/*
Copyright (c) MONAI Consortium
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 <torch/extension.h>

// Struct to easily cache descriptive information about a tensor.
// This is helpful as regular calls to the size and stride member
// functions of tensors appear to cause memory issues.
struct TensorDescription {
 public:
  TensorDescription(torch::Tensor tensor) {
    batchCount = tensor.size(0);
    batchStride = tensor.stride(0);

    channelCount = tensor.size(1);
    channelStride = tensor.stride(1);

    dimensions = tensor.dim() - 2;
    sizes = new int[dimensions];
    strides = new int[dimensions];

    for (int i = 0; i < dimensions; i++) {
      sizes[i] = tensor.size(i + 2);
      strides[i] = tensor.stride(i + 2);
    }
  }

  ~TensorDescription() {
    delete[] sizes;
    delete[] strides;
  }

  int batchCount;
  int batchStride;

  int channelCount;
  int channelStride;

  int dimensions;
  int* sizes;
  int* strides;
};