SmartRange.hh

/* ========================================================================= *
 *                                                                           *
 *                               OpenMesh                                    *
 *           Copyright (c) 2001-2025, RWTH-Aachen University                 *
 *           Department of Computer Graphics and Multimedia                  *
 *                          All rights reserved.                             *
 *                            www.openmesh.org                               *
 *                                                                           *
 *---------------------------------------------------------------------------*
 * This file is part of OpenMesh.                                            *
 *---------------------------------------------------------------------------*
 *                                                                           *
 * Redistribution and use in source and binary forms, with or without        *
 * modification, are permitted provided that the following conditions        *
 * are met:                                                                  *
 *                                                                           *
 * 1. Redistributions of source code must retain the above copyright notice, *
 *    this list of conditions and the following disclaimer.                  *
 *                                                                           *
 * 2. Redistributions in binary form must reproduce the above copyright      *
 *    notice, this list of conditions and the following disclaimer in the    *
 *    documentation and/or other materials provided with the distribution.   *
 *                                                                           *
 * 3. Neither the name of the copyright holder nor the names of its          *
 *    contributors may be used to endorse or promote products derived from   *
 *    this software without specific prior written permission.               *
 *                                                                           *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS       *
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED *
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A           *
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER *
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,  *
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,       *
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR        *
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF    *
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING      *
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS        *
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.              *
 *                                                                           *
 * ========================================================================= */
 
 
#pragma once
 
#include <utility>
#include <array>
#include <vector>
#include <set>
 
//== NAMESPACES ===============================================================
 
namespace OpenMesh {
 
//== FORWARD DECLARATION ======================================================
 
//== CLASS DEFINITION =========================================================
 
namespace  {
 
struct Identity
{
  template <typename T>
  T operator()(const T& _t) const { return _t; }
};
 
}
 
template <typename RangeT, typename HandleT, typename Functor>
struct FilteredSmartRangeT;
 
template <typename RangeT, typename HandleT>
struct SmartRangeT
{
  using Handle = HandleT;
  using SmartRange = SmartRangeT<RangeT, HandleT>;
  using Range = RangeT;
 
  // TODO: Someone with better c++ knowledge may improve the code below.
  
  auto size() const -> size_t
  {
      auto range = static_cast<const RangeT*>(this);
      return std::distance(range->begin(), range->end());
  }
 
  template <typename Functor>
  auto sum(Functor&& f) const -> typename std::decay<decltype (f(std::declval<HandleT>()))>::type
  {
    auto range = static_cast<const RangeT*>(this);
    auto begin = range->begin();
    auto end   = range->end();
    assert(begin != end);
    typename std::decay<decltype (f(*begin))>::type result = f(*begin);
    auto it = begin;
    ++it;
    for (; it != end; ++it)
        result += f(*it);
    return result;
  }
 
  template <typename Functor>
  auto avg(Functor&& f) const -> typename std::decay<decltype (f(std::declval<HandleT>()))>::type
  {
    auto range = static_cast<const RangeT*>(this);
    auto begin = range->begin();
    auto end   = range->end();
    assert(begin != end);
    typename std::decay<decltype (f(*begin))>::type result = f(*begin);
    auto it = begin;
    ++it;
    int n_elements = 1;
    for (; it != end; ++it)
    {
        result += f(*it);
      ++n_elements;
    }
    return (1.0 / n_elements) * result;
  }
 
  template <typename Functor, typename WeightFunctor>
  auto avg(Functor&& f, WeightFunctor&& w) const -> typename std::decay<decltype ((1.0/(w(std::declval<HandleT>())+w(std::declval<HandleT>())))*f(std::declval<HandleT>()))>::type
  {
    auto range = static_cast<const RangeT*>(this);
    auto begin = range->begin();
    auto end   = range->end();
    assert(begin != end);
    typename std::decay<decltype (w(*begin))>::type weight = w(*begin);
    typename std::decay<decltype (w(*begin)*f(*begin))>::type result = weight * f(*begin);
    typename std::decay<decltype (w(*begin)+w(*begin))>::type weight_sum = weight;
    auto it = begin;
    ++it;
    for (; it != end; ++it)
    {
      weight = w(*it);
      result += weight*f(*it);
      weight_sum += weight;
    }
    return (1.0 / weight_sum) * result;
  }
 
