X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/ebc5f7ed172f242031fc644120ce45f690b619bc..4bd1f48f0bf1ad1703be680ec2a38d626c6a2668:/src/xbt/config.cpp

diff --git a/src/xbt/config.cpp b/src/xbt/config.cpp
index 964343c37d..d2f380be0c 100644
--- a/src/xbt/config.cpp
+++ b/src/xbt/config.cpp
@@ -1,37 +1,858 @@
-/* Copyright (c) 2016. The SimGrid Team.
- * All rights reserved.                                                     */
+/* Copyright (c) 2004-2017. The SimGrid Team. All rights reserved.     */
 
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
 
+#include <cstdio>
+
+#include <algorithm>
+#include <cerrno>
+#include <cstring>
+#include <climits>
+
 #include <functional>
+#include <map>
+#include <stdexcept>
 #include <string>
+#include <type_traits>
+#include <typeinfo>
+#include <vector>
 
+#include <xbt/ex.hpp>
 #include <xbt/config.h>
 #include <xbt/config.hpp>
+#include "xbt/misc.h"
+#include "xbt/sysdep.h"
+#include "xbt/log.h"
+#include "xbt/dynar.h"
+
+XBT_LOG_NEW_DEFAULT_SUBCATEGORY(xbt_cfg, xbt, "configuration support");
+
+XBT_EXPORT_NO_IMPORT(xbt_cfg_t) simgrid_config = nullptr;
+extern "C" {
+  XBT_PUBLIC(void) sg_config_finalize();
+}
 
 namespace simgrid {
 namespace config {
 
-static void callCallback(const char* name, void* data)
+missing_key_error::~missing_key_error() = default;
+
+class Config;
+
+namespace {
+
+const char* true_values[] = {
+  "yes", "on", "true", "1"
+};
+const char* false_values[] = {
+  "no", "off", "false", "0"
+};
+
+static bool parseBool(const char* value)
+{
+  for (const char* const& true_value : true_values)
+    if (std::strcmp(true_value, value) == 0)
+      return true;
+  for (const char* const& false_value : false_values)
+    if (std::strcmp(false_value, value) == 0)
+      return false;
+  throw std::range_error("not a boolean");
+}
+
+static double parseDouble(const char* value)
+{
+  char* end;
+  errno = 0;
+  double res = std::strtod(value, &end);
+  if (errno == ERANGE)
+    throw std::range_error("out of range");
+  else if (errno)
+    xbt_die("Unexpected errno");
+  if (end == value || *end != '\0')
+    throw std::range_error("invalid double");
+  else
+    return res;
+}
+
+static long int parseLong(const char* value)
+{
+  char* end;
+  errno = 0;
+  long int res = std::strtol(value, &end, 0);
+  if (errno) {
+    if (res == LONG_MIN && errno == ERANGE)
+      throw std::range_error("underflow");
+    else if (res == LONG_MAX && errno == ERANGE)
+      throw std::range_error("overflow");
+    xbt_die("Unexpected errno");
+  }
+  if (end == value || *end != '\0')
+    throw std::range_error("invalid integer");
+  else
+    return res;
+}
+
+// ***** ConfigType *****
+
+/// A trait which define possible options types:
+template<class T> struct ConfigType;
+
+template<> struct ConfigType<int> {
+  static constexpr const char* type_name = "int";
+  static inline double parse(const char* value)
+  {
+    return parseLong(value);
+  }
+};
+template<> struct ConfigType<double> {
+  static constexpr const char* type_name = "double";
+  static inline double parse(const char* value)
+  {
+    return parseDouble(value);
+  }
+};
+template<> struct ConfigType<std::string> {
+  static constexpr const char* type_name = "string";
+  static inline std::string parse(const char* value)
+  {
+    return std::string(value);
+  }
+};
+template<> struct ConfigType<bool> {
+  static constexpr const char* type_name = "boolean";
+  static inline bool parse(const char* value)
+  {
+    return parseBool(value);
+  }
+};
+
+// **** Forward declarations ****
+
+class ConfigurationElement ;
+template<class T> class TypedConfigurationElement;
+
+// **** ConfigurationElement ****
+
+class ConfigurationElement {
+protected:
+  std::string key;
+  std::string desc;
