| author | Michael Krelin <hacker@klever.net> | 2004-07-05 01:53:09 (UTC) |
|---|---|---|
| committer | Michael Krelin <hacker@klever.net> | 2004-07-05 01:53:09 (UTC) |
| commit | a1487b3fc0313408525cd5b2f3bc4a462df351f7 (patch) (side-by-side diff) | |
| tree | 010aec6c2abd5ada2f909ac6798c93bf22508bf5 /shared-code/LRUCache.h | |
| download | klog-a1487b3fc0313408525cd5b2f3bc4a462df351f7.zip klog-a1487b3fc0313408525cd5b2f3bc4a462df351f7.tar.gz klog-a1487b3fc0313408525cd5b2f3bc4a462df351f7.tar.bz2 | |
initial commit into svn repository
git-svn-id: http://svn.klever.net/kin/klog/trunk@1 fe716a7a-6dde-0310-88d9-d003556173a8
| -rw-r--r-- | shared-code/LRUCache.h | 113 |
1 files changed, 113 insertions, 0 deletions
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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