71 lines
2.0 KiB
Kotlin
71 lines
2.0 KiB
Kotlin
package net.sergeych.lynon
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/**
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* Bit size-aware code, short [BitList] implementation, up to 64 bits (efficiency tradeoff).
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* E.g `Bits(0, 3) != Bits(0, 2). For longer, use [BitArray].
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*
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* Note that [bitListOf] creates [TinyBits] when possible.
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*/
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class TinyBits(initValue: ULong = 0U, override val size: Long = 0): BitList {
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private var bits: ULong = initValue
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constructor(value: ULong, size: Int): this(value, size.toLong()) {}
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override val indices: LongRange by lazy { 0..<size }
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override operator fun get(bitIndex: Long): Int {
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if( bitIndex !in indices) throw IndexOutOfBoundsException("index out of bounds: $bitIndex")
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val mask = 1UL shl (size - bitIndex - 1).toInt()
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return if (bits and mask != 0UL) 1 else 0
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}
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override fun set(bitIndex: Long, value: Int) {
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val mask = 1UL shl (size - bitIndex - 1).toInt()
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if( value == 1)
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bits = bits or mask
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else
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bits = bits and mask.inv()
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}
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override fun toString(): String {
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val result = StringBuilder()
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for (i in 0..<size) result.append(this[i])
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return result.toString()
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}
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val value by ::bits
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/**
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* Add bit shifting value to the left and return _new instance_
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*/
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fun insertBit(bit: Int): TinyBits {
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return TinyBits((bits shl 1) or bit.toULong(), size + 1)
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}
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override fun equals(other: Any?): Boolean {
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if (this === other) return true
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if (other == null || this::class != other::class) return false
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other as TinyBits
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if (size != other.size) return false
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if (bits != other.bits) return false
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return true
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}
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override fun hashCode(): Int {
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var result = size.hashCode()
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result = 31 * result + bits.hashCode()
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return result
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}
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companion object {
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fun of(vararg bits: Int): TinyBits {
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return TinyBits(0UL, bits.size).apply { bits.forEachIndexed { i, v -> this[i.toLong()] = v } }
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}
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}
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} |