d169b67680
Summary: In PlainTable, use one single byte to represent 8 bytes of internal bytes, if seqID = 0 and it is value type (which should be common for bottom most files). It is to save 7 bytes for uncompressed cases. Test Plan: make all check Reviewers: haobo, dhruba, kailiu Reviewed By: haobo CC: igor, leveldb Differential Revision: https://reviews.facebook.net/D15489
66 lines
2.2 KiB
C++
66 lines
2.2 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include <vector>
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#include <stdint.h>
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#include "rocksdb/slice.h"
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namespace rocksdb {
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struct Options;
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class Comparator;
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class BlockBuilder {
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public:
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BlockBuilder(int block_builder, const Comparator* comparator);
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explicit BlockBuilder(const Options& options, const Comparator* comparator);
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// Reset the contents as if the BlockBuilder was just constructed.
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void Reset();
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// REQUIRES: Finish() has not been callled since the last call to Reset().
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// REQUIRES: key is larger than any previously added key
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void Add(const Slice& key, const Slice& value);
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// Finish building the block and return a slice that refers to the
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// block contents. The returned slice will remain valid for the
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// lifetime of this builder or until Reset() is called.
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Slice Finish();
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// Returns an estimate of the current (uncompressed) size of the block
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// we are building.
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size_t CurrentSizeEstimate() const;
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// Returns an estimated block size after appending key and value.
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size_t EstimateSizeAfterKV(const Slice& key, const Slice& value) const;
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// Return true iff no entries have been added since the last Reset()
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bool empty() const {
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return buffer_.empty();
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}
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private:
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const int block_restart_interval_;
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const Comparator* comparator_;
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std::string buffer_; // Destination buffer
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std::vector<uint32_t> restarts_; // Restart points
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int counter_; // Number of entries emitted since restart
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bool finished_; // Has Finish() been called?
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std::string last_key_;
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// No copying allowed
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BlockBuilder(const BlockBuilder&);
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void operator=(const BlockBuilder&);
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};
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} // namespace rocksdb
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