Function GetLine

Common/ParameterFileParser/itkParameterFileParser.cxx:308–350

Returns a string_view to the line with the specified line number (counting "1-based").

// Returns a string_view to the line with the specified line number (counting "1-based").
std::string_view
GetLine(const std::string_view contents, const toml::source_index lineNumber)
{
  if (lineNumber == 0)
  {
    return {};
  }

  // The position of the first character of the specified line.
  const auto beginOfLine = [contents, lineNumber]() -> std::size_t {
    if (lineNumber == 1)
    {
      return 0;
    }

    const auto  numberOfChars = contents.size();
    std::size_t currentLineNumber{ 1 };

    for (std::size_t i{}; i < numberOfChars; ++i)
    {
      if (contents[i] == '\n')
      {
        ++currentLineNumber;

        if (currentLineNumber == lineNumber)
        {
          return i + 1;
        }
      }
    }
    return std::string_view::npos;
  }();

  if (beginOfLine >= contents.size())
  {
    return {};
  }

  const auto endOfLine = contents.find_first_of("\r\n", beginOfLine);

  return contents.substr(beginOfLine,
                         (endOfLine == std::string_view::npos) ? std::string_view::npos : (endOfLine - beginOfLine));
}


// Parses the specified TOML file, and returns its key-value pairs as an elastix ParameterMap.