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+// 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 "leveldb/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_