add oversampler

oversampling/WDL/destroycheck.h

@@ -0,0 +1,65 @@
+#ifndef _WDL_DESTROYCHECK_H_
+#define _WDL_DESTROYCHECK_H_
+
+// this is a useful class for verifying that an object (usually "this") hasn't been destroyed:
+// to use it you add a WDL_DestroyState as a member of your class, then use the WDL_DestroyCheck 
+// helper class (creating it when the pointer is known valid, and checking it later to see if it 
+// is still valid).
+//
+// example:
+// class myClass {
+//   WDL_DestroyState dest;
+//   ...
+// };
+//
+// calling code (on myClass *classInstnace):
+//  WDL_DestroyCheck chk(&classInstance->dest);
+//  somefunction();
+//  if (!chk.isOK()) printf("classInstance got deleted!\n");
+//
+// NOTE: only use this when these objects will be accessed from the same thread -- it will fail miserably
+// in a multithreaded environment
+
+
+
+
+class WDL_DestroyCheck
+{
+  public:
+    class WDL_DestroyStateNextRec { public: WDL_DestroyCheck *next; };
+
+    WDL_DestroyStateNextRec n, *prev; 
+    WDL_DestroyCheck(WDL_DestroyStateNextRec *state)
+    {
+      n.next=NULL;
+      if ((prev=state)) 
+      {
+        if ((n.next=prev->next)) n.next->prev = &n;
+        prev->next=this;
+      }
+    }
+    ~WDL_DestroyCheck() 
+    { 
+      if (prev)
+      {
+        prev->next = n.next; 
+        if (n.next) n.next->prev = prev; 
+      }
+    }
+
+    bool isOK() { return !!prev; }
+};
+
+class WDL_DestroyState : public WDL_DestroyCheck::WDL_DestroyStateNextRec
+{
+  public:
+    WDL_DestroyState() { next=NULL; }
+
+    ~WDL_DestroyState() 
+    { 
+      WDL_DestroyCheck *p = next;
+      while (p) { WDL_DestroyCheck *np = p->n.next; p->prev=NULL; p->n.next=NULL; p=np; }
+    }
+};
+
+#endif