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+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed
+ * with this work for additional information regarding copyright
+ * ownership. The ASF licenses this file to you under the Apache
+ * License, Version 2.0 (the "License"); you may not use this file
+ * except in compliance with the License. You may obtain a copy of
+ * the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#ifndef INCLUDED_O3TL_VECTOR_POOL_HXX
+#define INCLUDED_O3TL_VECTOR_POOL_HXX
+
+#include <utility>
+#include <vector>
+
+namespace o3tl
+{
+ namespace detail
+ {
+ template<typename ValueType, class Container> class simple_pool_impl :
+ public Container
+ {
+ typedef typename Container::value_type value_type;
+ std::ptrdiff_t mnFirstFreeIndex;
+
+ public:
+ simple_pool_impl() :
+ mnFirstFreeIndex(-1)
+ {}
+
+ std::ptrdiff_t alloc()
+ {
+ return store(ValueType());
+ }
+
+ std::ptrdiff_t store(const ValueType& rCopy)
+ {
+ if( mnFirstFreeIndex != -1 )
+ {
+ std::ptrdiff_t nIdx=mnFirstFreeIndex;
+ mnFirstFreeIndex = this->at(mnFirstFreeIndex).nextFree;
+ this->at(nIdx).value = rCopy;
+ this->at(nIdx).nextFree = -1;
+
+ return nIdx;
+ }
+ else
+ {
+ this->push_back(value_type(rCopy));
+ return this->size()-1;
+ }
+ }
+
+ void free( std::ptrdiff_t nIdx )
+ {
+ this->at(nIdx).nextFree = mnFirstFreeIndex;
+ mnFirstFreeIndex = nIdx;
+ }
+
+ const ValueType& get( std::ptrdiff_t nIdx ) const
+ {
+ return this->operator[](nIdx).value;
+ }
+ ValueType& get( std::ptrdiff_t nIdx )
+ {
+ return this->operator[](nIdx).value;
+ }
+ };
+
+ template< typename ValueType > struct struct_from_value
+ {
+ struct type
+ {
+ type() :
+ value(),
+ nextFree(-1)
+ {}
+ explicit type( ValueType val ) :
+ value(std::move(val)),
+ nextFree(-1)
+ {}
+
+ ValueType value;
+ std::ptrdiff_t nextFree;
+ };
+ };
+ }
+
+ /** Simple vector-based memory pool allocator
+
+ This template can be used to provide simple pooled memory
+ allocation from a container class that adheres to the stl
+ random access container concept. Note that alloc/free works
+ with _indices_ into the container!
+
+ @example
+ <pre>
+vector_pool<type> myPool;
+int nIdx=myPool.alloc();
+myPool[nIdx] = myVal;
+ ... do stuff ...
+myPool.free(nIdx);
+ </pre>
+ */
+ template<typename ValueType> struct vector_pool :
+ public detail::simple_pool_impl<ValueType,
+ std::vector<typename detail::struct_from_value<ValueType>::type > >
+ {};
+}
+
+#endif /* INCLUDED_O3TL_VECTOR_POOL_HXX */
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */