row_access.h

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/*    This file is part of the Gudhi Library - https://gudhi.inria.fr/ - which is released under MIT.
 *    See file LICENSE or go to https://gudhi.inria.fr/licensing/ for full license details.
 *    Author(s):       Hannah Schreiber
 *
 *    Copyright (C) 2022-24 Inria
 *
 *    Modification(s):
 *      - YYYY/MM Author: Description of the modification
 */
 
#ifndef PM_ROW_ACCESS_H
#define PM_ROW_ACCESS_H
 
#include <utility>  //std::swap
 
namespace Gudhi {
namespace persistence_matrix {
 
struct Dummy_row_access 
{
  friend void swap([[maybe_unused]] Dummy_row_access& d1, [[maybe_unused]] Dummy_row_access& d2) {}
 
  Dummy_row_access() {}
  template <typename Index, class Row_container>
  Dummy_row_access([[maybe_unused]] Index columnIndex, [[maybe_unused]] Row_container& rows) {}
};
 
template <class Master_matrix>
class Row_access 
{
 public:
  using Index = typename Master_matrix::Index;                  
  using ID_index = typename Master_matrix::ID_index;            
  using Matrix_entry = typename Master_matrix::Matrix_entry;    
  using Row_container = typename Master_matrix::Row_container;  
  Row_access();
  Row_access(Index columnIndex, Row_container* rows);
  Row_access(Row_access&& other) noexcept;
 
  void insert_entry(ID_index rowIndex, Matrix_entry* entry);
  void unlink(Matrix_entry* entry);
  void update_entry(const Matrix_entry& entry);
  Index get_column_index() const;
 
  friend void swap(Row_access& r1, Row_access& r2) {
    std::swap(r1.rows_, r2.rows_);
    std::swap(r1.columnIndex_, r2.columnIndex_);
  }
 
 protected:
  Index columnIndex_;         
  Row_container* rows_;  
 private:
  using Base_hook_matrix_row = typename Master_matrix::Base_hook_matrix_row;
};
 
template <class Master_matrix>
inline Row_access<Master_matrix>::Row_access()
    : columnIndex_(Master_matrix::template get_null_value<Index>()), rows_(nullptr)
{}
 
template <class Master_matrix>
inline Row_access<Master_matrix>::Row_access(Index columnIndex, Row_container* rows)
    : columnIndex_(columnIndex), rows_(rows) 
{}
 
template <class Master_matrix>
inline Row_access<Master_matrix>::Row_access(Row_access&& other) noexcept
    : columnIndex_(std::exchange(other.columnIndex_, 0)), rows_(other.rows_) 
{}
 
template <class Master_matrix>
inline void Row_access<Master_matrix>::insert_entry(ID_index rowIndex, Matrix_entry* entry) 
{
  if (rows_ == nullptr) return;
 
  if constexpr (!Master_matrix::Option_list::has_removable_rows) {
    if (rows_->size() < rowIndex + 1) rows_->resize(rowIndex + 1);
  }
 
  // if has_removable_rows should op[] create non existing entry? If not, use try_emplace()
  if constexpr (Master_matrix::Option_list::has_intrusive_rows) {
    rows_->operator[](rowIndex).push_back(*entry);
  } else {
    rows_->operator[](rowIndex).insert(*entry);
  }
}
 
template <class Master_matrix>
inline void Row_access<Master_matrix>::unlink(Matrix_entry* entry) 
{
  if (rows_ == nullptr) return;
 
  if constexpr (Master_matrix::Option_list::has_intrusive_rows) {
    entry->Base_hook_matrix_row::unlink();
  } else {
    if constexpr (Master_matrix::Option_list::has_removable_rows) {
      auto it = rows_->find(entry->get_row_index());
      it->second.erase(*entry);
    } else {
      rows_->operator[](entry->get_row_index()).erase(*entry);
    }
  }
}
 
template <class Master_matrix>
inline void Row_access<Master_matrix>::update_entry(const Matrix_entry& entry) 
{
  if constexpr (!Master_matrix::Option_list::has_intrusive_rows) {
    if (rows_ == nullptr) return;
    auto& row = rows_->at(entry.get_row_index());
    auto it = row.find(entry);
    it = row.erase(it);
    row.insert(it, entry);
  }
}
 
template <class Master_matrix>
inline typename Row_access<Master_matrix>::Index Row_access<Master_matrix>::get_column_index() const 
{
  return columnIndex_;
}
 
}  // namespace persistence_matrix
}  // namespace Gudhi
 
#endif  // PM_ROW_ACCESS_H