applied adjacenttag-spikvacant patch

config.def.h

@@ -85,6 +85,10 @@ static const Key keys[] = {
 	{ MODKEY,                       XK_period, focusmon,       {.i = +1 } },
 	{ MODKEY|ShiftMask,             XK_comma,  tagmon,         {.i = -1 } },
 	{ MODKEY|ShiftMask,             XK_period, tagmon,         {.i = +1 } },
+	{ MODKEY,                       XK_Right,  viewnext,       {0} },
+	{ MODKEY,                       XK_Left,   viewprev,       {0} },
+	{ MODKEY|ShiftMask,             XK_Right,  tagtonext,      {0} },
+	{ MODKEY|ShiftMask,             XK_Left,   tagtoprev,      {0} },
 	TAGKEYS(                        XK_1,                      0)
 	TAGKEYS(                        XK_2,                      1)
 	TAGKEYS(                        XK_3,                      2)

dwm.c

@@ -184,8 +184,10 @@ static void maprequest(XEvent *e);
 static void monocle(Monitor *m);
 static void motionnotify(XEvent *e);
 static void movemouse(const Arg *arg);
+static unsigned int nexttag(void);
 static Client *nexttiled(Client *c);
 static void pop(Client *c);
+static unsigned int prevtag(void);
 static void propertynotify(XEvent *e);
 static void quit(const Arg *arg);
 static Monitor *recttomon(int x, int y, int w, int h);
@@ -208,6 +210,8 @@ static void showhide(Client *c);
 static void spawn(const Arg *arg);
 static void tag(const Arg *arg);
 static void tagmon(const Arg *arg);
+static void tagtonext(const Arg *arg);
+static void tagtoprev(const Arg *arg);
 static void tile(Monitor *m);
 static void togglebar(const Arg *arg);
 static void togglefloating(const Arg *arg);
@@ -227,6 +231,8 @@ static void updatetitle(Client *c);
 static void updatewindowtype(Client *c);
 static void updatewmhints(Client *c);
 static void view(const Arg *arg);
+static void viewnext(const Arg *arg);
+static void viewprev(const Arg *arg);
 static Client *wintoclient(Window w);
 static Monitor *wintomon(Window w);
 static int xerror(Display *dpy, XErrorEvent *ee);
@@ -1207,6 +1213,29 @@ movemouse(const Arg *arg)
 	}
 }
 
+unsigned int
+nexttag(void)
+{
+	unsigned int seltag = selmon->tagset[selmon->seltags];
+	unsigned int usedtags = 0;
+	Client *c = selmon->clients;
+
+	if (!c)
+		return seltag;
+
+	/* skip vacant tags */
+	do {
+		usedtags |= c->tags;
+		c = c->next;
+	} while (c);
+
+	do {
+		seltag = seltag == (1 << (LENGTH(tags) - 1)) ? 1 : seltag << 1;
+	} while (!(seltag & usedtags));
+
+	return seltag;
+}
+
 Client *
 nexttiled(Client *c)
 {
@@ -1223,6 +1252,28 @@ pop(Client *c)
 	arrange(c->mon);
 }
 
+unsigned int
+prevtag(void)
+{
+	unsigned int seltag = selmon->tagset[selmon->seltags];
+	unsigned int usedtags = 0;
+	Client *c = selmon->clients;
+	if (!c)
+		return seltag;
+
+	/* skip vacant tags */
+	do {
+		usedtags |= c->tags;
+		c = c->next;
+	} while (c);
+
+	do {
+		seltag = seltag == 1 ? (1 << (LENGTH(tags) - 1)) : seltag >> 1;
+	} while (!(seltag & usedtags));
+
+	return seltag;
+}
+
 void
 propertynotify(XEvent *e)
 {
@@ -1689,6 +1740,36 @@ tagmon(const Arg *arg)
 	sendmon(selmon->sel, dirtomon(arg->i));
 }
 
+void
+tagtonext(const Arg *arg)
+{
+	unsigned int tmp;
+
+	if (selmon->sel == NULL)
+		return;
+
+	if ((tmp = nexttag()) == selmon->tagset[selmon->seltags])
+		return;
+
+	tag(&(const Arg){.ui = tmp });
+	view(&(const Arg){.ui = tmp });
+}
+
+void
+tagtoprev(const Arg *arg)
+{
+	unsigned int tmp;
+
+	if (selmon->sel == NULL)
+		return;
+
+	if ((tmp = prevtag()) == selmon->tagset[selmon->seltags])
+		return;
+
+	tag(&(const Arg){.ui = tmp });
+	view(&(const Arg){.ui = tmp });
+}
+
 void
 tile(Monitor *m)
 {
@@ -2067,6 +2148,18 @@ view(const Arg *arg)
 	arrange(selmon);
 }
 
+void
+viewnext(const Arg *arg)
+{
+	view(&(const Arg){.ui = nexttag()});
+}
+
+void
+viewprev(const Arg *arg)
+{
+	view(&(const Arg){.ui = prevtag()});
+}
+
 Client *
 wintoclient(Window w)
 {