4.2.0 • Published 4 months ago
bitfield v4.2.0
bitfield
A simple bitfield, compliant with the BitTorrent spec.
npm install bitfieldExample
import Bitfield from "bitfield";
const field = new Bitfield(256); // Create a bitfield with 256 bits.
field.set(128); // Set the 128th bit.
field.set(128, true); // Same as above.
field.get(128); // `true`
field.get(200); // `false` (all values are initialised to `false`)
field.get(1e3); // `false` (out-of-bounds is also false)
field.set(128, false); // Set the 128th bit to 0 again.
field.buffer; // The buffer used by the bitfield.Class: BitField
Constructors
Properties
Methods
Constructors
constructor
+ new BitField(data?: number | Uint8Array, opts?: BitFieldOptions): BitField
Parameters:
| Name | Type | Default value | Description |
|---|---|---|---|
data | number | Uint8Array | 0 | Either a number representing the maximum number of supported bytes, or a Uint8Array. |
opts? | { grow: number } | { grow: 0 } | grow:If you set an index that is out-of-bounds, the bitfield will automatically grow so that the bitfield is big enough to contain the given index, up to the given size (in bit). If you want the Bitfield to grow indefinitely, pass Infinity. |
Returns: BitField
Properties
buffer
• buffer: Uint8Array
The internal storage of the bitfield.
Methods
forEach
▸ forEach(fn: (bit: boolean, index: number) => void, start?: number, end?: number): void
Loop through the bits in the bitfield.
Parameters:
| Name | Type | Default value | Description |
|---|---|---|---|
fn | (bit: boolean, index: number) => void | - | Function to be called with the bit value and index. |
start | number | 0 | Index of the first bit to look at. |
end | number | this.buffer.length * 8 | Index of the first bit that should no longer be considered. |
Returns: void
get
▸ get(i: number): boolean
Get a particular bit.
Parameters:
| Name | Type | Description |
|---|---|---|
i | number | Bit index to retrieve. |
Returns: boolean
A boolean indicating whether the ith bit is set.
set
▸ set(i: number, value?: boolean): void
Set a particular bit.
Will grow the underlying array if the bit is out of bounds and the grow option is set.
Parameters:
| Name | Type | Default value | Description |
|---|---|---|---|
i | number | - | Bit index to set. |
value | boolean | true | Value to set the bit to. Defaults to true. |
Returns: void
setAll
▸ setAll(array: ArrayLike<boolean>, offset?: number): void
Set the bits in the bitfield to the values in the given array.
Parameters:
| Name | Type | Default value | Description |
|---|---|---|---|
array | ArrayLike<boolean> | - | Array of booleans to set the bits to. |
offset | number | 0 | Index of the first bit to set. |
Returns: void
License
MIT