terminal stream set mode and reset mode

src/terminal/ansi.zig

@@ -29,3 +29,16 @@ pub const RenditionAspect = enum(u16) {
     // user-generated.
     _,
 };
+
+/// Modes that can be set with with Set Mode (SM) (ESC [ h). The enum
+/// values correspond to the `?`-prefixed modes, since those are the ones
+/// of primary interest. The enum value is the mode value.
+pub const Mode = enum(u16) {
+    /// If set, the origin of the coordinate system is relative to the
+    /// current scroll region. If set the cursor is moved to the top left of
+    /// the current scroll region.
+    origin = 6,
+
+    // Non-exhaustive so that @intToEnum never fails for unsupported modes.
+    _,
+};

src/terminal/stream.zig

@@ -230,6 +230,18 @@ pub fn Stream(comptime Handler: type) type {
                     },
                 ) else log.warn("unimplemented CSI callback: {}", .{action}),
 
+                // SM - Set Mode
+                'h' => if (@hasDecl(T, "setMode")) {
+                    for (action.params) |mode|
+                        try self.handler.setMode(@intToEnum(ansi.Mode, mode), true);
+                } else log.warn("unimplemented CSI callback: {}", .{action}),
+
+                // RM - Reset Mode
+                'l' => if (@hasDecl(T, "setMode")) {
+                    for (action.params) |mode|
+                        try self.handler.setMode(@intToEnum(ansi.Mode, mode), false);
+                } else log.warn("unimplemented CSI callback: {}", .{action}),
+
                 // SGR - Select Graphic Rendition
                 'm' => if (@hasDecl(T, "selectGraphicRendition")) {
                     if (action.params.len == 0) {
@@ -310,3 +322,21 @@ test "stream: cursor right (CUF)" {
     try s.nextSlice("\x1B[5;4C");
     try testing.expectEqual(@as(u16, 0), s.handler.amount);
 }
+
+test "stream: set mode (SM) and reset mode (RM)" {
+    const H = struct {
+        mode: ansi.Mode = @intToEnum(ansi.Mode, 0),
+
+        pub fn setMode(self: *@This(), mode: ansi.Mode, v: bool) !void {
+            self.mode = @intToEnum(ansi.Mode, 0);
+            if (v) self.mode = mode;
+        }
+    };
+
+    var s: Stream(H) = .{ .handler = .{} };
+    try s.nextSlice("\x1B[?6h");
+    try testing.expectEqual(@as(ansi.Mode, .origin), s.handler.mode);
+
+    try s.nextSlice("\x1B[?6l");
+    try testing.expectEqual(@intToEnum(ansi.Mode, 0), s.handler.mode);
+}