chromium/third_party/leveldatabase/src/table/format.h

// 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_FORMAT_H_
#define STORAGE_LEVELDB_TABLE_FORMAT_H_

#include <cstdint>
#include <string>

#include "leveldb/slice.h"
#include "leveldb/status.h"
#include "leveldb/table_builder.h"

namespace leveldb {

class Block;
class RandomAccessFile;
struct ReadOptions;

// BlockHandle is a pointer to the extent of a file that stores a data
// block or a meta block.
class BlockHandle { … };

// Footer encapsulates the fixed information stored at the tail
// end of every table file.
class Footer { … };

// kTableMagicNumber was picked by running
//    echo http://code.google.com/p/leveldb/ | sha1sum
// and taking the leading 64 bits.
static const uint64_t kTableMagicNumber = …;

// 1-byte type + 32-bit crc
static const size_t kBlockTrailerSize = …;

struct BlockContents { … };

// Read the block identified by "handle" from "file".  On failure
// return non-OK.  On success fill *result and return OK.
Status ReadBlock(RandomAccessFile* file, const ReadOptions& options,
                 const BlockHandle& handle, BlockContents* result);

// Implementation details follow.  Clients should ignore,

inline BlockHandle::BlockHandle()
    : … { … }

}  // namespace leveldb

#endif  // STORAGE_LEVELDB_TABLE_FORMAT_H_