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#ifndef strings_h
#define strings_h
/* MSVC doesn't define ffs/ffsl. This dummy strings.h header is provided
* for both */
#ifdef _MSC_VER
# include <intrin.h>
# pragma intrinsic(_BitScanForward)
static __forceinline int ffsl(long x) {
unsigned long i;
if (_BitScanForward(&i, x)) {
return i + 1;
}
return 0;
}
static __forceinline int ffs(int x) {
return ffsl(x);
}
# ifdef _M_X64
# pragma intrinsic(_BitScanForward64)
# endif
static __forceinline int ffsll(unsigned __int64 x) {
unsigned long i;
#ifdef _M_X64
if (_BitScanForward64(&i, x)) {
return i + 1;
}
return 0;
#else
// Fallback for 32-bit build where 64-bit version not available
// assuming little endian
union {
unsigned __int64 ll;
unsigned long l[2];
} s;
s.ll = x;
if (_BitScanForward(&i, s.l[0])) {
return i + 1;
} else if(_BitScanForward(&i, s.l[1])) {
return i + 33;
}
return 0;
#endif
}
#else
# define ffsll(x) __builtin_ffsll(x)
# define ffsl(x) __builtin_ffsl(x)
# define ffs(x) __builtin_ffs(x)
#endif
#endif /* strings_h */
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