  template <typename Functor>
  auto any_of(Functor&& f) const -> bool
  {
    auto range = static_cast<const RangeT*>(this);
    for (auto e : *range)
      if (f(e))
        return true;
    return false;
  }
 
  template <typename Functor>
  auto all_of(Functor&& f) const -> bool
  {
    auto range = static_cast<const RangeT*>(this);
    for (auto e : *range)
      if (!f(e))
        return false;
    return true;
  }
 
  template <int n, typename Functor = Identity>
  auto to_array(Functor&& f = {}) const -> std::array<typename std::decay<decltype (f(std::declval<HandleT>()))>::type, n>
  {
    auto range = static_cast<const RangeT*>(this);
    std::array<typename std::decay<decltype (f(std::declval<HandleT>()))>::type, n> res;
    auto it = range->begin();
    auto end = range->end();
    int i = 0;
    while (i < n && it != end)
      res[i++] = f(*(it++));
    return res;
  }
 
  template <typename Functor = Identity>
  auto to_vector(Functor&& f = {}) const -> std::vector<typename std::decay<decltype (f(std::declval<HandleT>()))>::type>
  {
    auto range = static_cast<const RangeT*>(this);
    std::vector<typename std::decay<decltype (f(std::declval<HandleT>()))>::type> res;
    for (const auto& e : *range)
      res.push_back(f(e));
    return res;
  }
 
  template <typename Functor = Identity>
  auto to_set(Functor&& f = {}) const -> std::set<typename std::decay<decltype (f(std::declval<HandleT>()))>::type>
  {
    auto range = static_cast<const RangeT*>(this);
    std::set<typename std::decay<decltype (f(std::declval<HandleT>()))>::type> res;
    for (const auto& e : *range)
      res.insert(f(e));
    return res;
  }
 
  template <typename Functor>
  auto first(Functor&& f = {}) const -> HandleT
  {
    auto range = static_cast<const RangeT*>(this);
    for (const auto& e : *range)
      if (f(e))
        return e;
    return HandleT();
  }
 
  template <typename Functor>
  auto min(Functor&& f) const -> typename std::decay<decltype (f(std::declval<HandleT>()))>::type
  {
    using std::min;
 
    auto range = static_cast<const RangeT*>(this);
    auto it    = range->begin();
    auto end   = range->end();
    assert(it != end);
 
    typename std::decay<decltype (f(std::declval<HandleT>()))>::type res = f(*it);
    ++it;
 
    for (; it != end; ++it)
      res = min(res, f(*it));
 
    return res;
  }
 
  template <typename Functor>
  auto argmin(Functor&& f) const -> HandleT
  {
    auto range = static_cast<const RangeT*>(this);
    auto it    = range->begin();
    auto min_it = it;
    auto end   = range->end();
    assert(it != end);
 
    typename std::decay<decltype (f(std::declval<HandleT>()))>::type curr_min = f(*it);
    ++it;
 
    for (; it != end; ++it)
    {
      auto val = f(*it);
      if (val < curr_min)
      {
        curr_min = val;
        min_it = it;
      }
    }
 
    return *min_it;
  }
 
  template <typename Functor>
  auto max(Functor&& f) const -> typename std::decay<decltype (f(std::declval<HandleT>()))>::type
  {
    using std::max;
 
    auto range = static_cast<const RangeT*>(this);
    auto it    = range->begin();
    auto end   = range->end();
    assert(it != end);
 