+  bool isdefault = true;
+
+public:
+  /* Callback */
+  xbt_cfg_cb_t old_callback = nullptr;
+
+  ConfigurationElement(const char* key, const char* desc)
+    : key(key ? key : ""), desc(desc ? desc : "") {}
+  ConfigurationElement(const char* key, const char* desc, xbt_cfg_cb_t cb)
+    : key(key ? key : ""), desc(desc ? desc : ""), old_callback(cb) {}
+
+  virtual ~ConfigurationElement()=default;
+
+  virtual std::string getStringValue() = 0;
+  virtual void setStringValue(const char* value) = 0;
+  virtual const char* getTypeName() = 0;
+
+  template<class T>
+  T const& getValue() const
+  {
+    return dynamic_cast<const TypedConfigurationElement<T>&>(*this).getValue();
+  }
+  template<class T>
+  void setValue(T value)
+  {
+    dynamic_cast<TypedConfigurationElement<T>&>(*this).setValue(std::move(value));
+  }
+  template<class T>
+  void setDefaultValue(T value)
+  {
+    dynamic_cast<TypedConfigurationElement<T>&>(*this).setDefaultValue(std::move(value));
+  }
+  bool isDefault() const { return isdefault; }
+
+  std::string const& getDescription() const { return desc; }
+  std::string const& getKey() const { return key; }
+};
+
+// **** TypedConfigurationElement<T> ****
+
+// TODO, could we use boost::any with some Type* reference?
+template<class T>
+class TypedConfigurationElement : public ConfigurationElement {
+private:
+  T content;
+  std::function<void(T&)> callback;
+
+public:
+  TypedConfigurationElement(const char* key, const char* desc, T value = T())
+    : ConfigurationElement(key, desc), content(std::move(value))
+  {}
+  TypedConfigurationElement(const char* key, const char* desc, T value, xbt_cfg_cb_t cb)
+      : ConfigurationElement(key, desc, cb), content(std::move(value))
+  {}
+  TypedConfigurationElement(const char* key, const char* desc, T value, std::function<void(T&)> callback)
+      : ConfigurationElement(key, desc), content(std::move(value)), callback(std::move(callback))
+  {}
+  ~TypedConfigurationElement() = default;
+
+  std::string getStringValue() override;
+  const char* getTypeName() override;
+  void setStringValue(const char* value) override;
+
+  void update()
+  {
+    if (old_callback)
+      this->old_callback(key.c_str());
+    if (this->callback)
+      this->callback(this->content);
+  }
+
+  T const& getValue() const { return content; }
+
+  void setValue(T value)
+  {
+    this->content = std::move(value);
+    this->update();
+  }
+
+  void setDefaultValue(T value)
+  {
+    if (this->isdefault) {
+      this->content = std::move(value);
+      this->update();
+    } else {
+      XBT_DEBUG("Do not override configuration variable '%s' with value '%s' because it was already set.", key.c_str(),
+                to_string(value).c_str());
+    }
+  }
+};
+
+template<class T>
+std::string TypedConfigurationElement<T>::getStringValue() // override
+{
+  return to_string(content);
+}
+
+template<class T>
+void TypedConfigurationElement<T>::setStringValue(const char* value) // override
+{
+  this->content = ConfigType<T>::parse(value);
+  this->isdefault = false;
+  this->update();
+}
+
+template<class T>
+const char* TypedConfigurationElement<T>::getTypeName() // override
+{
+  return ConfigType<T>::type_name;
+}
+
+} // end of anonymous namespace
+
+// **** Config ****
+
+class Config {
+private:
+  // name -> ConfigElement:
+  std::map<std::string, simgrid::config::ConfigurationElement*> options;
+  // alias -> xbt_dict_elm_t from options:
+  std::map<std::string, simgrid::config::ConfigurationElement*> aliases;
+  bool warn_for_aliases = true;
+
+public:
+  Config() = default;
+  ~Config();
+
+  // No copy:
+  Config(Config const&) = delete;
+  Config& operator=(Config const&) = delete;
+
+  ConfigurationElement& operator[](const char* name);
+  template<class T>
