X-Git-Url: https://git.piment-noir.org/?a=blobdiff_plain;f=src%2Fqueue.ts;h=dab9f04c2783f5a5aa039a3af894780f1b5c639f;hb=b25a42cd89afca28b53dbecbec422595155ddfbc;hp=a2a613814e86dcd5ab13b7122d8c26a7e647d610;hpb=a0d415448af2d5a72c5349d3911f1bcdc3ff0fd2;p=poolifier.git

diff --git a/src/queue.ts b/src/queue.ts
index a2a61381..dab9f04c 100644
--- a/src/queue.ts
+++ b/src/queue.ts
@@ -6,24 +6,15 @@
  * @typeParam T - Type of queue items.
  */
 export class Queue<T> {
-  private items: Record<number, T>
-  private head: number
-  private tail: number
+  private items!: T[]
+  private offset!: number
+  /** The size of the queue. */
+  public size!: number
+  /** The maximum size of the queue. */
+  public maxSize!: number
 
   public constructor () {
-    this.items = {}
-    this.head = 0
-    this.tail = 0
-  }
-
-  /**
-   * Get the size of the queue.
-   *
-   * @returns The size of the queue.
-   * @readonly
-   */
-  public get size (): number {
-    return this.tail - this.head
+    this.clear()
   }
 
   /**
@@ -33,27 +24,79 @@ export class Queue<T> {
    * @returns The new size of the queue.
    */
   public enqueue (item: T): number {
-    this.items[this.tail] = item
-    this.tail++
+    this.items.push(item)
+    ++this.size
+    if (this.size > this.maxSize) {
+      this.maxSize = this.size
+    }
     return this.size
   }
 
   /**
    * Dequeue an item.
    *
-   * @returns The dequeued item.
-   * @returns `undefined` if the queue is empty.
+   * @returns The dequeued item or `undefined` if the queue is empty.
    */
   public dequeue (): T | undefined {
-    if (this.size <= 0) return undefined
-    const item = this.items[this.head]
-    // eslint-disable-next-line @typescript-eslint/no-dynamic-delete
-    delete this.items[this.head]
-    this.head++
-    if (this.head === this.tail) {
-      this.head = 0
-      this.tail = 0
+    if (this.size <= 0) {
+      return undefined
     }
+    const item = this.items[this.offset]
+    if (++this.offset * 2 >= this.items.length) {
+      this.items = this.items.slice(this.offset)
+      this.offset = 0
+    }
+    --this.size
     return item
   }
+
+  /**
+   * Peeks at the first item.
+   *
+   * @returns The first item or `undefined` if the queue is empty.
+   */
+  public peek (): T | undefined {
+    if (this.size <= 0) {
+      return undefined
+    }
+    return this.items[this.offset]
+  }
+
+  /**
+   * Clears the queue.
+   */
+  public clear (): void {
+    this.items = []
+    this.offset = 0
+    this.size = 0
+    this.maxSize = 0
+  }
+
+  /**
+   * Returns an iterator for the queue.
+   *
+   * @returns An iterator for the queue.
+   * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols
+   */
+  [Symbol.iterator] (): Iterator<T> {
+    const items = this.items
+    let i = this.offset
+
+    return {
+      next: () => {
+        if (i >= items.length) {
+          return {
+            value: undefined,
+            done: true
+          }
+        }
+        const value = items[i]
+        i++
+        return {
+          value,
+          done: false
+        }
+      }
+    }
+  }
 }