stl_pooled_alloc.h

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/* -*- mode:C++; c-basic-offset:4 -*-
     Shore-kits -- Benchmark implementations for Shore-MT
   
                       Copyright (c) 2007-2009
      Data Intensive Applications and Systems Labaratory (DIAS)
               Ecole Polytechnique Federale de Lausanne
   
                         All Rights Reserved.
   
   Permission to use, copy, modify and distribute this software and
   its documentation is hereby granted, provided that both the
   copyright notice and this permission notice appear in all copies of
   the software, derivative works or modified versions, and any
   portions thereof, and that both notices appear in supporting
   documentation.
   
   This code is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. THE AUTHORS
   DISCLAIM ANY LIABILITY OF ANY KIND FOR ANY DAMAGES WHATSOEVER
   RESULTING FROM THE USE OF THIS SOFTWARE.
*/

#ifndef __STL_POOLED_ALLOC
#define __STL_POOLED_ALLOC

#include "stl_pool.h"
#include <cassert>
#include <vector>
#include <list>
#include <set>
#include <map>

template<typename T>
class PooledAllocator {
public:
    typedef size_t size_type;            
    typedef ptrdiff_t difference_type;    

    typedef T value_type;            
    typedef T* pointer;            
    typedef T const* const_pointer;        
    typedef T& reference;            
    typedef T const& const_reference;    

    template<typename U>
    struct rebind {
        typedef PooledAllocator<U> other;
    };


    PooledAllocator(Pool* pool = 0) : m_pool(pool) {
        assert(!m_pool || sizeof(T) <= m_pool->GetGranularity());
    }


    template<typename U>
    PooledAllocator(PooledAllocator<U> const& arg) : m_pool(arg.m_pool) {
        assert(!m_pool || sizeof(T) <= m_pool->GetGranularity());
    }

    size_type max_size() const {
        return 0xffffffff;
    }


    pointer allocate(size_type count, std::allocator<void>::const_pointer /*hint*/ = 0) const {
        if (count == 1 && m_pool) {
            return reinterpret_cast<T*>( m_pool->Allocate());
        } else {
            return reinterpret_cast<T*>( new char[count * sizeof(T)] );
        }
    }


    void deallocate(pointer block, size_type count) const throw() {
        if (!block) {
            return;
        }

        assert(block && "null pointer argument");
        if (count == 1 && m_pool) {
            m_pool->Deallocate(block);
        } else {
            delete[] reinterpret_cast<char*>( block );
        }
    }


    void construct(pointer element, T const& arg) {
        new(element) T(arg);
    }


    void destroy(pointer element) {
        element->~T();
        //    element; // FIXME: genuinely bizarre 'unused parameter' bug with vs2003
    }

    pointer address(reference element) const {
        return &element;
    }

    const_pointer address(const_reference element) const {
        return &element;
    }

    Pool* m_pool;
};

template<>
class PooledAllocator<void> {
public:
    typedef size_t size_type;            
    typedef ptrdiff_t difference_type;    

    typedef void value_type;            
    typedef void* pointer;            
    typedef void const* const_pointer;        

    template<typename U>
    struct rebind {
        typedef PooledAllocator<U> other;
    };


    PooledAllocator() : m_pool(0) {}

    PooledAllocator(Pool* pool) : m_pool(pool) {}

    Pool* m_pool;
};

template<typename T, typename U>
bool operator==(PooledAllocator<T> const& left, PooledAllocator<U> const& right) {
    return left.m_pool == right.m_pool;
}

template<typename T, typename U>
bool operator!=(PooledAllocator<T> const& left, PooledAllocator<U> const& right) {
    return left.m_pool != right.m_pool;
}





template<typename Key, typename Value, class Traits = std::less<Key>>
struct PooledMap {
    typedef std::map<Key, Value, Traits, PooledAllocator<std::pair<Key, Value>>> Type;
};

template<typename Key, typename Value, class Traits = std::less<Key>>
struct PooledMultiMap {
    typedef std::multimap<Key, Value, Traits, PooledAllocator<std::pair<Key, Value>>> Type;
};

template<typename Value>
struct PooledList {
    typedef std::list<Value, PooledAllocator<Value>> Type;
};

template<typename Value, typename Traits = std::less<Value>>
struct PooledSet {
    typedef std::set<Value, Traits, PooledAllocator<Value>> Type;
};

template<typename Value>
struct PooledVec {
    typedef std::vector<Value, PooledAllocator<Value>> Type;
};

#endif // __STL_POOLED_ALLOC