1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
|
/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2003-2009, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
// $Id: Sequence.scala 16092 2008-09-12 10:37:06Z nielsen $
package scalax.collection.generic
import util.control.Breaks._
import annotation.unchecked.uncheckedVariance
import Sequence._
/** A non-strict projection of an iterable.
* @author Sean McDirmid
* @author Martin Odersky
* @note this should really be a virtual class of SequenceFactory
*/
trait SequenceView[+UC[/*+*/B] <: Sequence[B], /*+*/A] extends IterableView[UC, A] with Sequence[A] {
self =>
/** refined from Iterable.View */
val origin: Sequence[_]
override def newBuilder[A] = underlying.newBuilder[A].asInstanceOf[Builder[Sequence, A]]
trait Transformed[/*+*/B] extends SequenceView[UC, B] {
val origin = self
protected def asCC = asInstanceOf[SequenceView[UC, B]]
}
class Appended[/*+*/B >: A](that: Sequence[B]) extends Transformed[B] {
override def elements: Iterator[B] = self.elements ++ that.elements
override def length: Int = self.length + that.length
override def apply(idx: Int): B = {
val ll = self.length
if (idx < ll) self.apply(idx) else that.apply(idx - ll)
}
override def stringPrefix = self.stringPrefix + "A"
}
class Sliced(from: Int, to: Int) extends Transformed[A] {
override def elements: Iterator[A] = self.elements slice (from, to)
override lazy val length: Int = ((to min self.length) - (from max 0) min 0)
override def apply(idx: Int): A =
if (idx >= 0 && idx < length) self.apply(idx + from)
else throw new IndexOutOfBoundsException(idx.toString)
override def stringPrefix = self.stringPrefix + "S"
override def slice(from1: Int, to1: Int) =
new self.Sliced(from + (from1 min length max 0) , to + (to1 min length max 0)).asInstanceOf[SequenceView[UC, A]]
}
class Mapped[/*+*/B](f: A => B) extends Transformed[B] {
override def elements: Iterator[B] = self.elements map f
override def length: Int = self.length
override def apply(idx: Int): B = f(self.apply(idx))
override def stringPrefix = self.stringPrefix + "M"
}
class Reversed extends Transformed[A] {
override def elements: Iterator[A] = self.reversedElements
override def length: Int = self.length
override def apply(idx: Int): A = self.apply(length - 1 - idx)
override def stringPrefix = super.stringPrefix+"R"
}
class Patched[/*+*/B >: A](from: Int, patch: Sequence[B], replaced: Int) extends Transformed[B] {
val plen = patch.length
override def elements: Iterator[B] = self.elements patch (from, patch, replaced)
override def length: Int = self.length + plen - replaced
override def apply(idx: Int): B =
if (idx < from) self.apply(idx)
else if (idx < from + plen) patch.apply(idx - from)
else self.apply(idx - plen + replaced)
override def stringPrefix = super.stringPrefix+"P"
}
class Zipped[/*+*/B](that: Sequence[B]) extends Transformed[(A, B)] {
override def elements: Iterator[(A, B)] = self.elements zip that.elements
override def length = self.length min that.length
override def apply(idx: Int): (A, B) = (self.apply(idx), that.apply(idx))
override def stringPrefix = super.stringPrefix+"Z"
}
override def ++[B >: A](that: Iterable[B]): SequenceView[UC, B] =
new Appended[B](that.toSequence).asCC
override def ++[B >: A](that: Iterator[B]): SequenceView[UC, B] =
new Appended[B](that.toSequence).asCC
override def map[B](f: A => B): SequenceView[UC, B] =
new Mapped(f).asCC
override def reverse: SequenceView[UC, A] =
(new Reversed).asCC
def patch[B >: A](from: Int, patch: Sequence[B], replaced: Int): SequenceView[UC, B] =
if (0 <= from && from < length) new Patched(from, patch, replaced).asCC
else throw new IndexOutOfBoundsException(from.toString)
override def padTo[B >: A](len: Int, elem: B): SequenceView[UC, B] =
patch(length, fill((len - length) max 0)(elem), 0)
override def zip[B](that: Iterable[B]): SequenceView[UC, (A, B)] =
new Zipped(that.toSequence).asCC
override def zipWithIndex: SequenceView[UC, (A, Int)] =
zip((0 until length).asInstanceOf[Null]) // !@!
/*
override def zipAll[B, A1 >: A, B1 >: B](that: Iterable[B], thisElem: A1, thatElem: B1): SequenceView[UC, (A1, B1)] = {
val that1 = that.toSequence
self.padTo(that1.length, thisElem) zip that1.padTo(this.length, thatElem)//.asInstanceOf[SequenceView[UC, (A1, B1)]]
}*/
override def take(n: Int): SequenceView[UC, A] =
slice(0, n)
override def drop(n: Int): SequenceView[UC, A] =
slice(n, Math.MAX_INT)
override def splitAt(n: Int): (SequenceView[UC, A], SequenceView[UC, A]) = (take(n), drop(n))
override def slice(from: Int, until: Int): SequenceView[UC, A] =
new Sliced(from, until).asCC
override def takeWhile(p: A => Boolean): SequenceView[UC, A] =
take(prefixLength(p))
override def dropWhile(p: A => Boolean): SequenceView[UC, A] =
drop(prefixLength(p))
override def span(p: A => Boolean): (SequenceView[UC, A], SequenceView[UC, A]) = {
val n = prefixLength(p)
(take(n), drop(n))
}
// missing here because we can't do anything about them, so we fall back to default construction
// if an IterableView via newView: flatMap, filter, partition
}
|