Struct arrow::array::BufferBuilder

pub struct BufferBuilder<T: ArrowPrimitiveType> { /* fields omitted */ }

Builder for creating a Buffer object.

This builder is implemented for primitive types and creates a buffer with a zero-copy build() method.

See trait BufferBuilderTrait for further documentation and examples.

A Buffer is the underlying data structure of Arrow's Arrays.

For all supported types, there are type definitions for the generic version of BufferBuilder<T>, e.g. UInt8BufferBuilder.

Example:

use arrow::array::{UInt8BufferBuilder, BufferBuilderTrait};

let mut builder = UInt8BufferBuilder::new(100);
builder.append_slice(&[42, 43, 44]);
builder.append(45);
let buffer = builder.finish();

assert_eq!(unsafe { buffer.typed_data::<u8>() }, &[42, 43, 44, 45]);

Trait Implementations

impl BufferBuilderTrait<BooleanType> for BufferBuilder<BooleanType>

fn new(capacity: usize) -> Self

Creates a new builder with initial capacity for at least capacity elements of type T.

fn advance(&mut self, i: usize) -> Result<()>

Increases the number of elements in the internal buffer by n and resizes the buffer as needed.

fn append(&mut self, v: bool) -> Result<()>

Appends a value of type T into the builder, growing the internal buffer as needed.

fn append_n(&mut self, n: usize, v: bool) -> Result<()>

Appends a value of type T into the builder N times, growing the internal buffer as needed.

fn append_slice(&mut self, slice: &[bool]) -> Result<()>

Appends a slice of type T, growing the internal buffer as needed.

fn reserve(&mut self, n: usize) -> Result<()>

Reserves memory for at least n more elements of type T.

fn finish(&mut self) -> Buffer

Resets this builder and returns an immutable Buffer.

fn len(&self) -> usize

Returns the current number of array elements in the internal buffer.

fn is_empty(&self) -> bool

Returns whether the internal buffer is empty.

fn capacity(&self) -> usize

Returns the actual capacity (number of elements) of the internal buffer.

impl<T: ArrowPrimitiveType> BufferBuilderTrait<T> for BufferBuilder<T>

default fn new(capacity: usize) -> Self

Creates a new builder with initial capacity for at least capacity elements of type T.

fn len(&self) -> usize

Returns the current number of array elements in the internal buffer.

fn is_empty(&self) -> bool

Returns whether the internal buffer is empty.

fn capacity(&self) -> usize

Returns the actual capacity (number of elements) of the internal buffer.

default fn advance(&mut self, i: usize) -> Result<()>

Increases the number of elements in the internal buffer by n and resizes the buffer as needed.

default fn reserve(&mut self, n: usize) -> Result<()>

Reserves memory for at least n more elements of type T.

default fn append(&mut self, v: T::Native) -> Result<()>

Appends a value of type T into the builder, growing the internal buffer as needed.

default fn append_n(&mut self, n: usize, v: T::Native) -> Result<()>

Appends a value of type T into the builder N times, growing the internal buffer as needed.

default fn append_slice(&mut self, slice: &[T::Native]) -> Result<()>

Appends a slice of type T, growing the internal buffer as needed.

default fn finish(&mut self) -> Buffer

Resets this builder and returns an immutable Buffer.

impl<T: Debug + ArrowPrimitiveType> Debug for BufferBuilder<T>

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

Formats the value using the given formatter.