From: Emden Gansner <emdenrg@google.com>
Date: Wed, 3 May 2017 17:05:59 +0000 (-0400)
Subject: Fix incorrect bsearch for colors. This basically rolls back the changes from
X-Git-Tag: 2.42.0~177
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=27735a3c00757382ea353216b8598e83ea52e20c;p=graphviz

Fix incorrect bsearch for colors. This basically rolls back the changes from
e653d8054fe3c2313944a2a88f3ad7c374bd9b21 and a155276b30da0619979d0b7d5ae22cb05b9b7d16.
---

diff --git a/lib/gvc/gvrender.c b/lib/gvc/gvrender.c
index 57bbaf511..4b18aea05 100644
--- a/lib/gvc/gvrender.c
+++ b/lib/gvc/gvrender.c
@@ -183,6 +183,18 @@ pointf *gvrender_ptf_A(GVJ_t * job, pointf * af, pointf * AF, int n)
     return AF;
 }
 
+static int gvrender_comparestr(const void *s1, const void *s2)
+{
+    return strcmp(*(char **) s1, *(char **) s2);
+}
+
+/* gvrender_resolve_color:
+ * N.B. strcmp cannot be used in bsearch, as it will pass a pointer
+ * to an element in the array features->knowncolors (i.e., a char**)
+ * as an argument of the compare function, while the arguments to 
+ * strcmp are both char*. Given this, the first argument to
+ * bsearch must also be char**, so we use &tok.
+ */
 static void gvrender_resolve_color(gvrender_features_t * features,
 				   char *name, gvcolor_t * color)
 {
@@ -195,8 +207,8 @@ static void gvrender_resolve_color(gvrender_features_t * features,
     if (!features->knowncolors
 	||
 	(bsearch
-	 (tok, features->knowncolors, features->sz_knowncolors,
-	  sizeof(char *), (int(*)(const void*, const void*)) strcmp)) == NULL) {
+	 (&tok, features->knowncolors, features->sz_knowncolors,
+	  sizeof(char *), gvrender_comparestr)) == NULL) {
 	/* if tok was not found in known_colors */
 	rc = colorxlate(name, color, features->color_type);
 	if (rc != COLOR_OK) {