From: Matthew Fernandez <matthew.fernandez@gmail.com>
Date: Fri, 8 Jul 2022 00:24:05 +0000 (-0700)
Subject: patchwork nodecmp: rephrase comparator to avoid arithmetic
X-Git-Tag: 5.0.1~32^2~2
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=bcd684c3f21c6fba8cbff1658bace5032d35211f;p=graphviz

patchwork nodecmp: rephrase comparator to avoid arithmetic

cccb8b1d22a18031fc92d93133c7fa14ef7e1361 fixed an integer overflow in a
`memcmp`-/`strcmp`-like comparator. The same situation exists in the code
touched in this commit. Rather than wait for an edge case to expose an overflow
here, this change makes the same update, removing arithmetic and the consequent
possibility of overflow.
---

diff --git a/lib/patchwork/patchwork.c b/lib/patchwork/patchwork.c
index fb3d20101..22e2c6d1e 100644
--- a/lib/patchwork/patchwork.c
+++ b/lib/patchwork/patchwork.c
@@ -130,11 +130,13 @@ static treenode_t *mkTree (Agraph_t * g, attrsym_t* gp, attrsym_t* ap, attrsym_t
 
 static int nodecmp (treenode_t** p0, treenode_t** p1)
 {
-    double diff = (*p0)->area - (*p1)->area;
-
-    if (diff < 0) return 1;
-    else if (diff > 0) return -1;
-    else return 0;
+  if ((*p0)->area < (*p1)->area) {
+    return 1;
+  }
+  if ((*p0)->area > (*p1)->area) {
+    return -1;
+  }
+  return 0;
 }
 
 static void layoutTree(treenode_t * tree)