adt: allow choice between static and dynamic optional vector types

lib/include/srsran/adt/optional.h

@@ -22,6 +22,8 @@ template <typename T>
 class optional
 {
 public:
+  using value_type = T;
+
   optional() : has_val_(false) {}
   optional(const T& t) : has_val_(true) { storage.emplace(t); }
   optional(T&& t) : has_val_(true) { storage.emplace(std::move(t)); }

lib/include/srsran/adt/optional_array.h

@@ -19,16 +19,15 @@
 
 namespace srsran {
 
-/**
- * Array of optional items. The iteration is in order of indexes and correctly skips non-present items
- * Pointer/References/Iterators remain valid throughout the object lifetime
- * NOTE: The sorted iteration and pointer validation guarantees add some overhead if the array is very fragmented
- * @tparam T type of objects
- * @tparam N static size of max nof items
- */
-template <typename T, size_t N>
-class optional_array
+namespace detail {
+
+template <typename Vec>
+class base_optional_vector
 {
+  using base_t = base_optional_vector<Vec>;
+  using T      = typename Vec::value_type::value_type;
+
+protected:
   template <typename Obj>
   class iterator_impl
   {
@@ -42,22 +41,22 @@ class optional_array
     using reference         = Obj&;
 
     iterator_impl() = default;
-    iterator_impl(optional_array<T, N>* parent_, size_t idx_) : parent(parent_), idx(idx_)
+    iterator_impl(base_t* parent_, size_t idx_) : parent(parent_), idx(idx_)
     {
-      if (idx < parent->capacity() and not parent->contains(idx)) {
+      if (idx < parent->vec.size() and not parent->contains(idx)) {
         ++(*this);
       }
     }
 
     It& operator++()
     {
-      while (++idx < parent->capacity() and not parent->contains(idx)) {
+      while (++idx < parent->vec.size() and not parent->contains(idx)) {
       }
       return *this;
     }
     It& operator--()
     {
-      while (--idx < parent->capacity() and not parent->contains(idx)) {
+      while (--idx < parent->vec.size() and not parent->contains(idx)) {
       }
       return *this;
     }
@@ -69,24 +68,27 @@ class optional_array
     bool operator!=(const It& other) const { return not(*this == other); }
 
   protected:
-    friend class optional_array<T, N>;
+    friend base_t;
 
-    optional_array<T, N>* parent = nullptr;
-    size_t                idx    = N;
+    base_t* parent = nullptr;
+    size_t  idx    = std::numeric_limits<size_t>::max();
   };
 
+  size_t nof_elems = 0;
+  Vec    vec;
+
 public:
   using iterator       = iterator_impl<T>;
   using const_iterator = iterator_impl<const T>;
 
-  optional_array()                      = default;
-  optional_array(const optional_array&) = default;
-  optional_array(optional_array&& other) noexcept : vec(std::move(other.vec)), nof_elems(other.nof_elems)
+  base_optional_vector()                            = default;
+  base_optional_vector(const base_optional_vector&) = default;
+  base_optional_vector(base_optional_vector&& other) noexcept : vec(std::move(other.vec)), nof_elems(other.nof_elems)
   {
     other.nof_elems = 0;
   }
-  optional_array& operator=(const optional_array&) = default;
-  optional_array& operator                         =(optional_array&& other) noexcept
+  base_optional_vector& operator=(const base_optional_vector&) = default;
+  base_optional_vector& operator                               =(base_optional_vector&& other) noexcept
   {
     vec       = std::move(other.vec);
     nof_elems = other.nof_elems;
@@ -97,22 +99,19 @@ public:
   // Find first position that is empty
   size_t find_first_empty(size_t start_guess = 0)
   {
-    if (nof_elems == capacity()) {
-      return N;
+    if (nof_elems == vec.size()) {
+      return vec.size();
     }
-    for (size_t i = start_guess; i < N; ++i) {
+    for (size_t i = start_guess; i < vec.size(); ++i) {
       if (not vec[i].has_value()) {
         return i;
       }
     }
-    return N;
-  }
-  template <typename U>
-  void insert(size_t idx, U&& u)
-  {
-    nof_elems += contains(idx) ? 0 : 1;
-    vec[idx] = std::forward<U>(u);
+    return vec.size();
   }
+
+  bool contains(size_t idx) const { return idx < vec.size() and vec[idx].has_value(); }
+
   void erase(size_t idx)
   {
     if (contains(idx)) {
@@ -129,23 +128,62 @@ public:
     }
   }
 
