ACE/ace/Free_List.h

   1 /* -*- C++ -*- */
   2
   3 //=============================================================================
   4 /**
   5  *  @file    Free_List.h
   6  *
   7  *  @author Darrell Brunsch (brunsch@cs.wustl.edu)
   8  */
   9 //=============================================================================
  10
  11 #ifndef ACE_FREE_LIST_H
  12 #define ACE_FREE_LIST_H
  13 #include /**/ "ace/pre.h"
  14
  15 #include /**/ "ace/config-all.h"
  16
  17 #if !defined (ACE_LACKS_PRAGMA_ONCE)
  18 # pragma once
  19 #endif /* ACE_LACKS_PRAGMA_ONCE */
  20
  21 #include "ace/Global_Macros.h"
  22 #include "ace/Default_Constants.h"
  23 #include "ace/os_include/os_stddef.h"
  24
  25 ACE_BEGIN_VERSIONED_NAMESPACE_DECL
  26
  27 /**
  28  * @class ACE_Free_List
  29  *
  30  * @brief Implements a free list.
  31  *
  32  * This class maintains a free list of nodes of type T.
  33  */
  34 template <class T>
  35 class ACE_Free_List
  36 {
  37 public:
  38   /// Destructor - removes all the elements from the free_list.
  39   virtual ~ACE_Free_List () = default;
  40
  41   /// Inserts an element onto the free list (if it isn't past the high
  42   /// water mark).
  43   virtual void add (T *element) = 0;
  44
  45   /// Takes a element off the freelist and returns it.  It creates
  46   /// <inc> new elements if the size is at or below the low water mark.
  47   virtual T *remove () = 0;
  48
  49   /// Returns the current size of the free list.
  50   virtual size_t size () = 0;
  51
  52   /// Resizes the free list to @a newsize.
  53   virtual void resize (size_t newsize) = 0;
  54 };
  55
  56 /**
  57  * @class ACE_Locked_Free_List
  58  *
  59  * @brief Implements a free list.
  60  *
  61  * This class maintains a free list of nodes of type T.  It
  62  * depends on the type T having a get_next() and set_next()
  63  * method.  It maintains a mutex so the freelist can be used in
  64  * a multithreaded program .
  65  */
  66 template <class T, class ACE_LOCK>
  67 class ACE_Locked_Free_List : public ACE_Free_List<T>
  68 {
  69 public:
  70   /**
  71    * Constructor takes a @a mode (i.e., ACE_FREE_LIST_WITH_POOL or
  72    * ACE_PURE_FREE_LIST), a count of the number of nodes to
  73    * @a prealloc, a low and high water mark (@a lwm and @a hwm) that
  74    * indicate when to allocate more nodes, an increment value (@a inc)
  75    * that indicates how many nodes to allocate when the list must
  76    * grow.
  77    */
  78   ACE_Locked_Free_List (int mode = ACE_FREE_LIST_WITH_POOL,
  79                         size_t prealloc = ACE_DEFAULT_FREE_LIST_PREALLOC,
  80                         size_t lwm = ACE_DEFAULT_FREE_LIST_LWM,
  81                         size_t hwm = ACE_DEFAULT_FREE_LIST_HWM,
  82                         size_t inc = ACE_DEFAULT_FREE_LIST_INC);
  83
  84   /// Destructor - removes all the elements from the free_list.
  85   virtual ~ACE_Locked_Free_List ();
  86
  87   /// Inserts an element onto the free list (if it isn't past the high
  88   /// water mark).
  89   virtual void add (T *element);
  90
  91   /// Takes a element off the freelist and returns it.  It creates
  92   /// <inc> new elements if the size is at or below the low water mark.
  93   virtual T *remove ();
  94
  95   /// Returns the current size of the free list.
  96   virtual size_t size ();
  97
  98   /// Resizes the free list to @a newsize.
  99   virtual void resize (size_t newsize);
 100
 101   ACE_ALLOC_HOOK_DECLARE;
 102
 103 protected:
 104   /// Allocates @a n extra nodes for the freelist.
 105   virtual void alloc (size_t n);
 106
 107   /// Removes and frees @a n nodes from the freelist.
 108   virtual void dealloc (size_t n);
 109
 110   /// Free list operation mode, either ACE_FREE_LIST_WITH_POOL or
 111   /// ACE_PURE_FREE_LIST.
 112   int mode_;
 113
 114   /// Pointer to the first node in the freelist.
 115   T *free_list_;
 116
 117   /// Low water mark.
 118   size_t lwm_;
 119
 120   /// High water mark.
 121   size_t hwm_;
 122
 123   /// Increment value.
 124   size_t inc_;
 125
 126   /// Keeps track of the size of the list.
 127   size_t size_;
 128
 129   /// Synchronization variable for ACE_Timer_Queue.
 130   ACE_LOCK mutex_;
 131
 132 private:
 133   // = Don't allow these operations for now.
 134   ACE_Locked_Free_List (const ACE_Locked_Free_List<T, ACE_LOCK> &) = delete;
 135   void operator= (const ACE_Locked_Free_List<T, ACE_LOCK> &) = delete;
 136 };
 137
 138 ACE_END_VERSIONED_NAMESPACE_DECL
 139
 140 #include "ace/Free_List.cpp"
 141
 142 #include /**/ "ace/post.h"
 143 #endif /* ACE_FREE_LIST_H */