Struct CompressionInfo 

pub struct CompressionInfo {
    pub algorithm: String,
    pub option_pairs: Vec<(String, String)>,
    pub chunk_length: u32,
    pub max_compressed_length: u32,
    pub data_length: u64,
    pub chunk_offsets: Vec<u64>,
}

CompressionInfo.db file content parsed from binary format

Fields

algorithm: String

Compression algorithm simple name (e.g., “LZ4Compressor”, “SnappyCompressor”)

option_pairs: Vec<(String, String)>

Optional compression parameters from CompressionInfo.db Key-value pairs as written by CompressionMetadata.writeHeader()

chunk_length: u32

Size of uncompressed data chunks (bytes)

max_compressed_length: u32

Maximum compressed chunk length; if a compressed chunk reaches this size, the chunk was stored uncompressed in Data.db instead. Equals i32::MAX when minCompressRatio=0 (the default). Source: CompressionParams.java:186-189.

data_length: u64

Total uncompressed data length (bytes)

chunk_offsets: Vec<u64>

List of compressed chunk offsets in Data.db file

Each offset points to the start of a compressed-chunk record. The record consists of: [compressed_bytes][4-byte CRC32 of compressed_bytes] The delta between consecutive offsets therefore includes the trailing 4-byte CRC. See: CompressedSequentialWriter.java:203 chunkOffset += compressedLength + 4

Implementations

impl CompressionInfo

pub fn parse(data: &[u8]) -> Result<Self>

Parse CompressionInfo.db file from binary data.

Implements the deterministic layout from CompressionMetadata.java:375-392. No heuristics — every field is read at its authoritative position.

pub fn chunk_for_offset(&self, offset: u64) -> usize

Get the chunk index for a given offset in the uncompressed data

pub fn offset_within_chunk(&self, offset: u64) -> u64

Get the offset within a chunk for a given global offset

pub fn compressed_chunk_offset(&self, chunk_index: usize) -> Option<u64>

Get the compressed chunk offset for a given chunk index

pub fn compressed_chunk_size( &self, chunk_index: usize, total_compressed_size: u64, ) -> Option<u64>

Get the size of a compressed-chunk record (delta between consecutive offsets or end-of-file), INCLUDING the 4-byte trailing CRC appended inline in Data.db.

To get the actual compressed payload size, subtract 4 from the returned value. See: CompressedSequentialWriter.java:203 chunkOffset += compressedLength + 4

pub fn validate(&self) -> Result<()>

Validate the compression info structure

Trait Implementations

impl Clone for CompressionInfo

fn clone(&self) -> CompressionInfo

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for CompressionInfo

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.