monix.execution.atomic.AtomicChar.scala Maven / Gradle / Ivy
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/*
* Copyright (c) 2014-2019 by The Monix Project Developers.
* See the project homepage at: https://monix.io
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package monix.execution.atomic
import monix.execution.atomic.PaddingStrategy.NoPadding
import monix.execution.internal.atomic.{BoxedInt, Factory}
/** Atomic references wrapping `Char` values.
*
* Note that the equality test in `compareAndSet` is value based,
* since `Char` is a primitive.
*/
final class AtomicChar private (private[this] val ref: BoxedInt) extends AtomicNumber[Char] {
private[this] val mask = 255 + 255 * 256
def get(): Char = (ref.volatileGet() & mask).asInstanceOf[Char]
def set(update: Char): Unit = ref.volatileSet(update)
def lazySet(update: Char): Unit =
ref.lazySet(update)
def compareAndSet(expect: Char, update: Char): Boolean =
ref.compareAndSet(expect, update)
def getAndSet(update: Char): Char =
(ref.getAndSet(update) & mask).asInstanceOf[Char]
def increment(v: Int = 1): Unit =
ref.getAndAdd(v)
def add(v: Char): Unit =
ref.getAndAdd(v)
def incrementAndGet(v: Int = 1): Char =
((ref.getAndAdd(v) + v) & mask).asInstanceOf[Char]
def addAndGet(v: Char): Char =
((ref.getAndAdd(v) + v) & mask).asInstanceOf[Char]
def getAndIncrement(v: Int = 1): Char =
(ref.getAndAdd(v) & mask).asInstanceOf[Char]
def getAndAdd(v: Char): Char =
(ref.getAndAdd(v) & mask).asInstanceOf[Char]
def subtract(v: Char): Unit =
ref.getAndAdd(-v.asInstanceOf[Int])
def subtractAndGet(v: Char): Char =
((ref.getAndAdd(-v.asInstanceOf[Int]) - v) & mask).asInstanceOf[Char]
def getAndSubtract(v: Char): Char =
(ref.getAndAdd(-v.asInstanceOf[Int]) & mask).asInstanceOf[Char]
def decrement(v: Int = 1): Unit = increment(-v)
def decrementAndGet(v: Int = 1): Char = incrementAndGet(-v)
def getAndDecrement(v: Int = 1): Char = getAndIncrement(-v)
}
/** @define createDesc Constructs an [[AtomicChar]] reference, allowing
* for fine-tuning of the created instance.
*
* A [[PaddingStrategy]] can be provided in order to counter
* the "false sharing" problem.
*
* Note that for ''Scala.js'' we aren't applying any padding,
* as it doesn't make much sense, since Javascript execution
* is single threaded, but this builder is provided for
* syntax compatibility anyway across the JVM and Javascript
* and we never know how Javascript engines will evolve.
*/
object AtomicChar {
/** Builds an [[AtomicChar]] reference.
*
* @param initialValue is the initial value with which to initialize the atomic
*/
def apply(initialValue: Char): AtomicChar =
withPadding(initialValue, NoPadding)
/** $createDesc
*
* @param initialValue is the initial value with which to initialize the atomic
* @param padding is the [[PaddingStrategy]] to apply
*/
def withPadding(initialValue: Char, padding: PaddingStrategy): AtomicChar =
create(initialValue, padding, allowPlatformIntrinsics = true)
/** $createDesc
*
* Also this builder on top Java 8 also allows for turning off the
* Java 8 intrinsics, thus forcing usage of CAS-loops for
* `getAndSet` and for `getAndAdd`.
*
* @param initialValue is the initial value with which to initialize the atomic
* @param padding is the [[PaddingStrategy]] to apply
* @param allowPlatformIntrinsics is a boolean parameter that specifies whether
* the instance is allowed to use the Java 8 optimized operations
* for `getAndSet` and for `getAndAdd`
*/
def create(initialValue: Char, padding: PaddingStrategy, allowPlatformIntrinsics: Boolean): AtomicChar = {
new AtomicChar(
Factory.newBoxedInt(
initialValue,
boxStrategyToPaddingStrategy(padding),
true, // allowUnsafe
allowPlatformIntrinsics
))
}
/** $createDesc
*
* This builder guarantees to construct a safe atomic reference that
* does not make use of `sun.misc.Unsafe`. On top of platforms that
* don't support it, notably some versions of Android or on top of
* the upcoming Java 9, this might be desirable.
*
* NOTE that explicit usage of this builder is not usually necessary
* because [[create]] can auto-detect whether the underlying platform
* supports `sun.misc.Unsafe` and if it does, then its usage is
* recommended, because the "safe" atomic instances have overhead.
*
* @param initialValue is the initial value with which to initialize the atomic
* @param padding is the [[PaddingStrategy]] to apply
*/
def safe(initialValue: Char, padding: PaddingStrategy): AtomicChar = {
new AtomicChar(
Factory.newBoxedInt(
initialValue,
boxStrategyToPaddingStrategy(padding),
false, // allowUnsafe
false // allowJava8Intrinsics
))
}
}