diff options
Diffstat (limited to 'third_party/abseil_cpp/absl/hash/internal/city.cc')
| -rw-r--r-- | third_party/abseil_cpp/absl/hash/internal/city.cc | 27 |
1 files changed, 15 insertions, 12 deletions
diff --git a/third_party/abseil_cpp/absl/hash/internal/city.cc b/third_party/abseil_cpp/absl/hash/internal/city.cc index e122c184b60f..5460134e5762 100644 --- a/third_party/abseil_cpp/absl/hash/internal/city.cc +++ b/third_party/abseil_cpp/absl/hash/internal/city.cc @@ -200,10 +200,6 @@ static uint64_t Rotate(uint64_t val, int shift) { static uint64_t ShiftMix(uint64_t val) { return val ^ (val >> 47); } -static uint64_t HashLen16(uint64_t u, uint64_t v) { - return Hash128to64(uint128(u, v)); -} - static uint64_t HashLen16(uint64_t u, uint64_t v, uint64_t mul) { // Murmur-inspired hashing. uint64_t a = (u ^ v) * mul; @@ -214,6 +210,11 @@ static uint64_t HashLen16(uint64_t u, uint64_t v, uint64_t mul) { return b; } +static uint64_t HashLen16(uint64_t u, uint64_t v) { + const uint64_t kMul = 0x9ddfea08eb382d69ULL; + return HashLen16(u, v, kMul); +} + static uint64_t HashLen0to16(const char *s, size_t len) { if (len >= 8) { uint64_t mul = k2 + len * 2; @@ -253,9 +254,8 @@ static uint64_t HashLen17to32(const char *s, size_t len) { // Return a 16-byte hash for 48 bytes. Quick and dirty. // Callers do best to use "random-looking" values for a and b. -static std::pair<uint64_t, uint64_t> WeakHashLen32WithSeeds(uint64_t w, uint64_t x, - uint64_t y, uint64_t z, - uint64_t a, uint64_t b) { +static std::pair<uint64_t, uint64_t> WeakHashLen32WithSeeds( + uint64_t w, uint64_t x, uint64_t y, uint64_t z, uint64_t a, uint64_t b) { a += w; b = Rotate(b + a + z, 21); uint64_t c = a; @@ -266,8 +266,9 @@ static std::pair<uint64_t, uint64_t> WeakHashLen32WithSeeds(uint64_t w, uint64_t } // Return a 16-byte hash for s[0] ... s[31], a, and b. Quick and dirty. -static std::pair<uint64_t, uint64_t> WeakHashLen32WithSeeds(const char *s, uint64_t a, - uint64_t b) { +static std::pair<uint64_t, uint64_t> WeakHashLen32WithSeeds(const char *s, + uint64_t a, + uint64_t b) { return WeakHashLen32WithSeeds(Fetch64(s), Fetch64(s + 8), Fetch64(s + 16), Fetch64(s + 24), a, b); } @@ -310,8 +311,10 @@ uint64_t CityHash64(const char *s, size_t len) { uint64_t x = Fetch64(s + len - 40); uint64_t y = Fetch64(s + len - 16) + Fetch64(s + len - 56); uint64_t z = HashLen16(Fetch64(s + len - 48) + len, Fetch64(s + len - 24)); - std::pair<uint64_t, uint64_t> v = WeakHashLen32WithSeeds(s + len - 64, len, z); - std::pair<uint64_t, uint64_t> w = WeakHashLen32WithSeeds(s + len - 32, y + k1, x); + std::pair<uint64_t, uint64_t> v = + WeakHashLen32WithSeeds(s + len - 64, len, z); + std::pair<uint64_t, uint64_t> w = + WeakHashLen32WithSeeds(s + len - 32, y + k1, x); x = x * k1 + Fetch64(s); // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks. @@ -337,7 +340,7 @@ uint64_t CityHash64WithSeed(const char *s, size_t len, uint64_t seed) { } uint64_t CityHash64WithSeeds(const char *s, size_t len, uint64_t seed0, - uint64_t seed1) { + uint64_t seed1) { return HashLen16(CityHash64(s, len) - seed0, seed1); } |