, key))
					{
						*write++ = *it;
					}
				}

				_end = write;
			}
			else
			{
				_end = unique(_begin, _end);
			}
		}

		xpath_node_set::type_t type() const
		{