Struct hypercore::bitfield::SparseBitfield

pub struct SparseBitfield {
    pub pages: Pager,
    // some fields omitted
}

Bitfield instance.

Fields

pages: Pager

A memory-pager instance.

Implementations

impl Bitfield

pub fn new(page_size: usize) -> Bitfield

Create a new instance.

Panics

The page size must be a multiple of 2, and bigger than 0.

pub fn from_file(
    file: &mut File,
    page_size: usize,
    offset: Option<usize>
) -> Result<Bitfield, Error>

Create a new instance from a File.

pub fn set(&mut self, index: usize, value: bool) -> Change

Set a bit to true or false. Returns a boolean indicating if the value was changed.

pub fn get(&mut self, index: usize) -> bool

Get the value of a bit.

pub fn get_byte(&self, index: usize) -> u8

Get a byte from our internal buffers.

pub fn set_byte(&mut self, index: usize, byte: u8) -> Change

Set a byte to the right value inside our internal buffers.

pub fn page_size(&self) -> usize

Get the memory page size in bytes.

pub fn len(&self) -> usize

Get the amount of bits in the bitfield.

Examples

let mut bits = Bitfield::new(1024);
assert_eq!(bits.len(), 0);
bits.set(0, true);
assert_eq!(bits.len(), 8);
bits.set(1, true);
assert_eq!(bits.len(), 8);
bits.set(9, false);
assert_eq!(bits.len(), 16);

pub fn byte_len(&self) -> usize

Get the amount of bytes in the bitfield.

Examples

let mut bits = Bitfield::new(1024);
assert_eq!(bits.byte_len(), 0);
bits.set(0, true);
assert_eq!(bits.byte_len(), 1);
bits.set(1, true);
assert_eq!(bits.byte_len(), 1);
bits.set(9, false);
assert_eq!(bits.byte_len(), 2);

pub fn page_len(&self) -> usize

Get the amount of memory pages in the bitfield.

Examples

let mut bits = Bitfield::new(1024);
assert_eq!(bits.page_len(), 0);
bits.set(0, true);
assert_eq!(bits.page_len(), 1);
bits.set(1, true);
assert_eq!(bits.page_len(), 1);
bits.set(2, false);
assert_eq!(bits.page_len(), 1);
bits.set(1024 * 8 + 1, true);
assert_eq!(bits.page_len(), 2);

pub fn is_empty(&self) -> bool

Returns true if no bits are stored.

Examples

let mut bits = Bitfield::new(1024);
assert!(bits.is_empty());
bits.set(0, true);
assert!(!bits.is_empty());

pub fn iter(&mut self) -> Iter

Create an Iterator that iterates over all pages.

pub fn to_bytes(&self) -> Result<Vec<u8>, Error>

Based on Bitfield.prototype.toBuffer

Trait Implementations

impl Debug for Bitfield

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

Formats the value using the given formatter.

impl Default for Bitfield

Create a new instance with a page_size of 1kb.

fn default() -> Bitfield

Returns the "default value" for a type.