Replace inet_addr() with our inet_pton() wrapper

[metze/wireshark/wip.git] / wsutil / bits_ctz.h

diff --git a/wsutil/bits_ctz.h b/wsutil/bits_ctz.h
index 7fa9cd87add2b63e7943aae75d08d2b227677054..08125c04abb1f7b3f955acdfc4bc2cf252d4f729 100644 (file)
--- a/wsutil/bits_ctz.h
+++ b/wsutil/bits_ctz.h
@@ -1,8 +1,6 @@
 /*
  * bitz_ctz.h
  *
- * $Id$
- *
  * Wireshark - Network traffic analyzer
  * By Gerald Combs <gerald@wireshark.org>
  * Copyright 1998 Gerald Combs
@@ -27,22 +25,81 @@
 
 #include <glib.h>
 
+/* ws_ctz == trailing zeros == position of lowest set bit [0..63] */
+/* ws_ilog2 == position of highest set bit == 63 - leading zeros [0..63] */
+
+/* The return value of both ws_ctz and ws_ilog2 is undefined for x == 0 */
+
+#if defined(__GNUC__) && ((__GNUC__ > 3) || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4))
+
 static inline int
-ws_ctz(guint32 x)
+ws_ctz(guint64 x)
 {
-#if defined(__GNUC__) && ((__GNUC__ > 3) || (__GNUC__ == 3 && __GNUC_MINOR__ >= 4))
-       g_assert(x != 0);
+       return __builtin_ctzll(x);
+}
+
+static inline int
+ws_ilog2(guint64 x)
+{
+       return 63 - __builtin_clzll(x);
+}
 
-       return __builtin_ctz(x);
 #else
+
+static inline int
+__ws_ctz32(guint32 x)
+{
        /* From http://graphics.stanford.edu/~seander/bithacks.html#ZerosOnRightMultLookup */
-       static const int table[32] = {
+       static const guint8 table[32] = {
                0,   1, 28,  2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17,  4, 8,
                31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18,  6, 11,  5, 10, 9
        };
 
        return table[((guint32)((x & -(gint32)x) * 0x077CB531U)) >> 27];
-#endif
 }
 
+static inline int
+ws_ctz(guint64 x)
+{
+       guint32 hi = x >> 32;
+       guint32 lo = (guint32) x;
+
+       if (lo == 0)
+               return 32 + __ws_ctz32(hi);
+       else
+               return __ws_ctz32(lo);
+}
+
+static inline int
+__ws_ilog2_32(guint32 x)
+{
+       /* From http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogDeBruijn */
+       static const guint8 table[32] = {
+               0,  9,  1, 10, 13, 21,  2, 29, 11, 14, 16, 18, 22, 25,  3, 30,
+               8, 12, 20, 28, 15, 17, 24,  7, 19, 27, 23,  6, 26,  5,  4, 31
+       };
+
+       x |= x >> 1;
+       x |= x >> 2;
+       x |= x >> 4;
+       x |= x >> 8;
+       x |= x >> 16;
+
+       return table[((guint32)(x * 0x07C4ACDDU)) >> 27];
+}
+
+static inline int
+ws_ilog2(guint64 x)
+{
+       guint32 hi = x >> 32;
+       guint32 lo = (guint32) x;
+
+       if (hi == 0)
+               return __ws_ilog2_32(lo);
+       else
+               return 32 + __ws_ilog2_32(hi);
+}
+
+#endif
+
 #endif /* __WSUTIL_BITS_CTZ_H__ */