refactor

source/utils/circularBuffer.ts

@@ -0,0 +1,81 @@
+/*
+ * ClearURLs
+ * Copyright (c) 2017-2020 Kevin Röbert
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+export default class CircularBuffer<T> {
+    private buffer: T[]
+    public readonly capacity: number
+
+    /**
+     * Create a new circular buffer, that removes the oldes elements if the capacity is reached.
+     *
+     * @param capacity - the capacity of this queue
+     * @throws error if the capacity is <= 0
+     */
+    public constructor(capacity: number) {
+        if (capacity <= 0) {
+            throw new Error('The capacity must be > 0')
+        }
+
+        this.capacity = capacity
+        this.buffer = []
+    }
+
+    /**
+     * Returns true if the buffer is empty.
+     *
+     * @returns true if the buffer is empty otherwise false
+     */
+    public isEmpty() : boolean {
+        return this.buffer.length === 0
+    }
+
+    /**
+     * Returns true if the buffer is full.
+     *
+     * @returns true if the buffer is full otherwise false
+     */
+    public isFull() : boolean {
+        return this.buffer.length === this.capacity
+    }
+
+    /**
+     * Enqueues an item.
+     *
+     * @param item - item that should be enqueued
+     */
+    public enqueue(item: T) : void {
+        if (this.isFull()) {
+            this.buffer.shift()
+        }
+
+        this.buffer.push(item)
+    }
+
+    /**
+     * Returns the buffer in a fresh array.
+     *
+     * @returns the buffer
+     */
+    public toArray() : T[] {
+        return [...this.buffer]
+    }
+
+    get size() : number {
+        return this.buffer.length
+    }
+}