101 lines
2.8 KiB
C++
101 lines
2.8 KiB
C++
/*
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* This file is part of libgim.
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*
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* libgim is free software: you can redistribute it and/or modify it under the
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* terms of the GNU General Public License as published by the Free Software
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* Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* libgim is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License
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* along with libgim. If not, see <http://www.gnu.org/licenses/>.
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*
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* Copyright 2011 Danny Robson <danny@nerdcruft.net>
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*/
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#ifndef __UTIL_POOL_HPP
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#define __UTIL_POOL_HPP
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#include "nocopy.hpp"
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namespace util {
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template <typename T>
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class pool : public nocopy {
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protected:
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union node {
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char _data[sizeof (T)];
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node *_chain;
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};
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node *m_head;
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node *m_next;
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unsigned int m_capacity;
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public:
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pool (unsigned int _capacity):
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m_capacity (_capacity)
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{
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static_assert (sizeof (T) >= sizeof (uintptr_t),
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"pool<T>'s chained block system requires that T be at least pointer sized");
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m_head = (node *)operator new (sizeof (T) * m_capacity);
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m_next = m_head;
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for (unsigned int i = 0; i < m_capacity - 1; ++i)
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m_next[i]._chain = &m_next[i + 1];
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m_next[m_capacity - 1]._chain = NULL;
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}
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~pool () {
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CHECK (m_next != NULL);
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unsigned int doomed_count = 0;
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for (node *cursor = m_next; cursor != NULL; cursor = cursor->_chain)
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++doomed_count;
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CHECK_EQ (doomed_count, m_capacity);
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operator delete (m_head);
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}
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unsigned int capacity (void) const
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{ return m_capacity; }
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template <typename ...Args>
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T* acquire (Args&... args) {
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if (!m_next)
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throw std::bad_alloc ();
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node *newnext = m_next->_chain;
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T *data = (T*)&m_next->_data;
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try {
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new (data) T (args...);
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} catch (...) {
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m_next->_chain = newnext;
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throw;
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}
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m_next = newnext;
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return data;
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}
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void release (T *data) {
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data->~T();
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node *newnode = (node *)data;
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newnode->_chain = m_next;
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m_next = newnode;
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}
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};
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}
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#endif // __UTIL_POOL_HPP
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