indispensable/at.asitplus.signum.indispensable.io/BitSet

BitSet

@Serializable(with = BitSetSerializer::class)

class BitSet : Iterable<Boolean> (source)

Pure Kotlin Bit Set created by throwing a bunch of extension functions at a MutableList<Byte>. As a mental model: this BitSet grows from left to right, just like writing a text.

Note: The in-byte bit index and the global index (for iterating over the bytes contained in the list) run in opposing directions!

The toBitString function print our the bits as they are accessible, disregarding byte-alignment and memory layout:

val bitSet = BitSet()
bitSet[0] = true //1             (ByteArray representation: [1])
bitSet[2] = true //101           (ByteArray representation: [5])
bitSet[8] = true //10100000 1    (ByteArray representation: [5,1])

To inspect the actual memory layout of the underlying bytes (i.e. the result of calling toByteArray), use memDump.

Implements Iterable over bits. Use bytes to iterate over bytes

Constructors

BitSet

constructor(nbits: Long = 0)

Preallocates a buffer capable of holding nbits many bits

Types

Companion

object Companion

Properties

bytes

val bytes: List<Byte>

List view on the bytes backing this bit set. Changes to the bytes directly affect this bitset.

Functions

equals

open operator override fun equals(other: Any?): Boolean

forEachIndexed

inline fun forEachIndexed(block: (i: Long, it: Boolean) -> Unit)

This is the real deal, as it has Long indices

get

operator fun get(index: Long): Boolean

Returns the bit at index. Never throws an exception when index>=0, as getting a bit outside the underlying bytes' bounds returns false.

iterator

open operator override fun iterator(): Iterator<Boolean>

returns an iterator over bits. use bytes.iterator() to iterate over bytes

length

fun length(): Long

Current length of the bitset.

memDump

fun memDump(): String

Returns a binary representation of this bit set's memory layout, when packed into a byte array Bytes are separated by a single space. An empty byte array results in an empty string.

nextSetBit

fun nextSetBit(fromIndex: Long): Long

return the next bit set to true following fromIndex

set

fun set(index: Long)

shorthand for set(index,true)

operator fun set(index: Long, value: Boolean)

Sets the bit at index to value

toBitString

fun toBitString(): String

Returns all bits as they are accessible by the global bit index

toByteArray

fun toByteArray(): ByteArray

Allocates a fresh byte array and writes the values of this bitset's underlying bytes to it

toString

open override fun toString(): String