628 lines
17 KiB
Kotlin
628 lines
17 KiB
Kotlin
package me.alex_s168.kotlin_bits
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import kotlinx.io.*
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import kotlinx.io.files.Path
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import kotlinx.io.files.SystemFileSystem
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import kotlin.math.max
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import kotlin.math.min
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interface IndexableSequence<T>: Sequence<T> {
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operator fun get(index: Int): T
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}
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data class Obj<T>(val v: T)
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data class MutObj<T>(val v: T)
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fun <T> lazySequence(vararg init: Pair<Int, T>, default: Obj<T>?, f: (Int, (Int) -> T) -> T): IndexableSequence<T> =
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object : IndexableSequence<T> {
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val map = mutableMapOf(*init)
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var current: Int? = null
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fun comp(iIn: Int): T {
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val i = max(0, iIn)
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if (current == i)
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return (default ?: throw Exception("recursion detected")).v
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return map[i] ?: let {
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current = i
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val res = f(i, ::comp)
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map[i] = res
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current = null
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res
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}
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}
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override fun get(index: Int) = comp(index)
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override fun iterator(): Iterator<T> =
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object : Iterator<T> {
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override fun hasNext() = true
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private var i = 0
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override fun next(): T =
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comp(i ++)
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}
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}
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fun <T> easySequence(vararg init: Pair<Int, T?>, f: (Int, (Int) -> T?) -> T?): Sequence<T?> =
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lazySequence(*init, default = Obj(null)) { i, ff ->
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f(i) { index ->
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var indexC = index
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var v: T? = null
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while (indexC > 0 && v == null)
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v = ff(indexC --)
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v
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}
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}
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fun <I, T> Sequence<I>.easyMappingSequence(vararg init: Pair<Int, T?>, f: (Int, (Int) -> T?, (Int) -> I) -> T?): Sequence<T?> {
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val indexable = this.asIndexable()
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return easySequence(*init) { i, ff ->
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f(i, ff, indexable::get)
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}.limitBy(indexable)
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.removeNull()
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}
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fun <T> IndexableSequence<T>.modifier(mod: (Sequence<T>) -> Sequence<T>) =
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object : IndexableSequence<T> {
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val other = mod(this@modifier)
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override fun iterator(): Iterator<T> =
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other.iterator()
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override fun get(index: Int): T =
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this@modifier[index]
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}
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fun <T> Sequence<T>.removeNull(): Sequence<T> =
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mapNotNull { it }
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fun <T> IndexableSequence<T>.removeNull(): IndexableSequence<T> =
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modifier { it.removeNull() }
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fun <A, B> Sequence<A>.limitBy(other: Sequence<B>): Sequence<A> =
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object : Sequence<A> {
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override fun iterator(): Iterator<A> =
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object : Iterator<A> {
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val s = this@limitBy.iterator()
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val o = other.iterator()
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override fun hasNext(): Boolean =
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o.hasNext() && s.hasNext()
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override fun next(): A =
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s.next().also { o.next() }
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}
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}
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fun <A, B> IndexableSequence<A>.limitBy(other: Sequence<B>): IndexableSequence<A> =
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modifier { it.limitBy(other) }
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fun <T> Sequence<T>.asIndexable(): IndexableSequence<T> {
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if (this is IndexableSequence)
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return this
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return object : IndexableSequence<T> {
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val iter = this@asIndexable.iterator()
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val values = mutableListOf<T>()
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override fun get(index: Int): T {
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if (index >= values.size) {
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repeat(index + 1 - values.size) {
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values.add(iter.next())
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}
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}
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return values[index]
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}
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override fun iterator(): Iterator<T> =
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object : Iterator<T> {
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var i = 0
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override fun hasNext(): Boolean =
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i < values.size || iter.hasNext()
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override fun next(): T =
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get(i ++)
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}
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}
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}
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typealias Operator<I, O> = (I) -> O
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fun <T, O: Any> caching(tiedGet: () -> T, calc: (T) -> O) = object : Lazy<O> {
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private var lastTiedV = tiedGet()
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private var lastV: O? = null
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override val value: O get() {
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val nTied = tiedGet()
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if (lastTiedV != nTied) {
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lastTiedV = nTied
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lastV = calc(nTied)
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return lastV!!
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}
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if (lastV == null)
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lastV = calc(nTied)
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return lastV!!
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}
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override fun isInitialized(): Boolean =
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lastTiedV == tiedGet() && lastV != null
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}
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fun <T> selfInitializingSequence(block: () -> Sequence<T>): Sequence<T> =
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object : Sequence<T> {
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val seq by lazy(block)
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inner class Iter : Iterator<T> {
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val iter = seq.iterator()
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override fun hasNext(): Boolean =
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iter.hasNext()
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override fun next(): T =
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iter.next()
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}
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override fun iterator(): Iterator<T> =
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Iter()
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}
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class OperationChain<I, O> private constructor(
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private val impl: Impl = Impl()
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) {
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private var until = 0
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private class Impl {
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val seqe = mutableListOf<(Sequence<Any?>) -> Sequence<Any?>>()
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var finalized = false
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fun add(op: Operator<*, *>) {
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seqe += { seq: Sequence<Any?> ->
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seq.map(op as Operator<Any?, Any?>)
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}
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}
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fun addFlat(op: Operator<*, Sequence<*>>) {
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seqe += { seq: Sequence<Any?> ->
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seq.flatMap(op as Operator<Any?, Sequence<Any?>>)
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}
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}
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}
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fun <NO> map(op: Operator<O, NO>): OperationChain<I, NO> =
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OperationChain<I, NO>(impl.also { it.add(op) })
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.also { it.until = this.until + 1 }
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fun <NO> flatMap(op: Operator<O, Sequence<NO>>): OperationChain<I, NO> =
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OperationChain<I, NO>(impl.also { it.addFlat(op) })
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.also { it.until = this.until + 1 }
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fun <NO> map(op: OperationChain<O, NO>): OperationChain<I, NO> {
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if (!op.impl.finalized)
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throw Exception("Can not map un-finalized operation chain onto operation chain!")
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return flatMap(op::process)
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}
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fun <NO> modifier(op: Operator<Sequence<O>, Sequence<NO>>): OperationChain<I, NO> =
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OperationChain<I, NO>(impl.also { it.seqe.add(op as (Sequence<Any?>) -> Sequence<Any?>) })
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.also { it.until = this.until + 1 }
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fun finalize(): OperationChain<I, O> {
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if (impl.finalized)
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throw Exception("Can't finalize a finalized OperationChain!")
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impl.finalized = true
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return this
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}
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fun process(v: I): Sequence<O> =
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selfInitializingSequence {
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var seq = sequenceOf<Any?>(v)
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impl.seqe
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.asSequence()
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.take(until)
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.forEach { op ->
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seq = op(seq)
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}
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seq as Sequence<O>
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}
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fun processAll(v: Sequence<I>): Sequence<O> =
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v.flatMap { process(it) }
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companion object {
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internal fun <I> create(): OperationChain<I, I> =
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OperationChain()
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}
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}
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class Contents<T> internal constructor(
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private val iterable: Iterable<T>
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): Iterable<T> {
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override fun iterator(): Iterator<T> =
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iterable.iterator()
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override fun equals(other: Any?): Boolean {
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if (other !is Contents<*>)
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return false
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val it1 = this.iterable.iterator()
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val it2 = other.iterable.iterator()
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while (true) {
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val hasNext1 = it1.hasNext()
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val hasNext2 = it2.hasNext()
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if ((hasNext1 && !hasNext2) || (hasNext2 && !hasNext1))
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return false
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if (!hasNext1)
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return true
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if (it1.next() != it2.next())
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return false
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}
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}
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override fun hashCode(): Int =
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iterable.hashCode()
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override fun toString(): String =
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joinToString(
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separator = ", ",
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prefix = "[",
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postfix = "]"
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) {
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it.toString()
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}
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}
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val <T> Iterable<T>.contents get() =
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Contents(this)
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val <T> Sequence<T>.contents get() =
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Contents(this.asIterable())
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val <T> Array<T>.contents get() =
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Contents(this.asIterable())
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fun <T, O> Sequence<T>.map(chain: OperationChain<T, O>): Sequence<O> =
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chain.processAll(this)
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fun <I> chain(): OperationChain<I, I> =
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OperationChain.create()
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fun <I, O> OperationChain<I, O>.chunked(size: Int): OperationChain<I, List<O>> =
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modifier { it.chunked(size) }
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fun <I, O, R> OperationChain<I, O>.chunked(size: Int, transform: (List<O>) -> R): OperationChain<I, R> =
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modifier { it.chunked(size, transform) }
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fun <I, O> OperationChain<I, O>.filter(predicate: (O) -> Boolean): OperationChain<I, O> =
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modifier { it.filter(predicate) }
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fun <T> MutableList<T>.removeFirst(count: Int) {
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repeat(count) {
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removeFirst()
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}
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}
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fun <T> MutableList<T>.removeLast(count: Int) {
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repeat(count) {
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removeLast()
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}
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}
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interface BatchIterator<T>: Iterator<T> {
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fun next(limit: Int): List<T>
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fun next(dest: Array<T>): Int
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fun next(dest: MutableList<T>, limit: Int)
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}
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interface ByteBatchIterator: BatchIterator<Byte> {
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fun nextBytes(limit: Int): ByteArray
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fun nextBytes(dest: ByteArray): Int
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}
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interface BatchSequence<T>: Sequence<T> {
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override fun iterator(): BatchIterator<T>
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}
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interface ByteBatchSequence: BatchSequence<Byte> {
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override fun iterator(): ByteBatchIterator
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}
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/**
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* Batches all get operations on the sequence.
