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Diffstat (limited to 'src/library/scalax/collection/Iterator.scala')
| -rwxr-xr-x | src/library/scalax/collection/Iterator.scala | 965 |
1 files changed, 0 insertions, 965 deletions
diff --git a/src/library/scalax/collection/Iterator.scala b/src/library/scalax/collection/Iterator.scala deleted file mode 100755 index dc80c10f6b..0000000000 --- a/src/library/scalax/collection/Iterator.scala +++ /dev/null @@ -1,965 +0,0 @@ -/* __ *\ -** ________ ___ / / ___ Scala API ** -** / __/ __// _ | / / / _ | (c) 2003-2008, LAMP/EPFL ** -** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ ** -** /____/\___/_/ |_/____/_/ | | ** -** |/ ** -\* */ - -// $Id: Iterator.scala 15939 2008-08-26 14:33:17Z stepancheg $ - - -package scalax.collection - -import scala.collection.mutable.{Buffer, ListBuffer, ArrayBuffer} - -/** The <code>Iterator</code> object provides various functions for - * creating specialized iterators. - * - * @author Martin Odersky - * @author Matthias Zenger - * @version 2.8 - */ -object Iterator { - - val empty = new Iterator[Nothing] { - def hasNext: Boolean = false - def next(): Nothing = throw new NoSuchElementException("next on empty iterator") - } - - def apply[A](args: A*): Iterator[A] = args.asInstanceOf[Iterable[A]].elements // !!! - - /** Concatenate all the argument iterators into a single iterator. - * - * @param xss the lists that are to be concatenated - * @return the concatenation of all the lists - */ - def concat[A](xss: Iterator[A]*): Iterator[A] = - xss.asInstanceOf[Iterable[Iterator[A]]].elements.flatten // !!! - - /** An iterator that returns the same element a number of times - * @param len The number of elements returned - * @param elem The element returned each time - */ - def fill[A](len: Int)(elem: => A) = new Iterator[A] { - private var i = 0 - def hasNext: Boolean = i < len - def next(): A = - if (hasNext) { i += 1; elem } - else empty.next() - } - - /** An iterator that returns values of a function <code>f(0), ..., f(n-1)</code>, - * for given `f` and `n`. - */ - def tabulate[A](n: Int)(f: Int => A) = new Iterator[A] { - private var i = 0 - def hasNext: Boolean = i < n - def next(): A = - if (hasNext) { val result = f(i); i += 1; result } - else empty.next() - } - - /** Nn iterator with elements - * <code>e<sub>n+1</sub> = e<sub>n</sub> + 1</code> - * where <code>e<sub>0</sub> = start</code> - * and <code>e<sub>i</sub> < end</code>. However, - * if <code>start ≥ end</code>, then it will return an empty range. - * - * @param start the start value of the iterator - * @param end the end value of the iterator - * @return the iterator with values in range <code>[start;end)</code>. - */ - def range(start: Int, end: Int): Iterator[Int] = range(start, end, 1) - - /** Create an iterator with elements - * <code>e<sub>n+1</sub> = e<sub>n</sub> + step</code> - * where <code>e<sub>0</sub> = start</code> - * and elements are in the range between <code>start</code> (inclusive) - * and <code>end</code> (exclusive) - * - * @param start the start value of the iterator - * @param end the end value of the iterator - * @param step the increment value of the iterator (must be positive or negative) - * @return the iterator with values in range <code>[start;end)</code>. - */ - def range(start: Int, end: Int, step: Int) = new Iterator[Int] { - private var i = start - def hasNext: Boolean = (step <= 0 || i < end) && (step >= 0 || i > end) - def next(): Int = - if (hasNext) { val result = i; i += step; result } - else empty.next() - } - - /** An iterator that repeatedly applies a given function to a start value. - * - * @param start the start value of the iteratpr - * @param len the number of elements returned by the iterator - * @param f the function that's repeatedly applied - * @return the iterator returning values <code>(start, f(start), f(f(start)), ..., f<sup>len-1</sup>(start))</code> - */ - def iterate(start: Int, len: Int)(f: Int => Int) = new Iterator[Int] { - private var acc = start - private var i = 0 - def hasNext: