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+/*
+ * Copyright 2019 The libgav1 Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LIBGAV1_SRC_UTILS_ARRAY_2D_H_
+#define LIBGAV1_SRC_UTILS_ARRAY_2D_H_
+
+#include <cassert>
+#include <cstddef>
+#include <cstring>
+#include <memory>
+#include <new>
+#include <type_traits>
+
+#include "src/utils/compiler_attributes.h"
+
+namespace libgav1 {
+
+// Exposes a 1D allocated memory buffer as a 2D array.
+template <typename T>
+class Array2DView {
+ public:
+  Array2DView() = default;
+  Array2DView(int rows, int columns, T* const data) {
+    Reset(rows, columns, data);
+  }
+
+  // Copyable and Movable.
+  Array2DView(const Array2DView& rhs) = default;
+  Array2DView& operator=(const Array2DView& rhs) = default;
+
+  void Reset(int rows, int columns, T* const data) {
+    rows_ = rows;
+    columns_ = columns;
+    data_ = data;
+  }
+
+  int rows() const { return rows_; }
+  int columns() const { return columns_; }
+
+  T* operator[](int row) { return const_cast<T*>(GetRow(row)); }
+
+  const T* operator[](int row) const { return GetRow(row); }
+
+ private:
+  const T* GetRow(int row) const {
+    assert(row < rows_);
+    const ptrdiff_t offset = static_cast<ptrdiff_t>(row) * columns_;
+    return data_ + offset;
+  }
+
+  int rows_ = 0;
+  int columns_ = 0;
+  T* data_ = nullptr;
+};
+
+// Allocates and owns the contiguous memory and exposes an Array2DView of
+// dimension |rows| x |columns|.
+template <typename T>
+class Array2D {
+ public:
+  Array2D() = default;
+
+  // Copyable and Movable.
+  Array2D(const Array2D& rhs) = default;
+  Array2D& operator=(const Array2D& rhs) = default;
+
+  LIBGAV1_MUST_USE_RESULT bool Reset(int rows, int columns,
+                                     bool zero_initialize = true) {
+    size_ = rows * columns;
+    // If T is not a trivial type, we should always reallocate the data_
+    // buffer, so that the destructors of any existing objects are invoked.
+    if (!std::is_trivial<T>::value || allocated_size_ < size_) {
+      // Note: This invokes the global operator new if T is a non-class type,
+      // such as integer or enum types, or a class type that is not derived
+      // from libgav1::Allocable, such as std::unique_ptr. If we enforce a
+      // maximum allocation size or keep track of our own heap memory
+      // consumption, we will need to handle the allocations here that use the
+      // global operator new.
+      if (zero_initialize) {
+        data_.reset(new (std::nothrow) T[size_]());
+      } else {
+        data_.reset(new (std::nothrow) T[size_]);
+      }
+      if (data_ == nullptr) {
+        allocated_size_ = 0;
+        return false;
+      }
+      allocated_size_ = size_;
+    } else if (zero_initialize) {
+      // Cast the data_ pointer to void* to avoid the GCC -Wclass-memaccess
+      // warning. The memset is safe because T is a trivial type.
+      void* dest = data_.get();
+      memset(dest, 0, sizeof(T) * size_);
+    }
+    data_view_.Reset(rows, columns, data_.get());
+    return true;
+  }
+
+  int rows() const { return data_view_.rows(); }
+  int columns() const { return data_view_.columns(); }
+  size_t size() const { return size_; }
+  T* data() { return data_.get(); }
+  const T* data() const { return data_.get(); }
+
+  T* operator[](int row) { return data_view_[row]; }
+
+  const T* operator[](int row) const { return data_view_[row]; }
+
+ private:
+  std::unique_ptr<T[]> data_ = nullptr;
+  size_t allocated_size_ = 0;
+  size_t size_ = 0;
+  Array2DView<T> data_view_;
+};
+
+}  // namespace libgav1
+
+#endif  // LIBGAV1_SRC_UTILS_ARRAY_2D_H_