// twheel_bitops.c — ctz/clz for timing wheel (included by twheel.c)

#include <stdint.h>

#if defined(__GNUC__) && !defined(TWHEEL_DISABLE_GNUC_BITOPS)
#define ctz64(n) __builtin_ctzll(n)
#define clz64(n) __builtin_clzll(n)
#if LONG_BITS == 32
#define ctz32(n) __builtin_ctzl(n)
#define clz32(n) __builtin_clzl(n)
#else
#define ctz32(n) __builtin_ctz(n)
#define clz32(n) __builtin_clz(n)
#endif
#elif defined(_MSC_VER) && !defined(TWHEEL_DISABLE_MSVC_BITOPS)
#include <intrin.h>
static __inline int ctz32(unsigned long val) { DWORD z=0; _BitScanForward(&z,val); return z; }
static __inline int clz32(unsigned long val) { DWORD z=0; _BitScanReverse(&z,val); return z; }
#ifdef _WIN64
static __inline int ctz64(uint64_t val) { DWORD z=0; _BitScanForward64(&z,val); return z; }
static __inline int clz64(uint64_t val) { DWORD z=0; _BitScanReverse64(&z,val); return z; }
#else
static __inline int ctz64(uint64_t val) { uint32_t lo=(uint32_t)val,hi=(uint32_t)(val>>32); return lo?ctz32(lo):32+ctz32(hi); }
static __inline int clz64(uint64_t val) { uint32_t lo=(uint32_t)val,hi=(uint32_t)(val>>32); return hi?clz32(hi):32+clz32(lo); }
#endif
#else
#define process_(one, cz_bits, bits) if (x < ( one << (cz_bits - bits))) { rv += bits; x <<= bits; }
static inline int clz64(uint64_t x) { int rv=0; process_(UINT64_C(1),64,32); process_(UINT64_C(1),64,16); process_(UINT64_C(1),64,8); process_(UINT64_C(1),64,4); process_(UINT64_C(1),64,2); process_(UINT64_C(1),64,1); return rv; }
static inline int clz32(uint32_t x) { int rv=0; process_(UINT32_C(1),32,16); process_(UINT32_C(1),32,8); process_(UINT32_C(1),32,4); process_(UINT32_C(1),32,2); process_(UINT32_C(1),32,1); return rv; }
#undef process_
#define process_(one, bits) if ((x & ((one << (bits))-1)) == 0) { rv += bits; x >>= bits; }
static inline int ctz64(uint64_t x) { int rv=0; process_(UINT64_C(1),32); process_(UINT64_C(1),16); process_(UINT64_C(1),8); process_(UINT64_C(1),4); process_(UINT64_C(1),2); process_(UINT64_C(1),1); return rv; }
static inline int ctz32(uint32_t x) { int rv=0; process_(UINT32_C(1),16); process_(UINT32_C(1),8); process_(UINT32_C(1),4); process_(UINT32_C(1),2); process_(UINT32_C(1),1); return rv; }
#undef process_
#endif