Boolean = i < len - def next(): Int = - if (hasNext) { val result = f(acc); i += 1; result } - else empty.next() - } - - /** An infinite iterator that repeatedly applies a given function to a start value. - * - * @param start the start value of the iteratpr - * @param f the function that's repeatedly applied - * @return the iterator returning values <code>(start, f(start), f(f(start)), ..., f<sup>len-1</sup>(start))</code> - */ - def iterate(start: Int)(f: Int => Int) = new Iterator[Int] { - private var acc = start - private var i = 0 - def hasNext: Boolean = true - def next(): Int = { val result = f(acc); i += 1; result } - } - - /** Create an iterator with elements - * <code>e<sub>n+1</sub> = e<sub>n</sub> + 1</code> - * where <code>e<sub>0</sub> = start</code>. - * - * @param start the start value of the iterator - * @return the iterator starting at value <code>start</code>. - */ - def from(start: Int): Iterator[Int] = from(start, 1) - - /** Create an iterator with elements - * <code>e<sub>n+1</sub> = e<sub>n</sub> + step</code> - * where <code>e<sub>0</sub> = start</code>. - * - * @param start the start value of the iterator - * @param step the increment value of the iterator - * @return the iterator starting at value <code>start</code>. - */ - def from(start: Int, step: Int): Iterator[Int] = new Iterator[Int] { - private var i = 0 - def hasNext: Boolean = true - def next(): Int = { val result = i; i += 1; result } - } - - class IteratorIteratorOps[A](its: Iterator[Iterator[A]]) { - /** Create an iterator that is the concantenation of all iterators - * returned by a given iterator of iterators. - * @param its The iterator which returns on each call to next - * a new iterator whose elements are to be concatenated to the result. - */ - def flatten: Iterator[A] = new Iterator[A] { - private var it = its.next - def hasNext: Boolean = { - while (!it.hasNext && its.hasNext) it = its.next - it.hasNext - } - def next(): A = - if (hasNext) it.next - else empty.next() - } - } - - implicit def iteratorIteratorWrapper[A](its: Iterator[Iterator[A]]): IteratorIteratorOps[A] = - new IteratorIteratorOps[A](its) - - /** - * @param x the element - * @return the iterator with one single element - * @deprecated use Iterator(x) instead - */ - @deprecated def single[a](x: a) = new Iterator[a] { - private var hasnext = true - def hasNext: Boolean = hasnext - def next(): a = - if (hasnext) { hasnext = false; x } - else empty.next() - } - - /** @deprecated use `xs.elements` instead - */ - @deprecated def fromValues[a](xs: a*) = xs.elements - - /** - * @param xs the array of elements - * @see also: RandomAccessSeq.elements and slice - * @deprecated use `xs.elements` instead - */ - @deprecated def fromArray[a](xs: Array[a]): Iterator[a] = - fromArray(xs, 0, xs.length) - - /** - * @param xs the array of elements - * @param start the start index - * @param length the length - * @see also: RandomAccessSeq.elements and slice - * @deprecated use `xs.slice(start, start + length).elements` instead - */ - @deprecated def fromArray[a](xs: Array[a], start: Int, length: Int): Iterator[a] = - xs.slice(start, start + length).elements.asInstanceOf[Iterator[a]] // !!! - - /** - * @param str the given string - * @return the iterator on <code>str</code> - * @deprecated replaced by <code>str.elements</code> - */ - @deprecated def fromString(str: String): Iterator[Char] = - str.elements.asInstanceOf[Iterator[Char]] // !!! - - /** - * @param n the product arity - * @return the iterator on <code>Product<n></code>. - * @deprecated use product.productElements instead - */ - @deprecated def fromProduct(n: Product): Iterator[Any] = new Iterator[Any] { - private var c: Int = 0 - private val cmax = n.productArity - def hasNext = c < cmax - def next() = { val a = n productElement c; c += 1; a } - } - - /** Create an iterator with elements - * <code>e<sub>n+1</sub> = step(e<sub>n</sub>)</code> - * where <code>e<sub>0</sub> = start</code> - * and elements are in the range between <code>start</code> (inclusive) - * and <code>end</code> (exclusive) - * - * @param start the start value of the iterator - * @param end the end value of the iterator - * @param step the increment function of the iterator, must be monotonically increasing or decreasing - * @return the iterator with values in range <code>[start;end)</code>. - * @deprecated use Iterator.iterate(start, end - start)(step) instead - */ - @deprecated def range(start: Int, end: Int, step: Int => Int) = new Iterator[Int] { - private val up = step(start) > start - private val down = step(start) < start - private var i = start - def hasNext: Boolean = (!up || i < end) && (!down || i > end) - def next(): Int = - if (hasNext) { val j = i; i = step(i); j } - else empty.next() - } - - /** Create an iterator with elements - * <code>e<sub>n+1</sub> = step(e<sub>n</sub>)</code> - * where <code>e<sub>0</sub> = start</code>. - * - * @param start the start value of the iterator - * @param step the increment function of the iterator - * @return the iterator starting at value <code>start</code>. - * @deprecated use iterate(start)(step) instead - */ - @deprecated def from(start: Int, step: Int => Int): Iterator[Int] = new Iterator[Int] { - private var i = start - override def hasNext: Boolean = true - def next(): Int = { val j = i; i = step(i); j } - } - - /** Create an iterator that is the concantenation of all iterators - * returned by a given iterator of iterators. - * @param its The iterator which returns on each call to next - * a new iterator whose elements are to be concatenated to the result. - * @deprecated use its.flatten instead - */ - @deprecated def flatten[T](its: Iterator[Iterator[T]]): Iterator[T] = new Iterator[T] { - private var it = its.next - def hasNext: Boolean = { - while (!it.hasNext && its.hasNext) it = its.next - it.hasNext - } - def next(): T = - if (hasNext) it.next - else empty.next() - } -} - -import Iterator.empty - -/** Iterators are data structures that allow to iterate over a sequence - * of elements. They have a <code>hasNext</code> method for checking - * if there is a next element available, and a <code>next</code> method - * which returns the next element and discards it from the iterator. - * - * @author Martin Odersky, Matthias Zenger - * @version 2.8 - */ -trait Iterator[+A] { -self => - - /** Does this iterator provide another element? - */ - def hasNext: Boolean - - /** Returns the next element. - */ - def next(): A - - /** Returns a new iterator that iterates only over the first <code>n</code> - * elements. - * - * @param n the number of elements to take - * @return the new iterator - */ - def take(n: Int): Iterator[A] = new Iterator[A] { - private var remaining = n - def hasNext = remaining > 0 && self.hasNext - def next(): A = - if (hasNext) { remaining -= 1; self.next } - else throw new NoSuchElementException("next on empty iterator") - } - - /** Removes the first <code>n</code> elements from this iterator. - * - * @param n the number of elements to drop - * @return the new iterator - */ - def drop(n: Int): Iterator[A] = - if (n > 0 && hasNext) { next(); drop(n - 1) } else this - - /** A sub-iterator of <code>until - from elements - * starting at index <code>from</code> - * - * @param from The index of the first element of the slice - * @param until The index of the element following the slice - */ - def slice(from: Int, until: Int): Iterator[A] = drop(from).take(until - from) - - /** Returns a new iterator that maps all elements of this iterator - * to new elements using function <code>f</code>. - */ - def map[B](f: A => B): Iterator[B] = new Iterator[B] { - def hasNext = self.hasNext - def next() = f(self.next()) - } - - /** Returns a new iterator that first yields the elements of this - * iterator followed by the elements provided by iterator <code>that</code>. - * @deprecated use <code>++</code> - */ - def append[B >: A](that: Iterator[B]) = new Iterator[B] { - def hasNext = self.hasNext || that.hasNext - def next() = (if (self.hasNext) self else that).next() - } - - /** Returns a new iterator that first yields the elements of