IndexEnumerator.h

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/*
 * Copyright (c) 2018 Samsung Electronics Co., Ltd. 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 __NNFW_MISC_TENSOR_INDEX_ENUMERATOR_H__
#define __NNFW_MISC_TENSOR_INDEX_ENUMERATOR_H__
 
#include "misc/tensor/Shape.h"
#include "misc/tensor/Index.h"
 
namespace nnfw
{
namespace misc
{
namespace tensor
{
class IndexEnumerator
{
public:
  explicit IndexEnumerator(const Shape &shape) : _shape(shape), _cursor(0), _index(shape.rank())
  {
    const uint32_t rank = _shape.rank();
 
    for (uint32_t axis = 0; axis < rank; ++axis)
    {
      _index.at(axis) = 0;
    }
 
    for (_cursor = 0; _cursor < rank; ++_cursor)
    {
      if (_index.at(_cursor) < _shape.dim(_cursor))
      {
        break;
      }
    }
  }
 
public:
  IndexEnumerator(IndexEnumerator &&) = delete;
  IndexEnumerator(const IndexEnumerator &) = delete;
 
public:
  bool valid(void) const { return _cursor < _shape.rank(); }
 
public:
  const Index &curr(void) const { return _index; }
 
public:
  void advance(void)
  {
    const uint32_t rank = _shape.rank();
 
    // Find axis to be updated
    while ((_cursor < rank) && !(_index.at(_cursor) + 1 < _shape.dim(_cursor)))
    {
      ++_cursor;
    }
 
    if (_cursor == rank)
    {
      return;
    }
 
    // Update index
    _index.at(_cursor) += 1;
 
    for (uint32_t axis = 0; axis < _cursor; ++axis)
    {
      _index.at(axis) = 0;
    }
 
    // Update cursor
    _cursor = 0;
  }
 
public:
  const Shape _shape; 
 
private:
  uint32_t _cursor;
  Index _index;
};
 
} // namespace tensor
} // namespace misc
} // namespace nnfw
 
#endif // __NNFW_MISC_TENSOR_INDEX_ENUMERATOR_H__