+  TypedConfigurationElement<T>& getTyped(const char* name);
+  void alias(const char* realname, const char* aliasname);
+
+  template<class T, class... A>
+  simgrid::config::TypedConfigurationElement<T>*
+    registerOption(const char* name, A&&... a)
+  {
+    xbt_assert(options.find(name) == options.end(), "Refusing to register the config element '%s' twice.", name);
+    TypedConfigurationElement<T>* variable = new TypedConfigurationElement<T>(name, std::forward<A>(a)...);
+    XBT_DEBUG("Register cfg elm %s (%s) of type %s @%p in set %p)", name, variable->getDescription().c_str(),
+              variable->getTypeName(), variable, this);
+    options.insert({name, variable});
+    variable->update();
+    return variable;
+  }
+
+  // Debug:
+  void dump(const char *name, const char *indent);
+  void showAliases();
+  void help();
+
+protected:
+  ConfigurationElement* getDictElement(const char* name);
+};
+
+Config::~Config()
+{
+  XBT_DEBUG("Frees cfg set %p", this);
+  for (auto const& elm : options)
+    delete elm.second;
+}
+
+inline ConfigurationElement* Config::getDictElement(const char* name)
+{
+  auto opt = options.find(name);
+  if (opt != options.end()) {
+    return opt->second;
+  } else {
+    auto als = aliases.find(name);
+    if (als != aliases.end()) {
+      ConfigurationElement* res = als->second;
+      if (warn_for_aliases)
+        XBT_INFO("Option %s has been renamed to %s. Consider switching.", name, res->getKey().c_str());
+      return res;
+    } else {
+      throw simgrid::config::missing_key_error(std::string("Bad config key: ") + name);
+    }
+  }
+}
+
+inline ConfigurationElement& Config::operator[](const char* name)
+{
+  return *(getDictElement(name));
+}
+
+void Config::alias(const char* realname, const char* aliasname)
+{
+  xbt_assert(aliases.find(aliasname) == aliases.end(), "Alias '%s' already.", aliasname);
+  ConfigurationElement* element = this->getDictElement(realname);
+  xbt_assert(element, "Cannot define an alias to the non-existing option '%s'.", realname);
+  this->aliases.insert({aliasname, element});
+}
+
+/** @brief Dump a config set for debuging purpose
+ *
+ * @param name The name to give to this config set
+ * @param indent what to write at the beginning of each line (right number of spaces)
+ */
+void Config::dump(const char *name, const char *indent)
+{
+  if (name)
+    printf("%s>> Dumping of the config set '%s':\n", indent, name);
+
+  for (auto const& elm : options)
+    printf("%s  %s: ()%s) %s", indent, elm.first.c_str(), elm.second->getTypeName(),
+           elm.second->getStringValue().c_str());
+
+  if (name)
+    printf("%s<< End of the config set '%s'\n", indent, name);
+  fflush(stdout);
+}
+
+/** @brief Displays the declared aliases and their description */
+void Config::showAliases()
+{
+  bool old_warn_for_aliases = false;
+  std::swap(warn_for_aliases, old_warn_for_aliases);
+  for (auto const& elm : aliases)
+    printf("   %s: %s\n", elm.first.c_str(), (*this)[elm.first.c_str()].getDescription().c_str());
+  std::swap(warn_for_aliases, old_warn_for_aliases);
+}
+
+/** @brief Displays the declared options and their description */
+void Config::help()
+{
+  for (auto const& elm : options) {
+    simgrid::config::ConfigurationElement* variable = this->options.at(elm.first);
+    printf("   %s: %s\n", elm.first.c_str(), variable->getDescription().c_str());
+    printf("       Type: %s; ", variable->getTypeName());
+    printf("Current value: %s\n", variable->getStringValue().c_str());
+  }
+}
+
+// ***** getConfig *****
+
+template<class T>
+XBT_PUBLIC(T const&) getConfig(const char* name)
+{
+  return (*simgrid_config)[name].getValue<T>();
+}
+
+template XBT_PUBLIC(int const&) getConfig<int>(const char* name);
+template XBT_PUBLIC(double const&) getConfig<double>(const char* name);
