Struct CodecTunables 

pub struct CodecTunables {
    pub quality: u8,
    pub zstd_quality: u8,
    pub xz_level: u8,
    pub ppmd_order: u8,
    pub ppmd7_budget: usize,
    pub ppmd8_budget: usize,
    pub bzip2_block_kb: u32,
    pub lzma_dict_mb: u32,
}

Codec-agnostic tunables. Every codec reads only the fields it understands; the rest are ignored. The struct is the single source of truth for “what knobs does the writer want to turn” — adding a new knob is one field here, not a new compress_with_* function per codec (OCP).

Fields

quality: u8

Brotli quality (0..=11). Codecs without a quality parameter ignore this. Historically this also served as a ZSTD level proxy — decoupled below since the two scales diverged (omnizip 0.21.12+ runs the optimal parser at every zstd level >= L3, so brotli’s default q11 was silently pushing zstd into the slow band).

zstd_quality: u8

ZSTD quality (0..=22 via level_for_quality). 0 = fast-tier default. Independent of quality (brotli) by design.

xz_level: u8

XZ preset (0..=9). 0 = preset 6 (xz’s balanced default). Independent of quality (brotli) — see zstd_quality.

ppmd_order: u8

PPMd7 / PPMd8 context-model order (1..=16).

ppmd7_budget: usize

PPMd7 context-tree memory budget in bytes. 0 = codec default.

ppmd8_budget: usize

PPMd8 context-tree memory budget in bytes. 0 = codec default.

bzip2_block_kb: u32

BZip2 block size in KB (100..=900). Maps to level 1..=9.

lzma_dict_mb: u32

LZMA dictionary size in MB. Reserved — no pure-Rust LZMA encoder exists yet; field is here so profiles can declare intent and we wire it when omnizip-lzma ships an encoder.

Implementations

impl CodecTunables

pub fn from_quality(quality: u8) -> Self

Build tunables carrying only quality. Codecs that don’t override compress_with_tunables see no difference from compress(plaintext).

Trait Implementations

impl Clone for CodecTunables

fn clone(&self) -> CodecTunables

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CodecTunables

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

Formats the value using the given formatter.

impl Default for CodecTunables

fn default() -> Self

Returns the “default value” for a type.