    typename std::decay<decltype (f(std::declval<HandleT>()))>::type res = f(*it);
    ++it;
 
    for (; it != end; ++it)
      res = max(res, f(*it));
 
    return res;
  }
 
 
  template <typename Functor>
  auto argmax(Functor&& f) const -> HandleT
  {
    auto range = static_cast<const RangeT*>(this);
    auto it    = range->begin();
    auto max_it = it;
    auto end   = range->end();
    assert(it != end);
 
    typename std::decay<decltype (f(std::declval<HandleT>()))>::type curr_max = f(*it);
    ++it;
 
    for (; it != end; ++it)
    {
      auto val = f(*it);
      if (val > curr_max)
      {
        curr_max = val;
        max_it = it;
      }
    }
 
    return *max_it;
  }
 
  template <typename Functor>
  auto minmax(Functor&& f) const -> std::pair<typename std::decay<decltype (f(std::declval<HandleT>()))>::type,
                                        typename std::decay<decltype (f(std::declval<HandleT>()))>::type>
  {
    return std::make_pair(this->min(f), this->max(f));
  }
 
 
  template <typename Functor>
  auto count_if(Functor&& f) const -> int
  {
    int count = 0;
    auto range = static_cast<const RangeT*>(this);
    for (const auto& e : *range)
      if (f(e))
        ++count;
    return count;
  }
 
 
  template <typename Functor>
  auto for_each(Functor&& f) const -> void
  {
    auto range = static_cast<const RangeT*>(this);
    for (const auto& e : *range)
      f(e);
  }
 
 
  template <typename Functor>
  auto filtered(Functor&& f) const -> FilteredSmartRangeT<SmartRange, Handle, Functor>
  {
    auto range = static_cast<const RangeT*>(this);
    return FilteredSmartRangeT<SmartRange, Handle, Functor>(std::forward<Functor>(f), (*range).begin(), (*range).end());
  }
};
 
 
template <typename RangeT, typename HandleT, typename Functor>
struct FilteredSmartRangeT : public SmartRangeT<FilteredSmartRangeT<RangeT, HandleT, Functor>, HandleT>
{
  using BaseRange = SmartRangeT<FilteredSmartRangeT<RangeT, HandleT, Functor>, HandleT>;
  using BaseIterator = decltype((std::declval<typename RangeT::Range>().begin()));
 
  struct FilteredIterator : public BaseIterator
  {
 
    FilteredIterator(Functor f, BaseIterator it, BaseIterator end): BaseIterator(it), f_(f), end_(end)
    {
      if (!BaseIterator::operator==(end_) && !f_(*(*this))) // if start is not valid go to first valid one
        operator++();
    }
 
    FilteredIterator(const FilteredIterator& other) = default;
 
    FilteredIterator& operator=(const FilteredIterator& other)
    {
      BaseIterator::operator=(other);
      end_ = other.end_;
      return *this;
    }
 
    FilteredIterator& operator++()
    {
      if (BaseIterator::operator==(end_)) // don't go past end
        return *this;
 
      // go to next valid one
      do
        BaseIterator::operator++();
      while (BaseIterator::operator!=(end_) && !f_(*(*this)));
      return *this;
    }
 
    Functor f_;        // Should iterators always get a reference to filter stored in range?
                       // Should iterators stay valid after range goes out of scope?
    BaseIterator end_;
  };
 
  FilteredSmartRangeT(Functor&& f, BaseIterator begin, BaseIterator end) : f_(std::forward<Functor>(f)), begin_(std::move(begin)), end_(std::move(end)){}
  FilteredIterator begin() const { return FilteredIterator(f_, begin_, end_); }
  FilteredIterator end()   const { return FilteredIterator(f_, end_, end_); }
 
  Functor f_;
  BaseIterator begin_;
  BaseIterator end_;
};
 
 
 
//=============================================================================
} // namespace OpenMesh
//=============================================================================
 
//=============================================================================