Enum EncodingType 

#[repr(u8)]
pub enum EncodingType {
    DeltaOfDelta = 0,
    Chimp = 1,
    Gorilla = 2,
    IntegerI64 = 3,
    IntegerU64 = 4,
    Dictionary = 5,
    Bitmap = 6,
    PlainF64 = 7,
    PlainI64 = 8,
    PlainU64 = 9,
    PlainBool = 10,
    PlainString = 11,
    Nullable = 12,
    Rle = 13,
    VarintI64 = 14,
    VarintU64 = 15,
    Chimp128 = 16,
    ForI64 = 17,
    ForU64 = 18,
    Patas = 19,
    Alp = 20,
    Pco = 21,
    PcoI64 = 22,
    PcoU64 = 23,
    DecimalI128 = 24,
    Bytes = 25,
}

Discriminant tag stored as the first byte of every EncodedBlock.

Variants

DeltaOfDelta = 0

Delta-of-delta for timestamps.

Kept as a selectable codec — it still wins on a perfect metronome — but no longer the default: see ColumnEncoder::encode_timestamps.

Chimp = 1

Chimp XOR for floats.

Gorilla = 2

Gorilla XOR for floats.

IntegerI64 = 3

Delta + ZigZag for i64.

IntegerU64 = 4

Delta + ZigZag for u64.

Dictionary = 5

Dictionary encoding for strings.

Bitmap = 6

Bitmap for booleans.

PlainF64 = 7

Plain f64.

PlainI64 = 8

Plain i64.

PlainU64 = 9

Plain u64.

PlainBool = 10

Plain bool.

PlainString = 11

Plain string.

Nullable = 12

Nullable wrapper — validity bitmap + inner encoded payload.

Payload format:

[inner_encoding: u8][total_count: u32 LE][validity_bitmap: ceil(count/8) bytes][inner_payload…]

Bit 1 in the validity bitmap means the value is present; 0 means null. Only non-null values are encoded in inner_payload.

Rle = 13

Run-length encoding for columns with repeated consecutive values.

VarintI64 = 14

Delta + ZigZag + LEB128 varint for i64.

Better than IntegerI64 for sparse or highly variable data where most deltas are small but occasional outliers would inflate the fixed bit width.

VarintU64 = 15

Delta + ZigZag + LEB128 varint for u64.

Chimp128 = 16

Chimp128 ring-buffer XOR for floats.

ForI64 = 17

Frame-of-Reference for narrow-range integers.

ForU64 = 18

Frame-of-Reference for narrow-range unsigned integers.

Patas = 19

Patas byte-aligned XOR for floats (VLDB 2023).

Alp = 20

ALP adaptive lossless floating-point compression (SIGMOD 2024).

A second opinion behind Pco for f64 columns whose values originated as decimals — which most sensor, meter and price data does. See crate::alp.

Pco = 21

Pcodec for floats (Loncaric 2025): mode recovery, delta, binned ANS. Leads every float candidate list — see crate::pco.

PcoI64 = 22

Pcodec for signed integers, and the default timestamp codec.

PcoU64 = 23

Pcodec for unsigned integers.

DecimalI128 = 24

Exact decimal mantissas (i128) — see crate::decimal.

Not a codec of its own so much as a shape: the narrow form, which is nearly every real decimal column, delegates straight to the i64 stack above and therefore inherits RLE, FOR, varint and pco.

Bytes = 25

Opaque byte strings — a count, then a length and payload per value.

For columns whose values are composite objects rather than numbers: today, native histograms. There is deliberately no clever codec here. A histogram’s own encoding already packs it, and a second-guessing layer over an opaque blob would compress nothing while adding a decoder to audit — so this is a framing, and the general-purpose block compression underneath the segment does the rest.

Implementations

impl EncodingType

pub const ALL: &'static [Self]

Every encoding type, in tag order.

Complete by construction — generated from the same list as the enum itself, so a codec cannot be added without appearing here, and therefore in the fuzz corpus.

pub fn from_tag(tag: u8) -> Result<Self>

Convert a u8 tag to an EncodingType.

Errors

Returns EncodingError::UnsupportedEncoding for unknown tags.

pub fn tag(self) -> u8

Return the u8 discriminant.

Trait Implementations

impl Clone for EncodingType

fn clone(&self) -> EncodingType

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for EncodingType

impl Debug for EncodingType

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

Formats the value using the given formatter.

impl Display for EncodingType

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

Formats the value using the given formatter.

impl Eq for EncodingType

impl PartialEq for EncodingType

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for EncodingType