+template XBT_PUBLIC(bool const&) getConfig<bool>(const char* name);
+template XBT_PUBLIC(std::string const&) getConfig<std::string>(const char* name);
+
+// ***** alias *****
+
+void alias(const char* realname, const char* aliasname)
+{
+  simgrid_config->alias(realname, aliasname);
+}
+
+// ***** declareFlag *****
+
+template<class T>
+XBT_PUBLIC(void) declareFlag(const char* name, const char* description,
+  T value, std::function<void(const T&)> callback)
+{
+  if (simgrid_config == nullptr) {
+    simgrid_config = xbt_cfg_new();
+    atexit(sg_config_finalize);
+  }
+  simgrid_config->registerOption<T>(
+    name, description, std::move(value), std::move(callback));
+}
+
+template XBT_PUBLIC(void) declareFlag(const char* name,
+  const char* description, int value, std::function<void(int const &)> callback);
+template XBT_PUBLIC(void) declareFlag(const char* name,
+  const char* description, double value, std::function<void(double const &)> callback);
+template XBT_PUBLIC(void) declareFlag(const char* name,
+  const char* description, bool value, std::function<void(bool const &)> callback);
+template XBT_PUBLIC(void) declareFlag(const char* name,
+  const char* description, std::string value, std::function<void(std::string const &)> callback);
+
+}
+}
+
+// ***** C bindings *****
+
+xbt_cfg_t xbt_cfg_new()        { return new simgrid::config::Config(); }
+void xbt_cfg_free(xbt_cfg_t * cfg) { delete *cfg; }
+
+void xbt_cfg_dump(const char *name, const char *indent, xbt_cfg_t cfg)
+{
+  cfg->dump(name, indent);
+}
+
+/*----[ Registering stuff ]-----------------------------------------------*/
+
+void xbt_cfg_register_double(const char *name, double default_value,
+  xbt_cfg_cb_t cb_set, const char *desc)
+{
+  if (simgrid_config == nullptr)
+    simgrid_config = xbt_cfg_new();
+  simgrid_config->registerOption<double>(name, desc, default_value, cb_set);
+}
+
+void xbt_cfg_register_int(const char *name, int default_value,xbt_cfg_cb_t cb_set, const char *desc)
+{
+  if (simgrid_config == nullptr) {
+    simgrid_config = xbt_cfg_new();
+    atexit(&sg_config_finalize);
+  }
+  simgrid_config->registerOption<int>(name, desc, default_value, cb_set);
+}
+
+void xbt_cfg_register_string(const char *name, const char *default_value, xbt_cfg_cb_t cb_set, const char *desc)
+{
+  if (simgrid_config == nullptr) {
+    simgrid_config = xbt_cfg_new();
+    atexit(sg_config_finalize);
+  }
+  simgrid_config->registerOption<std::string>(name, desc,
+    default_value ? default_value : "", cb_set);
+}
+
+void xbt_cfg_register_boolean(const char *name, const char*default_value,xbt_cfg_cb_t cb_set, const char *desc)
+{
+  if (simgrid_config == nullptr) {
+    simgrid_config = xbt_cfg_new();
+    atexit(sg_config_finalize);
+  }
+  simgrid_config->registerOption<bool>(name, desc, simgrid::config::parseBool(default_value), cb_set);
+}
+
+void xbt_cfg_register_alias(const char *realname, const char *aliasname)
+{
+  if (simgrid_config == nullptr) {
+    simgrid_config = xbt_cfg_new();
+    atexit(sg_config_finalize);
+  }
+  simgrid_config->alias(realname, aliasname);
+}
+
+void xbt_cfg_aliases() { simgrid_config->showAliases(); }
+void xbt_cfg_help()    { simgrid_config->help(); }
+
+/*----[ Setting ]---------------------------------------------------------*/
+
+/** @brief Add values parsed from a string into a config set
+ *
+ * @param options a string containing the content to add to the config set. This is a '\\t',' ' or '\\n' or ','
+ * separated list of variables. Each individual variable is like "[name]:[value]" where [name] is the name of an
+ * already registered variable, and [value] conforms to the data type under which this variable was registered.
+ *
+ * @todo This is a crude manual parser, it should be a proper lexer.
