parameters.h

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// The libMesh Finite Element Library.
// Copyright (C) 2002-2025 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner

// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.

// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA



#ifndef LIBMESH_PARAMETERS_H
#define LIBMESH_PARAMETERS_H

// Local includes
#include "libmesh/libmesh_common.h"
#include "libmesh/reference_counted_object.h"
#include "libmesh/print_trace.h"

// C++ includes
#include <cstddef>
#include <map>
#include <sstream>
#include <string>
#include <typeinfo>
#include <vector>
#include <memory>

namespace libMesh
{
template<typename P>
void print_helper(std::ostream & os, const P * param);

template<typename P>
void print_helper(std::ostream & os, const std::vector<P> * param);

template<typename P>
void print_helper(std::ostream & os, const std::vector<std::vector<P>> * param);

template<typename P>
void print_helper(std::ostream & os, const std::vector<std::vector<std::vector<P>>> * param);

template<typename P1, typename P2, typename C, typename A>
void print_helper(std::ostream & os, const std::map<P1, P2, C, A> * param);

class Parameters
{
public:

  Parameters () = default;

  Parameters (const Parameters &);

  virtual ~Parameters () = default;

  virtual Parameters & operator= (const Parameters & source);

  virtual Parameters & operator+= (const Parameters & source);

  template <typename T>
  bool have_parameter (std::string_view) const;

  template <typename T>
  const T & get (std::string_view) const;

  template <typename T>
  void insert (const std::string &);

  template <typename T>
  T & set (const std::string &);

  virtual void set_attributes(const std::string &, bool /*inserted_only*/) {}

  void remove (std::string_view);

  std::size_t n_parameters () const { return _values.size(); }

#ifdef LIBMESH_HAVE_RTTI

  template <typename T>
  unsigned int n_parameters () const;
#endif // LIBMESH_HAVE_RTTI

  virtual void clear ();

  void print (std::ostream & os=libMesh::out) const;

  class Value : public ReferenceCountedObject<Value>
  {
  public:

    virtual ~Value() = default;

#ifdef LIBMESH_HAVE_RTTI

    virtual std::string type () const = 0;
#endif // LIBMESH_HAVE_RTTI

    virtual void print(std::ostream &) const = 0;

    virtual std::unique_ptr<Value> clone () const = 0;
  };

  template <typename T>
  class Parameter : public Value
  {
  public:

    const T & get () const { return _value; }

    T & set () { return _value; }

#ifdef LIBMESH_HAVE_RTTI

    virtual std::string type () const override;
#endif // LIBMESH_HAVE_RTTI

    virtual void print(std::ostream &) const override;

    virtual std::unique_ptr<Value> clone () const override;

  private:
    T _value;
  };

  typedef std::map<std::string, std::unique_ptr<Value>, std::less<>> map_type;

  typedef map_type::iterator iterator;

  typedef map_type::const_iterator const_iterator;

  iterator begin();

  const_iterator begin() const;

  iterator end();

  const_iterator end() const;

protected:

  map_type _values;
};

// ------------------------------------------------------------
// Parameters::Parameter<> class inline methods

// This only works with Run-Time Type Information, even though
// typeid(T) *should* be determinable at compile time regardless...
#ifdef LIBMESH_HAVE_RTTI
template <typename T>
inline
std::string Parameters::Parameter<T>::type () const
{
  return demangle(typeid(T).name());
}
#endif

template <typename T>
inline
void Parameters::Parameter<T>::print (std::ostream & os) const
{
  // Call helper function overloaded for basic scalar and vector types
  print_helper(os, static_cast<const T *>(&_value));
}

template <typename T>
inline
std::unique_ptr<Parameters::Value> Parameters::Parameter<T>::clone () const
{
  auto copy = std::make_unique<Parameter<T>>();

  copy->_value = this->_value; // assign value

  return copy; // as unique_ptr to base class
}


// ------------------------------------------------------------
// Parameters class inline methods
inline
void Parameters::clear ()
{
  _values.clear();
}



inline
Parameters & Parameters::operator= (const Parameters & source)
{
  this->Parameters::clear();
  *this += source;

  return *this;
}

inline
Parameters & Parameters::operator+= (const Parameters & source)
{
  // Overwrite each value (if it exists) or create a new entry
  for (const auto & [key, value] : source._values)
    _values[key] = value->clone();

  return *this;
}

inline
Parameters::Parameters (const Parameters & p)
{
  // calls assignment operator
  *this = p;
}



inline
void Parameters::print (std::ostream & os) const
{
  Parameters::const_iterator it = _values.begin();

  os << "Name\t Type\t Value\n"
     << "---------------------\n";
  while (it != _values.end())
    {
      os << " "   << it->first
#ifdef LIBMESH_HAVE_RTTI
         << "\t " << it->second->type()
#endif // LIBMESH_HAVE_RTTI
         << "\t ";   it->second->print(os);
      os << '\n';

