Add LineStartPosition to replace common idiom LineStart(LineFromPosition(x)) as

this shortens code. LineStartPosition is also noexcept which allows callers to
be noexcept.

3 files changed, 21 insertions, 23 deletions

diff --git a/src/Document.cxx b/src/Document.cxx
index afe6717a1..2c04bbaae 100644
--- a/src/Document.cxx
+++ b/src/Document.cxx
@@ -453,8 +453,8 @@ Range Document::LineRange(Sci::Line line) const noexcept {
 	return {cb.LineStart(line), cb.LineStart(line + 1)};
 }
 
-bool Document::IsLineStartPosition(Sci::Position position) const {
-	return LineStart(LineFromPosition(position)) == position;
+bool Document::IsLineStartPosition(Sci::Position position) const noexcept {
+	return LineStartPosition(position) == position;
 }
 
 Sci_Position SCI_METHOD Document::LineEnd(Sci_Position line) const {
@@ -477,6 +477,10 @@ Sci::Line Document::SciLineFromPosition(Sci::Position pos) const noexcept {
 	return cb.LineFromPosition(pos);
 }
 
+Sci::Position Document::LineStartPosition(Sci::Position position) const noexcept {
+	return cb.LineStart(cb.LineFromPosition(position));
+}
+
 Sci::Position Document::LineEndPosition(Sci::Position position) const noexcept {
 	return cb.LineEnd(cb.LineFromPosition(position));
 }
@@ -767,7 +771,7 @@ Sci::Position Document::MovePositionOutsideChar(Sci::Position pos, Sci::Position
 		} else {
 			// Anchor DBCS calculations at start of line because start of line can
 			// not be a DBCS trail byte.
-			const Sci::Position posStartLine = cb.LineStart(cb.LineFromPosition(pos));
+			const Sci::Position posStartLine = LineStartPosition(pos);
 			if (pos == posStartLine)
 				return pos;
 
@@ -850,7 +854,7 @@ Sci::Position Document::NextPosition(Sci::Position pos, int moveDir) const noexc
 			} else {
 				// Anchor DBCS calculations at start of line because start of line can
 				// not be a DBCS trail byte.
-				const Sci::Position posStartLine = cb.LineStart(cb.LineFromPosition(pos));
+				const Sci::Position posStartLine = LineStartPosition(pos);
 				// See http://msdn.microsoft.com/en-us/library/cc194792%28v=MSDN.10%29.aspx
 				// http://msdn.microsoft.com/en-us/library/cc194790.aspx
 				if ((pos - 1) <= posStartLine) {
@@ -3079,7 +3083,7 @@ public:
 
