added fixed-size stack implementation

stack.hh

@@ -0,0 +1,63 @@
+/*
+Fixed-size stack
+
+Copyright 2020 Ahmet Inan <inan@aicodix.de>
+*/
+
+#pragma once
+
+namespace DSP {
+
+template <typename TYPE, int SIZE>
+class Stack
+{
+	TYPE buf[SIZE];
+	int pos;
+public:
+	Stack() : pos(-1)
+	{
+	}
+	void clear()
+	{
+		pos = -1;
+	}
+	void push(TYPE input)
+	{
+		assert(pos < SIZE-1);
+		buf[++pos] = input;
+	}
+	void pop()
+	{
+		assert(pos >= 0);
+		--pos;
+	}
+	TYPE top()
+	{
+		assert(pos >= 0);
+		return buf[pos];
+	}
+	TYPE first()
+	{
+		assert(pos >= 0);
+		return buf[0];
+	}
+	bool empty()
+	{
+		return pos == -1;
+	}
+	bool full()
+	{
+		return pos == SIZE-1;
+	}
+	int size()
+	{
+		return pos+1;
+	}
+	int max_size()
+	{
+		return SIZE;
+	}
+};
+
+}
+