tensorflow/lite/micro/kernels/space_to_batch_nd.cc

/* Copyright 2021 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.
==============================================================================*/

#include "tensorflow/lite/kernels/internal/reference/space_to_batch_nd.h"

#include "tensorflow/lite/c/common.h"
#include "tensorflow/lite/kernels/internal/tensor_ctypes.h"
#include "tensorflow/lite/kernels/internal/types.h"
#include "tensorflow/lite/kernels/kernel_util.h"
#include "tensorflow/lite/micro/kernels/kernel_util.h"

namespace tflite {

namespace {

constexpr int kInputTensor = 0;
constexpr int kBlockShapeTensor = 1;
constexpr int kCropsTensor = 2;
constexpr int kOutputTensor = 0;

constexpr int kInputDims = 4;
constexpr int kOutputDims = 4;

}  // namespace.

void* Init(TfLiteContext* context, const char* buffer, size_t length) {
  TFLITE_DCHECK(context->AllocatePersistentBuffer != nullptr);
  return context->AllocatePersistentBuffer(context, sizeof(SpaceToBatchParams));
}

TfLiteStatus Prepare(TfLiteContext* context, TfLiteNode* node) {
  TF_LITE_ENSURE_EQ(context, NumInputs(node), 3);
  TF_LITE_ENSURE_EQ(context, NumOutputs(node), 1);

  const TfLiteTensor* input = GetInput(context, node, kInputTensor);
  TfLiteTensor* output = GetOutput(context, node, kOutputTensor);
  TF_LITE_ENSURE(context, input != nullptr && output != nullptr);

  SpaceToBatchParams* params =
      static_cast<SpaceToBatchParams*>(node->user_data);
  params->output_offset = output->params.zero_point;

  // Only 4D input and output tensors are supported for this op on TFLM.
  TF_LITE_ENSURE_EQ(context, NumDimensions(input), kInputDims);
  TF_LITE_ENSURE_EQ(context, NumDimensions(output), kOutputDims);
  TF_LITE_ENSURE_EQ(context, input->type, output->type);

  // Input and output must have the same flat size since TFLM does not support
  // tensor resizing.
  TF_LITE_ENSURE_EQ(context, GetTensorShape(input).FlatSize(),
                    GetTensorShape(output).FlatSize());
  return kTfLiteOk;
}

TfLiteStatus Eval(TfLiteContext* context, TfLiteNode* node) {
  TFLITE_DCHECK(node->user_data != nullptr);
  const SpaceToBatchParams& params =
      *(static_cast<const SpaceToBatchParams*>(node->user_data));

  const TfLiteEvalTensor* input =
      tflite::micro::GetEvalInput(context, node, kInputTensor);
  const TfLiteEvalTensor* block_shape =
      tflite::micro::GetEvalInput(context, node, kBlockShapeTensor);
  const TfLiteEvalTensor* crops =
      tflite::micro::GetEvalInput(context, node, kCropsTensor);
  TfLiteEvalTensor* output =
      tflite::micro::GetEvalOutput(context, node, kOutputTensor);

  switch (input->type) {  // Already know in/out types are same.
    case kTfLiteFloat32:
      reference_ops::SpaceToBatchND(
          params, tflite::micro::GetTensorShape(input),
          tflite::micro::GetTensorData<float>(input),
          tflite::micro::GetTensorShape(block_shape),
          tflite::micro::GetTensorData<int32_t>(block_shape),
          tflite::micro::GetTensorShape(crops),
          tflite::micro::GetTensorData<int32_t>(crops),
          tflite::micro::GetTensorShape(output),
          tflite::micro::GetTensorData<float>(output));
      break;
    case kTfLiteInt8:
      reference_ops::SpaceToBatchND(
          params, tflite::micro::GetTensorShape(input),
          tflite::micro::GetTensorData<int8_t>(input),
          tflite::micro::GetTensorShape(block_shape),
          tflite::micro::GetTensorData<int32_t>(block_shape),
          tflite::micro::GetTensorShape(crops),
          tflite::micro::GetTensorData<int32_t>(crops),
          tflite::micro::GetTensorShape(output),
          tflite::micro::GetTensorData<int8_t>(output));
      break;
    default:
      TF_LITE_KERNEL_LOG(context, "Type %s (%d) not supported.",
                         TfLiteTypeGetName(input->type), input->type);
      return kTfLiteError;
  }
  return kTfLiteOk;
}

TfLiteRegistration Register_SPACE_TO_BATCH_ND() {
  return {/*init=*/Init,
          /*free=*/nullptr,
          /*prepare=*/Prepare,
          /*invoke=*/Eval,
          /*profiling_string=*/nullptr,
          /*builtin_code=*/0,
          /*custom_name=*/nullptr,
          /*version=*/0};
}

}  // namespace tflite