scalax.collection.NonEmpty.scala Maven / Gradle / Ivy
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package scalax.collection
import scala.collection.{IterableFactory, IterableOnce}
import scala.collection.immutable.Iterable
import scala.collection.mutable.Buffer
import scala.util.chaining._
protected trait UnchangedSizeOps[+A, CC[+X] <: NonEmpty[X]] {
def iterator: Iterator[A]
/** The element at `index` starting with 0 looked up in a non-safe way.
* @throws IndexOutOfBoundsException if `index` is negative or greater or equal to this collection's size.
*/
def apply(index: Int): A
/** Whether an element at `index` exists. */
def isDefinedAt(index: Int): Boolean
/** Whether `elem` is included in this collection. */
def contains[B >: A](elem: B): Boolean = exists(_ == elem)
/** Whether an element satisfying the predicate `p` exists. */
def exists(p: A => Boolean): Boolean = find(p).isDefined
/** Finds an element satisfying the predicate `p` if any. */
def find(p: A => Boolean): Option[A]
/** Whether all elements satisfy the predicate `p`. */
def forall(p: A => Boolean): Boolean
/** Calls `f` on all elements of this collection for side effects. */
def foreach[U](f: A => U): Unit
/** Gets the element at `index` if any. */
def get(index: Int): Option[A] = if (isDefinedAt(index)) Some(apply(index)) else None
/** The first element. */
def head: A
/** The number of elements in this collection. */
def size: Int
/** Applies `f` to a start value and all elements of this collection, going left to right. */
def foldLeft[B](zero: B)(f: (B, A) => B): B = iterator.foldLeft(zero)(f)
/** Applies `f` to all elements of this collection, going left to right. */
def reduceLeft[B >: A](f: (B, A) => B): B = iterator.reduceLeft(f)
/** Builds a new collection by applying a function to all elements of this collection. */
def map[B](f: A => B): CC[B]
final def reverse: CC[A] = newUnsafeBuilder.result(iterator.toList.reverse)
final def toList: List[A] = iterator.toList
final def zip[B](that: IterableOnce[B]): CC[(A, B)] = newUnsafeBuilder.result(iterator zip that)
final def zip[B](that: NonEmpty[B]): CC[(A, B)] = newUnsafeBuilder.result(iterator zip that.iterator)
final def zipWithIndex: CC[(A, Int)] = newUnsafeBuilder.result(iterator.zipWithIndex)
protected def apply[B >: A](index: Int, more: Iterable[B], start: Int): B =
if (index < 0) throw new IndexOutOfBoundsException
else
try more.iterator.drop(index - start).next()
catch {
case _: Exception => throw new IndexOutOfBoundsException
}
protected def newUnsafeBuilder[B]: NonEmptyBuilder.Unsafe[B, CC]
}
protected trait LengtheningOps[+A, CC[+X] <: NonEmpty[X]] {
this: UnchangedSizeOps[A, CC] =>
/** Concatenates the elements of this collection and those of `suffix` into a new collection. */
def concat[B >: A](suffix: IterableOnce[B]): CC[B] = appendedAll(suffix)
/** Alias for `concat` */
final def ++[B >: A](that: IterableOnce[B]): CC[B] = concat(that)
/** Alias for `concat` */
final def ++[B >: A](that: NonEmpty[B]): CC[B] = concat(that.iterator)
/** Creates a new collection with `elem` as its first element followed by the elements of this collection. */
def prepended[B >: A](elem: B): CC[B]
/** Creates a new collection with the elements of this collection and `elem` appended. */
def appended[B >: A](elem: B): CC[B]
/** Alias for `prepended` */
final def +:[B >: A](elem: B): CC[B] = prepended(elem)
/** Alias for `appended` */
final def :+[B >: A](elem: B): CC[B] = appended(elem)
