Struct BlockBuilder 

pub struct BlockBuilder {
    buf: BytesMut,
    compress_buf: BytesMut,
    restart_count: usize,
    restart_points: Vec<u32>,
    last_key: Vec<u8>,
    entry_count: usize,
    compression_algorithm: CompressionAlgorithm,
    table_id: Option<TableId>,
    restart_points_type_index: Vec<RestartPoint>,
}

BlockBuilder encodes and appends block to a buffer.

Fields

buf: BytesMut

Write buffer.

compress_buf: BytesMut

Compress buffer

restart_count: usize

Entry interval between restart points.

restart_points: Vec<u32>

Restart points.

last_key: Vec<u8>

Last key.

entry_count: usize

Count of entries in current block.

compression_algorithm: CompressionAlgorithm

Compression algorithm.

table_id: Option<TableId>

restart_points_type_index: Vec<RestartPoint>

Implementations

impl BlockBuilder

pub fn new(options: BlockBuilderOptions) -> Self

pub fn add( &mut self, table_id: TableId, encoded_key_without_table_id: &[u8], value: &[u8], )

Appends a kv pair to the block using pre-encoded key.

This method accepts a pre-encoded key (table_key + epoch, without table_id) to avoid redundant encoding operations. This is useful when the caller has already encoded the full key and wants to reuse it.

NOTE: Key must be added in ASCEND order.

Format

entry (kv pair): | overlap len (len_type) | diff len (len_type) | value len(len_type) | diff key | value |

Panics

Panic if key is not added in ASCEND order or table_id mismatch.

pub fn add_for_test(&mut self, full_key: FullKey<&[u8]>, value: &[u8])

fn add_encoded_impl(&mut self, key: &[u8], value: &[u8])

Core implementation that accepts pre-encoded key. This is used by both add and add_for_test to avoid code duplication.

pub fn get_last_key(&self) -> &[u8]

pub fn is_empty(&self) -> bool

pub fn clear(&mut self)

pub fn uncompressed_block_size(&mut self) -> usize

Calculate block size without compression.

pub fn build(&mut self) -> &[u8]

Finishes building block.

Format

compressed: | entries | restart point 0 (4B) | ... | restart point N-1 (4B) | N (4B) | restart point index 0 (5B)| ... | restart point index N-1 (5B) | N (4B) | table id (4B)
uncompressed: | compression method (1B) | xxhash64 checksum (8B) |

Panics

Panic if there is compression error.

pub fn compress_block( buf: Bytes, target_compression: CompressionAlgorithm, ) -> HummockResult<Bytes>

pub fn compress( buf: &[u8], compression_algorithm: CompressionAlgorithm, compress_writer: BytesMut, ) -> BytesMut

pub fn approximate_len(&self) -> usize

Approximate block len (uncompressed).

pub fn debug_valid(&self)

pub fn table_id(&self) -> Option<TableId>

fn buf_reserve_size(option: &BlockBuilderOptions) -> usize