From 0967515f4c4e5813522e9a4798548b7178905c74 Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@sbcglobal.net>
Date: Fri, 16 Jan 2015 00:46:05 -0500
Subject: pcr/wmii-hg: fix a bug

---
 pcr/wmii-hg/fix-for-weird-xinerama-settings.patch | 63 +++++++++++++++++++++++
 1 file changed, 63 insertions(+)
 create mode 100644 pcr/wmii-hg/fix-for-weird-xinerama-settings.patch

(limited to 'pcr/wmii-hg/fix-for-weird-xinerama-settings.patch')

diff --git a/pcr/wmii-hg/fix-for-weird-xinerama-settings.patch b/pcr/wmii-hg/fix-for-weird-xinerama-settings.patch
new file mode 100644
index 000000000..cf8963b9c
--- /dev/null
+++ b/pcr/wmii-hg/fix-for-weird-xinerama-settings.patch
@@ -0,0 +1,63 @@
+I (Luke Shumaker) wrote this patch to fix a bug where if Xinerama is
+(mis)configured such that there are two screens with the same size and
+position, then wmii removes both of them from the list, resulting in
+nscreens=0, which causes a segfault when it tries to dereference
+screen[0].  This is the case by default with a recent version of the
+drivers for my Nvidia 9400GT (where the DVI and VGA ports mirror
+eachother).
+
+Plus, the code's more efficient now, because it does everything in
+place, instead of needing to malloc another list.
+
+diff -ru wmii-hg-2823.orig/cmd/wmii/main.c wmii-hg-2823/cmd/wmii/main.c
+--- wmii-hg-2823.orig/cmd/wmii/main.c	1989-12-31 19:00:00.000000000 -0500
++++ wmii-hg-2823/cmd/wmii/main.c	2015-01-15 23:51:34.325953828 -0500
+@@ -163,7 +163,7 @@
+ void
+ init_screens(void) {
+ 	static int old_n, old_nscreens;
+-	Rectangle *rects, *r;
++	Rectangle *rects;
+ 	View *v;
+ 	int i, j, n, m;
+ 
+@@ -178,23 +178,26 @@
+ 
+ 	/* Reallocate screens, zero any new ones. */
+ 	rects = xinerama_screens(&n);
+-	r = malloc(n * sizeof *r);
+ 
+ 	/* Weed out subsumed/cloned screens */
+-	for(m=-1; m < n; n=m) {
+-		for(i=n-1, m=0; i >= 0; i--) {
+-			for(j=0; j < n; j++)
+-				if (i != j &&
+-				    eqrect(rects[i],
+-					   rect_intersection(rects[i], rects[j])))
+-					break;
+-			if (j == n)
+-				r[m++] = rects[i];
++	for(m=0, i=0; i < n; i++) {
++		for(j=0; j < n; j++) {
++			if (i != j &&
++			    /* rects[i] is entirely contained in rects[j] */
++			    eqrect(rects[i], rect_intersection(rects[i], rects[j])) &&
++			    /* but if they are the same, accept the first */
++			    (i > j || ! eqrect(rects[i], rects[j]))) {
++				/* remove rects[i] from rects[] */
++				break;
++			}
++		}
++		if (j < n) {/* hit "break" */
++			/* remove rects[i] from rects[] */
++			n--;
++			for(j=i; j < n; j++)
++				rects[j] = rects[j+1];
+ 		}
+-		for(i=m-1, j=0; i >= 0; i--)
+-			rects[j++] = r[i];
+ 	}
+-	free(r);
+ 
+ 	m = nscreens;
+ 	nscreens_new = keep_screens ? max(n, nscreens) : n;
-- 
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