Merge commit 'b3cd242c6a0c1ef3e7dc63c870604f4ccc92c7a8' as 'Subtrees/hyperleveldb'

Subtrees/hyperleveldb/table/block_builder.h

@@ -0,0 +1,57 @@
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#ifndef STORAGE_LEVELDB_TABLE_BLOCK_BUILDER_H_
+#define STORAGE_LEVELDB_TABLE_BLOCK_BUILDER_H_
+
+#include <vector>
+
+#include <stdint.h>
+#include "hyperleveldb/slice.h"
+
+namespace leveldb {
+
+struct Options;
+
+class BlockBuilder {
+ public:
+  explicit BlockBuilder(const Options* options);
+
+  // Reset the contents as if the BlockBuilder was just constructed.
+  void Reset();
+
+  // REQUIRES: Finish() has not been callled since the last call to Reset().
+  // REQUIRES: key is larger than any previously added key
+  void Add(const Slice& key, const Slice& value);
+
+  // Finish building the block and return a slice that refers to the
+  // block contents.  The returned slice will remain valid for the
+  // lifetime of this builder or until Reset() is called.
+  Slice Finish();
+
+  // Returns an estimate of the current (uncompressed) size of the block
+  // we are building.
+  size_t CurrentSizeEstimate() const;
+
+  // Return true iff no entries have been added since the last Reset()
+  bool empty() const {
+    return buffer_.empty();
+  }
+
+ private:
+  const Options*        options_;
+  std::string           buffer_;      // Destination buffer
+  std::vector<uint32_t> restarts_;    // Restart points
+  int                   counter_;     // Number of entries emitted since restart
+  bool                  finished_;    // Has Finish() been called?
+  std::string           last_key_;
+
+  // No copying allowed
+  BlockBuilder(const BlockBuilder&);
+  void operator=(const BlockBuilder&);
+};
+
+}  // namespace leveldb
+
+#endif  // STORAGE_LEVELDB_TABLE_BLOCK_BUILDER_H_