+ */
+void xbt_cfg_set_parse(const char *options)
+{
+  if (not options || not strlen(options)) { /* nothing to do */
+    return;
+  }
+  char *optionlist_cpy = xbt_strdup(options);
+
+  XBT_DEBUG("List to parse and set:'%s'", options);
+  char *option = optionlist_cpy;
+  while (1) {                   /* breaks in the code */
+    if (not option)
+      break;
+    char *name = option;
+    int len = strlen(name);
+    XBT_DEBUG("Still to parse and set: '%s'. len=%d; option-name=%ld", name, len, (long) (option - name));
+
+    /* Pass the value */
+    while (option - name <= (len - 1) && *option != ' ' && *option != '\n' && *option != '\t' && *option != ',') {
+      XBT_DEBUG("Take %c.", *option);
+      option++;
+    }
+    if (option - name == len) {
+      XBT_DEBUG("Boundary=EOL");
+      option = nullptr;            /* don't do next iteration */
+    } else {
+      XBT_DEBUG("Boundary on '%c'. len=%d;option-name=%ld", *option, len, (long) (option - name));
+      /* Pass the following blank chars */
+      *(option++) = '\0';
+      while (option - name < (len - 1) && (*option == ' ' || *option == '\n' || *option == '\t')) {
+        /*      fprintf(stderr,"Ignore a blank char.\n"); */
+        option++;
+      }
+      if (option - name == len - 1)
+        option = nullptr;          /* don't do next iteration */
+    }
+    XBT_DEBUG("parse now:'%s'; parse later:'%s'", name, option);
+
+    if (name[0] == ' ' || name[0] == '\n' || name[0] == '\t')
+      continue;
+    if (not strlen(name))
+      break;
+
+    char *val = strchr(name, ':');
+    xbt_assert(val, "Option '%s' badly formatted. Should be of the form 'name:value'", name);
+    /* don't free(optionlist_cpy) if the assert fails, 'name' points inside it */
+    *(val++) = '\0';
+
+    if (strncmp(name, "path", strlen("path")))
+      XBT_INFO("Configuration change: Set '%s' to '%s'", name, val);
+
+    try {
+      (*simgrid_config)[name].setStringValue(val);
+    }
+    catch (simgrid::config::missing_key_error& e) {
+      goto on_missing_key;
+    }
+    catch (...) {
+      goto on_exception;
+    }
+  }
+
+  free(optionlist_cpy);
+  return;
+
+  /* Do not THROWF from a C++ exception catching context, or some cleanups will be missing */
+on_missing_key:
+  free(optionlist_cpy);
+  THROWF(not_found_error, 0, "Could not set variables %s", options);
+  return;
+on_exception:
+  free(optionlist_cpy);
+  THROWF(unknown_error, 0, "Could not set variables %s", options);
+}
+
+// Horrible mess to translate C++ exceptions to C exceptions:
+// Exit from the catch block (and do the correct exception cleaning) before attempting to THROWF.
+#define TRANSLATE_EXCEPTIONS(...) \
+  catch(simgrid::config::missing_key_error& e) { THROWF(not_found_error, 0, __VA_ARGS__); abort(); } \
+  catch(...) { THROWF(not_found_error, 0, __VA_ARGS__); abort(); }
+
+/** @brief Set the value of a variable, using the string representation of that value
+ *
+ * @param key name of the variable to modify
+ * @param value string representation of the value to set
+ */
+
+void xbt_cfg_set_as_string(const char *key, const char *value)
+{
+  try {
+    (*simgrid_config)[key].setStringValue(value);
+    return;
+  }
+  TRANSLATE_EXCEPTIONS("Could not set variable %s as string %s", key, value);
+}
+
+/** @brief Set an integer value to \a name within \a cfg if it wasn't changed yet
+ *
+ * This is useful to change the default value of a variable while allowing
+ * users to override it with command line arguments
+ */
+void xbt_cfg_setdefault_int(const char *key, int value)
+{
+  try {
+    (*simgrid_config)[key].setDefaultValue<int>(value);
+    return;
+  }
+  TRANSLATE_EXCEPTIONS("Could not set variable %s to default integer %i", key, value);
+}
+
+/** @brief Set an integer value to \a name within \a cfg if it wasn't changed yet
+ *
+ * This is useful to change the default value of a variable while allowing
+ * users to override it with command line arguments
+ */
+void xbt_cfg_setdefault_double(const char *key, double value)
+{
+  try {
+    (*simgrid_config)[key].setDefaultValue<double>(value);
+    return;
+  }
+  TRANSLATE_EXCEPTIONS("Could not set variable %s to default double %f", key, value);
+}
+
+/** @brief Set a string value to \a name within \a cfg if it wasn't changed yet
