Merge commit '180c6d0b440961cbc873c4d045eb8b2daa1364e9'

[sliver-openvswitch.git] / lib / util.h

diff --git a/lib/util.h b/lib/util.h
index a8d8665..f5589e3 100644 (file)
--- a/lib/util.h
+++ b/lib/util.h
@@ -23,6 +23,7 @@
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include "compiler.h"
 
@@ -62,6 +63,17 @@
 #define BUILD_ASSERT_DECL_GCCONLY(EXPR) ((void) 0)
 #endif
 
+/* Like the standard assert macro, except:
+ *
+ *   - Writes the failure message to the log.
+ *
+ *   - Not affected by NDEBUG. */
+#define ovs_assert(CONDITION)                                           \
+    if (!OVS_LIKELY(CONDITION)) {                                       \
+        ovs_assert_failure(SOURCE_LOCATOR, __func__, #CONDITION);       \
+    }
+void ovs_assert_failure(const char *, const char *, const char *) NO_RETURN;
+
 /* Casts 'pointer' to 'type' and issues a compiler warning if the cast changes
  * anything other than an outermost "const" or "volatile" qualifier.
  *
@@ -96,22 +108,6 @@ is_pow2(uintmax_t x)
     return IS_POW2(x);
 }
 
-/* Returns the rightmost 1-bit in 'x' (e.g. 01011000 => 00001000), or 0 if 'x'
- * is 0. */
-static inline uintmax_t
-rightmost_1bit(uintmax_t x)
-{
-    return x & -x;
-}
-
-/* Returns 'x' with its rightmost 1-bit changed to a zero (e.g. 01011000 =>
- * 01010000), or 0 if 'x' is 0. */
-static inline uintmax_t
-zero_rightmost_1bit(uintmax_t x)
-{
-    return x & (x - 1);
-}
-
 #ifndef MIN
 #define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
 #endif
@@ -242,11 +238,73 @@ char *xreadlink(const char *filename);
 char *follow_symlinks(const char *filename);
 
 void ignore(bool x OVS_UNUSED);
+\f
+/* Bitwise tests. */
+
+/* Returns the number of trailing 0-bits in 'n'.  Undefined if 'n' == 0.
+ *
+ * This compiles to a single machine instruction ("bsf") with GCC on x86. */
+#if !defined(UINT_MAX) || !defined(UINT32_MAX)
+#error "Someone screwed up the #includes."
+#elif __GNUC__ >= 4 && UINT_MAX == UINT32_MAX
+static inline int
+raw_ctz(uint32_t n)
+{
+    return __builtin_ctz(n);
+}
+#else
+/* Defined in util.c. */
+int raw_ctz(uint32_t n);
+#endif
+
+/* Returns the number of trailing 0-bits in 'n', or 32 if 'n' is 0. */
+static inline int
+ctz(uint32_t n)
+{
+    return n ? raw_ctz(n) : 32;
+}
+
 int log_2_floor(uint32_t);
 int log_2_ceil(uint32_t);
-int ctz(uint32_t);
-int popcount(uint32_t);
+unsigned int popcount(uint32_t);
+
+/* Returns the rightmost 1-bit in 'x' (e.g. 01011000 => 00001000), or 0 if 'x'
+ * is 0. */
+static inline uintmax_t
+rightmost_1bit(uintmax_t x)
+{
+    return x & -x;
+}
+
+/* Returns 'x' with its rightmost 1-bit changed to a zero (e.g. 01011000 =>
+ * 01010000), or 0 if 'x' is 0. */
+static inline uintmax_t
+zero_rightmost_1bit(uintmax_t x)
+{
+    return x & (x - 1);
+}
 
+/* Returns the index of the rightmost 1-bit in 'x' (e.g. 01011000 => 3), or 32
+ * if 'x' is 0.
+ *
+ * Unlike the other functions for rightmost 1-bits, this function only works
+ * with 32-bit integers. */
+static inline uint32_t
+rightmost_1bit_idx(uint32_t x)
+{
+    return x ? ctz(x) : 32;
+}
+
+/* Returns the index of the rightmost 1-bit in 'x' (e.g. 01011000 => 6), or 32
+ * if 'x' is 0.
+ *
+ * This function only works with 32-bit integers. */
+static inline uint32_t
+leftmost_1bit_idx(uint32_t x)
+{
+    return x ? log_2_floor(x) : 32;
+}
+\f
 bool is_all_zeros(const uint8_t *, size_t);
 bool is_all_ones(const uint8_t *, size_t);
 void bitwise_copy(const void *src, unsigned int src_len, unsigned int src_ofs,