git-svn-id: https://profuse.googlecode.com/svn/branches/v2@204 aa027e90-d47c-11dd-86d7-074df07e0730

2026-04-21 05:16:58 +00:00 · 2010-03-19 17:42:13 +00:00
parent 12385a19dc
commit 1ac9b03e47
2 changed files with 0 additions and 0 deletions
@@ -0,0 +1,120 @@
+#ifndef __BLOCKCACHE_H__
+#define __BLOCKCACHE_H__
+
+#include <stdint.h>
+#include <vector>
+
+namespace Device {
+
+class BlockDevice;
+class MappedFile;
+
+
+class BlockCache {
+public:
+
+    BlockCache *Create(BlockDevice *device, unsigned size = 16);
+
+    virtual ~BlockCache();
+
+    bool readOnly() { return _readOnly; }
+    unsigned blocks() { return _blocks; }
+    BlockDevice *device() { return _device; }
+    
+        
+    virtual void sync() = 0;
+    virtual void write(unsigned block, const void *bp);
+    virtual void read(unsigned block, void *bp);
+
+    virtual void *acquire(unsigned block) = 0;
+    virtual void release(unsigned block, bool dirty) = 0;
+    virtual void markDirty(unsigned block) = 0;
+    
+    void release(unsigned block) { release(block, false); }
+
+protected:
+    BlockCache(BlockDevice *device);
+
+    BlockDevice *_device;
+private
+    unsigned _blocks;
+    bool _readOnly;
+};
+
+
+class ConcreteBlockCache : public BlockCache {
+public:
+    ConcreteBlockCache(BlockDevice *device, unsigned size = 16);
+    virtual ~ConcreteBlockCache();
+    
+    virtual void sync();
+    virtual void write(unsigned block, const void *vp) = 0;
+
+
+    virtual void *acquire(unsigned block);
+    virtual void release(unsigned block, bool dirty);
+    virtual void markDirty(unsigned block);
+
+
+private:
+    struct Entry {
+        unsigned block;
+        unsigned count;
+        bool dirty;
+        
+        struct Entry *next;
+        struct Entry *prev;
+        struct Entry *nextHash;
+        
+        uint8_t buffer[512];
+    
+    };
+
+    enum { HashTableSize = 23 };
+    
+    std::vector<Entry *>_buffers;
+    
+    Entry *_hashTable[HashTableSize];
+    
+    Entry *_first;
+    Entry *_last;
+
+
+    unsigned hashFunction(unsigned block);
+    
+    Entry *findEntry(unsigned block);
+    void removeEntry(unsigned block);
+    void addEntry(Entry *);
+    
+    Entry *newEntry(unsigned block);
+    
+    void pushEntry(Entry *);
+    
+    void setLast(Entry *);
+    
+    incrementCount(Entry *);
+    decrementCount(Entry *);
+};
+
+class MappedBlockCache : public BlockCache {
+    public:
+    
+    MappedBlockCache(BlockDevice *, void *data);
+    virtual ~MappedBlockCache();
+    
+    virtual void sync() = 0;
+    virtual void write(unsigned block, const void *vp);
+
+
+    virtual void *acquire(unsigned block);
+    virtual void release(unsigned block, bool dirty);
+    virtual void markDirty(unsigned block);
+    
+    private:
+        void *_data;
+    
+};
+
+} // namespace
+
+#endif