Struct DictionaryRleEncoder 

pub struct DictionaryRleEncoder;

Dictionary + Run-Length Encoding Hybrid

Combines dictionary encoding with run-length encoding for high repetition data. Perfect for categorical columns with repeated values.

Examples

let values = vec!["NY", "NY", "NY", "TX", "TX", "CA"];
let (encoded, dict) = DictionaryRleEncoder::compress_with_rle(&values)?;
// Dictionary: {"NY": 0, "TX": 1, "CA": 2}
// Encoded: [(0, 3), (1, 2), (2, 1)]  // (value, count) pairs
// Compression: 6 values → 3 runs = 50% reduction

Implementations

impl DictionaryRleEncoder

pub fn compress_with_rle( values: &[&str], ) -> Result<(Vec<u8>, HashMap<String, u32>), BinaryFormatError>

Compress strings using dictionary + RLE

Returns (compressed runs, dictionary) Runs are encoded as (dict_id, count) pairs

pub fn decompress_rle( bytes: &[u8], dictionary: &HashMap<String, u32>, ) -> Result<Vec<String>, BinaryFormatError>

Decompress RLE-encoded values

Trait Implementations

impl Debug for DictionaryRleEncoder

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

Formats the value using the given formatter.