Conversion to signed

array.h

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <array>
+#include <cassert>
+
+template <class T, int32_t N>
+struct Array : std::array<T, N> {
+  using reference = typename std::array<T, N>::reference;
+  using const_reference = typename std::array<T, N>::const_reference;
+  using size_type = typename std::array<T, N>::size_type;
+
+  constexpr int32_t ssize() const;
+
+  constexpr reference at(int32_t pos);
+  constexpr const_reference at(int32_t pos) const;
+};
+
+template <class T, int32_t N>
+constexpr int32_t Array<T, N>::ssize() const {
+  auto size = this->size();
+  assert(size < INT32_MAX);
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wshorten-64-to-32"
+  return size;
+#pragma clang diagnostic pop
+}
+
+template <class T, int32_t N>
+constexpr typename Array<T, N>::reference Array<T, N>::at(int32_t pos) {
+  assert(pos >= 0);
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wshorten-64-to-32"
+  return std::array<T, N>::at(static_cast<size_type>(pos));
+#pragma clang diagnostic pop
+}
+
+template <class T, int32_t N>
+constexpr typename Array<T, N>::const_reference Array<T, N>::at(int32_t pos) const {
+  assert(pos >= 0);
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wshorten-64-to-32"
+  return std::array<T, N>::at(static_cast<size_type>(pos));
+#pragma clang diagnostic pop
+}