string_format.h

#pragma once
 
#include <memory>
#include <string>
 
#include "pflib/Exception.h"
 
namespace pflib::utility {
 
template <typename... Args>
std::string string_format(const std::string& format, Args... args) {
  // length of string without the closing null byte \0
  int size_s = std::snprintf(nullptr, 0, format.c_str(), args...);
  if (size_s < 0) {
    PFEXCEPTION_RAISE("string_format",
                      "error during formating of string " + format);
  }
  // need one larger for the closing null byte
  auto size = static_cast<std::size_t>(size_s + 1);
  std::unique_ptr<char[]> buffer(new char[size]);
  // do format again, but this time we know the size and that it works!
  std::snprintf(buffer.get(), size, format.c_str(), args...);
  // remove trailing null byte when copying into std::string
  return std::string(buffer.get(), buffer.get() + size - 1);
}
 
}  // namespace pflib::utility