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*/
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fun <T> BatchSequence<T>.batched(count: Int): BatchSequence<T> =
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object : BatchSequence<T> {
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inner class Iter: BatchIterator<T> {
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val parent = this@batched.iterator()
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var batch = mutableListOf<T>()
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override fun next(limit: Int): List<T> {
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if (!hasNext())
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throw Exception("no next")
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val c = min(limit, batch.size)
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val ret = batch.take(c)
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batch.removeFirst(c)
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return ret
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}
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override fun next(dest: MutableList<T>, limit: Int) {
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if (!hasNext())
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throw Exception("no next")
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val c = min(limit, batch.size)
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dest.addAll(batch.subList(0, max(0, c-1)))
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batch.removeFirst(c)
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return
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}
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override fun next(dest: Array<T>): Int {
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if (!hasNext())
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throw Exception("no next")
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val c = min(dest.size, batch.size)
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batch.subList(0, max(0, c-1)).forEachIndexed { i, t ->
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dest[i] = t
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}
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batch.removeFirst(c)
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return c
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}
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override fun next(): T {
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if (!hasNext())
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throw Exception("no next")
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val v = batch.first()
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batch.removeFirst()
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return v
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}
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override fun hasNext(): Boolean {
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while (batch.isEmpty()) {
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if (!parent.hasNext())
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return false
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parent.next(batch, count)
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}
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return true
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}
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}
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override fun iterator(): BatchIterator<T> =
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Iter()
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}
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fun <T> Sequence<T>.asBatch(): BatchSequence<T> =
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object : BatchSequence<T> {
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inner class Iter: BatchIterator<T> {
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var iter = this@asBatch.iterator()
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override fun next(limit: Int): List<T> =
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mutableListOf<T>()
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.also { next(it, limit) }
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override fun next(dest: MutableList<T>, limit: Int) {
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for (i in 0..<limit) {
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if (!iter.hasNext())
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break
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dest.add(iter.next())
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}
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}
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override fun next(dest: Array<T>): Int {
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var i = 0
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while (i < dest.size) {
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if (!iter.hasNext())
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break
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dest[i ++] = iter.next()
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}
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return i
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}
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override fun next(): T {
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return iter.next()
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}
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override fun hasNext(): Boolean {
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return iter.hasNext()
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}
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}
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override fun iterator(): BatchIterator<T> =
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Iter()
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}
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/*
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# Batched sequences
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## Source
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You should make all your sources return `BatchSequence<T>`
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and then you can use the `.batched(count: Int)` function
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to drastically decrease the amount of single reads in the original source.
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Example:
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```kt
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File("text.txt") // File
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.openRead() // BatchSequence<Byte>
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.batched(64) // BatchSequence<Byte>
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```
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with this, if `.openRead()` returns a dumb sequence that always only gets one byte at once,
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you can speed up the reading process by a lot
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## Sink
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You should make all your sinks take `BatchSequence<T>`
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and then you can use the `.asBatch()` function to allow
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the sink to get multiple bytes at once
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Example:
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```kt
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val data = myData // Sequence<Byte>
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.asBatch() // BatchSequence<Byte>
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File("text.txt")
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.write(data)
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```
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# Lazy Sequences
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When writing recursive functions like Fibonacci, it is often easier and faster to use
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lazy sequences.
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Example:
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```kt
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val fib = lazySequence(0 to 1) { i, f ->
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f(i-1) + f(i-2)
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}
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println(fib[10])
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```
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Note: If we call f for any number below 0, it will call f(0) instead.