-  bool contains(size_t idx) const { return idx < N and vec[idx].has_value(); }
-
   T&       operator[](size_t idx) { return *vec[idx]; }
   const T& operator[](size_t idx) const { return *vec[idx]; }
 
   bool   empty() const { return nof_elems == 0; }
   size_t size() const { return nof_elems; }
-  static size_t capacity() { return N; }
 
   iterator       begin() { return iterator{this, 0}; }
-  iterator       end() { return iterator{this, N}; }
+  iterator       end() { return iterator{this, vec.size()}; }
   const_iterator begin() const { return const_iterator{this, 0}; }
-  const_iterator end() const { return const_iterator{this, N}; }
+  const_iterator end() const { return const_iterator{this, vec.size()}; }
+};
 
-private:
-  size_t                     nof_elems = 0;
-  std::array<optional<T>, N> vec;
+} // namespace detail
+
+/**
+ * Array of optional items. The iteration is in order of indexes and correctly skips non-present items
+ * Pointer/References/Iterators remain valid throughout the object lifetime
+ * NOTE: The sorted iteration and pointer validation guarantees add some overhead if the array is very fragmented
+ * @tparam T type of objects
+ * @tparam N static size of max nof items
+ */
+template <typename T, size_t N>
+class optional_array : public detail::base_optional_vector<std::array<optional<T>, N> >
+{
+  using base_t = detail::base_optional_vector<std::array<optional<T>, N> >;
+
+public:
+  template <typename U>
+  void insert(size_t idx, U&& u)
+  {
+    this->nof_elems += this->contains(idx) ? 0 : 1;
+    this->vec[idx] = std::forward<U>(u);
+  }
+};
+
+/**
+ * Contrarily to optional_array, this class may allocate and cause pointer/reference/iterator invalidation.
+ * However, the indexes will remain valid.
+ * @tparam T
+ */
+template <typename T>
+class optional_vector : public detail::base_optional_vector<std::vector<optional<T> > >
+{
+  using base_t = detail::base_optional_vector<std::vector<optional<T> > >;
+
+public:
+  /// May allocate and cause pointer invalidation
+  template <typename U>
+  void insert(size_t idx, U&& u)
+  {
+    if (not this->contains(idx)) {
+      this->nof_elems++;
+      this->vec.resize(std::max(idx + 1, this->vec.size()));
+    }
+    this->vec[idx] = std::forward<U>(u);
+  }
 };
 
 } // namespace srsran

lib/test/adt/optional_array_test.cc

@@ -15,7 +15,7 @@
 
 namespace srsran {
 
-void test_slot_table()
+void test_optional_array()
 {
   optional_array<int, 5> table1;
   TESTASSERT(table1.size() == 0 and table1.empty());
@@ -42,6 +42,33 @@ void test_slot_table()
   TESTASSERT(table1.size() == 1);
 }
 
+void test_optional_vector()
+{
+  optional_vector<int> table1;
+  TESTASSERT(table1.size() == 0 and table1.empty());
+
+  TESTASSERT(not table1.contains(0));
+  table1.insert(0, 5);
+  TESTASSERT(table1.size() == 1 and not table1.empty());
+  table1.erase(0);
+  TESTASSERT(table1.size() == 0 and table1.empty());
+  table1.insert(1, 3);
+  table1.insert(4, 2);
+  TESTASSERT(table1.size() == 2);
+  TESTASSERT(table1[4] == 2 and table1[1] == 3);
+
+  size_t count   = 0;
+  int    array[] = {3, 2};
+  for (int e : table1) {
+    TESTASSERT(array[count++] == e);
+  }
+
+  auto it = table1.begin();
+  TESTASSERT(*it == 3);
+  table1.erase(it);
+  TESTASSERT(table1.size() == 1);
+}
+
 } // namespace srsran
 
 int main(int argc, char** argv)
@@ -51,7 +78,8 @@ int main(int argc, char** argv)
 
   srsran::test_init(argc, argv);
 
-  srsran::test_slot_table();
+  srsran::test_optional_array();
+  srsran::test_optional_vector();
 
   printf("Success\n");
   return SRSRAN_SUCCESS;