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+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __BLI_VECTOR_ADAPTOR_HH__
+#define __BLI_VECTOR_ADAPTOR_HH__
+
+/** \file
+ * \ingroup bli
+ *
+ * A `blender::VectorAdaptor` is a container with a fixed maximum size and does not own the
+ * underlying memory. When an adaptor is constructed, you have to provide it with an uninitialized
+ * array that will be filled when elements are added to the vector. The vector adaptor is not able
+ * to grow. Therefore, it is undefined behavior to add more elements than fit into the provided
+ * buffer.
+ */
+
+#include "BLI_span.hh"
+
+namespace blender {
+
+template<typename T> class VectorAdaptor {
+ private:
+  T *begin_;
+  T *end_;
+  T *capacity_end_;
+
+ public:
+  VectorAdaptor() : begin_(nullptr), end_(nullptr), capacity_end_(nullptr)
+  {
+  }
+
+  VectorAdaptor(T *data, int64_t capacity, int64_t size = 0)
+      : begin_(data), end_(data + size), capacity_end_(data + capacity)
+  {
+  }
+
+  VectorAdaptor(MutableSpan<T> span) : VectorAdaptor(span.data(), span.size(), 0)
+  {
+  }
+
+  void append(const T &value)
+  {
+    BLI_assert(end_ < capacity_end_);
+    new (end_) T(value);
+    end_++;
+  }
+
+  void append(T &&value)
+  {
+    BLI_assert(end_ < capacity_end_);
+    new (end_) T(std::move(value));
+    end_++;
+  }
+
+  void append_n_times(const T &value, int64_t n)
+  {
+    BLI_assert(end_ + n <= capacity_end_);
+    uninitialized_fill_n(end_, n, value);
+    end_ += n;
+  }
+
+  void extend(Span<T> values)
+  {
+    BLI_assert(end_ + values.size() <= capacity_end_);
+    uninitialized_copy_n(values.data(), values.size(), end_);
+    end_ += values.size();
+  }
+
+  int64_t capacity() const
+  {
+    return capacity_end_ - begin_;
+  }
+
+  int64_t size() const
+  {
+    return end_ - begin_;
+  }
+
+  bool is_empty() const
+  {
+    return begin_ == end_;
+  }
+
+  bool is_full() const
+  {
+    return end_ == capacity_end_;
+  }
+};
+
+}  // namespace blender
+
+#endif /* __BLI_VECTOR_ADAPTOR_HH__ */