Implement Caret upwards and downwards move in overlay_edit_text

rpcs3/Emu/RSX/Overlays/overlay_edit_text.cpp

@@ -5,6 +5,30 @@ namespace rsx
 {
 	namespace overlays
 	{
+		static size_t get_line_start(const std::u32string& text, size_t pos)
+		{
+			if (pos == 0)
+			{
+				return 0;
+			}
+			const size_t line_start = text.rfind('\n', pos - 1);
+			if (line_start == std::string::npos)
+			{
+				return 0;
+			}
+			return line_start + 1;
+		}
+
+		static size_t get_line_end(const std::u32string& text, size_t pos)
+		{
+			const size_t line_end = text.find('\n', pos);
+			if (line_end == std::string::npos)
+			{
+				return text.length();
+			}
+			return line_end;
+		}
+
 		void edit_text::move_caret(direction dir)
 		{
 			switch (dir)
@@ -28,10 +52,45 @@ namespace rsx
 				break;
 			}
 			case up:
+			{
+				const size_t current_line_start = get_line_start(text, caret_position);
+				if (current_line_start == 0)
+				{
+					// This is the first line, so caret moves to the very beginning
+					caret_position = 0;
+					refresh();
+					break;
+				}
+				const size_t caret_pos_in_line = caret_position - current_line_start;
+				const size_t prev_line_end     = current_line_start - 1;
+				const size_t prev_line_start   = get_line_start(text, prev_line_end);
+				// TODO : Save caret position to some kind of buffer, so after switching back and forward, caret would be on initial position
+				caret_position = std::min(prev_line_end, prev_line_start + caret_pos_in_line);
+
+				refresh();
+				break;
+			}
 			case down:
-				// TODO
+			{
+				const size_t current_line_end = get_line_end(text, caret_position);
+				if (current_line_end == text.length())
+				{
+					// This is the last line, so caret moves to the very end
+					caret_position = current_line_end;
+					refresh();
+					break;
+				}
+				const size_t current_line_start = get_line_start(text, caret_position);
+				const size_t caret_pos_in_line  = caret_position - current_line_start;
+				const size_t next_line_start    = current_line_end + 1;
+				const size_t next_line_end      = get_line_end(text, next_line_start);
+				// TODO : Save caret position to some kind of buffer, so after switching back and forward, caret would be on initial position
+				caret_position = std::min(next_line_end, next_line_start + caret_pos_in_line);
+
+				refresh();
 				break;
 			}
+			}
 		}
 
 		void edit_text::insert_text(const std::u32string& str)