Native-Specific Overrides

package scala.collection.immutable

/* private[immutable] */ object VM {
  /**
   * Performs a release memory fence operation using native atomic operations.
   * Ensures that all memory operations before this fence are visible to other threads
   * before any memory operations after the fence.
   * 
   * Used internally by immutable collections for thread-safe operations.
   * Implementation: atomic_thread_fence(memory_order_release)
   */
  def releaseFence(): Unit
}

import scala.collection.immutable.VM

// Used internally by collections, but can be called directly for custom thread-safe operations
class ThreadSafeCounter {
  @volatile private var count = 0
  
  def increment(): Unit = {
    count += 1
    VM.releaseFence() // Ensure visibility to other threads
  }
  
  def get(): Int = count
}

abstract class Enumeration(initial: Int) extends Serializable {
  /**
   * Creates an enumeration starting from id 0.
   */
  def this(): Enumeration
  
  /**
   * The values of this enumeration as a set.
   * @return ValueSet containing all defined enumeration values
   */
  def values: ValueSet
  
  /**
   * Returns the enumeration value with the given id.
   * @param x the id of the value
   * @return the enumeration value
   * @throws NoSuchElementException if no value with given id exists
   */
  def apply(x: Int): Value
  
  /**
   * Returns the enumeration value with the given name.
   * @param s the name of the value
   * @return the enumeration value
   * @throws NoSuchElementException if no value with given name exists
   */
  def withName(s: String): Value
  
  /**
   * The highest integer amongst those used to identify values in this enumeration.
   * @return the maximum id used
   */
  def maxId: Int
  
  /**
   * Returns the string representation of this enumeration (the class name).
   * @return the class name without package and $ suffix
   */
  override def toString: String
  
  /**
   * Creates a fresh value, part of this enumeration, with auto-generated id.
   * @return new enumeration value
   */
  protected def Value: Value
  
  /**
   * Creates a fresh value with specified id.
   * @param i unique identifier for this value
   * @return new enumeration value
   */
  protected def Value(i: Int): Value
  
  /**
   * Creates a fresh value with specified name.
   * @param name human-readable name for this value
   * @return new enumeration value
   */
  protected def Value(name: String): Value
  
  /**
   * Creates a fresh value with specified id and name.
   * @param i unique identifier for this value
   * @param name human-readable name for this value
   * @return new enumeration value
   */
  protected def Value(i: Int, name: String): Value
}

abstract class Enumeration#Value extends Ordered[Value] with Serializable {
  /**
   * The unique identifier of this enumeration value.
   * @return the id as an integer
   */
  def id: Int
  
  /**
   * Compares this value with another enumeration value.
   * @param that the value to compare with
   * @return negative, zero, or positive integer as this value is less than, equal to, or greater than that
   */
  def compare(that: Value): Int
  
  /**
   * Creates a ValueSet containing this value and another value.
   * @param v the other value to include
   * @return ValueSet containing both values
   */
  def +(v: Value): ValueSet
}

class Enumeration#ValueSet extends immutable.SortedSet[Value] with Serializable {
  /**
   * Tests whether this set contains the given value.
   * @param v the value to test
   * @return true if the value is in this set
   */
  def contains(v: Value): Boolean
  
  /**
   * Creates a new set with an additional value.
   * @param value the value to add
   * @return new ValueSet containing the additional value
   */
  def +(value: Value): ValueSet
  
  /**
   * Creates a new set with a value removed.
   * @param value the value to remove
   * @return new ValueSet without the specified value
   */
  def -(value: Value): ValueSet
  
  /**
   * Creates an iterator over the values in this set in increasing order of their ids.
   * @return iterator over the enumeration values
   */
  def iterator: Iterator[Value]
  
  /**
   * Creates a bit mask for the zero-adjusted ids in this set.
   * @return array of longs representing the bit mask
   */
  def toBitMask: Array[Long]
}

object Enumeration#ValueSet {
  /**
   * The empty value set.
   */
  val empty: ValueSet
  
  /**
   * Creates a value set consisting of given elements.
   * @param elems the values to include
   * @return ValueSet containing the specified values
   */
  def apply(elems: Value*): ValueSet
  
  /**
   * Creates a value set from a bit mask representation.
   * @param elems array of longs representing the bit mask
   * @return ValueSet corresponding to the bit mask
   */
  def fromBitMask(elems: Array[Long]): ValueSet
  
  /**
   * Creates a builder for constructing ValueSets.
   * @return mutable builder for ValueSet
   */
  def newBuilder: mutable.Builder[Value, ValueSet]
}

protected class Enumeration#Val(i: Int, name: String) extends Value with Serializable {
  /**
   * Creates a Val with specified id and auto-generated name.
   * @param i the unique identifier
   */
  def this(i: Int): Val
  
  /**
   * Creates a Val with auto-generated id and specified name.
   * @param name the human-readable name
   */
  def this(name: String): Val
  
  /**
   * Creates a Val with auto-generated id and name.
   */
  def this(): Val
  
  /**
   * The unique identifier of this value.
   * @return the id as an integer
   */
  def id: Int
  
  /**
   * String representation of this value (name or placeholder).
   * @return the name if provided, otherwise a placeholder with id and class
   */
  override def toString(): String
}

object Enumeration#ValueOrdering extends Ordering[Value] {
  /**
   * Compares two enumeration values by their ids.
   * @param x first value
   * @param y second value
   * @return negative, zero, or positive integer comparison result
   */
  def compare(x: Value, y: Value): Int
}

object Color extends Enumeration {
  type Color = Value
  val Red, Green, Blue, Yellow, Orange = Value
}

object Priority extends Enumeration {
  val Low = Value(1, "low")
  val Medium = Value(5, "medium") 
  val High = Value(10, "high")
}

// Usage
val color = Color.Red
val priority = Priority.withName("high")

// Create sets of values
val primaryColors = Color.ValueSet(Color.Red, Color.Green, Color.Blue)
val importantPriorities = Priority.High + Priority.Medium

// Iterate over all values
for (c <- Color.values) {
  println(s"Color: $c (id: ${c.id})")
}