Function MapFromWindowsEnvironment

cpp-subprocess/subprocess.hpp:441–484

env_map_t MapFromWindowsEnvironment() Imports current Environment in a C-string table Parses the strings by splitting on the first "=" per line Creates a map of the variables Returns the map

  // * Creates a map of the variables
  // * Returns the map
  inline env_map_t MapFromWindowsEnvironment(){
      wchar_t *variable_strings_ptr;
      wchar_t *environment_strings_ptr;
      std::wstring delimiter(L"=");
      int del_len = delimiter.length();
      env_map_t mapped_environment;

      // Get a pointer to the environment block.
      environment_strings_ptr = GetEnvironmentStringsW();
      // If the returned pointer is NULL, exit.
      if (environment_strings_ptr == NULL)
      {
          throw OSError("GetEnvironmentStringsW", 0);
      }

      // Variable strings are separated by NULL byte, and the block is
      // terminated by a NULL byte.

      variable_strings_ptr = (wchar_t *) environment_strings_ptr;

      //Since the environment map ends with a null, we can loop until we find it.
      while (*variable_strings_ptr)
      {
          // Create a string from Variable String
          platform_str_t current_line(variable_strings_ptr);
          // Find the first "equals" sign.
          auto pos = current_line.find(delimiter);
          // Assuming it's not missing ...
          if(pos!=std::wstring::npos){
              // ... parse the key and value.
              platform_str_t key = current_line.substr(0, pos);
              platform_str_t value = current_line.substr(pos + del_len);
              // Map the entry.
              mapped_environment[key] = value;
          }
          // Jump to next line in the environment map.
          variable_strings_ptr += std::wcslen(variable_strings_ptr) + 1;
      }
      // We're done with the old environment map buffer.
      FreeEnvironmentStringsW(environment_strings_ptr);

      // Return the map.
      return mapped_environment;
  }

  // env_vector_t WindowsEnvironmentVectorFromMap(const env_map_t &source_map)
  // * Creates a vector buffer for the new environment string table