From fb8b43dbce8bc310718614384297aeaabb9a3cbb Mon Sep 17 00:00:00 2001
From: Michael Krelin <hacker@klever.net>
Date: Mon, 05 Jul 2004 01:53:09 +0000
Subject: initial commit into svn repository

git-svn-id: http://svn.klever.net/kin/bigbrother/trunk@1 fe716a7a-6dde-0310-88d9-d003556173a8
---
(limited to 'shared-code/LRUCache.h')

diff --git a/shared-code/LRUCache.h b/shared-code/LRUCache.h
new file mode 100644
index 0000000..569e829
--- a/dev/null
+++ b/shared-code/LRUCache.h
@@ -0,0 +1,113 @@
+#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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