root/lang/c/mpio/trunk/mp/mempool.pre.h @ 19040

//
// mp::mempool
//
// Copyright (C) 2008 FURUHASHI Sadayuki
//
//    Licensed 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.
//

#ifndef MP_MEMPOOL_H__
#define MP_MEMPOOL_H__

#include <stdexcept>
#include <cstdlib>
#include <limits>
#include "mp/utility.h"

#ifndef MP_POOL_DEFAULT_ALLOCATION_SIZE
#define MP_POOL_DEFAULT_ALLOCATION_SIZE 32*1024
#endif

#ifndef MP_POOL_DEFAULT_LOTS_IN_CHUNK
#define MP_POOL_DEFAULT_LOTS_IN_CHUNK 4
#endif

#ifndef MP_POOL_ALLOCATOR_DEFAULT_OBJECTS_IN_CHUNK
#define MP_POOL_ALLOCATOR_DEFAULT_OBJECTS_IN_CHUNK 1024
#endif

namespace mp {

static const size_t POOL_DEFAULT_ALLOCATION_SIZE = MP_POOL_DEFAULT_ALLOCATION_SIZE;
static const size_t POOL_DEFAULT_LOTS_IN_CHUNK = MP_POOL_DEFAULT_LOTS_IN_CHUNK;
static const size_t POOL_ALLOCATOR_DEFAULT_OBJECTS_IN_CHUNK = MP_POOL_ALLOCATOR_DEFAULT_OBJECTS_IN_CHUNK;

template < size_t EstimatedAllocationSize = POOL_DEFAULT_ALLOCATION_SIZE,
           size_t OptimalLotsInChunk = POOL_DEFAULT_LOTS_IN_CHUNK >
class mempool {
public:
        mempool();
        ~mempool();

public:
        //! Allocate memory from the pool.
        /* The allocated memory have to be freed using free() function. */
        inline void* malloc(size_t size);

        //! Free the allocated memory.
        inline void free(void* x);

        //! Template version of malloc()
        template <size_t size>
                inline void* malloc();

public:
        //! Destroy the constructed object.
        template <typename T>
                inline void destroy(T* x);

        //! Allocate memory from the pool and construct object.
        template <typename T>
                inline T* construct();
MP_ARGS_BEGIN
        template <typename T, MP_ARGS_TEMPLATE>
                inline T* construct(MP_ARGS_PARAMS);
MP_ARGS_END

private:
        struct chunk_t {
                chunk_t* next;
                chunk_t* prev;
                size_t free;
                size_t lots;
                size_t size;
        };
        struct data_t {
                chunk_t* chunk;
        };

private:
        chunk_t* m_free;
        chunk_t* m_used;

private:
        void* expand_free(size_t req);
        void splice_to_used(chunk_t* chunk);
        void splice_to_free(chunk_t* chunk);

private:
        mempool(const mempool&);
};


template < typename ThreadTag = main_thread_tag,
           size_t EstimatedAllocationSize = POOL_DEFAULT_ALLOCATION_SIZE,
           size_t OptimalLotsInChunk = POOL_DEFAULT_LOTS_IN_CHUNK >
class singleton_mempool {
public:
        typedef mempool<EstimatedAllocationSize, OptimalLotsInChunk> pool_type;

        static void* malloc(size_t size)
                { return pool().malloc(size); }

        static void free(void* x)
                { pool().free(x); }

        template <size_t size>
        static void* malloc()
                { return pool().malloc<size>(); }

public:
        template <typename T>
        static void destroy(T* x)
                { return pool().destroy<T>(x); }

        template <typename T>
        static T* construct()
                { return pool().construct<T>(); }
MP_ARGS_BEGIN
        template <typename T, MP_ARGS_TEMPLATE>
        static T* construct(MP_ARGS_PARAMS)
                { return pool().construct<T, MP_ARGS_TYPES>(MP_ARGS_FUNC); }
MP_ARGS_END

private:
        static pool_type& pool()
        {
                static pool_type object;
                return object;
        }
};


template < typename T,
                typename ThreadTag = main_thread_tag,
                size_t OptimalObjectsInChunk = POOL_ALLOCATOR_DEFAULT_OBJECTS_IN_CHUNK >
class mempool_allocator {
private:
        typedef singleton_mempool<ThreadTag, sizeof(T), OptimalObjectsInChunk> pool;

public:
        typedef size_t size_type;
        typedef ptrdiff_t difference_type;
        typedef T* pointer;
        typedef const T* const_pointer;
        typedef T& reference;
        typedef const T& const_reference;
        typedef T value_type;

        template <class U>
        struct rebind { typedef mempool_allocator<U> other; };

        mempool_allocator() throw() {}
        mempool_allocator(const mempool_allocator&) throw() {}
        template <class U> mempool_allocator(const mempool_allocator<U>&) throw() {}

        ~mempool_allocator() throw() {}

        pointer address(reference r)
                { return &r; }

        const_pointer address(const_reference s)
                { return &s; }

        size_type max_size() throw()
                { return std::numeric_limits<size_t>::max() / sizeof(T); }

        pointer allocate(size_type num, const_pointer hint = 0)
        {
                const pointer p = static_cast<pointer>( pool::malloc(sizeof(T) * num) );
                if (p == 0) { throw std::bad_alloc(); }
                return p;
        }

        void deallocate(pointer p, size_type num)
        {
                if(p == 0) { return; }
                pool::free(p);
        }

        void construct(pointer p, const T& r)
                { new ( reinterpret_cast<void*>(p) ) T(r); }

        void destroy(pointer p)
                { p->~T(); }
};


}  // namespace mp

template <class T1, class T2>
bool operator==(const mp::mempool_allocator<T1>&, const mp::mempool_allocator<T2>&) throw() { return true; }

template <class T1, class T2>
bool operator!=(const mp::mempool_allocator<T1>&, const mp::mempool_allocator<T2>&) throw() { return false; }

#include "mp/mempool_impl.h"

#endif /* mp/mempool.h */