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// Copyright (c) Meta Platforms, Inc. and affiliates.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
#include <cstdint>
#include <string>
#include "rocksdb/rocksdb_namespace.h"
#include "rocksdb/status.h"
#include "rocksdb/wide_columns.h"
namespace ROCKSDB_NAMESPACE {
class Slice;
// Wide-column serialization/deserialization primitives.
//
// The two main parts of the layout are 1) a sorted index containing the column
// names and column value sizes and 2) the column values themselves. Keeping the
// index and the values separate will enable selectively reading column values
// down the line. Note that currently the index has to be fully parsed in order
// to find out the offset of each column value.
//
// Legend: cn = column name, cv = column value, cns = column name size, cvs =
// column value size.
//
// +----------+--------------+----------+-------+----------+---...
// | version | # of columns | cns 1 | cn 1 | cvs 1 |
// +----------+--------------+------------------+--------- +---...
// | varint32 | varint32 | varint32 | bytes | varint32 |
// +----------+--------------+----------+-------+----------+---...
//
// ... continued ...
//
// ...---+----------+-------+----------+-------+---...---+-------+
// | cns N | cn N | cvs N | cv 1 | | cv N |
// ...---+----------+-------+----------+-------+---...---+-------+
// | varint32 | bytes | varint32 | bytes | | bytes |
// ...---+----------+-------+----------+-------+---...---+-------+
class WideColumnSerialization {
public:
static Status Serialize(const WideColumns& columns, std::string& output);
static Status Serialize(const Slice& value_of_default,
const WideColumns& other_columns,
std::string& output);
static Status Deserialize(Slice& input, WideColumns& columns);
static WideColumns::const_iterator Find(const WideColumns& columns,
const Slice& column_name);
static Status GetValueOfDefaultColumn(Slice& input, Slice& value);
static constexpr uint32_t kCurrentVersion = 1;
private:
static Status SerializeImpl(const Slice* value_of_default,
const WideColumns& columns, std::string& output);
};
inline Status WideColumnSerialization::Serialize(const WideColumns& columns,
std::string& output) {
constexpr Slice* value_of_default = nullptr;
return SerializeImpl(value_of_default, columns, output);
}
inline Status WideColumnSerialization::Serialize(
const Slice& value_of_default, const WideColumns& other_columns,
std::string& output) {
return SerializeImpl(&value_of_default, other_columns, output);
}
} // namespace ROCKSDB_NAMESPACE
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