this - * iterator followed by the elements provided by iterator <code>that</code>. - */ - def ++[B >: A](that: => Iterator[B]) = new Iterator[B] { - // optimize a little bit to prevent n log n behavior. - var cur : Iterator[B] = self - def hasNext = cur.hasNext || (cur eq self) && { cur = that; hasNext } - def next() = { hasNext; cur.next } - } - - /** Applies the given function <code>f</code> to each element of - * this iterator, then concatenates the results. - * - * @param f the function to apply on each element. - * @return an iterator over <code>f(a<sub>0</sub>), ... , - * f(a<sub>n</sub>)</code> if this iterator yields the - * elements <code>a<sub>0</sub>, ..., a<sub>n</sub></code>. - */ - def flatMap[B](f: A => Iterator[B]): Iterator[B] = new Iterator[B] { - private var cur: Iterator[B] = empty - def hasNext: Boolean = - cur.hasNext || self.hasNext && { cur = f(self.next); hasNext } - def next(): B = (if (hasNext) cur else empty).next() - } - - /** Returns an iterator over all the elements of this iterator that - * satisfy the predicate <code>p</code>. The order of the elements - * is preserved. - * - * @param p the predicate used to filter the iterator. - * @return the elements of this iterator satisfying <code>p</code>. - */ - def filter(p: A => Boolean): Iterator[A] = { - val self = buffered - new Iterator[A] { - private def skip() = while (self.hasNext && !p(self.head)) self.next() - def hasNext = { skip(); self.hasNext } - def next() = { skip(); self.next() } - } - } - - /** Returns an iterator over the longest prefix of this iterator such that - * all elements of the result satisfy the predicate <code>p</code>. - * The order of the elements is preserved. - * - * The behavior of <code>this</code> iterator is undefined after this method invocation. - * - * @param p the predicate used to filter the iterator. - * @return the longest prefix of this iterator satisfying <code>p</code>. - */ - def takeWhile(p: A => Boolean): Iterator[A] = { - val self = buffered - new Iterator[A] { - def hasNext = { self.hasNext && p(self.head) } - def next() = (if (hasNext) self else empty).next() - } - } - - /** Partitions this iterator in two iterators according to a predicate. - * - * @param p the predicate on which to partition - * @return a pair of iterators: the iterator that satisfies the predicate - * <code>p</code> and the iterator that does not. - * The relative order of the elements in the resulting iterators - * is the same as in the original iterator. - */ - def partition(p: A => Boolean): (Iterator[A], Iterator[A]) = { - val self = buffered - class PartitionIterator(p: A => Boolean) extends Iterator[A] { - var other: PartitionIterator = _ - val lookahead = new scala.collection.mutable.Queue[A] - def skip() = - while (self.hasNext && !p(self.head)) { - other.lookahead += self.next - } - def hasNext = !lookahead.isEmpty || self.hasNext - def next() = if (lookahead.isEmpty) self.next() else lookahead.dequeue() - } - val l = new PartitionIterator(p) - val r = new PartitionIterator(!p(_)) - l.other = r - r.other = l - (l, r) - } - - /** Skips longest sequence of elements of this iterator which satisfy given - * predicate <code>p</code>, and returns an iterator of the remaining elements. - * - * The behavior of <code>this</code> iterator is undefined after this method invocation. - * - * @param p the predicate used to skip elements. - * @return an iterator consisting of the remaining elements - */ - def dropWhile(p: A => Boolean): Iterator[A] = { - val self = buffered - new Iterator[A] { - var dropped = false - private def skip() = - if (!dropped) { - while (self.hasNext && p(self.head)) self.next() - dropped = true - } - def hasNext = { skip(); self.hasNext } - def next() = { skip(); self.next() } - } - } - - /** Return an iterator formed from this iterator and the specified iterator - * <code>that</code> by associating each element of the former with - * the element at the same position in the latter. - * If one of the two iterators is longer than the other, its remaining elements are ignored. - * - * @return an iterator yielding <code>{a<sub>0</sub>,b<sub>0</sub>}, - * {a<sub>1</sub>,b<sub>1</sub>}, ...