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BitSet.scala
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BitSet.scala
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/*
* Copyright (c) 2021 Typelevel
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package cats.parse
import java.util.BitSet
object BitSetUtil {
type Tpe = BitSet
@inline final val isScalaJs = false
@inline final val isScalaJvm = true
@inline final def isSet(b: BitSet, idx: Int): Boolean =
// BitSet can't deal with negatives, so mask those out
b.get(idx & Int.MaxValue)
// we require a sorted, nonEmpty, charArray
def bitSetFor(charArray: Array[Char]): BitSet = {
val min = charArray(0).toInt
val bs = new BitSet(charArray(charArray.length - 1).toInt + 1 - min)
var idx = 0
while (idx < charArray.length) {
bs.set(charArray(idx).toInt - min)
idx += 1
}
bs
}
def isSingleton(t: Tpe): Boolean = t.cardinality() == 1
// what are all the Chars in these bitsets
def union(bs: List[(Int, BitSet)]): Iterable[Char] = {
def toIter(m: Int, bs: BitSet): Iterator[Char] =
Iterator
.iterate(0) { m => bs.nextSetBit(m + 1) }
.takeWhile(_ >= 0)
.map { i => (m + i).toChar }
bs.iterator.flatMap { case (m, bs) => toIter(m, bs) }.toSet
}
}