Method FindText

scintilla/src/Document.cxx:1487–1641

* Find text in document, supporting both forward and backward * searches (just pass minPos > maxPos to do a backward search) * Has not been tested with backwards DBCS searches yet. */

 * Has not been tested with backwards DBCS searches yet.
 */
long Document::FindText(int minPos, int maxPos, const char *search,
                        bool caseSensitive, bool word, bool wordStart, bool regExp, int flags,
                        int *length) {
	if (*length <= 0)
		return minPos;
	if (regExp) {
		if (!regex)
			regex = CreateRegexSearch(&charClass);
		return regex->FindText(this, minPos, maxPos, search, caseSensitive, word, wordStart, flags, length);
	} else {

		const bool forward = minPos <= maxPos;
		const int increment = forward ? 1 : -1;

		// Range endpoints should not be inside DBCS characters, but just in case, move them.
		const int startPos = MovePositionOutsideChar(minPos, increment, false);
		const int endPos = MovePositionOutsideChar(maxPos, increment, false);

		// Compute actual search ranges needed
		const int lengthFind = *length;

		//Platform::DebugPrintf("Find %d %d %s %d\n", startPos, endPos, ft->lpstrText, lengthFind);
		const int limitPos = Platform::Maximum(startPos, endPos);
		int pos = startPos;
		if (!forward) {
			// Back all of a character
			pos = NextPosition(pos, increment);
		}
		if (caseSensitive) {
			const int endSearch = (startPos <= endPos) ? endPos - lengthFind + 1 : endPos;
			const char charStartSearch =  search[0];
			while (forward ? (pos < endSearch) : (pos >= endSearch)) {
				if (CharAt(pos) == charStartSearch) {
					bool found = (pos + lengthFind) <= limitPos;
					for (int indexSearch = 1; (indexSearch < lengthFind) && found; indexSearch++) {
						found = CharAt(pos + indexSearch) == search[indexSearch];
					}
					if (found && MatchesWordOptions(word, wordStart, pos, lengthFind)) {
						return pos;
					}
				}
				if (!NextCharacter(pos, increment))
					break;
			}
		} else if (SC_CP_UTF8 == dbcsCodePage) {
			const size_t maxFoldingExpansion = 4;
			std::vector<char> searchThing(lengthFind * UTF8MaxBytes * maxFoldingExpansion + 1);
			const int lenSearch = static_cast<int>(
				pcf->Fold(&searchThing[0], searchThing.size(), search, lengthFind));
			char bytes[UTF8MaxBytes + 1];
			char folded[UTF8MaxBytes * maxFoldingExpansion + 1];
			while (forward ? (pos < endPos) : (pos >= endPos)) {
				int widthFirstCharacter = 0;
				int posIndexDocument = pos;
				int indexSearch = 0;
				bool characterMatches = true;
				for (;;) {
					const unsigned char leadByte = static_cast<unsigned char>(cb.CharAt(posIndexDocument));