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# Operation Chains
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TODO
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# Contents
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TODO
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# Monads
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TODO
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# Easy Sequence
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TODO
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# Easy Mapping Sequence
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TODO
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# Obj and MutObj
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TODO
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*/
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data class Monad<O>(
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val impure: () -> O
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)
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fun <O> unit(v: O): Monad<O> =
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Monad { v }
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fun unit(): Monad<Unit> =
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Monad { Unit }
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fun <I, O> Monad<I>.bind(op: (I) -> O): Monad<O> =
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Monad { op(this@bind.impure()) }
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fun Monad<String>.print() =
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bind { print(it) }
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fun Monad<String>.asPath() =
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bind { Path(it) }
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fun ByteBatchSequence.stringify(batch: Int = 64): Sequence<String> {
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val iter = iterator()
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return generateSequence {
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if (iter.hasNext())
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iter.nextBytes(batch).decodeToString()
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else null
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}
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}
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fun (() -> RawSource).readerSequence(): ByteBatchSequence =
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object : ByteBatchSequence {
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inner class Iter: ByteBatchIterator {
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val buffered = this@readerSequence().buffered()
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override fun nextBytes(limit: Int): ByteArray {
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val out = ByteArray(limit)
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var i = 0
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while (!(buffered.exhausted() || i == limit - 1))
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out[i ++] = buffered.readByte()
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return out.sliceArray(0..i)
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}
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override fun nextBytes(dest: ByteArray): Int =
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nextBytes(dest.size).also { it.copyInto(dest) }.size
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override fun next(limit: Int): List<Byte> =
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nextBytes(limit).toList()
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override fun next(dest: MutableList<Byte>, limit: Int) {
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for (x in nextBytes(limit)) {
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dest.add(x)
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}
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}
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override fun next(dest: Array<Byte>): Int {
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var i = 0
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for (x in nextBytes(dest.size)) {
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dest[i ++] = x
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}
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return i
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}
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override fun next(): Byte =
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buffered.readByte()
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override fun hasNext(): Boolean =
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!buffered.exhausted()
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}
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override fun iterator(): ByteBatchIterator =
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Iter()
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}
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fun <T> Iterable<Monad<T>>.rewrap(): Monad<Sequence<T>> =
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Monad {
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val iter = this@rewrap.iterator()
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generateSequence {
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if (iter.hasNext())iter.next().impure()
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else null
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}
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}
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fun <T> Sequence<Monad<T>>.rewrap(): Monad<Sequence<T>> =
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Monad {
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val iter = this@rewrap.iterator()
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sequence { if (iter.hasNext()) yield(iter.next().impure()) }
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|
}
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|
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fun Sequence<Monad<Unit>>.combine(): Monad<Unit> =
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Monad { this@combine.forEach { it.impure() } }
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|
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fun Iterable<Monad<Unit>>.combineIter(): Monad<Unit> =
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Monad { this@combineIter.forEach { it.impure() } }
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|
|
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fun Monad<Sequence<Monad<Unit>>>.combine(): Monad<Unit> =
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|
Monad { this@combine.impure().forEach { it.impure() } }
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|
|
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fun Monad<Iterable<Monad<Unit>>>.combineIter(): Monad<Unit> =
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|
Monad { this@combineIter.impure().forEach { it.impure() } }
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|
|
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fun <T, R> Monad<Iterable<T>>.mapIter(transform: (T) -> R): Monad<Iterable<R>> =
|
|
bind { it.map { x -> transform(x) } }
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|
|
|
fun <T, R> Monad<Sequence<T>>.map(transform: (T) -> R): Monad<Sequence<R>> =
|
|
bind { it.map { x -> transform(x) } }
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|
|
|
fun <T> Monad<Sequence<Sequence<T>>>.flatten(): Monad<Sequence<T>> =
|
|
bind { it.flatten() }
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|
|
|
fun Monad<ByteBatchSequence>.stringify(batch: Int = 64): Monad<Sequence<String>> =
|
|
bind { it.stringify(batch) }
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|
|
|
fun Monad<Path>.read() =
|
|
bind { p -> { SystemFileSystem.source(p) }.readerSequence() }
|
|
|
|
fun readIn() =
|
|
Monad { generateSequence { readln() } }
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|
|
|
/*
|
|
fun main() {
|
|
val chain = chain<Int>()
|
|
.map(Int::toString)
|
|
.map(String::reversed)
|
|
.finalize()
|
|
println(chain.process(120).contents)
|
|
}*/
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