2 files changed, 38 insertions, 0 deletions
diff --git a/src/Document.cxx b/src/Document.cxx
index a44a51f12..7d34dace1 100644
--- a/src/Document.cxx
+++ b/src/Document.cxx
@@ -787,6 +787,27 @@ int SCI_METHOD Document::GetRelativePosition(int positionStart, int characterOff
 	return pos;
 }
 
+int Document::GetRelativePositionUTF16(int positionStart, int characterOffset) const {
+	int pos = positionStart;
+	if (dbcsCodePage) {
+		const int increment = (characterOffset > 0) ? 1 : -1;
+		while (characterOffset != 0) {
+			const int posNext = NextPosition(pos, increment);
+			if (posNext == pos)
+				return INVALID_POSITION;
+			if (abs(pos-posNext) > 3)	// 4 byte character = 2*UTF16.
+				characterOffset -= increment;
+			pos = posNext;
+			characterOffset -= increment;
+		}
+	} else {
+		pos = positionStart + characterOffset;
+		if ((pos < 0) || (pos > Length()))
+			return INVALID_POSITION;
+	}
+	return pos;
+}
+
 int SCI_METHOD Document::GetCharacterAndWidth(int position, int *pWidth) const {
 	int character;
 	int bytesInCharacter = 1;
@@ -1308,6 +1329,21 @@ int Document::CountCharacters(int startPos, int endPos) const {
 	return count;
 }
 
+int Document::CountUTF16(int startPos, int endPos) const {
+	startPos = MovePositionOutsideChar(startPos, 1, false);
+	endPos = MovePositionOutsideChar(endPos, -1, false);
+	int count = 0;
+	int i = startPos;
+	while (i < endPos) {
+		count++;
+		const int next = NextPosition(i, 1);
+		if ((next - i) > 3)
+			count++;
+		i = next;
+	}
+	return count;
+}
+
 int Document::FindColumn(int line, int column) {
 	int position = LineStart(line);
 	if ((line >= 0) && (line < LinesTotal())) {
diff --git a/src/Document.h b/src/Document.h
index e808bb37f..5e66dc2b6 100644
--- a/src/Document.h
+++ b/src/Document.h
@@ -279,6 +279,7 @@ public:
 	int NextPosition(int pos, int moveDir) const;
 	bool NextCharacter(int &pos, int moveDir) const;	// Returns true if pos changed
 	int SCI_METHOD GetRelativePosition(int positionStart, int characterOffset) const;
+	int GetRelativePositionUTF16(int positionStart, int characterOffset) const;
 	int SCI_METHOD GetCharacterAndWidth(int position, int *pWidth) const;
 	int SCI_METHOD CodePage() const;
 	bool SCI_METHOD IsDBCSLeadByte(char ch) const;
@@ -322,6 +323,7 @@ public:
 	int GetLineIndentPosition(int line) const;
 	int GetColumn(int position);
 	int CountCharacters(int startPos, int endPos) const;
+	int CountUTF16(int startPos, int endPos) const;
 	int FindColumn(int line, int column);
 	void Indent(bool forwards, int lineBottom, int lineTop);
 	static std::string TransformLineEnds(const char *s, size_t len, int eolModeWanted);