</code> where - * <code>a<sub>i</sub></code> are the elements from this iterator - * and <code>b<sub>i</sub></code> are the elements from iterator - * <code>that</code>. - */ - def zip[B](that: Iterator[B]) = new Iterator[(A, B)] { - def hasNext = self.hasNext && that.hasNext - def next = (self.next, that.next) - } - - /** Return an iterator that pairs each element of this iterator - * with its index, counting from 0. - * - * @return an iterator yielding <code>{a<sub>0</sub>,0}, - * {a<sub>1</sub>,1}...</code> where <code>a<sub>i</sub></code> - * are the elements from this iterator. - */ - def zipWithIndex = new Iterator[(A, Int)] { - var idx = 0 - def hasNext = self.hasNext - def next = { - val ret = (self.next, idx) - idx += 1 - ret - } - } - - /** Returns an iterator formed from this iterator and the specified iterator - * <code>that</code> by associating each element of the former with - * the element at the same position in the latter. - * - * @param that iterator <code>that</code> may have a different length - * as the self iterator. - * @param thisElem element <code>thisElem</code> is used to fill up the - * resulting iterator if the self iterator is shorter than - * <code>that</code> - * @param thatElem element <code>thatElem</code> is used to fill up the - * resulting iterator if <code>that</code> is shorter than - * the self iterator - * @return <code>Iterator((a<sub>0</sub>,b<sub>0</sub>), ..., - * (a<sub>n</sub>,b<sub>n</sub>), (elem,b<sub>n+1</sub>), - * ..., {elem,b<sub>m</sub>})</code> - * when <code>[a<sub>0</sub>, ..., a<sub>n</sub>] zip - * [b<sub>0</sub>, ..., b<sub>m</sub>]</code> is - * invoked where <code>m > n</code>. - */ - def zipAll[B, A1 >: A, B1 >: B](that: Iterator[B], thisElem: A1, thatElem: B1) = new Iterator[(A1, B1)] { - def hasNext = self.hasNext || that.hasNext - def next(): (A1, B1) = - if (self.hasNext) { - if (that.hasNext) (self.next(), that.next()) - else (self.next(), thatElem) - } else { - if (that.hasNext) (thisElem, that.next()) - else empty.next() - } - } - - /** Apply a function <code>f</code> to all elements of this - * iterable object. - * - * @param f a function that is applied to every element. - */ - def foreach(f: A => Unit) { while (hasNext) f(next()) } - - /** Apply a predicate <code>p</code> to all elements of this - * iterable object and return <code>true</code> iff the predicate yields - * <code>true</code> for all elements. - * - * @param p the predicate - * @return <code>true</code> iff the predicate yields <code>true</code> - * for all elements. - */ - def forall(p: A => Boolean): Boolean = { - var res = true - while (res && hasNext) res = p(next()) - res - } - - /** Apply a predicate <code>p</code> to all elements of this - * iterable object and return true, iff there is at least one - * element for which <code>p</code> yields <code>true</code>. - * - * @param p the predicate - * @return <code>true</code> iff the predicate yields <code>true</code> - * for at least one element. - */ - def exists(p: A => Boolean): Boolean = { - var res = false - while (!res && hasNext) res = p(next()) - res - } - - /** Tests if the given value <code>elem</code> is a member of this iterator. - * - * @param elem element whose membership has to be tested. - * @return <code>true</code> iff there is an element of this iterator which - * is equal (w.r.t. <code>==</code>) to <code>elem</code>. - */ - def contains(elem: Any): Boolean = exists { _ == elem } - - /** Find and return the first element of the iterable object satisfying a - * predicate, if any. - * - * @param p the predicate - * @return the first element in the iterable object satisfying - * <code>p</code>, or <code>None</code> if none exists. - */ - def find(p: A => Boolean): Option[A] = { - var res: Option[A] = None - while (res.isEmpty && hasNext) { - val e = next() - if (p(e)) res = Some(e) - } - res - } - - /** Returns index of the first element satisying a predicate, or -1. - * - * @note may not terminate for infinite-sized collections. - * @param p the predicate - * @return the index of the first element satisfying <code>p</code>, - * or -1 if such an element does not exist - */ - def indexWhere(p: A => Boolean): Int = { - var i = 0 - var found = false - while (!found && hasNext) { - if (p(next())) { - found = true - } else { - i += 1 - } - } - if (found) i else -1 - } - - /** Returns index of the first element satisying a predicate, or -1. - * - * @deprecated use `indexWhere` instead - */ - @deprecated def findIndexOf(p: A => Boolean): Int = indexWhere(p) - - /** Returns the index of the first occurence of the specified - * object in this iterable object. - * - * @note may not terminate for infinite-sized collections. - * @param elem element to search for. - * @return the index in this sequence of the first occurence of the - * specified element, or -1 if the sequence does not contain - * this element. - */ - def indexOf[B >: A](elem: B): Int = { - var i = 0 - var found = false - while (!found && hasNext) { - if (next() == elem) { - found = true - } else { - i += 1 - } - } - if (found) i else -1 - } - - /** Combines the elements of this iterator together using the binary - * operator <code>op</code>, from left to right, and starting with - * the value <code>z</code>. - * - * @return <code>op(... (op(op(z,a<sub>0</sub>),a<sub>1</sub>) ...), - * a<sub>n</sub>)</code> if the iterator yields elements - * <code>a<sub>0</sub>, a<sub>1</sub>, ..., a<sub>n</sub></code>. - */ - def foldLeft[B](z: B)(op: (B, A) => B): B = { - var acc = z - while (hasNext) acc = op(acc, next()) - acc - } - - /** Combines the elements of this iterator together using the binary - * operator <code>op</code>, from right to left, and starting with - * the value <code>z</code>. - * - * @return <code>a<sub>0</sub> op (... op (a<sub>n</sub> op z)...)</code> - * if the iterator yields elements <code>a<sub>0</sub>, a<sub>1</sub>, ..., - * a<sub>n</sub></code>. - */ - def foldRight[B](z: B)(op: (A, B) => B): B = { - def fold(z: B): B = if (hasNext) op(next(), fold(z)) else z - fold(z) - } - - /** Similar to <code>foldLeft</code> but can be used as - * an operator with the order of iterator and zero arguments reversed. - * That is, <code>z /: xs</code> is the same as <code>xs foldLeft z</code>. - * - * @param z the left argument of the first application of <code>op</code> - * (evaluation occurs from left to right). - * @param op the applied operator. - * @return the result value - * @see <code><a href="#foldLeft">foldLeft</a></code>. - */ - def /:[B](z: B)(op: (B, A) => B): B = foldLeft(z)(op) - - /** An alias for <code>foldRight</code>. - * That is, <code>xs :\ z</code> is the same as <code>xs foldRight z</code>. - * - * @param z the right argument of the first application of <code>op</code> - * (evaluation occurs from right to left). - * @param op the applied operator. - * @return the result value. - * @see <code><a href="#foldRight">foldRight</a></code>. - */ - def :\[B](z: B)(op: (A, B) => B): B = foldRight(z)(op) - - /** Combines the elements of this iterator together using the binary - * operator <code>op</code>, from left to right - * @param op The operator to apply - * @return <code>op(... op(a<sub>0</sub>,a<sub>1</sub>), ..., a<sub>n</sub>)</code> - if the iterator yields elements - * <code>a<sub>0</sub>, a<sub>1</sub>, ..., a<sub>n</sub></code>. - * @throws Predef.UnsupportedOperationException if the iterator is empty. - */ - def reduceLeft[B >: A](op: (B, A) => B): B = { - if (hasNext) foldLeft[B](next())(op) - else throw new UnsupportedOperationException("empty.reduceLeft") - } - - /** Combines the elements of this iterator together using the binary - * operator <code>op</code>, from right to left - * @param op The operator to apply - * - * @return <code>a<sub>0</sub> op (... op (a<sub>n-1</sub> op a<sub>n</sub>)...)