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Diffstat (limited to 'qpid/cpp/include/qpid/InlineVector.h')
-rw-r--r-- | qpid/cpp/include/qpid/InlineVector.h | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/qpid/cpp/include/qpid/InlineVector.h b/qpid/cpp/include/qpid/InlineVector.h new file mode 100644 index 0000000000..c55db295f3 --- /dev/null +++ b/qpid/cpp/include/qpid/InlineVector.h @@ -0,0 +1,68 @@ +#ifndef QPID_INLINEVECTOR_H +#define QPID_INLINEVECTOR_H + +/* + * + * 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 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + * + */ + +#include "qpid/InlineAllocator.h" +#include <vector> + +namespace qpid { + +/** + * A vector that stores up to Max elements in inline storage, + * otherwise uses normal vector allocation. + * + * NOTE: depends on some non-standard but highly probably assumptions + * about how std::vector uses its allocator, they are true for g++. + * - default constructor does not allocate. + * - reserve(N) does not allocate more than N elements. + * - vector never re-allocates when size() < capacity() + */ +template <class T, size_t Max, class Alloc=std::allocator<T> > +class InlineVector : public std::vector<T, InlineAllocator<Alloc, Max> > +{ + typedef std::vector<T, InlineAllocator<Alloc, Max> > Base; + public: + typedef typename Base::allocator_type allocator_type; + typedef typename Base::value_type value_type; + typedef typename Base::size_type size_type; + + explicit InlineVector(const allocator_type& a=allocator_type()) : Base(a) { + this->reserve(Max); + } + + explicit InlineVector(size_type n, const value_type& x = value_type(), + const allocator_type& a=allocator_type()) : Base(a) + { + this->reserve(std::max(n, Max)); + this->insert(this->end(), n, x); + } + + InlineVector(const InlineVector& x) : Base() { + this->reserve(std::max(x.size(), Max)); + *this = x; + } +}; + +} // namespace qpid + +#endif /*!QPID_INLINEVECTOR_H*/ |