core/utils.h: add OSMO_LIKELY / OSMO_UNLIKELY macros

Change-Id: I0b029654ba050f079eed4a0574a3fa8019677067
---
M include/osmocom/core/utils.h
1 file changed, 9 insertions(+), 0 deletions(-)


git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/46/27046/1

diff --git a/include/osmocom/core/utils.h b/include/osmocom/core/utils.h
index 327aa3d..30d8be6 100644
--- a/include/osmocom/core/utils.h
+++ b/include/osmocom/core/utils.h
@@ -38,6 +38,15 @@
 /*! Copy a C-string into a sized buffer using sizeof to detect buffer's size */
 #define OSMO_STRLCPY_ARRAY(array, src) osmo_strlcpy(array, src, sizeof(array))
 
+/*! Branch prediction optimizations */
+#if defined(__GNUC__)
+#define OSMO_LIKELY(exp) __builtin_expect (!!(exp), 1)
+#define OSMO_UNLIKELY(exp) __builtin_expect (!!(exp), 0)
+#else
+#define OSMO_LIKELY(exp) exp
+#define OSMO_UNLIKELY(exp) exp
+#endif
+
 /*! A mapping between human-readable string and numeric value */
 struct value_string {
 	uint32_t value;		/*!< numeric value */

