#if MAX_SIZE_MALLOC
/*************************************************
* function: find best fit node in max size
**************************************************/

MNG_NODE* find_best_fit_node(unsigned int size)
{
    MNG_NODE* pCur = pFreeList;
    MNG_NODE* pPre = pCur;
 MNG_NODE* pFind = NULL;

    while(pCur)
    {
  if(pCur->size > (size + sizeof(MNG_NODE)))
  {
      if(NULL == pFind || pFind->size < pCur->size)
   {
       pFind = pCur;
   }
  }

        pPre = pCur;
        pCur = pCur->next;
    }  

    if(NULL == pFind)
        return NULL;

 pPre = find_previous_node_in_list(pFind, pFreeList);
    if(NULL == pPre)
        pFreeList = pFreeList->next;
    else
        pPre->next = pFind->next;

    return pFind;
}
#endif

/*************************************************
* function: implement memory allocation
**************************************************/

static void* _mem_malloc(unsigned int size)
{
    MNG_NODE* pOld;
    MNG_NODE* pNew;

    pOld = find_best_fit_node(size);
    if(NULL == pOld)
        return NULL;

    pNew = (MNG_NODE*)((char*)pOld + sizeof(MNG_NODE) + pOld->size - (sizeof(MNG_NODE) + size));
    pNew->size = size;
    pOld->size -= sizeof(MNG_NODE) + size;

    add_node_into_list_head(pOld, &pFreeList);
    add_node_into_list_head(pNew, &pAllocList);

    return (void*)((char*)pNew + sizeof(MNG_NODE));
}

/*************************************************
* function: memory allocation
**************************************************/

void* mem_malloc(unsigned int size)
{
    if(0 == size)
        return NULL;

    if(size > (MEM_BUFFER_LENGTH - sizeof(MNG_NODE)))
        return NULL;

    return _mem_malloc(size);
}

/*************************************************
* function: find previous node
**************************************************/

MNG_NODE* find_previous_node_in_list(MNG_NODE* pNode, MNG_NODE* pList)
{
    MNG_NODE* pFind = pList;
    MNG_NODE* pPre = NULL;
   
    while(pFind && pFind != pNode)
    {
        pPre = pFind;
        pFind = pFind->next;
    }

    if(NULL == pFind)
        return NULL;

    return pPre;
}