+ *
+ * This is useful to change the default value of a variable while allowing
+ * users to override it with command line arguments
+ */
+void xbt_cfg_setdefault_string(const char *key, const char *value)
 {
-  (*(std::function<void(const char*)>*) data)(name);
+  try {
+    (*simgrid_config)[key].setDefaultValue<std::string>(value ? value : "");
+    return;
+  }
+  TRANSLATE_EXCEPTIONS("Could not set variable %s to default string %s", key, value);
 }
 
-static void freeCallback(void* data)
+/** @brief Set an boolean value to \a name within \a cfg if it wasn't changed yet
+ *
+ * This is useful to change the default value of a variable while allowing
+ * users to override it with command line arguments
+ */
+void xbt_cfg_setdefault_boolean(const char *key, const char *value)
 {
-  delete (std::function<void(const char*)>*) data;
+  try {
+    (*simgrid_config)[key].setDefaultValue<bool>(simgrid::config::parseBool(value));
+    return;
+  }
+  TRANSLATE_EXCEPTIONS("Could not set variable %s to default boolean %s", key, value);
 }
 
-void registerConfig(const char* name, const char* description,
-  e_xbt_cfgelm_type_t type,
-  std::function<void(const char*)> callback)
+/** @brief Set an integer value to \a name within \a cfg
+ *
+ * @param key the name of the variable
+ * @param value the value of the variable
+ */
+void xbt_cfg_set_int(const char *key, int value)
 {
-  std::function<void(const char*)>* code
-    = new std::function<void(const char*)>(std::move(callback));
-  xbt_cfg_register_ext(name, description, type,
-    callCallback, code, freeCallback);
+  try {
+    (*simgrid_config)[key].setValue<int>(value);
+    return;
+  }
+  TRANSLATE_EXCEPTIONS("Could not set variable %s to integer %i", key, value);
 }
 
+/** @brief Set or add a double value to \a name within \a cfg
+ *
+ * @param key the name of the variable
+ * @param value the double to set
+ */
+void xbt_cfg_set_double(const char *key, double value)
+{
+  try {
+    (*simgrid_config)[key].setValue<double>(value);
+    return;
+  }
+  TRANSLATE_EXCEPTIONS("Could not set variable %s to double %f", key, value);
 }
-}
\ No newline at end of file
+
+/** @brief Set or add a string value to \a name within \a cfg
+ *
+ * @param key the name of the variable
+ * @param value the value to be added
+ *
+ */
+void xbt_cfg_set_string(const char *key, const char *value)
+{
+  try {
+    (*simgrid_config)[key].setValue<std::string>(value ? value : "");
+    return;
+  }
+  TRANSLATE_EXCEPTIONS("Could not set variable %s to string %s", key, value);
+}
+
+/** @brief Set or add a boolean value to \a name within \a cfg
+ *
+ * @param key the name of the variable
+ * @param value the value of the variable
+ */
+void xbt_cfg_set_boolean(const char *key, const char *value)
+{
+  try {
+    (*simgrid_config)[key].setValue<bool>(simgrid::config::parseBool(value));
+    return;
+  }
+  TRANSLATE_EXCEPTIONS("Could not set variable %s to boolean %s", key, value);
+}
+
+
+/* Say if the value is the default value */
+int xbt_cfg_is_default_value(const char *key)
+{
+  try {
+    return (*simgrid_config)[key].isDefault() ? 1 : 0;
+  }
+  TRANSLATE_EXCEPTIONS("Could not get variable %s", key);
+}
+
+/*----[ Getting ]---------------------------------------------------------*/
+/** @brief Retrieve an integer value of a variable (get a warning if not uniq)
+ *
+ * @param key the name of the variable
+ *
+ * Returns the first value from the config set under the given name.
+ */
+int xbt_cfg_get_int(const char *key)
+{
+  try {
+    return (*simgrid_config)[key].getValue<int>();
+  }
+  TRANSLATE_EXCEPTIONS("Could not get variable %s", key);
+}
+
+/** @brief Retrieve a double value of a variable (get a warning if not uniq)
+ *
+ * @param key the name of the variable
+ *
+ * Returns the first value from the config set under the given name.
+ */
+double xbt_cfg_get_double(const char *key)
+{
+  try {
+    return (*simgrid_config)[key].getValue<double>();
+  }
+  TRANSLATE_EXCEPTIONS("Could not get variable %s", key);
+}
+
+/** @brief Retrieve a string value of a variable (get a warning if not uniq)
+ *
+ * @param key the name of the variable
+ *
+ * Returns the first value from the config set under the given name.