 #endif
 
-std::regex_constants::match_flag_type MatchFlags(const Document *doc, Sci::Position startPos, Sci::Position endPos) {
+std::regex_constants::match_flag_type MatchFlags(const Document *doc, Sci::Position startPos, Sci::Position endPos) noexcept {
 	std::regex_constants::match_flag_type flagsMatch = std::regex_constants::match_default;
 	if (!doc->IsLineStartPosition(startPos))
 		flagsMatch |= std::regex_constants::match_not_bol;
diff --git a/src/Document.h b/src/Document.h
index 8889d6454..f7f4eeedd 100644
--- a/src/Document.h
+++ b/src/Document.h
@@ -455,8 +455,9 @@ public:
 	int MarkerHandleFromLine(Sci::Line line, int which) const noexcept;
 	Sci_Position SCI_METHOD LineStart(Sci_Position line) const override;
 	[[nodiscard]] Range LineRange(Sci::Line line) const noexcept;
-	bool IsLineStartPosition(Sci::Position position) const;
+	bool IsLineStartPosition(Sci::Position position) const noexcept;
 	Sci_Position SCI_METHOD LineEnd(Sci_Position line) const override;
+	Sci::Position LineStartPosition(Sci::Position position) const noexcept;
 	Sci::Position LineEndPosition(Sci::Position position) const noexcept;
 	bool IsLineEndPosition(Sci::Position position) const noexcept;
 	bool IsPositionInLineEnd(Sci::Position position) const noexcept;
diff --git a/src/Editor.cxx b/src/Editor.cxx
index dd2fc7e98..7d4417115 100644
--- a/src/Editor.cxx
+++ b/src/Editor.cxx
@@ -623,12 +623,10 @@ void Editor::InvalidateWholeSelection() {
    at the beginning and end of the region lines. */
 SelectionRange Editor::LineSelectionRange(SelectionPosition currentPos_, SelectionPosition anchor_) const {
 	if (currentPos_ > anchor_) {
-		anchor_ = SelectionPosition(
-			pdoc->LineStart(pdoc->LineFromPosition(anchor_.Position())));
+		anchor_ = SelectionPosition(pdoc->LineStartPosition(anchor_.Position()));
 		currentPos_ = SelectionPosition(pdoc->LineEndPosition(currentPos_.Position()));
 	} else {
-		currentPos_ = SelectionPosition(
-			pdoc->LineStart(pdoc->LineFromPosition(currentPos_.Position())));
+		currentPos_ = SelectionPosition(pdoc->LineStartPosition(currentPos_.Position()));
 		anchor_ = SelectionPosition(pdoc->LineEndPosition(anchor_.Position()));
 	}
 	return SelectionRange(currentPos_, anchor_);
@@ -2192,8 +2190,7 @@ void Editor::InsertPasteShape(const char *text, Sci::Position len, PasteShape sh
 		PasteRectangular(sel.Start(), text, len);
 	} else {
 		if (shape == PasteShape::line) {
-			const Sci::Position insertPos =
-				pdoc->LineStart(pdoc->LineFromPosition(sel.MainCaret()));
+			const Sci::Position insertPos = pdoc->LineStartPosition(sel.MainCaret());
 			Sci::Position lengthInserted = pdoc->InsertString(insertPos, text, len);
 			// add the newline if necessary
 			if ((len > 0) && (text[len - 1] != '\n' && text[len - 1] != '\r')) {
@@ -3515,8 +3512,7 @@ int Editor::HorizontalMove(Message iMessage) {
 			break;
 		case Message::HomeRectExtend:
 		case Message::HomeExtend: // only when sel.IsRectangular() && sel.MoveExtends()
-			spCaret = SelectionPosition(
-				pdoc->LineStart(pdoc->LineFromPosition(spCaret.Position())));
+			spCaret = SelectionPosition(pdoc->LineStartPosition(spCaret.Position()));
 			break;
 		case Message::VCHomeRectExtend:
 		case Message::VCHomeExtend: // only when sel.IsRectangular() && sel.MoveExtends()
@@ -3539,8 +3535,7 @@ int Editor::HorizontalMove(Message iMessage) {
 		SelectionPosition selAtLimit = (NaturalDirection(iMessage) > 0) ? sel.Limits().end : sel.Limits().start;
 		switch (iMessage) {
 		case Message::Home:
-			selAtLimit = SelectionPosition(
-				pdoc->LineStart(pdoc->LineFromPosition(selAtLimit.Position())));
+			selAtLimit = SelectionPosition(pdoc->LineStartPosition(selAtLimit.Position()));
 			break;
 		case Message::VCHome:
 			selAtLimit = SelectionPosition(pdoc->VCHomePosition(selAtLimit.Position()));
@@ -3604,8 +3599,7 @@ int Editor::HorizontalMove(Message iMessage) {
 				break;
 			case Message::Home:
 			case Message::HomeExtend:
-				spCaret = SelectionPosition(
-					pdoc->LineStart(pdoc->LineFromPosition(spCaret.Position())));
+				spCaret = SelectionPosition(pdoc->LineStartPosition(spCaret.Position()));
 				break;
 			case Message::HomeDisplay:
 			case Message::HomeDisplayExtend:
@@ -3615,8 +3609,7 @@ int Editor::HorizontalMove(Message iMessage) {
 			case Message::HomeWrapExtend:
 				spCaret = MovePositionSoVisible(StartEndDisplayLine(spCaret.Position(), true), -1);
 				if (spCaretNow <= spCaret)
-					spCaret = SelectionPosition(
-						pdoc->LineStart(pdoc->LineFromPosition(spCaret.Position())));
+					spCaret = SelectionPosition(pdoc->LineStartPosition(spCaret.Position()));
 				break;
 			case Message::VCHome:
 			case Message::VCHomeExtend:
@@ -3766,7 +3759,7 @@ int Editor::DelWordOrLine(Message iMessage) {
 			break;
 		case Message::DelLineLeft:
 			rangeDelete = Range(
-				pdoc->LineStart(pdoc->LineFromPosition(sel.Range(r).caret.Position())),
+				pdoc->LineStartPosition(sel.Range(r).caret.Position()),
 				sel.Range(r).caret.Position());
 			break;
 		case Message::DelLineRight:
@@ -4608,7 +4601,7 @@ void Editor::WordSelection(Sci::Position pos) {
 		// Extend forward to the word containing the character to the left of pos.
 		// Skip ExtendWordSelect if the line is empty or if pos is the first position on the line.
 		// This ensures that a series of empty lines isn't counted as a single "word".
-		if (pos > pdoc->LineStart(pdoc->LineFromPosition(pos)))
+		if (pos > pdoc->LineStartPosition(pos))
 			pos = pdoc->ExtendWordSelect(pdoc->MovePositionOutsideChar(pos - 1, -1), 1);
 		TrimAndSetSelection(pos, wordSelectAnchorStartPos);
 	} else {
@@ -4722,7 +4715,7 @@ void Editor::ButtonDownWithModifiers(Point pt, unsigned int curTime, KeyMod modi
 			} else {
 				// Selecting backwards, or anchor beyond last character on line. In these cases,
 				// we select the word containing the character to the *left* of the anchor.
-				if (charPos > pdoc->LineStart(pdoc->LineFromPosition(charPos))) {
+				if (charPos > pdoc->LineStartPosition(charPos)) {
 					startWord = pdoc->ExtendWordSelect(charPos, -1);
 					endWord = pdoc->ExtendWordSelect(startWord, 1);
 				} else {