Struct EncodingMask

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

A bitmask representing the Encodings employed while encoding a Parquet column chunk.

The Parquet ColumnMetaData struct contains an array that indicates what encodings were used when writing that column chunk. For memory and performance reasons, this crate reduces that array to bitmask, where each bit position represents a different Encoding. This struct contains that bitmask, and provides methods to interact with the data.

Example

// read parquet metadata from a file
let file = open_parquet_file("some_path.parquet");
let mut reader = ParquetMetaDataReader::new();
reader.try_parse(&file).unwrap();
let metadata = reader.finish().unwrap();

// find the encodings used by the first column chunk in the first row group
let col_meta = metadata.row_group(0).column(0);
let encodings = col_meta.encodings_mask();

// check to see if a particular encoding was used
let used_rle = encodings.is_set(Encoding::RLE);

// check to see if all of a set of encodings were used
let used_all = encodings.all_set([Encoding::RLE, Encoding::PLAIN].iter());

// convert mask to a Vec<Encoding>
let encodings_vec = encodings.encodings().collect::<Vec<_>>();

Implementations

impl EncodingMask

pub fn try_new(val: i32) -> Result<Self>

Attempt to create a new EncodingMask from an integer.

This will return an error if a bit outside the allowable range is set.

pub fn as_i32(&self) -> i32

Return an integer representation of this EncodingMask.

pub fn new_from_encodings<'a>( encodings: impl Iterator<Item = &'a Encoding>, ) -> Self

Create a new EncodingMask from a collection of Encodings.

pub fn insert(&mut self, val: Encoding)

Mark the given Encoding as present in this mask.

pub fn is_set(&self, val: Encoding) -> bool

Test if a given Encoding is present in this mask.

pub fn all_set<'a>(&self, encodings: impl Iterator<Item = &'a Encoding>) -> bool

Test if all Encodings in a given set are present in this mask.

pub fn encodings(&self) -> impl Iterator<Item = Encoding>

Return an iterator over all Encodings present in this mask.

Trait Implementations

impl Clone for EncodingMask

fn clone(&self) -> EncodingMask

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for EncodingMask

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

Formats the value using the given formatter.

impl Default for EncodingMask

fn default() -> EncodingMask

Returns the “default value” for a type.

impl PartialEq for EncodingMask

fn eq(&self, other: &EncodingMask) -> 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 EncodingMask

impl Eq for EncodingMask

impl StructuralPartialEq for EncodingMask