WDL/sharedpool.h

   1 /*
   2   WDL - sharedpool.h
   3   Copyright (C) 2006 and later, Cockos Incorporated
   4
   5   This software is provided 'as-is', without any express or implied
   6   warranty.  In no event will the authors be held liable for any damages
   7   arising from the use of this software.
   8
   9   Permission is granted to anyone to use this software for any purpose,
  10   including commercial applications, and to alter it and redistribute it
  11   freely, subject to the following restrictions:
  12
  13   1. The origin of this software must not be misrepresented; you must not
  14      claim that you wrote the original software. If you use this software
  15      in a product, an acknowledgment in the product documentation would be
  16      appreciated but is not required.
  17   2. Altered source versions must be plainly marked as such, and must not be
  18      misrepresented as being the original software.
  19   3. This notice may not be removed or altered from any source distribution.
  20
  21
  22
  23   This file defines a template for a simple object pool.
  24
  25   Objects are keyed by string (filename, or otherwise). The caller can add or get an object,
  26   increase or decrease its reference count (if it reaches zero the object is deleted).
  27
  28
  29   If you delete the pool itself, all objects are deleted, regardless of their reference count.
  30
  31 */
  32
  33
  34 #ifndef _WDL_SHAREDPOOL_H_
  35 #define _WDL_SHAREDPOOL_H_
  36
  37 #include "ptrlist.h"
  38
  39 template<class OBJ> class WDL_SharedPool
  40 {
  41   public:
  42     WDL_SharedPool() { }
  43     ~WDL_SharedPool() { m_listobjk.Empty(true); /* do not release m_list since it's redundant */ }
  44
  45     void Add(OBJ *obj, const char *n) // no need to AddRef() after add, it defaults to a reference count of 1.
  46     {
  47       if (obj && n)
  48       {
  49         Ent *p = new Ent(obj,n);
  50         m_list.InsertSorted(p,_sortfunc_name);
  51         m_listobjk.InsertSorted(p,_sortfunc_obj);
  52       }
  53     }
  54
  55     OBJ *Get(const char *s)
  56     {
  57       struct { void *obj; const char *name; } tmp = { NULL, s };
  58       Ent *t = m_list.Get(m_list.FindSorted((Ent *)&tmp,_sortfunc_name));
  59
  60       if (t && t->obj)
  61       {
  62         t->refcnt++;
  63         return t->obj;
  64       }
  65
  66       return 0;
  67
  68     }
  69
  70     void AddRef(OBJ *obj)
  71     {
  72       Ent *ent = m_listobjk.Get(m_listobjk.FindSorted((Ent *)&obj,_sortfunc_obj));
  73       if (ent) ent->refcnt++;
  74     }
  75
  76     void Release(OBJ *obj)
  77     {
  78       int x = m_listobjk.FindSorted((Ent *)&obj,_sortfunc_obj);
  79       Ent *ent = m_listobjk.Get(x);
  80       if (ent && !--ent->refcnt)
  81       {
  82         m_list.Delete(m_list.FindSorted(ent,_sortfunc_name));
  83         m_listobjk.Delete(x,true);
  84       }
  85     }
  86
  87     OBJ *EnumItems(int x)
  88     {
  89       Ent *e=m_list.Get(x);
  90       return e?e->obj:NULL;
  91     }
  92
  93   private:
  94
  95     class Ent
  96     {
  97       public:
  98         OBJ *obj; // this order is used elsewhere for its own advantage
  99         char *name;
 100
 101         int refcnt;
 102
 103         Ent(OBJ *o, const char *n) { obj=o; name=strdup(n); refcnt=1; }
 104         ~Ent() { delete obj; free(name); }
 105
 106     };
 107
 108
 109
 110     static int _sortfunc_name(const Ent **a, const Ent **b)
 111     {
 112       return stricmp((*a)->name,(*b)->name);
 113     }
 114     static int _sortfunc_obj(const Ent **a, const Ent **b)
 115     {
 116       if ((INT_PTR)(*a)->obj < (INT_PTR)(*b)->obj) return -1;
 117       if ((INT_PTR)(*a)->obj > (INT_PTR)(*b)->obj) return 1;
 118       return 0;
 119     }
 120
 121     WDL_PtrList<Ent> m_list, // keyed by name
 122                      m_listobjk; // keyed by OBJ
 123
 124
 125 };
 126
 127
 128 #endif//_WDL_SHAREDPOOL_H_