Enum CodecSpec

pub enum CodecSpec {
    Gamma,
    Delta,
    Unary,
    Rice {
        log2_b: Option<u8>,
    },
    Zeta {
        k: Option<u64>,
    },
    Golomb {
        b: Option<u64>,
    },
    Omega,
    Pi {
        k: Option<u64>,
    },
    ExpGolomb {
        k: Option<u64>,
    },
    VByteLe,
    VByteBe,
    FixedLength {
        num_bits: Option<u8>,
    },
    Auto,
    Explicit(Codes),
}

Specifies the compression codec and its parameters for an IntVec.

This enum allows for either explicitly setting the parameters for codes like Rice and Zeta, or requesting that IntVec automatically selects suitable parameters based on the data distribution during construction.

Variants

Gamma

Use Elias γ-coding.

The implied probability distribution is approximately 1 / (2*x^2). This code is parameter-free and is generally effective for data distributions skewed towards small values.

Delta

Use Elias δ-coding. This is the default codec spec.

The implied probability distribution is approximately 1 / (2*x*log(x)^2). Delta coding is also parameter-free and tends to be more efficient than Gamma for larger integer values.

Unary

Use Unary coding.

Represents the number n with n zeros followed by a one. It is only efficient for very small integers, particularly 0 and 1.

Rice

Use Rice-coding.

A special case of Golomb coding suitable for geometrically distributed data.

• If log2_b is Some(val), uses the specified parameter.
• If log2_b is None (on slice-based builder), an optimal parameter is estimated from the data’s average value.

Fields

log2_b: Option<u8>

Zeta

Use Boldi-Vigna ζ-coding.

The implied probability distribution is approximately 1 / x^(1 + 1/k). This code is effective for power-law distributions.

• If k is Some(val), uses the specified parameter (k > 0).
• If k is None (on slice-based builder), a default of k=3 is used.

Fields

k: Option<u64>

Golomb

Use Golomb-coding.

Suitable for geometrically distributed data.

• If b is Some(val), uses the specified parameter (b > 0).
• If b is None (on slice-based builder), an optimal parameter is estimated from the data’s average value.

Fields

b: Option<u64>

Omega

Use Elias-Fano ω-coding, a universal code for positive integers.

Pi

Use an alternative universal code for positive integers.

• If k is Some(val), uses the specified parameter (k > 0).
• If k is None (on slice-based builder), a default of k=3 is used.

Fields

k: Option<u64>

ExpGolomb

Use Elias-Fano Exponential-Golomb coding.

• If k is Some(val), uses the specified parameter.
• If k is None (on slice-based builder), a default of k=2 is used.

Fields

k: Option<u64>

VByteLe

Use VByte encoding with Little-Endian byte order. Efficient for integers that fit within a few bytes.

VByteBe

Use VByte encoding with Big-Endian byte order.

FixedLength

Use fixed-width integer encoding.

Optimal for uniformly distributed data within a known range.

• If num_bits is Some(val), uses the specified number of bits.
• If num_bits is None (on slice-based builder), the minimum bits required for the largest value in the data is used.

Fields

num_bits: Option<u8>

Auto

Automatically select the best variable-length code based on the data.

This is the recommended default for the slice-based builder. This option is not supported for the iterator-based builder.

Explicit(Codes)

Use an explicitly provided code from the dsi-bitstream library enum.

This is an escape hatch for advanced use cases or for codes not yet directly enumerated in CodecSpec.

Trait Implementations

impl Clone for CodecSpec

fn clone(&self) -> CodecSpec

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CodecSpec

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

Formats the value using the given formatter.

impl Default for CodecSpec

fn default() -> CodecSpec

Returns the “default value” for a type.

impl PartialEq for CodecSpec

fn eq(&self, other: &CodecSpec) -> 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 Copy for CodecSpec

impl Eq for CodecSpec

impl StructuralPartialEq for CodecSpec