Add SizedStack for later Region usages

BauSystem_API/src/de/steamwar/bausystem/shared/SizedStack.java

@@ -0,0 +1,143 @@
+/*
+ * This file is a part of the SteamWar software.
+ *
+ * Copyright (C) 2021  SteamWar.de-Serverteam
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package de.steamwar.bausystem.shared;
+
+@SuppressWarnings({"unused", "UnusedReturnValue"})
+public class SizedStack<T> {
+
+    private int maxSize;
+    private T[] data;
+    private int size;
+    private int head;
+
+    public SizedStack(int size) {
+        this.maxSize = size;
+        //noinspection unchecked
+        this.data = (T[]) new Object[this.maxSize];
+        this.head = 0;
+        this.size = 0;
+    }
+
+    public T push(final T element) {
+        this.data[this.head] = element;
+        this.increaseHead();
+        this.increaseSize();
+        return element;
+    }
+
+    public T pop() {
+        this.decreaseHead();
+        this.decreaseSize();
+        final T result = this.data[this.head];
+        this.data[this.head] = null;
+        return result;
+    }
+
+    public T peek() {
+        return this.data[this.head];
+    }
+
+    public boolean empty() {
+        return this.size == 0;
+    }
+
+    protected boolean canEqual(final Object other) {
+        return other instanceof SizedStack;
+    }
+
+    private void increaseHead() {
+        this.head++;
+        while (this.head > this.maxSize - 1) {
+            this.head -= this.maxSize;
+        }
+    }
+
+    private void decreaseHead() {
+        this.head--;
+        while (this.head < 0) {
+            this.head += this.maxSize;
+        }
+    }
+
+    private void increaseSize() {
+        if (this.size < this.maxSize) {
+            this.size++;
+        }
+    }
+
+    private void decreaseSize() {
+        if (this.size > 0) {
+            this.size--;
+        }
+    }
+
+    @Override
+    public int hashCode() {
+        final int PRIME = 59;
+        int result = 1;
+        result = result * PRIME + this.maxSize;
+        result = result * PRIME + this.toString().hashCode();
+        result = result * PRIME + this.size;
+        return result;
+    }
+
+    @Override
+    public boolean equals(final Object o) {
+        if (o == this) {
+            return true;
+        }
+        if (!(o instanceof SizedStack)) {
+            return false;
+        }
+        final SizedStack<?> other = (SizedStack<?>) o;
+        if (!other.canEqual(this)) {
+            return false;
+        }
+        if (this.maxSize != other.maxSize) {
+            return false;
+        }
+        if (this.size != other.size) {
+            return false;
+        }
+        if (!this.data.getClass().equals(other.data.getClass())) {
+            return false;
+        }
+        return this.toString().equals(other.toString());
+    }
+
+    public int getMaxSize() {
+        return maxSize;
+    }
+
+    public int getSize() {
+        return size;
+    }
+
+    @Override
+    public String toString() {
+        final StringBuilder result = new StringBuilder("[");
+        for (int i = 0; i < this.size - 1; i++) {
+            result.append(this.data[(this.head - i - 1 < 0) ? (this.head - i - 1 + this.maxSize) : (this.head - i - 1)]).append(",");
+        }
+        result.append(this.data[(this.head - this.size < 0) ? (this.head - this.size + this.maxSize) : (this.head - this.size)]);
+        result.append("]");
+        return result.toString();
+    }
+}