</code> - * if the iterator yields elements <code>a<sub>0</sub>, a<sub>1</sub>, ..., - * a<sub>n</sub></code>. - - * @throws Predef.UnsupportedOperationException if the iterator is empty. - */ - def reduceRight[B >: A](op: (A, B) => B): B = { - if (!hasNext) throw new UnsupportedOperationException("empty.reduceRight") - foldRight[B](next())(op) - } - - /** Returns a buffered iterator from this iterator. - */ - def buffered = new BufferedIterator[A] { - private var hd: A = _ - private var hdDefined: Boolean = false - - def head: A = { - if (!hdDefined) { - hd = next() - hdDefined = true - } - hd - } - - def hasNext = - hdDefined || self.hasNext - - def next = - if (hdDefined) { - hdDefined = false - hd - } else self.next - } - - /** Returns a counted iterator from this iterator. - * @deprecated use @see zipWithIndex in Iterator - */ - @deprecated def counted = new CountedIterator[A] { - private var cnt = -1 - def count = cnt - def hasNext: Boolean = self.hasNext - def next(): A = { cnt += 1; self.next } - } - - /** Creates two new iterators that both iterate over the same elements - * than this iterator (in the same order). - * - * @return a pair of iterators - */ - def duplicate: (Iterator[A], Iterator[A]) = { - var xs: List[A] = Nil - var ahead: Iterator[A] = null - class Partner extends Iterator[A] { - var ys: List[A] = Nil - def hasNext: Boolean = self.synchronized ( - ((this == ahead) && self.hasNext) || - ((this != ahead) && (!xs.isEmpty || !ys.isEmpty || self.hasNext)) - ) - def next(): A = self.synchronized { - if (this == ahead) { - val e = self.next() - xs = e :: xs; e - } else { - if (ys.isEmpty) { - ys = xs.reverse - xs = Nil - } - ys match { - case Nil => - val e = self.next() - ahead = this - xs = e :: xs; e - case z :: zs => - ys = zs; z - } - } - } - } - ahead = new Partner - (ahead, new Partner) - } - - def patch[B >: A](from: Int, ps: Seq[B], replaced: Int) = new Iterator[B] { - private val plen = ps.length - private var origElems = self - private val patchElems = ps.elements - private var i = 0 - def hasNext: Boolean = - if (i < from) origElems.hasNext - else patchElems.hasNext || origElems.hasNext - def next(): B = { - val result: B = - if (i < from || i >= from + plen) origElems.next() - else patchElems.next() - i += 1 - if (i == from) origElems = origElems drop replaced - result - } - } - - /** Fills the given array <code>xs</code> with at most `len` elements of - * this iterator starting at position `start`. - * Copying will stop once either the end of the current iterable is reached or - * `len` elements have been copied. - * - * @param xs the array to fill. - * @param start starting index. - * @param len number of elements to copy - * @pre the array must be large enough to hold all elements. - */ - def copyToArray[B >: A](xs: Array[B], start: Int, len: Int): Unit = { - var i = start - val end = start + len - while (hasNext && i < end) { - xs(i) = next() - i += 1 - } - } - - /** Fills the given array <code>xs</code> with the elements of - * this iterator starting at position <code>start</code> - * until either the end of the current iterator or the end of array `xs` is reached. - * - * @param xs the array to fill. - * @param start starting index. - * @pre the array must be large enough to hold all elements. - */ - def copyToArray[B >: A](xs: Array[B], start: Int): Unit = - copyToArray(xs, start, xs.length - start) - - /** Fills the given array <code>xs</code> with the elements of - * this iterator starting at position <code>0</code> - * until either the end of the current iterator or the end of array `xs` is reached. - * - * @param xs the array to fill. - * @pre the array must be large enough to hold all elements. - */ - def copyToArray[B >: A](xs: Array[B]): Unit = copyToArray(xs, 0, xs.length) - - /** Fills the given array <code>xs</code> with the elements of - * this sequence starting at position <code>start</code>. Like <code>copyToArray</code>, - * but designed to accomodate IO stream operations. - * - * @param xs the array to fill. - * @param start the starting index. - * @param sz the maximum number of elements to be read. - * @pre the array must be large enough to hold <code>sz</code> elements. - * @deprecated