Function train_fastcover_dict 

pub fn train_fastcover_dict(
    samples: &[u8],
    sample_sizes: &[usize],
    dict_size: usize,
    options: &FastCoverOptions,
    finalize: FinalizeOptions,
) -> Result<Vec<u8>>

Available on crate feature dict-builder only.

Train a FastCOVER dictionary of at most dict_size bytes with the k and d given (the reference’s ZDICT_trainFromBuffer_fastCover).

As train_cover_dict, over a hashed frequency table of 2^f counts; the entropy tables are drawn from the share of samples accel sets.

Errors

As train_cover_dict, and when d is below 4, f exceeds 31 or accel exceeds 10. A table too large for memory is an OutOfMemory error.

Examples

use structured_zstd::dictionary::{
    CoverOptions, FastCoverOptions, FinalizeOptions, train_fastcover_dict,
};

let mut samples = Vec::new();
let mut sizes = Vec::new();
for i in 0..200u32 {
    let line = format!("tenant=demo table=orders key={i} region=eu status=shipped\n");
    sizes.push(line.len());
    samples.extend_from_slice(line.as_bytes());
}
let options = FastCoverOptions {
    cover: CoverOptions { k: 64, ..FastCoverOptions::default().cover },
    ..FastCoverOptions::default()
};
let dict = train_fastcover_dict(&samples, &sizes, 4096, &options, FinalizeOptions::default())
    .unwrap();
assert!(dict.len() <= 4096);