      ++it;
    }
}



// Declare this now that Parameters::print() is defined.
// By declaring this early we can use it in subsequent
// methods.  Required for gcc-4.0.2 -- 11/30/2005, BSK
inline
std::ostream & operator << (std::ostream & os, const Parameters & p)
{
  p.print(os);
  return os;
}



template <typename T>
inline
bool Parameters::have_parameter (std::string_view name) const
{
  Parameters::const_iterator it = _values.find(name);

  if (it != _values.end())
    {
#ifdef LIBMESH_HAVE_RTTI

      if (dynamic_cast<const Parameter<T> *>(it->second.get()))
        return true;

#else // !LIBMESH_HAVE_RTTI

      // cast_ptr will simply do a static_cast here when RTTI is not
      // enabled, and it will return a non-nullptr regardless of
      // whether or not the cast actually succeeds.
      libmesh_warning("Parameters::have_parameter() may return false positives when RTTI is not enabled.");

      if (cast_ptr<const Parameter<T> *>(it->second.get()))
        return true;

#endif
    }

  return false;
}



template <typename T>
inline
const T & Parameters::get (std::string_view name) const
{
  if (!this->have_parameter<T>(name))
    {
      std::ostringstream oss;

      oss << "ERROR: no";
#ifdef LIBMESH_HAVE_RTTI
      oss << ' ' << demangle(typeid(T).name());
#endif
      oss << " parameter named \""
          << name << "\" found.\n\n"
          << "Known parameters:\n"
          << *this;

      libmesh_error_msg(oss.str());
    }

  Parameters::const_iterator it = _values.find(name);

  libmesh_assert(it != _values.end());
  libmesh_assert(it->second);

  // Get pointer to derived type
  auto ptr = cast_ptr<Parameter<T> *>(it->second.get());

  // Return const reference
  return ptr->get();
}

template <typename T>
inline
void Parameters::insert (const std::string & name)
{
  if (!this->have_parameter<T>(name))
    _values[name] = std::make_unique<Parameter<T>>();

  set_attributes(name, true);
}


template <typename T>
inline
T & Parameters::set (const std::string & name)
{
  if (!this->have_parameter<T>(name))
    _values[name] = std::make_unique<Parameter<T>>();

  set_attributes(name, false);

  // Get pointer to existing or just-added entry
  auto ptr = cast_ptr<Parameter<T> *>(_values[name].get());

  // Return writeable reference
  return ptr->set();
}

inline
void Parameters::remove (std::string_view name)
{
  Parameters::iterator it = _values.find(name);

  if (it != _values.end())
    _values.erase(it);
}



#ifdef LIBMESH_HAVE_RTTI
template <typename T>
inline
unsigned int Parameters::n_parameters () const
{
  unsigned int cnt = 0;

  for (const auto & pr : _values)
    if (dynamic_cast<Parameter<T> *>(pr.second.get()))
      cnt++;

  return cnt;
}
#endif

inline
Parameters::iterator Parameters::begin()
{
  return _values.begin();
}

inline
Parameters::const_iterator Parameters::begin() const
{
  return _values.begin();
}

inline
Parameters::iterator Parameters::end()
{
  return _values.end();
}

inline
Parameters::const_iterator Parameters::end() const
{
  return _values.end();
}

//non-member scalar print function
template<typename P>
void print_helper(std::ostream & os, const P * param)
{
  os << *param;
}

template<>
inline
void print_helper(std::ostream & os, const char * param)
{
  // Specialization so that we don't print out unprintable characters
  os << static_cast<int>(*param);
}

template<>
inline
void print_helper(std::ostream & os, const unsigned char * param)
{
  // Specialization so that we don't print out unprintable characters
  os << static_cast<int>(*param);
}

//non-member vector print function
template<typename P>
void print_helper(std::ostream & os, const std::vector<P> * param)
{
  for (const auto & p : *param)
    os << p << " ";
}

//non-member vector<vector> print function
template<typename P>
void print_helper(std::ostream & os, const std::vector<std::vector<P>> * param)
{
  for (const auto & pv : *param)
    for (const auto & p : pv)
      os << p << " ";
}

//non-member vector<vector<vector>> print function
template<typename P>
void print_helper(std::ostream & os, const std::vector<std::vector<std::vector<P>>> * param)
{
  for (const auto & pvv : *param)
    for (const auto & pv : pvv)
      for (const auto & p : pv)
        os << p << " ";
}

//non-member map print function
template<typename P1, typename P2, typename C, typename A>
void print_helper(std::ostream & os, const std::map<P1, P2, C, A> * param)
{
  os << '{';
  std::size_t sz = param->size();
  for (auto KV : *param)
    {
      os << '\'' << KV.first << "\' => \'" << KV.second << '\'';
      if (--sz)
        os << ", ";
    }
  os << '}';
}


} // namespace libMesh

#endif // LIBMESH_PARAMETERS_H