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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_QUANTIZER_H_
+#define LIBGAV1_SRC_QUANTIZER_H_
+
+#include <cstdint>
+
+#include "src/utils/constants.h"
+#include "src/utils/dynamic_buffer.h"
+#include "src/utils/segmentation.h"
+#include "src/utils/types.h"
+
+namespace libgav1 {
+
+using QuantizerMatrix = std::array<
+    std::array<std::array<DynamicBuffer<uint8_t>, kNumTransformSizes>,
+               kNumPlaneTypes>,
+    kNumQuantizerLevelsForQuantizerMatrix>;
+
+// Implements the dequantization functions of Section 7.12.2.
+class Quantizer {
+ public:
+  Quantizer(int bitdepth, const QuantizerParameters* params);
+
+  // Returns the quantizer value for the dc coefficient for the given plane.
+  // The caller should call GetQIndex() with Tile::current_quantizer_index_ as
+  // the |base_qindex| argument, and pass the return value as the |qindex|
+  // argument to this method.
+  int GetDcValue(Plane plane, int qindex) const;
+
+  // Returns the quantizer value for the ac coefficient for the given plane.
+  // The caller should call GetQIndex() with Tile::current_quantizer_index_ as
+  // the |base_qindex| argument, and pass the return value as the |qindex|
+  // argument to this method.
+  int GetAcValue(Plane plane, int qindex) const;
+
+ private:
+  const QuantizerParameters& params_;
+  const int16_t* dc_lookup_;
+  const int16_t* ac_lookup_;
+};
+
+// Initialize the quantizer matrix.
+bool InitializeQuantizerMatrix(QuantizerMatrix* quantizer_matrix);
+
+// Get the quantizer index for the |index|th segment.
+//
+// This function has two use cases. What should be passed as the |base_qindex|
+// argument depends on the use case.
+// 1. While parsing the uncompressed header or transform type, pass
+//    Quantizer::base_index.
+//    Note: In this use case, the caller only cares about whether the return
+//    value is zero.
+// 2. To generate the |qindex| argument to Quantizer::GetDcQuant() or
+//    Quantizer::GetAcQuant(), pass Tile::current_quantizer_index_.
+int GetQIndex(const Segmentation& segmentation, int index, int base_qindex);
+
+}  // namespace libgav1
+
+#endif  // LIBGAV1_SRC_QUANTIZER_H_