CppNet/base/MemoryPool.h

#ifndef HEADER_BASE_MMEMORYPOOL
#define HEADER_BASE_MMEMORYPOOL

#include <new>
#include <map>
#include <mutex>
#include <thread>
#include <vector>
#include <cstring>        //for memset
#include <stdexcept>      //for logic_error
#include <functional>

#include "BlockMemoryPool.h"

namespace base {

    static const int __align = 8;
    static const int __max_bytes = 256;
    static const int __number_of_free_lists = __max_bytes / __align;
    static const int __number_add_nodes = 20;

    class CMemoryPool {
    public:
        // bulk memory size. 
        // everytime add nodes num
        CMemoryPool(const int large_sz, const int add_num);
        ~CMemoryPool();
    
        //for object. invocation of constructors and destructors
        template<typename T, typename... Args >
        T* PoolNew(Args&&... args);
        template<typename T>
        void PoolDelete(T* &c);
    
        //for continuous memory
        template<typename T>
        T* PoolMalloc(int size);
        template<typename T>
        void PoolFree(T* &m, int len);
    
        //for bulk memory. 
        //return one bulk memory node
        template<typename T>
        T* PoolLargeMalloc();
        template<typename T>
        void PoolLargeFree(T* &m);
    
        std::thread::id GetCreateThreadId();
    
        //return bulk memory size
        int GetLargeSize();
        // return length of bulk memory
        int GetLargeBlockLength();

        // release half memory
        void ReleaseLargeHalf();

        void ExpansionLarge(int num = 0);
    
    private:
        int RoundUp(int size, int align = __align) {
            return ((size + align - 1) & ~(align - 1));
        }
    
        int FreeListIndex(int size, int align = __align) {
            return (size + align - 1) / align - 1;
        }
    
        void* ReFill(int size, int num = __number_add_nodes);
        void* ChunkAlloc(int size, int& nums);
        
    private:
        union MemNode {
            MemNode*    _next;
            char        _data[1];
        };
    
        MemNode*     _free_list[__number_of_free_lists];    
        char*        _pool_start;                    
        char*        _pool_end;                
        std::thread::id            _create_thread_id;
        std::vector<char*>         _malloc_vec;
        std::recursive_mutex       _mutex;

        CBlockMemoryPool           _block_pool;
    };
    
    template<typename T, typename... Args>
    T* CMemoryPool::PoolNew(Args&&... args) {
        int sz = sizeof(T);
        if (sz > __max_bytes) {
            void* bytes = malloc(sz);
            T* res = new(bytes) T(std::forward<Args>(args)...);
            return res;
        }
    
        std::unique_lock<std::recursive_mutex> lock(_mutex);
        MemNode** my_free = &(_free_list[FreeListIndex(sz)]);
        MemNode* result = *my_free;
        if (result == nullptr) {
            void* bytes = ReFill(RoundUp(sz));
            T* res = new(bytes) T(std::forward<Args>(args)...);
            return res;
        }
        *my_free = result->_next;
        T* res = new(result) T(std::forward<Args>(args)...);
        return res;
    }
    
    template<typename T>
    void CMemoryPool::PoolDelete(T* &c) {
        if (!c) {
            return;
        }
    
        int sz = sizeof(T);
        if (sz > __max_bytes) {
            c->~T();
            free(c);
            c = nullptr;
            return;
        }
    
        MemNode* node = (MemNode*)c;
        std::unique_lock<std::recursive_mutex> lock(_mutex);
        MemNode** my_free = &(_free_list[FreeListIndex(sz)]);
    
        c->~T();
        node->_next = *my_free;
        *my_free = node;
        c = nullptr;
    }
    
    template<typename T>
    T* CMemoryPool::PoolMalloc(int sz) {
        if (sz > __max_bytes) {
            void* bytes = malloc(sz);
            memset(bytes, 0, sz);
            return (T*)bytes;
        }
    
        std::unique_lock<std::recursive_mutex> lock(_mutex);
        MemNode** my_free = &(_free_list[FreeListIndex(sz)]);
        MemNode* result = *my_free;
        if (result == nullptr) {
            void* bytes = ReFill(RoundUp(sz));
            memset(bytes, 0, sz);
            return (T*)bytes;
        }
    
        *my_free = result->_next;
        memset(result, 0, sz);
        return (T*)result;
    }
    
    template<typename T>
    void CMemoryPool::PoolFree(T* &m, int len) {
        if (!m) {
            return;
        }
    
        if (len > __max_bytes) {
            free(m);
            m = nullptr;
            return;
        }
    
        MemNode* node = (MemNode*)m;
        std::unique_lock<std::recursive_mutex> lock(_mutex);
        MemNode** my_free = &(_free_list[FreeListIndex(len)]);
    
        node->_next = *my_free;
        *my_free = node;
        m = nullptr;
    }
    
    template<typename T>
    T* CMemoryPool::PoolLargeMalloc() {
        T* ret = (T*)_block_pool.PoolLargeMalloc();
        return ret;
    }
    
    template<typename T>
    void CMemoryPool::PoolLargeFree(T* &m) {
        if (!m) {
            return;
        }
        
        _block_pool.PoolLargeFree((void*&)m);
        m = nullptr;
    }
}

#endif