mirror of
https://github.com/zerotier/ZeroTierOne.git
synced 2024-12-22 22:32:22 +00:00
46 lines
1.3 KiB
C++
46 lines
1.3 KiB
C++
#if !defined(PQXX_CONCAT_HXX)
|
|
# define PQXX_CONCAT_HXX
|
|
|
|
# include <string>
|
|
# include <string_view>
|
|
|
|
# include "pqxx/strconv.hxx"
|
|
|
|
namespace pqxx::internal
|
|
{
|
|
/// Convert item to a string, write it into [here, end).
|
|
template<typename TYPE>
|
|
void render_item(TYPE const &item, char *&here, char *end)
|
|
{
|
|
here = string_traits<TYPE>::into_buf(here, end, item) - 1;
|
|
}
|
|
|
|
|
|
// C++20: Support non-random_access_range ranges.
|
|
/// Efficiently combine a bunch of items into one big string.
|
|
/** Use this as an optimised version of string concatentation. It takes just
|
|
* about any type; it will represent each item as a string according to its
|
|
* @ref string_traits.
|
|
*
|
|
* This is a simpler, more specialised version of @ref separated_list for a
|
|
* statically known series of items, possibly of different types.
|
|
*/
|
|
template<typename... TYPE>
|
|
[[nodiscard]] inline std::string concat(TYPE... item)
|
|
{
|
|
std::string buf;
|
|
// Size to accommodate string representations of all inputs, minus their
|
|
// terminating zero bytes.
|
|
buf.resize(size_buffer(item...));
|
|
|
|
char *const data{buf.data()};
|
|
char *here = data;
|
|
char *end = data + std::size(buf);
|
|
(render_item(item, here, end), ...);
|
|
|
|
buf.resize(static_cast<std::size_t>(here - data));
|
|
return buf;
|
|
}
|
|
} // namespace pqxx::internal
|
|
#endif
|