Remove some apparently-unneeded includes.

[libpcap] / optimize.c

diff --git a/optimize.c b/optimize.c
index f045e7ad91e24485d6cc6fd79f20541e21f93ba0..ad2fdb3127ae583af2f968e91cd53b59465d9961 100644 (file)
--- a/optimize.c
+++ b/optimize.c
@@ -21,9 +21,7 @@
  *  Optimization module for BPF code intermediate representation.
  */
 
-#ifdef HAVE_CONFIG_H
 #include <config.h>
-#endif
 
 #include <pcap-types.h>
 
@@ -119,7 +117,7 @@ pcap_set_print_dot_graph(int value)
   #define lowest_set_bit(mask) ((u_int)__builtin_ctz(mask))
 #elif defined(_MSC_VER)
   /*
-   * Visual Studio; we support only 2005 and later, so use
+   * Visual Studio; we support only 2015 and later, so use
    * _BitScanForward().
    */
 #include <intrin.h>
@@ -142,33 +140,14 @@ lowest_set_bit(int mask)
        return (u_int)bit;
 }
 #else
-/*
- * None of the above.
- * Use a perfect-hash-function-based function.
- */
-static u_int
-lowest_set_bit(int mask)
-{
-       unsigned int v = (unsigned int)mask;
-
-       static const u_int MultiplyDeBruijnBitPosition[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
-       };
-
-       /*
-        * We strip off all but the lowermost set bit (v & ~v),
-        * and perform a minimal perfect hash on it to look up the
-        * number of low-order zero bits in a table.
-        *
-        * See:
-        *
-        *      http://7ooo.mooo.com/text/ComputingTrailingZerosHOWTO.pdf
-        *
-        *      http://supertech.csail.mit.edu/papers/debruijn.pdf
-        */
-       return (MultiplyDeBruijnBitPosition[((v & -v) * 0x077CB531U) >> 27]);
-}
+  /*
+   * POSIX.1-2001 says ffs() is in <strings.h>.  Every supported non-Windows OS
+   * (including Linux with musl libc and uclibc-ng) has the header and (except
+   * HP-UX) declares the function there.  HP-UX declares the function in
+   * <string.h>, which has already been included.
+   */
+  #include <strings.h>
+  #define lowest_set_bit(mask) ((u_int)(ffs((mask)) - 1))
 #endif
 
 /*