scafacos.cpp

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/*
 * Copyright (C) 2022 The ESPResSo project
 *
 * This file is part of ESPResSo.
 *
 * ESPResSo is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * ESPResSo 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "config/config.hpp"
 
#if defined(ESPRESSO_SCAFACOS) or defined(ESPRESSO_SCAFACOS_DIPOLES)
 
#include "script_interface/Variant.hpp"
#include "script_interface/get_value.hpp"
 
#include "scafacos.hpp"
 
#include "core/scafacos/ScafacosContextBase.hpp"
 
#include <utils/demangle.hpp>
 
#include <algorithm>
#include <functional>
#include <iomanip>
#include <iterator>
#include <optional>
#include <span>
#include <sstream>
#include <stdexcept>
#include <string>
#include <type_traits>
#include <utility>
#include <variant>
#include <vector>
 
namespace ScriptInterface {
namespace Scafacos {
 
std::vector<std::string> available_methods() {
  return ScafacosContextBase::available_methods();
}
 
struct ConvertToStringVector {
  using result_type = std::vector<std::string>;
 
  auto operator()(std::string const &value) const { return result_type{value}; }
 
  template <typename T> result_type operator()(T const &value) const {
    if constexpr (std::is_arithmetic_v<T>) {
      return operator()(to_str(value));
    }
    throw std::runtime_error("Cannot convert " + Utils::demangle<T>());
  }
 
  auto operator()(result_type const &values) const { return values; }
 
  template <typename T, std::size_t N>
  auto operator()(std::span<T, N> const values) const {
    result_type values_str;
    for (auto const &v : values) {
      if constexpr (std::is_same_v<std::remove_cvref_t<T>, Variant>) {
        values_str.emplace_back(std::visit(*this, v).front());
      } else {
        values_str.emplace_back(to_str(v));
      }
    }
    return values_str;
  }
 
  template <typename T> auto operator()(std::vector<T> const &values) const {
    return (*this)(std::span(values.begin(), values.size()));
  }
 
  template <typename T, std::size_t N>
  auto operator()(Utils::Vector<T, N> const &values) const {
    return (*this)(std::span(values.begin(), N));
  }
 
private:
  template <typename T>
    requires std::is_arithmetic_v<T>
  std::string to_str(T const &value) const {
    std::ostringstream serializer;
    if constexpr (std::is_floating_point_v<T>) {
      serializer << std::scientific << std::setprecision(17);
    }
    serializer << value;
    return serializer.str();
  }
};
 
struct GetParameterList {
  using result_type = std::unordered_map<std::string, Variant>;
 
  auto operator()(result_type const &obj) const { return obj; }
 
  template <typename T>
  auto operator()(std::unordered_map<T, Variant> const &obj) const {
    // handle the case of the empty dict, which can have any key type
    return (obj.empty()) ? result_type{} : invalid(obj);
  }
 
  template <typename T> auto operator()(T const &obj) const {
    return invalid(obj);
  }
 
private:
  template <typename T> auto invalid(T const &obj) const {
    return get_value<result_type>(obj);
  }
};
 
std::string serialize_parameters(Variant const &pack) {
  auto const parameters = std::visit(GetParameterList(), pack);
  if (parameters.empty()) {
    throw std::invalid_argument(
        "ScaFaCoS methods require at least 1 parameter");
  }
  auto const visitor = ConvertToStringVector();
  std::string method_params = "";
  for (auto const &[name, values] : parameters) {
    method_params += "," + name;
    for (auto const &value : std::visit(visitor, values)) {
      method_params += "," + value;
    }
  }
  return method_params.substr(1);
}
 
template <typename T>
std::optional<Variant> string_to_number(std::string const &s) {
  auto deserializer = std::istringstream(s);
  T result;
  deserializer >> result;
  if (deserializer.fail() or not deserializer.eof()) {
    return {};
  }
  return Variant{result};
}
 
std::unordered_map<std::string, Variant>
deserialize_parameters(std::string const &parameters) {
  /*
   * ScaFaCoS parameters are serialized to a comma-separated string.
   * Key-value pairs can be split with a look ahead: when the next
   * item is a string, it is a parameter name and the current list
   * of arithmetic values belong to the current parameter name.
   * The only exception is string-valued parameters; in that case
   * the current list of arithmetic values is empty.
   */
  auto const numbers = std::string("-0123456789");
  std::unordered_map<std::string, Variant> method_params{};
  std::vector<std::string> flat_array;
  std::istringstream buffer;
  buffer.str(parameters);
  for (std::string line; std::getline(buffer, line, ',');) {
    flat_array.emplace_back(line);
  }
  for (auto it = flat_array.begin(); it != flat_array.end();) {
    auto const parameter_name = *it;
    auto parameter_list = std::vector<Variant>{};
    for (++it; it != flat_array.end(); ++it) {
      if ((numbers.find(it->front()) == std::string::npos) and
          not parameter_list.empty()) {
        break;
      }
      auto result = Variant{*it};
      if (auto converted = string_to_number<int>(*it)) {
        result = Variant{*converted};
      } else if (auto converted = string_to_number<double>(*it)) {
        result = Variant{*converted};
      }
      parameter_list.emplace_back(result);
    }
    assert(not parameter_list.empty());
    if (parameter_list.size() == 1ul) {
      method_params[parameter_name] = parameter_list.front();
    } else {
      method_params[parameter_name] = Variant{std::move(parameter_list)};
    }
  }
  return method_params;
}
 
} // namespace Scafacos
} // namespace ScriptInterface
 
#endif // ESPRESSO_SCAFACOS or ESPRESSO_SCAFACOS_DIPOLES