final def prependedAll[B >: A](prefix: IterableOnce[B]): CC[B] = newUnsafeBuilder.result(prefix.iterator ++ iterator)
final def prependedAll[B >: A](prefix: NonEmpty[B]): CC[B] = prependedAll(prefix.iterator)
/** Alias for `prependedAll` */
final def ++:[B >: A](prefix: IterableOnce[B]): CC[B] = prependedAll(prefix)
/** Alias for `prependedAll` */
final def ++:[B >: A](prefix: NonEmpty[B]): CC[B] = prependedAll(prefix.iterator)
final def appendedAll[B >: A](suffix: IterableOnce[B]): CC[B] = newUnsafeBuilder.result(iterator ++ suffix.iterator)
final def appendedAll[B >: A](suffix: NonEmpty[B]): CC[B] = appendedAll(suffix.iterator)
/** Alias for `appendedAll` */
final def :++[B >: A](suffix: IterableOnce[B]): CC[B] = appendedAll(suffix)
/** Alias for `appendedAll` */
final def :++[B >: A](suffix: NonEmpty[B]): CC[B] = appendedAll(suffix.iterator)
}
protected trait ShorteningOps[+A, CC[+X] <: NonEmpty[X], SCC[+_] <: Iterable[_]] {
this: UnchangedSizeOps[A, CC] =>
protected def newEscapingBuilder[B]: NonEmptyBuilder.Escaping[B, SCC]
/** Creates a `List` with all elements of this collection that satisfy the predicate `p` */
final def filter(p: A => Boolean): SCC[A] = newEscapingBuilder.result(iterator filter p)
/** Creates a `List` with all elements of this collection that don't satisfy the predicate `p` */
final def filterNot(p: A => Boolean): SCC[A] = filter(!p(_))
/** Creates a `List` by applying `f` to all elements of this collection and using the elements of every result. */
final def flatMap[B](f: A => IterableOnce[B]): SCC[B] = newEscapingBuilder.result(iterator flatMap f)
/** Creates a `List` with all elements of this collection that satisfy `pf` */
final def collect[B](pf: PartialFunction[A, B]): SCC[B] = newEscapingBuilder.result(iterator collect pf)
}
/** @define ESCAPING creates a collection of the same type and returns it in a `Right`
* unless the number of remaining elements is too small in which case it escapes to a `Left[List]`.
*/
protected trait ShorteningEitherOps[+A, CC[+X] <: NonEmpty[X], SCC[+_] <: Iterable[_]] {
this: UnchangedSizeOps[A, CC] =>
protected def newConditionalBuilder[B]: NonEmptyBuilder.Conditional[B, CC, SCC]
/** Same as `filter` but $ESCAPING */
def filterEither(p: A => Boolean): Either[SCC[A], CC[A]] = newConditionalBuilder.result(iterator filter p)
/** Same as `filterNot` but $ESCAPING */
def filterNotEither(p: A => Boolean): Either[SCC[A], CC[A]] = filterEither(!p(_))
/** Same as `flatMap` but $ESCAPING */
final def flatMapEither[B](f: A => IterableOnce[B]): Either[SCC[B], CC[B]] =
newConditionalBuilder.result(iterator flatMap f)
/** Same as `collect` but $ESCAPING */
def collectEither[B](pf: PartialFunction[A, B]): Either[SCC[B], CC[B]] =
newConditionalBuilder.result(iterator collect pf)
}
protected trait NonEmptyOps[+A, CC[+X] <: NonEmpty[X], SCC[+_] <: Iterable[_]]
extends UnchangedSizeOps[A, CC]
with LengtheningOps[A, CC]
with ShorteningOps[A, CC, SCC]
with ShorteningEitherOps[A, CC, SCC]
sealed trait NonEmpty[+A] {
/** Iterates over all elements of this collection. */
def iterator: Iterator[A]
}
protected trait NonEmptyFactory[CC[+X] <: NonEmpty[X]] {
/** Tries to create a non-empty collection populated with the elements of `source`. */
def from[A](source: IterableOnce[A]): Option[CC[A]]
/** Creates a non-empty collection populated with the elements of `source` in a non-safe way.
* @throws IllegalArgumentException if `source` does not contain enough elements.
