diff -r 000000000000 -r 31a43d94cc26 include/VersionDictionary.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/VersionDictionary.h	Sun Sep 20 15:14:12 2009 -0700
@@ -0,0 +1,127 @@
+/*
+ *  VersionDictionary.h
+ *  Ottoman
+ *
+ *  Created by Jens Alfke on 8/21/09.
+ *  Copyright 2009 Jens Alfke. All rights reserved.
+ *  BSD-Licensed: See the file "LICENSE.txt" for details.
+ */
+
+#ifndef _MOOSEYARD_VERSIONDICTIONARY_
+#define _MOOSEYARD_VERSIONDICTIONARY_
+#include "Dictionary.h"
+
+namespace Mooseyard {
+    
+    class File;
+    class Index;
+    
+    /** A persistent Dictionary embedded in a memory-mapped file, 
+        representing one complete version of an Ottoman dictionary. */
+    class VersionDictionary :public Dictionary {
+    public:
+        
+        /** The generation number. The first version in a new file is zero. */
+        int generation() const;
+        
+        /** The absolute time at which this version was written to the file. */
+        time_t timestamp() const;
+        
+        /** The previous version, before this one was saved. */
+        const VersionDictionary* previousVersion() const;
+        
+        /** Is this the latest version in the file? */
+        bool isLatestVersion() const;
+        
+        virtual int count() const;
+        virtual Blob get (Key) const;
+        class Iterator;
+        virtual Dictionary::Iterator* iterate() const;
+        
+        class ChangeIterator;
+        /** Iterates over the changes between this dictionary and the previous version. */
+        virtual ChangeIterator* iterateChanges() const;
+
+        
+        // Stuff you probably won't need to use:
+        
+        File* file() const                                          {return _file;}
+        explicit VersionDictionary (File*);
+        VersionDictionary (File *file, FilePosition trailerPosition);
+        
+    private:
+        /** The type of the trailer chunk that's used as the position of the dictionary. */
+        static const uint16_t kChunkType = 3;
+        
+        struct IndexPositions {
+            LittleEndian<FilePosition> position[256];
+            LittleEndian<FilePosition>& operator[] (int i)              {return position[i];}
+            LittleEndian<FilePosition> const& operator[] (int i) const  {return position[i];}
+        };
+                
+        class Trailer;
+        const Trailer* _trailer() const;
+        const Index* _index (int i) const;
+        void _read (FilePosition trailerPosition =0);
+        static FilePosition _append (const VersionDictionary *baseDict, 
+                                     const Dictionary *addDict, 
+                                     File *dstFile, 
+                                     bool replace);
+        
+        File *_file;
+        FilePosition _trailerPosition, _previousTrailerPosition;
+        IndexPositions _indexPositions;
+        int _count;
+        mutable const VersionDictionary *_previousVersion;
+        
+#if VERSIONDICTIONARY_TESTING
+    public:
+#endif
+        static VersionDictionary* create (File *file, const Dictionary *srcDict);
+        VersionDictionary* byAppending (const Dictionary* d) const     {return _appendAndOpen(d,_file,false);}
+        VersionDictionary* byReplacing (const Dictionary* d) const     {return _appendAndOpen(d,_file,true);}
+        VersionDictionary* _appendAndOpen (const Dictionary *addDict, File *dstFile, bool replace) const;
+        
+        friend class Ottoman;
+        UNCOPYABLE(VersionDictionary);
+    };
+    
+    
+    class VersionDictionary::Iterator :public Dictionary::Iterator {
+    public:
+        explicit Iterator (const VersionDictionary*);
+        virtual ~Iterator();
+        virtual Key key() const;
+        virtual Blob value() const;
+        virtual bool next();
+        virtual bool hasValue() const;
+    private:
+        bool nextIndex();
+        
+        const VersionDictionary *_file;
+        int _bucket;
+        Dictionary::Iterator *_iter;
+        UNCOPYABLE(Iterator);
+    };
+    
+    
+    class VersionDictionary::ChangeIterator :public Dictionary::Iterator {
+    public:
+        explicit ChangeIterator (const VersionDictionary*);
+        virtual ~ChangeIterator();
+        virtual Key key() const;
+        virtual Blob value() const;
+        virtual bool next();
+        virtual bool hasValue() const;
+    private:
+        bool nextIndex();
+        
+        const VersionDictionary *_file;
+        int _bucket;
+        Dictionary::Iterator *_iter;
+        UNCOPYABLE(ChangeIterator);
+    };
+
+}
+
+#endif //_MOOSEYARD_VERSIONDICTIONARY_