Method concat

Sming/Wiring/WString.cpp:336–367

/*********************************************/

bool String::concat(const char* cstr, size_t length)
{
	if(length == 0) {
		return true; // Nothing to add
	}
	if(!cstr) {
		return false; // Bad argument (length is non-zero)
	}

	auto len = this->length();
	size_t newlen = len + length;

	// Appending all or part of self requires special handling
	auto buf = buffer();
	if(cstr >= buf && cstr < (buf + len)) {
		auto offset = cstr - buf;
		if(!reserve(newlen)) {
			return false;
		}
		buf = buffer();
		memcpy(buf + len, buf + offset, length);
		setlen(newlen);
		return true;
	}

	if(!reserve(newlen)) {
		return false;
	}
	memcpy(buffer() + len, cstr, length);
	setlen(newlen);
	return true;
}

bool String::concat(const FlashString& fstr)
{