From 827ae07c1ec73c8fe48dc4182726c38c3e9c992f Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 26 Aug 2009 01:41:34 +0200
Subject: macro: add PA_CLIP_SUB() for saturated subtraction

---
 src/pulsecore/macro.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'src/pulsecore/macro.h')

diff --git a/src/pulsecore/macro.h b/src/pulsecore/macro.h
index ce88c1b9..87684ad3 100644
--- a/src/pulsecore/macro.h
+++ b/src/pulsecore/macro.h
@@ -157,6 +157,17 @@ static inline size_t PA_PAGE_ALIGN(size_t l) {
 #define PA_ROUND_DOWN(a, b) (((a) / (b)) * (b))
 #endif
 
+#ifdef __GNUC__
+#define PA_CLIP_SUB(a, b)                       \
+    __extension__ ({                            \
+            typeof(a) _a = (a);                 \
+            typeof(b) _b = (b);                 \
+            _a > _b ? _a - _b : 0;              \
+        })
+#else
+#define PA_CLIP_SUB(a, b) ((a) > (b) ? (a) - (b) : 0)
+#endif
+
 /* This type is not intended to be used in exported APIs! Use classic "int" there! */
 #ifdef HAVE_STD_BOOL
 typedef _Bool pa_bool_t;
-- 
cgit