Implement a return app stack

Each opened app (screen) is pushed on a stack, which is then popped from
when returning instead of hard coded "previous apps". Return swipe and
refresh directions are automatically determined from the app transition.

1 files changed, 38 insertions, 0 deletions

diff --git a/src/StaticStack.h b/src/StaticStack.h
new file mode 100644
index 00000000..64886604
--- /dev/null
+++ b/src/StaticStack.h
@@ -0,0 +1,38 @@
+#include <array>
+#include <cstddef>
+
+template <typename T, size_t N> class StaticStack {
+public:
+  T Pop();
+  void Push(T element);
+  void Reset();
+  T Top();
+
+private:
+  std::array<T, N> elementArray;
+  // Number of elements in stack, points to the next empty slot
+  size_t stackPointer = 0;
+};
+
+// Returns random data when popping from empty array.
+template <typename T, size_t N> T StaticStack<T, N>::Pop() {
+  if (stackPointer > 0) {
+    stackPointer--;
+  }
+  return elementArray[stackPointer];
+}
+
+template <typename T, size_t N> void StaticStack<T, N>::Push(T element) {
+  if (stackPointer < elementArray.size()) {
+    elementArray[stackPointer] = element;
+    stackPointer++;
+  }
+}
+
+template <typename T, size_t N> void StaticStack<T, N>::Reset() {
+  stackPointer = 0;
+}
+
+template <typename T, size_t N> T StaticStack<T, N>::Top() {
+  return elementArray[stackPointer - 1];
+}