construct/ircd/stringops.cc

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2019 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.

std::string
ircd::replace(const string_view &s,
              const char &before,
              const string_view &after)
{
	const uint32_t occurs
	(
		std::count(begin(s), end(s), before)
	);

	const size_t size
	{
		occurs? s.size() + (occurs * after.size()):
		        s.size() - occurs
	};

	return string(size, [&s, &before, &after]
	(const mutable_buffer &buf)
	{
		char *p{begin(buf)};
		std::for_each(begin(s), end(s), [&before, &after, &p]
		(const char &c)
		{
			if(c == before)
			{
				memcpy(p, after.data(), after.size());
				p += after.size();
			}
			else *p++ = c;
		});

		return std::distance(begin(buf), p);
	});
}