Struct ZstdDictionary 

pub struct ZstdDictionary(/* private fields */);

A validated, size-bounded zstd dictionary blob.

Type invariant: self.len() <= MAX_DICT_SIZE (112 KiB) and the first four bytes are the zstd dictionary magic 0xEC30A437. All public constructors funnel through the private new_checked gate; callers outside this module cannot construct an invalid value.

Sharing is performed once at the enum level via Arc<ZstdDictionary> in crate::compression::secure::ByteCodec::ZstdDict. The inner Vec<u8> is intentionally not wrapped in a second Arc — that would create double indirection with no benefit.

Examples

use pjson_rs::compression::zstd::{ZstdDictCompressor, ZstdDictionary, N_TRAIN};

// Build enough samples for training (at least 8 needed by libzstd; N_TRAIN = 32).
let item = b"{\"id\":1,\"name\":\"test\",\"value\":42,\"active\":true}";
let samples: Vec<Vec<u8>> = (0..N_TRAIN).map(|i| {
    format!("{{\"id\":{i},\"name\":\"item\",\"value\":{},\"active\":true}}", i * 10)
        .into_bytes()
}).collect();

let dict = ZstdDictCompressor::train(&samples, 65536).expect("training should succeed");
assert!(dict.len() <= 65536);
assert!(!dict.is_empty());

Implementations

impl ZstdDictionary

pub fn from_bytes(bytes: Vec<u8>) -> Result<Self>

Construct a ZstdDictionary from a raw byte blob produced by libzstd.

Validates the magic header and the 112 KiB size cap.

Errors

Returns Error::CompressionError if:

• bytes is empty
• bytes.len() > MAX_DICT_SIZE
• the first four bytes are not the zstd dictionary magic 0xEC30A437

Examples

use pjson_rs::compression::zstd::ZstdDictionary;

// Empty bytes are rejected.
assert!(ZstdDictionary::from_bytes(vec![]).is_err());

// Bytes without the correct magic are rejected.
assert!(ZstdDictionary::from_bytes(vec![0x00, 0x01, 0x02, 0x03]).is_err());

// A blob larger than MAX_DICT_SIZE is rejected.
use pjson_rs::compression::zstd::MAX_DICT_SIZE;
let oversized = vec![0x37u8, 0xA4, 0x30, 0xEC]
    .into_iter()
    .chain(std::iter::repeat(0u8).take(MAX_DICT_SIZE))
    .collect::<Vec<_>>();
assert!(ZstdDictionary::from_bytes(oversized).is_err());

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

Returns the raw dictionary bytes.

pub fn len(&self) -> usize

Returns the dictionary size in bytes (always <= MAX_DICT_SIZE).

pub fn is_empty(&self) -> bool

Returns true if the dictionary has no bytes.

This can never be true for a successfully constructed ZstdDictionary because new_checked rejects empty inputs. The method exists to satisfy Clippy’s len_without_is_empty requirement.

Trait Implementations

impl Clone for ZstdDictionary

fn clone(&self) -> ZstdDictionary

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ZstdDictionary

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

Formats the value using the given formatter.

impl PartialEq for ZstdDictionary

fn eq(&self, other: &ZstdDictionary) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for ZstdDictionary

impl StructuralPartialEq for ZstdDictionary