*/
def fromUnsafe[A](source: IterableOnce[A]): CC[A]
/** Optional extractor to get a `Seq` extracted. */
object Seq {
def unapplySeq[A](nonEmpty: CC[A]): Some[Seq[A]] = Some(nonEmpty.iterator.to(scala.Seq))
}
}
protected object NonEmptyBuilder {
protected[collection] trait Builder[A, +R] {
protected val buf = Buffer.empty[A]
def clear(): Unit = buf.clear()
def addOne(elem: A): this.type = { buf += elem; this }
def +=(elem: A): this.type = addOne(elem)
def result(it: IterableOnce[A]): R
}
protected[collection] class Unsafe[A, CC[+X] <: NonEmpty[X]](factory: NonEmptyFactory[CC]) extends Builder[A, CC[A]] {
private def from(it: IterableOnce[A]): CC[A] = factory.fromUnsafe(it).tap(_ => clear())
def result(): CC[A] = from(buf)
def result(it: IterableOnce[A]): CC[A] = from(it)
}
protected[collection] class Escaping[A, CC[+_]](factory: IterableFactory[CC]) extends Builder[A, CC[A]] {
private def from(it: IterableOnce[A]): CC[A] = factory.from(it).tap(_ => clear())
def result(): CC[A] = from(buf)
def result(it: IterableOnce[A]): CC[A] = from(it)
}
protected[collection] class Conditional[A, CC[+X] <: NonEmpty[X], SCC[+_] <: Iterable[_]](
minSize: Int,
nonEmptyFactory: NonEmptyFactory[CC],
escapingFactory: IterableFactory[SCC]
) extends Builder[A, Either[SCC[A], CC[A]]] {
require(minSize > 0)
def result(): Either[SCC[A], CC[A]] = {
if (buf.size >= minSize) Right(nonEmptyFactory.fromUnsafe(buf))
else Left(escapingFactory.from(buf))
}.tap(_ => clear())
def result(iterableOnce: IterableOnce[A]): Either[SCC[A], CC[A]] = {
def lookAhead(): (Boolean, Iterator[A]) = iterableOnce match {
case it: Iterator[A] =>
var i = 0
while (i < minSize && it.hasNext) {
buf += it.next()
i += 1
}
(i == minSize, buf.iterator ++ it)
case iterable: Iterable[A] =>
val it = iterable.iterator
var i = 0
while (i < minSize && it.hasNext)
i += 1
(i == minSize, iterable.iterator)
}
(lookAhead() match {
case (true, it) => Right(nonEmptyFactory.fromUnsafe(it))
case (false, it) => Left(escapingFactory.from(it))
}).tap(_ => clear())
}
}
}
/** Collection of at least one element.
*/
final case class OneOrMore[+A](head: A, tail: Iterable[A]) extends NonEmpty[A] with NonEmptyOps[A, OneOrMore, List] {
def iterator: Iterator[A] = Iterator.oneOrMore(head, tail)
def find(p: A => Boolean): Option[A] =
if (p(head)) Some(head)
else tail find p
def forall(p: A => Boolean): Boolean = p(head) && tail.forall(p)
def foreach[U](f: A => U): Unit = {
f(head)
tail.map(f)
}
def apply(index: Int): A =
if (index == 0) head
else apply(index, tail, 1)
def isDefinedAt(index: Int): Boolean = index == 0 || index < tail.size + 1
def size: Int = tail.size + 1
def map[B](f: A => B): OneOrMore[B] = new OneOrMore(f(head), tail.map(f))
def prepended[B >: A](elem: B): OneOrMore[B] = OneOrMore(elem, Iterable(head) concat tail)
def appended[B >: A](elem: B): OneOrMore[B] = OneOrMore(head, tail concat Iterator.single(elem))
protected def newConditionalBuilder[B]: NonEmptyBuilder.Conditional[B, OneOrMore, List] =
new NonEmptyBuilder.Conditional[B, OneOrMore, List](minSize = 1, OneOrMore, List)
protected def newEscapingBuilder[B]: NonEmptyBuilder.Escaping[B, List] =
new NonEmptyBuilder.Escaping[B, List](List)
protected def newUnsafeBuilder[B]: NonEmptyBuilder.Unsafe[B, OneOrMore] =
new NonEmptyBuilder.Unsafe[B, OneOrMore](OneOrMore)
}
object OneOrMore extends NonEmptyFactory[OneOrMore] {
/** Factory to pass elements individually. */
def apply[A](head: A, more: A*): OneOrMore[A] = OneOrMore(head, more)
/** Factory to create a `OneOrMore` containing the single element `head`. */
def one[A](head: A): OneOrMore[A] = OneOrMore(head, Nil)
/** Factory to create a `OneOrMore` containing at leas the two elements `head` and `_2`. */
def more[A](head: A, _2: A, more: A*): OneOrMore[A] = OneOrMore(head, Iterable(_2) concat more)
/** `Some[OneOrMore]` populated with the elements of `source` if it contains at least one element, otherwise `None`.
