#ifndef BITSCAN_H
#define BITSCAN_H
+#include <assert.h>
#include <stdint.h>
+#include <string.h>
#if defined(_MSC_VER)
#include <intrin.h>
#define ffs __builtin_ffs
#elif defined(_MSC_VER) && (_M_IX86 || _M_ARM || _M_AMD64 || _M_IA64)
static inline
-int ffs(unsigned i)
+int ffs(int i)
{
unsigned long index;
if (_BitScanForward(&index, i))
}
#else
extern
-int ffs(unsigned i);
+int ffs(int i);
#endif
#ifdef HAVE___BUILTIN_FFSLL
#define ffsll __builtin_ffsll
#elif defined(_MSC_VER) && (_M_AMD64 || _M_ARM || _M_IA64)
static inline int
-ffsll(uint64_t i)
+ffsll(long long int i)
{
unsigned long index;
if (_BitScanForward64(&index, i))
}
#else
extern int
-ffsll(uint64_t val);
+ffsll(long long int val);
#endif
}
+/**
+ * Find last bit set in a word. The least significant bit is 1.
+ * Return 0 if no bits are set.
+ * Essentially ffs() in the reverse direction.
+ */
+static inline unsigned
+util_last_bit(unsigned u)
+{
+#if defined(HAVE___BUILTIN_CLZ)
+ return u == 0 ? 0 : 32 - __builtin_clz(u);
+#elif defined(_MSC_VER) && (_M_IX86 || _M_ARM || _M_AMD64 || _M_IA64)
+ unsigned long index;
+ if (_BitScanReverse(&index, u))
+ return index + 1;
+ else
+ return 0;
+#else
+ unsigned r = 0;
+ while (u) {
+ r++;
+ u >>= 1;
+ }
+ return r;
+#endif
+}
+
+/**
+ * Find last bit set in a word. The least significant bit is 1.
+ * Return 0 if no bits are set.
+ * Essentially ffsll() in the reverse direction.
+ */
+static inline unsigned
+util_last_bit64(uint64_t u)
+{
+#if defined(HAVE___BUILTIN_CLZLL)
+ return u == 0 ? 0 : 64 - __builtin_clzll(u);
+#elif defined(_MSC_VER) && (_M_AMD64 || _M_ARM || _M_IA64)
+ unsigned long index;
+ if (_BitScanReverse64(&index, u))
+ return index + 1;
+ else
+ return 0;
+#else
+ unsigned r = 0;
+ while (u) {
+ r++;
+ u >>= 1;
+ }
+ return r;
+#endif
+}
+
+/**
+ * Find last bit in a word that does not match the sign bit. The least
+ * significant bit is 1.
+ * Return 0 if no bits are set.
+ */
+static inline unsigned
+util_last_bit_signed(int i)
+{
+ if (i >= 0)
+ return util_last_bit(i);
+ else
+ return util_last_bit(~(unsigned)i);
+}
+
+/* Returns a bitfield in which the first count bits starting at start are
+ * set.
+ */
+static inline unsigned
+u_bit_consecutive(unsigned start, unsigned count)
+{
+ assert(start + count <= 32);
+ if (count == 32)
+ return ~0;
+ return ((1u << count) - 1) << start;
+}
+
+static inline uint64_t
+u_bit_consecutive64(unsigned start, unsigned count)
+{
+ assert(start + count <= 64);
+ if (count == 64)
+ return ~(uint64_t)0;
+ return (((uint64_t)1 << count) - 1) << start;
+}
+
+
#ifdef __cplusplus
}
#endif