use copyToArray instead - */ - @deprecated def readInto[B >: A](xs: Array[B], start: Int, sz: Int) { - var i = start - while (hasNext && i - start < sz) { - xs(i) = next - i += 1 - } - } - @deprecated def readInto[B >: A](xs: Array[B], start: Int) { - readInto(xs, start, xs.length - start) - } - @deprecated def readInto[B >: A](xs: Array[B]) { - readInto(xs, 0, xs.length) - } - - /** Copy all elements to a buffer - * @param The buffer to which elements are copied - */ - def copyToBuffer[B >: A](dest: Buffer[B]) { - while (hasNext) dest += next - } - - /** Transform this iterator into a list of all elements. - * - * @return a list which enumerates all elements of this iterator. - */ - def toList: List[A] = { - val res = new ListBuffer[A] - while (hasNext) res += next - res.toList - } - - /** - * Create a stream which contains all the elements of this iterator. - */ - def toStream: Stream[A] = - if (hasNext) Stream.cons(next, toStream) else Stream.empty - - /** - * Create a sequence which contains all the elements of this iterator. - */ - def toSeq: Seq[A] = { - val buffer = new ArrayBuffer[A] - this copyToBuffer buffer - buffer.readOnly - } - - /** Collect elements into a seq. - * - * @return a sequence which enumerates all elements of this iterator. - * @deprecated use toSeq instead - */ - @deprecated def collect: Seq[A] = { - val buffer = new ArrayBuffer[A] - this copyToBuffer buffer - buffer.readOnly - } - - /** Returns a string representation of the elements in this iterator. The resulting string - * begins with the string <code>start</code> and is finished by the string - * <code>end</code>. Inside, the string representations of elements (w.r.t. - * the method <code>toString()</code>) are separated by the string - * <code>sep</code>. - * <p/> - * Ex: <br/> - * <code>List(1, 2, 3).mkString("(", "; ", ")") = "(1; 2; 3)"</code> - * - * @param start starting string. - * @param sep separator string. - * @param end ending string. - * @return a string representation of this iterable object. - */ - def mkString(start: String, sep: String, end: String): String = { - val buf = new StringBuilder - addString(buf, start, sep, end).toString - } - - /** Returns a string representation of this iterable object. The string - * representations of elements (w.r.t. the method <code>toString()</code>) - * are separated by the string <code>sep</code>. - * - * @param sep separator string. - * @return a string representation of this iterable object. - */ - def mkString(sep: String): String = this.mkString("", sep, "") - - /** Returns a string representation of this iterable object. The string - * representations of elements (w.r.t. the method <code>toString()</code>) - * are separated by a comma. - * - * @return a string representation of this iterable object. - */ - def mkString: String = - mkString("") - - /** Write all elements of this iterator into given string builder. - * The written text begins with the string <code>start</code> and is finished by the string - * <code>end</code>. Inside, the string representations of elements (w.r.t. - * the method <code>toString()</code>) are separated by the string - * <code>sep</code>. - */ - def addString(buf: StringBuilder, start: String, sep: String, end: String): StringBuilder = { - buf.append(start) - val elems = this - if (elems.hasNext) buf.append(elems.next) - while (elems.hasNext) { - buf.append(sep); buf.append(elems.next) - } - buf.append(end) - } - - /** Write all elements of this iterator into given string builder. - * The string representations of elements (w.r.t. the method <code>toString()</code>) - * are separated by the string <code>sep</code>. - */ - def addString(buf: StringBuilder, sep: String): StringBuilder = - addString(buf, "", sep, "") - - /** Write all elements of this string into given string builder without using - * any separator between consecutive elements. - */ - def addString(buf: StringBuilder): StringBuilder = - addString(buf, "", "", "") - - override def toString = (if (hasNext) "non-empty" else "empty")+" iterator" - -} |