Method InsertString

src/textbuf.cpp:157–215

* Insert a string into the text buffer. If maxwidth of the Textbuf is zero, * we don't care about the visual-length but only about the physical * length of the string. * @param str String to insert. * @param marked Replace the currently marked text with the new text. * @param caret Move the caret to this point in the insertion string. * @param insert_location Position at which to insert the

 * @return True on successful change of Textbuf, or false otherwise.
 */
bool Textbuf::InsertString(std::string_view str, bool marked, std::optional<size_t> caret, std::optional<size_t> insert_location, std::optional<size_t> replacement_end)
{
	uint16_t insertpos = (marked && this->marklength != 0) ? this->markpos : this->caretpos;
	if (insert_location.has_value()) {
		insertpos = static_cast<uint16_t>(*insert_location);
		if (insertpos >= this->buf.size()) return false;

		if (replacement_end.has_value()) {
			this->DeleteText(insertpos, static_cast<uint16_t>(*replacement_end), str.empty());
		}
	} else {
		if (marked) this->DiscardMarkedText(str.empty());
	}

	if (str.empty()) return false;

	uint16_t chars = 0;
	uint16_t bytes;
	{
		Utf8View view(str);
		auto cur = view.begin();
		const auto end = view.end();
		while (cur != end) {
			if (!IsValidChar(*cur, this->afilter)) break;

			auto next = cur;
			++next;
			if (this->buf.size() + next.GetByteOffset() >= this->max_bytes) break;
			if (this->chars + chars + 1 > this->max_chars) break;

			cur = next;
			chars++;
		}
		bytes = static_cast<uint16_t>(cur.GetByteOffset());
	}
	if (bytes == 0) return false;

	/* Move caret if needed. */
	if (caret.has_value()) this->caretpos = insertpos + static_cast<uint16_t>(*caret);

	if (marked) {
		this->markpos = insertpos;
		this->markend = insertpos + bytes;
	}

	this->buf.insert(insertpos, str.substr(0, bytes));

	this->chars += chars;
	if (!marked && !caret.has_value()) this->caretpos += bytes;
	assert(this->buf.size() < this->max_bytes);
	assert(this->chars <= this->max_chars);

	this->UpdateStringIter();
	this->UpdateWidth();
	this->UpdateCaretPosition();
	this->UpdateMarkedText();

	return true;