mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-12-30 12:10:37 +00:00
75 lines
2.8 KiB
C
75 lines
2.8 KiB
C
|
//------------------------------------------------------------------------------
|
||
|
|
// File: Cache.h
|
||
|
|
//
|
||
|
|
// Desc: DirectShow base classes - efines a non-MFC generic cache class.
|
||
|
|
//
|
||
|
|
// Copyright (c) 1992-2001 Microsoft Corporation. All rights reserved.
|
||
|
|
//------------------------------------------------------------------------------
|
||
|
|
|
||
|
|
|
||
|
|
/* This class implements a simple cache. A cache object is instantiated
|
||
|
|
with the number of items it is to hold. An item is a pointer to an
|
||
|
|
object derived from CBaseObject (helps reduce memory leaks). The cache
|
||
|
|
can then have objects added to it and removed from it. The cache size
|
||
|
|
is fixed at construction time and may therefore run out or be flooded.
|
||
|
|
If it runs out it returns a NULL pointer, if it fills up it also returns
|
||
|
|
a NULL pointer instead of a pointer to the object just inserted */
|
||
|
|
|
||
|
|
/* Making these classes inherit from CBaseObject does nothing for their
|
||
|
|
functionality but it allows us to check there are no memory leaks */
|
||
|
|
|
||
|
|
/* WARNING Be very careful when using this class, what it lets you do is
|
||
|
|
store and retrieve objects so that you can minimise object creation
|
||
|
|
which in turns improves efficiency. However the object you store is
|
||
|
|
exactly the same as the object you get back which means that it short
|
||
|
|
circuits the constructor initialisation phase. This means any class
|
||
|
|
variables the object has (eg pointers) are highly likely to be invalid.
|
||
|
|
Therefore ensure you reinitialise the object before using it again */
|
||
|
|
|
||
|
|
|
||
|
|
#ifndef __CACHE__
|
||
|
|
#define __CACHE__
|
||
|
|
|
||
|
|
|
||
|
|
class CCache : CBaseObject {
|
||
|
|
|
||
|
|
/* Make copy constructor and assignment operator inaccessible */
|
||
|
|
|
||
|
|
CCache(const CCache &refCache);
|
||
|
|
CCache &operator=(const CCache &refCache);
|
||
|
|
|
||
|
|
private:
|
||
|
|
|
||
|
|
/* These are initialised in the constructor. The first variable points to
|
||
|
|
an array of pointers, each of which points to a CBaseObject derived
|
||
|
|
object. The m_iCacheSize is the static fixed size for the cache and the
|
||
|
|
m_iUsed defines the number of places filled with objects at any time.
|
||
|
|
We fill the array of pointers from the start (ie m_ppObjects[0] first)
|
||
|
|
and then only add and remove objects from the end position, so in this
|
||
|
|
respect the array of object pointers should be treated as a stack */
|
||
|
|
|
||
|
|
CBaseObject **m_ppObjects;
|
||
|
|
const INT m_iCacheSize;
|
||
|
|
INT m_iUsed;
|
||
|
|
|
||
|
|
public:
|
||
|
|
|
||
|
|
CCache(__in_opt LPCTSTR pName,INT iItems);
|
||
|
|
virtual ~CCache();
|
||
|
|
|
||
|
|
/* Add an item to the cache */
|
||
|
|
CBaseObject *AddToCache(__in CBaseObject *pObject);
|
||
|
|
|
||
|
|
/* Remove an item from the cache */
|
||
|
|
CBaseObject *RemoveFromCache();
|
||
|
|
|
||
|
|
/* Delete all the objects held in the cache */
|
||
|
|
void RemoveAll(void);
|
||
|
|
|
||
|
|
/* Return the cache size which is set during construction */
|
||
|
|
INT GetCacheSize(void) const {return m_iCacheSize;};
|
||
|
|
};
|
||
|
|
|
||
|
|
#endif /* __CACHE__ */
|
||
|
|
|