+ * If there is more than one value, it will issue a warning.
+ * Returns nullptr if there is no value.
+ *
+ * \warning the returned value is the actual content of the config set
+ */
+char *xbt_cfg_get_string(const char *key)
+{
+  try {
+    return (char*) (*simgrid_config)[key].getValue<std::string>().c_str();
+  }
+  TRANSLATE_EXCEPTIONS("Could not get variable %s", key);
+}
+
+/** @brief Retrieve a boolean value of a variable (get a warning if not uniq)
+ *
+ * @param key the name of the variable
+ *
+ * Returns the first value from the config set under the given name.
+ * If there is more than one value, it will issue a warning.
+ */
+int xbt_cfg_get_boolean(const char *key)
+{
+  try {
+    return (*simgrid_config)[key].getValue<bool>() ? 1 : 0;
+  }
+  TRANSLATE_EXCEPTIONS("Could not get variable %s", key);
+}
+
+#ifdef SIMGRID_TEST
+
+#include <string>
+
+#include "xbt.h"
+#include "xbt/ex.h"
+#include <xbt/ex.hpp>
+
+#include <xbt/config.hpp>
+
+XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(xbt_cfg);
+
+XBT_TEST_SUITE("config", "Configuration support");
+
+XBT_PUBLIC_DATA(xbt_cfg_t) simgrid_config;
+
+static void make_set()
+{
+  simgrid_config = nullptr;
+  xbt_log_threshold_set(&_XBT_LOGV(xbt_cfg), xbt_log_priority_critical);
+  xbt_cfg_register_int("speed", 0, nullptr, "");
+  xbt_cfg_register_string("peername", "", nullptr, "");
+  xbt_cfg_register_string("user", "", nullptr, "");
+}                               /* end_of_make_set */
+
+XBT_TEST_UNIT("memuse", test_config_memuse, "Alloc and free a config set")
+{
+  auto temp = simgrid_config;
+  make_set();
+  xbt_test_add("Alloc and free a config set");
+  xbt_cfg_set_parse("peername:veloce user:bidule");
+  xbt_cfg_free(&simgrid_config);
+  simgrid_config = temp;
+}
+
+XBT_TEST_UNIT("use", test_config_use, "Data retrieving tests")
+{
+  auto temp = simgrid_config;
+  make_set();
+  xbt_test_add("Get a single value");
+  {
+    /* get_single_value */
+    xbt_cfg_set_parse("peername:toto:42 speed:42");
+    int ival = xbt_cfg_get_int("speed");
+    if (ival != 42)
+      xbt_test_fail("Speed value = %d, I expected 42", ival);
+  }
+
+  xbt_test_add("Access to a non-existant entry");
+  {
+    try {
+      xbt_cfg_set_parse("color:blue");
+    } catch(xbt_ex& e) {
+      if (e.category != not_found_error)
+        xbt_test_exception(e);
+    }
+  }
+  xbt_cfg_free(&simgrid_config);
+  simgrid_config = temp;
+}
+
+XBT_TEST_UNIT("c++flags", test_config_cxx_flags, "C++ flags")
+{
+  auto temp = simgrid_config;
+  make_set();
+  xbt_test_add("C++ declaration of flags");
+
+  simgrid::config::Flag<int> int_flag("int", "", 0);
+  simgrid::config::Flag<std::string> string_flag("string", "", "foo");
+  simgrid::config::Flag<double> double_flag("double", "", 0.32);
+  simgrid::config::Flag<bool> bool_flag1("bool1", "", false);
+  simgrid::config::Flag<bool> bool_flag2("bool2", "", true);
+
+  xbt_test_add("Parse values");
+  xbt_cfg_set_parse("int:42 string:bar double:8.0 bool1:true bool2:false");
+  xbt_test_assert(int_flag == 42, "Check int flag");
+  xbt_test_assert(string_flag == "bar", "Check string flag");
+  xbt_test_assert(double_flag == 8.0, "Check double flag");
+  xbt_test_assert(bool_flag1, "Check bool1 flag");
+  xbt_test_assert(not bool_flag2, "Check bool2 flag");
+
+  xbt_cfg_free(&simgrid_config);
+  simgrid_config = temp;
+}
+
+#endif                          /* SIMGRID_TEST */