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#ifndef __LRUCACHE_H
#define __LRUCACHE_H
namespace Klever {
template<class IDX,class ARGIDX,class DATA>
class CLRUCache : public CObject {
public:
struct CacheEntry {
enum cacheState {
cacheClean, cacheDirty, cacheEmpty
};
cacheState m_State;
UINT m_hits;
IDX m_idx;
DATA* m_pData;
CacheEntry() { m_State=cacheEmpty; VERIFY(m_pData=new DATA); m_hits=0; }
virtual ~CacheEntry() { delete m_pData; }
};
typedef CMap<IDX,ARGIDX,CacheEntry*,CacheEntry*> CCacheMap;
typedef CList<CacheEntry*,CacheEntry*> CCacheList;
CCacheList m_Cache;
CCacheMap m_Map;
CLRUCache(UINT cacheSize) {
for(int tmp=0;tmp<cacheSize;tmp++){
CacheEntry* p = new CacheEntry;
m_Cache.AddTail(p);
}
}
virtual ~CLRUCache() {
Flush();
POSITION p = m_Cache.GetHeadPosition();
while(p){
CacheEntry* c = m_Cache.GetNext(p);
delete c;
}
}
DATA* GetCached(ARGIDX idx,BOOL bLoad=TRUE) {
CacheEntry* rv;
if(m_Map.Lookup(idx,rv)){
rv->m_hits++;
PopUp(rv);
return rv->m_pData;
}
if(!bLoad)
return NULL;
rv = m_Cache.GetTail();
ASSERT(rv);
switch(rv->m_State){
case CacheEntry::cacheDirty:
FlushEntry(rv);
case CacheEntry::cacheClean:
m_Map.RemoveKey(rv->m_idx);
rv->m_State=CacheEntry::cacheEmpty;
case CacheEntry::cacheEmpty:
break;
default:
ASSERT(FALSE);
}
if(!_ReadIn(idx,rv->m_pData))
return NULL;
rv->m_hits=1;
rv->m_State=CacheEntry::cacheClean;
rv->m_idx=idx;
m_Map[idx]=rv;
PopUp(rv);
return rv->m_pData;
}
BOOL MakeDirty(ARGIDX idx) {
CacheEntry* pEntry;
if(m_Map.Lookup(idx,pEntry)){
ASSERT(pEntry->m_State==CacheEntry::cacheClean || pEntry->m_State==CacheEntry::cacheDirty);
pEntry->m_State=CacheEntry::cacheDirty;
return TRUE;
}
return FALSE;
}
BOOL Flush() {
POSITION p = m_Cache.GetHeadPosition();
while(p){
CacheEntry* pEntry = m_Cache.GetNext(p);
ASSERT(pEntry);
FlushEntry(pEntry);
}
return TRUE;
}
BOOL FlushEntry(CacheEntry* pEntry) {
if(pEntry->m_State==CacheEntry::cacheDirty){
BOOL rv = _WriteOut(pEntry->m_idx,pEntry->m_pData);
if(rv)
pEntry->m_State=CacheEntry::cacheClean;
}
return FALSE;
}
void PopUp(CacheEntry* pEntry) {
POSITION p = m_Cache.Find(pEntry);
ASSERT(p);
m_Cache.RemoveAt(p);
VERIFY(m_Cache.AddHead(pEntry));
}
virtual BOOL _ReadIn(ARGIDX idx,DATA* data) = 0;
virtual BOOL _WriteOut(ARGIDX idx,DATA* data) = 0;
};
};
#endif // __LRUCACHE_H
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