From: Alan T. DeKok <aland@freeradius.org>
Date: Sun, 30 Aug 2020 08:56:59 +0000 (-0400)
Subject: add COMPARE_PREFER_SMALLER / LARGER
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c8b0cbf2006b04426ee698fd99871ab5339e0302;p=thirdparty%2Ffreeradius-server.git

add COMPARE_PREFER_SMALLER / LARGER

for ordered comparisons
---

diff --git a/src/lib/util/heap.h b/src/lib/util/heap.h
index 1cf0663925d..90e5a68d983 100644
--- a/src/lib/util/heap.h
+++ b/src/lib/util/heap.h
@@ -36,6 +36,19 @@ extern "C" {
 
 typedef int32_t fr_heap_iter_t;
 
+#ifndef STABLE_COMPARE
+/*
+ *	The first comparison returns +1 for a>b, and -1 for a<b
+ *	The second comparison returns -1 for a>b, and +1 for a<b
+ *
+ *	Use STABLE_COMPARE when you don't really care about ordering,
+ *	you just want _an_ ordering.
+ */
+#define COMPARE_PREFER_SMALLER(_a,_b) (((_a) > (_b)) - ((_a) < (_b)))
+#define COMPARE_PREFER_LARGER(_a,_b) (((_a) < (_b)) - ((_a) > (_b)))
+#define STABLE_COMPARE COMPARE_PREFER_SMALLER
+#endif
+
 /*
  *  Return negative numbers to put 'a' at the top of the heap.
  *  Return positive numbers to put 'b' at the top of the heap.
diff --git a/src/lib/util/rbtree.h b/src/lib/util/rbtree.h
index 40370e9c84a..7a2af7a6653 100644
--- a/src/lib/util/rbtree.h
+++ b/src/lib/util/rbtree.h
@@ -56,9 +56,15 @@ typedef void (*rb_free_t)(void *data);
 
 #ifndef STABLE_COMPARE
 /*
- *	This comparison returns +1 for a>b, and -1 for a<b
+ *	The first comparison returns +1 for a>b, and -1 for a<b
+ *	The second comparison returns -1 for a>b, and +1 for a<b
+ *
+ *	Use STABLE_COMPARE when you don't really care about ordering,
+ *	you just want _an_ ordering.
  */
-#define STABLE_COMPARE(_a,_b) (((_a) > (_b)) - ((_a) < (_b)))
+#define COMPARE_PREFER_SMALLER(_a,_b) (((_a) > (_b)) - ((_a) < (_b)))
+#define COMPARE_PREFER_LARGER(_a,_b) (((_a) < (_b)) - ((_a) > (_b)))
+#define STABLE_COMPARE COMPARE_PREFER_SMALLER
 #endif
 
 /** Creates a red black that verifies elements are of a specific talloc type