From 598eeab09f9c377e65f886b147e037e7972dadf9 Mon Sep 17 00:00:00 2001
From: Christian Heller <c.heller@plomlompom.de>
Date: Sat, 24 Aug 2013 05:10:43 +0200
Subject: [PATCH] Re-wrote shift_active_win() to manipulate chain by merely
 changing the chain pointers instead of actually re-building the whole window
 chain. Uses new internal helper functions shift_win_forward() /
 shift_win_backward().

---
 src/windows.c | 111 +++++++++++++++++++++++++++++++++++++++++++++++++-
 src/windows.h |   7 +---
 2 files changed, 112 insertions(+), 6 deletions(-)

diff --git a/src/windows.c b/src/windows.c
index 2c29a1d..ec176ed 100644
--- a/src/windows.c
+++ b/src/windows.c
@@ -58,6 +58,12 @@ static void draw_wins_bordercorners(struct Win * w, WINDOW * pad);
 
 
 
+/* Shift active window forwards / backwards in window chain. */
+static void shift_win_forward(struct WinMeta * wmeta);
+static void shift_win_backward(struct WinMeta * wmeta);
+
+
+
 static uint8_t refit_pad(struct WinMeta * wmeta)
 {
     /* Determine rightmost window column. */
@@ -269,6 +275,88 @@ static void draw_wins_bordercorners(struct Win * w, WINDOW * pad)
 
 
 
+static void shift_win_forward(struct WinMeta * wmeta)
+{
+    if (wmeta->active == wmeta->chain_end)
+    {
+        wmeta->chain_end = wmeta->active->prev;
+        wmeta->chain_end->next = 0;
+        wmeta->active->next = wmeta->chain_start;
+        wmeta->active->next->prev = wmeta->active;
+        wmeta->chain_start = wmeta->active;
+        wmeta->chain_start->prev = 0;
+    }
+    else
+    {
+        struct Win * old_prev = wmeta->active->prev;
+        struct Win * old_next = wmeta->active->next;
+        if (wmeta->chain_end == wmeta->active->next)
+        {
+            wmeta->chain_end = wmeta->active;
+            wmeta->active->next = 0;
+        }
+        else
+        {
+            wmeta->active->next = old_next->next;
+            wmeta->active->next->prev = wmeta->active;
+        }
+        if (wmeta->chain_start == wmeta->active)
+        {
+            wmeta->chain_start = old_next;
+        }
+        else
+        {
+            old_prev->next = old_next;
+        }
+        old_next->prev = old_prev;
+        old_next->next = wmeta->active;
+        wmeta->active->prev = old_next;
+    }
+}
+
+
+
+static void shift_win_backward(struct WinMeta * wmeta)
+{
+    if (wmeta->active == wmeta->chain_start)
+    {
+        wmeta->chain_start = wmeta->active->next;
+        wmeta->chain_start->prev = 0;
+        wmeta->active->prev = wmeta->chain_end;
+        wmeta->active->prev->next = wmeta->active;
+        wmeta->chain_end = wmeta->active;
+        wmeta->chain_end->next = 0;
+    }
+    else
+    {
+        struct Win * old_prev = wmeta->active->prev;
+        struct Win * old_next = wmeta->active->next;
+        if (wmeta->chain_start == wmeta->active->prev)
+        {
+            wmeta->chain_start = wmeta->active;
+            wmeta->active->prev = 0;
+        }
+        else
+        {
+            wmeta->active->prev = old_prev->prev;
+            wmeta->active->prev->next = wmeta->active;
+        }
+        if (wmeta->chain_end == wmeta->active)
+        {
+            wmeta->chain_end = old_prev;
+        }
+        else
+        {
+            old_next->prev = old_prev;
+        }
+        old_prev->next = old_next;
+        old_prev->prev = wmeta->active;
+        wmeta->active->next = old_prev;
+    }
+}
+
+
+
 extern uint8_t init_win_meta(WINDOW * screen, struct WinMeta * wmeta)
 {
     wmeta->screen              = screen;
@@ -445,7 +533,7 @@ extern void cycle_active_win(struct WinMeta * wmeta, char dir)
 
 
 
-extern uint8_t shift_active_win(struct WinMeta * wmeta, char dir)
+extern uint8_t shift_active_win_old(struct WinMeta * wmeta, char dir)
 {
     if (0 != wmeta->active                         /* No shifting with less   */
         && wmeta->chain_start != wmeta->chain_end  /* than 2 windows visible. */
@@ -548,6 +636,27 @@ extern uint8_t shift_active_win(struct WinMeta * wmeta, char dir)
 
 
 
+extern void shift_active_win(struct WinMeta * wmeta, char dir)
+{
+    if (   0 == wmeta->active
+        || wmeta->chain_start == wmeta->chain_end
+        || (dir != 'f' && dir != 'b'))
+    {
+        return;
+    }
+    if ('f' == dir)
+    {
+        shift_win_forward(wmeta);
+    }
+    else
+    {
+        shift_win_backward(wmeta);
+    }
+    update_wins(wmeta, wmeta->chain_start);
+}
+
+
+
 extern void draw_all_wins(struct WinMeta * wmeta)
 {
     /* Empty everything before filling it a-new. */
diff --git a/src/windows.h b/src/windows.h
index 9414dd5..3a6ebd5 100644
--- a/src/windows.h
+++ b/src/windows.h
@@ -148,11 +148,8 @@ extern void cycle_active_win(struct WinMeta * wmeta, char dir);
 
 
 /* Move active window forwards (set dir="f") or backwards (set dir="b"). Wrap
- * around in the window chain if start / end of it is met.
- *
- * Return 0 on success, and 1 on (ncurses window/pad memory allocation) error.
- */
-extern uint8_t shift_active_win(struct WinMeta * wmeta, char dir);
+ * around in the window chain if start / end of it is met. */
+extern void shift_active_win(struct WinMeta * wmeta, char dir);
 
 
 
-- 
2.30.2