gpp_prune_path.hpp

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/*
 * MIT License
 *
 * Copyright (c) 2021 Dima Dorezyuk
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
 
#pragma once
 
#include <gpp_interface/post_planning_interface.hpp>
 
#include <iterator>
 
namespace gpp_prune_path {
 
namespace internal {
 
template <typename _Iter>
_Iter
prune(_Iter _begin, _Iter _end, size_t _step) {
  if (_step < 2)
    return _end;
  // find the distance between _begin and end
  const auto distance = std::distance(_begin, _end);
 
  // we prune such that we always include the first and last element of the
  // sequence. if the distance is less than three, we cannot prune.
  if (distance < 2)
    return _end;
 
  // find the end of our source.
  // note: we denote the source (s) as the iterator from where we are copying
  // data; the destination is denoted with (d).
  const _Iter d_end = _begin + (distance + _step - 2) / _step;
 
  // inplace pruning.
  // note: don't use std::move, as it doesn't work for ros-msgs...
  for (_Iter s_begin = _begin; _begin != d_end; ++_begin, s_begin += _step)
    *_begin = *s_begin;
 
  // last element must be updated separatelly:
  *_begin++ = *std::prev(_end);
 
  return _begin;
}
}  // namespace internal
 
// short-cut
using gpp_interface::PostPlanningInterface;
 
struct GppPrunePath : public PostPlanningInterface {
  bool
  postProcess(const Pose &_start, const Pose &_goal, Path &_path,
              double &_cost) override;
 
  void
  initialize(const std::string &_name, Map *_map) override;
 
private:
  int step_ = 0;
};
 
}  // namespace gpp_prune_path