Merge pull request #624 from mitchellh/xt-cr

xterm audit: carriage return

src/terminal/Terminal.zig

@@ -136,6 +136,12 @@ const ScrollingRegion = struct {
     // Precondition: top < bottom
     top: usize,
     bottom: usize,
+
+    // Left/right scroll regions.
+    // Precondition: right > left
+    // Precondition: right <= cols - 1
+    left: usize,
+    right: usize,
 };
 
 /// Initialize a new terminal.
@@ -152,6 +158,8 @@ pub fn init(alloc: Allocator, cols: usize, rows: usize) !Terminal {
         .scrolling_region = .{
             .top = 0,
             .bottom = rows - 1,
+            .left = 0,
+            .right = cols - 1,
         },
         .pwd = std.ArrayList(u8).init(alloc),
     };
@@ -326,6 +334,8 @@ pub fn resize(self: *Terminal, alloc: Allocator, cols_req: usize, rows: usize) !
     self.scrolling_region = .{
         .top = 0,
         .bottom = rows - 1,
+        .left = 0,
+        .right = cols - 1,
     };
 }
 
@@ -1524,11 +1534,16 @@ pub fn carriageReturn(self: *Terminal) void {
     const tracy = trace(@src());
     defer tracy.end();
 
-    // TODO: left/right margin mode
-    // TODO: origin mode
-
-    self.screen.cursor.x = 0;
+    // Always reset pending wrap state
     self.screen.cursor.pending_wrap = false;
+
+    // In origin mode we always move to the left margin
+    self.screen.cursor.x = if (self.modes.get(.origin))
+        self.scrolling_region.left
+    else if (self.screen.cursor.x >= self.scrolling_region.left)
+        self.scrolling_region.left
+    else
+        0;
 }
 
 /// Linefeed moves the cursor to the next line.
@@ -1759,11 +1774,8 @@ pub fn setScrollingRegion(self: *Terminal, top: usize, bottom: usize) void {
         b = self.rows;
     }
 
-    self.scrolling_region = .{
-        .top = t - 1,
-        .bottom = b - 1,
-    };
-
+    self.scrolling_region.top = t - 1;
+    self.scrolling_region.bottom = b - 1;
     self.setCursorPos(1, 1);
 }
 
@@ -1871,7 +1883,12 @@ pub fn fullReset(self: *Terminal, alloc: Allocator) void {
     self.screen.saved_cursor = .{};
     self.screen.selection = null;
     self.screen.kitty_keyboard = .{};
-    self.scrolling_region = .{ .top = 0, .bottom = self.rows - 1 };
+    self.scrolling_region = .{
+        .top = 0,
+        .bottom = self.rows - 1,
+        .left = 0,
+        .right = self.cols - 1,
+    };
     self.previous_char = null;
     self.eraseDisplay(alloc, .scrollback, false);
     self.eraseDisplay(alloc, .complete, false);
@@ -2195,6 +2212,37 @@ test "Terminal: carriage return unsets pending wrap" {
     try testing.expect(t.screen.cursor.pending_wrap == false);
 }
 
+test "Terminal: carriage return origin mode moves to left margin" {
+    var t = try init(testing.allocator, 5, 80);
+    defer t.deinit(testing.allocator);
+
+    t.modes.set(.origin, true);
+    t.screen.cursor.x = 0;
+    t.scrolling_region.left = 2;
+    t.carriageReturn();
+    try testing.expectEqual(@as(usize, 2), t.screen.cursor.x);
+}
+
+test "Terminal: carriage return left of left margin moves to zero" {
+    var t = try init(testing.allocator, 5, 80);
+    defer t.deinit(testing.allocator);
+
+    t.screen.cursor.x = 1;
+    t.scrolling_region.left = 2;
+    t.carriageReturn();
+    try testing.expectEqual(@as(usize, 0), t.screen.cursor.x);
+}
+
+test "Terminal: carriage return right of left margin moves to left margin" {
+    var t = try init(testing.allocator, 5, 80);
+    defer t.deinit(testing.allocator);
+
+    t.screen.cursor.x = 3;
+    t.scrolling_region.left = 2;
+    t.carriageReturn();
+    try testing.expectEqual(@as(usize, 2), t.screen.cursor.x);
+}
+
 test "Terminal: backspace" {
     var t = try init(testing.allocator, 80, 80);
     defer t.deinit(testing.allocator);