Method SetString

src/os/windows/string_uniscribe.cpp:517–567

virtual */

/* virtual */ void UniscribeStringIterator::SetString(std::string_view s)
{
	this->utf16_to_utf8.clear();
	this->str_info.clear();
	this->cur_pos = 0;

	/* Uniscribe operates on UTF-16, thus we have to convert the input string.
	 * To be able to return proper offsets, we have to create a mapping at the same time. */
	std::vector<wchar_t> utf16_str;     ///< UTF-16 copy of the string.
	Utf8View view(s);
	for (auto it = view.begin(), end = view.end(); it != end; ++it) {
		size_t idx = it.GetByteOffset();
		char32_t c = *it;
		if (c < 0x10000) {
			utf16_str.push_back((wchar_t)c);
		} else {
			/* Make a surrogate pair. */
			utf16_str.push_back((wchar_t)(0xD800 + ((c - 0x10000) >> 10)));
			utf16_str.push_back((wchar_t)(0xDC00 + ((c - 0x10000) & 0x3FF)));
			this->utf16_to_utf8.push_back(idx);
		}
		this->utf16_to_utf8.push_back(idx);
	}
	this->utf16_to_utf8.push_back(s.size());

	/* Query Uniscribe for word and cluster break information. */
	this->str_info.resize(utf16_to_utf8.size());

	if (!utf16_str.empty()) {
		/* Itemize string into language runs. */
		std::vector<SCRIPT_ITEM> runs = UniscribeItemizeString(&utf16_str[0], (int32_t)utf16_str.size());

		for (std::vector<SCRIPT_ITEM>::const_iterator run = runs.begin(); !runs.empty() && run != runs.end() - 1; run++) {
			/* Get information on valid word and character break.s */
			int len = (run + 1)->iCharPos - run->iCharPos;
			std::vector<SCRIPT_LOGATTR> attr(len);
			ScriptBreak(&utf16_str[run->iCharPos], len, &run->a, &attr[0]);

			/* Extract the information we're interested in. */
			for (size_t c = 0; c < attr.size(); c++) {
				/* First character of a run is always a valid word break. */
				this->str_info[c + run->iCharPos].word_stop = attr[c].fWordStop || c == 0;
				this->str_info[c + run->iCharPos].char_stop = attr[c].fCharStop;
			}
		}
	}

	/* End-of-string is always a valid stopping point. */
	this->str_info.back().char_stop = true;
	this->str_info.back().word_stop = true;
}

/* virtual */ size_t UniscribeStringIterator::SetCurPosition(size_t pos)
{