tkrzw::SkipRecord Class Reference

Key and value record structure in the file skip database. More...

#include <tkrzw_dbm_skip_impl.h>

Public Member Functions
	SkipRecord (File *file, int32_t offset_width, int32_t step_unit, int32_t max_level)
	Constructor. More...
	~SkipRecord ()
	Destructor. More...
SkipRecord &	operator= (SkipRecord &&rhs)
	Assigns the internal state from another moved record object. More...
Status	ReadMetadataKey (int64_t offset, int64_t index)
	Reads the metadata and the key. More...
Status	ReadBody ()
	Reads the body data and fill all the properties. More...
std::string_view	GetKey () const
	Gets the key data. More...
std::string_view	GetValue () const
	Gets the value data. More...
const std::vector< int64_t > &	GetStepOffsets () const
	Gets the offsets of the records to skip to. More...
int32_t	GetLevel () const
	Gets the level of the record. More...
int64_t	GetIndex () const
	Gets the index of the record. More...
int64_t	GetOffset () const
	Gets the offset of the record. More...
int32_t	GetWholeSize () const
	Gets the whole size of the record. More...
void	SetData (int64_t index, const char *key_ptr, int32_t key_size, const char *value_ptr, int32_t value_size)
	Sets the actual data of the record. More...
Status	Write ()
	Writes the record in the file. More...
Status	UpdatePastRecords (int64_t index, int64_t offset, std::vector< int64_t > *past_offsets) const
	Updates past records which refer to this record. More...
Status	Search (int64_t record_base, SkipRecordCache *cache, std::string_view key, bool upper)
	Searches records for the one with the same key. More...
Status	SearchByIndex (int64_t record_base, SkipRecordCache *cache, int64_t index)
	Searches records for the one with the same index. More...
File *	GetFile () const
	Gets the file object. More...
char *	Serialize () const
	Searializes the internal data. More...
void	Deserialize (int64_t index, const char *serialized)
	Deserializes a string and prepare the internal data. More...

Detailed Description

Key and value record structure in the file skip database.

Constructor & Destructor Documentation

SkipRecord()

tkrzw::SkipRecord::SkipRecord	(	File *	file,
		int32_t	offset_width,
		int32_t	step_unit,
		int32_t	max_level
	)

Constructor.

Parameters

file	The pointer to the file object.
offset_width	The width of the offset data.
step_unit	The unit of stepping.
max_level	The maximum level of the skip list.

~SkipRecord()

tkrzw::SkipRecord::~SkipRecord

(

)

Destructor.

Member Function Documentation

operator=()

SkipRecord& tkrzw::SkipRecord::operator=

(

SkipRecord &&

rhs

)

Assigns the internal state from another moved record object.

Parameters

rhs	The other record object.

ReadMetadataKey()

Status tkrzw::SkipRecord::ReadMetadataKey	(	int64_t	offset,
		int64_t	index
	)

Reads the metadata and the key.

Parameters

offset	The offset of the record.
index	The index of the record.

Returns

The result status.

If successful, the key data is always read. However the value data is not always read. To read it, call ReadBody.

ReadBody()

Status tkrzw::SkipRecord::ReadBody

(

)

Reads the body data and fill all the properties.

Returns

The result status.

GetKey()

std::string_view tkrzw::SkipRecord::GetKey

(

)

const

Gets the key data.

Returns

The key data.

GetValue()

std::string_view tkrzw::SkipRecord::GetValue

(

)

const

Gets the value data.

Returns

The value data. The data might be nullptr if the body hasn't been read.

GetStepOffsets()

const std::vector<int64_t>& tkrzw::SkipRecord::GetStepOffsets

(

)

const

Gets the offsets of the records to skip to.

Returns

The offsets of the records to skip to.

GetLevel()

int32_t tkrzw::SkipRecord::GetLevel

(

)

const

Gets the level of the record.

Returns

The level of the record.

GetIndex()

int64_t tkrzw::SkipRecord::GetIndex

(

)

const

Gets the index of the record.

Returns

The index of the record.

GetOffset()

int64_t tkrzw::SkipRecord::GetOffset

(

)

const

Gets the offset of the record.

Returns

The offset of the record.

GetWholeSize()

int32_t tkrzw::SkipRecord::GetWholeSize

(

)

const

Gets the whole size of the record.

Returns

The whole size of the record.

SetData()

void tkrzw::SkipRecord::SetData	(	int64_t	index,
		const char *	key_ptr,
		int32_t	key_size,
		const char *	value_ptr,
		int32_t	value_size
	)

Sets the actual data of the record.

Parameters

index	The index of the record.
key_ptr	The pointer to a key buffer.
key_size	The size of the key buffer.
value_ptr	The pointer to a value buffer.
value_size	The size of the value buffer.

Write()

Status tkrzw::SkipRecord::Write

(

)

Writes the record in the file.

Returns

The result status.

UpdatePastRecords()

Status tkrzw::SkipRecord::UpdatePastRecords	(	int64_t	index,
		int64_t	offset,
		std::vector< int64_t > *	past_offsets
	)		const

Updates past records which refer to this record.

Parameters

index	The index of the record.
offset	The offset of the record.
past_offsets	The pointer to a vector of offsets of the past records, whose size must be the same as the maximum level.

Returns

The result status.

Search()

Status tkrzw::SkipRecord::Search	(	int64_t	record_base,
		SkipRecordCache *	cache,
		std::string_view	key,
		bool	upper
	)

Searches records for the one with the same key.

Parameters

record_base	The record base offset.
cache	The cache for skip records.
key	The key to match with.
upper	If true, the first upper record is retrieved if there's no record matching.

Returns

The result status.

SearchByIndex()

Status tkrzw::SkipRecord::SearchByIndex	(	int64_t	record_base,
		SkipRecordCache *	cache,
		int64_t	index
	)

Searches records for the one with the same index.

Parameters

record_base	The record base offset.
cache	The cache for skip records.
index	The index of the target record.

Returns

The result status.

GetFile()

File* tkrzw::SkipRecord::GetFile

(

)

const

Gets the file object.

Returns

The pointer to the file object.

Serialize()

char* tkrzw::SkipRecord::Serialize

(

)

const

Searializes the internal data.

Returns

The result string. The caller has the ownership.

Deserialize()

void tkrzw::SkipRecord::Deserialize	(	int64_t	index,
		const char *	serialized
	)

Deserializes a string and prepare the internal data.

Parameters

index	The index of the serialized record.
serialized	The serialized string. Ownership is not taken.