*/
def from[A](source: IterableOnce[A]): Option[OneOrMore[A]] = {
val it = source.iterator
if (it.hasNext) Some(OneOrMore(it.next(), it.toList))
else None
}
/** Creates a `OneOrMore[A]` populated with the elements of `source` in a non-safe way.
* @throws IllegalArgumentException if `source` is empty.
*/
def fromUnsafe[A](source: IterableOnce[A]): OneOrMore[A] =
from(Iterable.from(source)).getOrElse(
throw new IllegalArgumentException("empty 'source' passed to OneOrMore.fromUnsafe")
)
}
/** Collection of at least two elements.
*/
final case class Several[+A](head: A, _2: A, more: Iterable[A]) extends NonEmpty[A] with NonEmptyOps[A, Several, List] {
def iterator: Iterator[A] = Iterator.several(head, _2, more)
def find(p: A => Boolean): Option[A] =
if (p(head)) Some(head)
else if (p(_2)) Some(_2)
else more find p
def forall(p: A => Boolean): Boolean = p(head) && p(_2) && more.forall(p)
def foreach[U](f: A => U): Unit = {
f(head)
f(_2)
more.map(f)
}
def apply(index: Int): A =
if (index == 0) head
else if (index == 1) _2
else apply(index, more, 2)
def isDefinedAt(index: Int): Boolean = index == 0 || index == 1 || index < more.size + 2
def size: Int = more.size + 2
def map[B](f: A => B): Several[B] = new Several(f(head), f(_2), more.map(f))
def prepended[B >: A](elem: B): Several[B] = Several(elem, head, Iterable(_2) concat more)
def appended[B >: A](elem: B): Several[B] = Several(head, _2, more concat Iterator.single(elem))
protected def newConditionalBuilder[B]: NonEmptyBuilder.Conditional[B, Several, List] =
new NonEmptyBuilder.Conditional[B, Several, List](minSize = 2, Several, List)
protected def newEscapingBuilder[B]: NonEmptyBuilder.Escaping[B, List] =
new NonEmptyBuilder.Escaping[B, List](List)
protected def newUnsafeBuilder[B]: NonEmptyBuilder.Unsafe[B, Several] =
new NonEmptyBuilder.Unsafe[B, Several](Several)
def toOneOrMore: OneOrMore[A] = OneOrMore(head, (Iterator.single(_2) ++ more.iterator).toSeq)
}
object Several extends NonEmptyFactory[Several] {
/** Factory to pass elements individually. */
def apply[A](_1: A, _2: A, more: A*): Several[A] = Several(_1, _2, more)
/** `Some[Several]` populated with the elements of `source` if `source` contains at least two elements, otherwise `None`.
*/
def from[A](source: IterableOnce[A]): Option[Several[A]] = {
val it = source.iterator
if (it.hasNext) {
val _1 = it.next()
if (it.hasNext) {
val _2 = it.next()
Some(Several(_1, _2, it.toList))
} else None
} else None
}
/** Creates a `Several` populated with the elements of `source` in a non-safe way.
* @throws IllegalArgumentException if `iterable` has less than two elements.
*/
def fromUnsafe[A](source: IterableOnce[A]): Several[A] =
from(source).getOrElse(
throw new IllegalArgumentException(s"'source' of size ${source.iterator.size} passed to Several.fromUnsafe")
)
}
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