/* Copyright 2024 The TensorFlow Authors. All Rights Reserved.

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 TENSORFLOW_LITE_MICRO_MICRO_COMPRESSION_H_
#define TENSORFLOW_LITE_MICRO_MICRO_COMPRESSION_H_

#ifdef USE_TFLM_COMPRESSION

#include "tensorflow/lite/c/common.h"

namespace tflite {

//
// Compressed tensors
//

static constexpr const char* kCompressionMetadataString =
    "COMPRESSION_METADATA";

enum class CompressionScheme : uint8_t {
  kBinQuant,
};

struct LookupTableData {
  static constexpr size_t kMaxBitWidth = 7;
  static constexpr size_t kMaxValueTableChannelStride = 128;

  const void* value_table;             // Pointer into FlatBuffer Values.
  uint8_t value_table_channel_stride;  // elements per channel
  uint8_t compressed_bit_width : 3;    // 1 to 7 bits
  bool is_per_channel_quantized : 1;   // tensor is per-channel quantized
  bool use_alternate_axis : 1;         // shape default channel:
                                       // 0 = first, 1 = last
  uint8_t reserved : 3;
};

union CompressionData {
  LookupTableData* lut_data;
};

struct CompressionTensorData {
  CompressionScheme scheme;
  CompressionData data;
};

struct CompressedTensorList {
  // Sparsely populated array with the same number of elements as there are
  // tensors in the Subgraph. An alternative would include a tensor index in
  // the struct for each and walk the list on look up. This could be slow.
  const CompressionTensorData** tensors;
};

}  // namespace tflite

#endif  // USE_TFLM_COMPRESSION
#endif  // TENSORFLOW_LITE_MICRO_MICRO_COMPRESSION_H_