Simplify SelectionRange::Intersect and add SelectionRange constructor from

positions without virtual space.
Add unit tests.

2 files changed, 18 insertions, 14 deletions

diff --git a/src/Selection.cxx b/src/Selection.cxx
index 7b517cc4a..20fb1efca 100644
--- a/src/Selection.cxx
+++ b/src/Selection.cxx
@@ -170,20 +170,15 @@ bool SelectionRange::ContainsCharacter(SelectionPosition spCharacter) const noex
 }
 
 SelectionSegment SelectionRange::Intersect(SelectionSegment check) const noexcept {
-	const SelectionSegment inOrder(caret, anchor);
-	if ((inOrder.start <= check.end) || (inOrder.end >= check.start)) {
-		SelectionSegment portion = check;
-		if (portion.start < inOrder.start)
-			portion.start = inOrder.start;
-		if (portion.end > inOrder.end)
-			portion.end = inOrder.end;
-		if (portion.start > portion.end)
-			return SelectionSegment();
-		else
-			return portion;
-	} else {
-		return SelectionSegment();
-	}
+	const SelectionSegment inOrder = AsSegment();
+	if ((inOrder.start > check.end) || (inOrder.end < check.start)) {
+		// Nothing in common, not even touching so return empty *invalid* segment
+		return {};
+	}
+	return {
+		std::max(check.start, inOrder.start),
+		std::min(check.end, inOrder.end)
+	};
 }
 
 void SelectionRange::Swap() noexcept {
diff --git a/src/Selection.h b/src/Selection.h
index 57de92a57..8ffcbb0bb 100644
--- a/src/Selection.h
+++ b/src/Selection.h
@@ -81,6 +81,12 @@ struct SelectionSegment {
 			end = a;
 		}
 	}
+	constexpr SelectionSegment(Sci::Position a, Sci::Position b) :
+		SelectionSegment(SelectionPosition(a), SelectionPosition(b)) {
+	}
+	[[nodiscard]] constexpr bool operator ==(const SelectionSegment &other) const noexcept {
+		return (start == other.start) && (end == other.end);
+	}
 	bool Empty() const noexcept {
 		return start == end;
 	}
@@ -115,6 +121,9 @@ struct SelectionRange {
 	constexpr SelectionRange(Sci::Position caret_, Sci::Position anchor_) noexcept : caret(caret_), anchor(anchor_) {
 	}
 	explicit SelectionRange(std::string_view sv);
+	SelectionSegment AsSegment() const noexcept {
+		return {caret, anchor};
+	}
 	bool Empty() const noexcept {
 		return anchor == caret;
 	}