The Tor Browser: comparison other-licenses/nsis/Contrib/CityHash/cityhash/city.cpp

--1:000000000000
+:58bd5242300e
+// Copyright (c) 2011 Google, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+//
+// CityHash Version 1, by Geoff Pike and Jyrki Alakuijala
+//
+// This file provides CityHash64() and related functions.
+//
+// It's probably possible to create even faster hash functions by
+// writing a program that systematically explores some of the space of
+// possible hash functions, by using SIMD instructions, or by
+// compromising on hash quality.
+#include "city.h"
+#include <algorithm>
+using namespace std;
+#define UNALIGNED_LOAD64(p) (*(const uint64*)(p))
+#define UNALIGNED_LOAD32(p) (*(const uint32*)(p))
+#if !defined(LIKELY)
+#if defined(__GNUC__)
+#define LIKELY(x) (__builtin_expect(!!(x), 1))
+#else
+#define LIKELY(x) (x)
+#endif
+#endif
+// Some primes between 2^63 and 2^64 for various uses.
+static const uint64 k0 = 0xc3a5c85c97cb3127;
+static const uint64 k1 = 0xb492b66fbe98f273;
+static const uint64 k2 = 0x9ae16a3b2f90404f;
+static const uint64 k3 = 0xc949d7c7509e6557;
+// Bitwise right rotate.  Normally this will compile to a single
+// instruction, especially if the shift is a manifest constant.
+static uint64 Rotate(uint64 val, int shift) {
+// Avoid shifting by 64: doing so yields an undefined result.
+return shift == 0 ? val : ((val >> shift) | (val << (64 - shift)));
+}
+// Equivalent to Rotate(), but requires the second arg to be non-zero.
+// On x86-64, and probably others, it's possible for this to compile
+// to a single instruction if both args are already in registers.
+static uint64 RotateByAtLeast1(uint64 val, int shift) {
+return (val >> shift) | (val << (64 - shift));
+}
+static uint64 ShiftMix(uint64 val) {
+return val ^ (val >> 47);
+}
+static uint64 HashLen16(uint64 u, uint64 v) {
+return Hash128to64(uint128(u, v));
+}
+static uint64 HashLen0to16(const char *s, size_t len) {
+if (len > 8) {
+uint64 a = UNALIGNED_LOAD64(s);
+uint64 b = UNALIGNED_LOAD64(s + len - 8);
+return HashLen16(a, RotateByAtLeast1(b + len, len)) ^ b;
+}
+if (len >= 4) {
+uint64 a = UNALIGNED_LOAD32(s);
+return HashLen16(len + (a << 3), UNALIGNED_LOAD32(s + len - 4));
+}
+if (len > 0) {
+uint8 a = s[0];
+uint8 b = s[len >> 1];
+uint8 c = s[len - 1];
+uint32 y = static_cast<uint32>(a) + (static_cast<uint32>(b) << 8);
+uint32 z = len + (static_cast<uint32>(c) << 2);
+return ShiftMix(y * k2 ^ z * k3) * k2;
+}
+return k2;
+}
+// This probably works well for 16-byte strings as well, but it may be overkill
+// in that case.
+static uint64 HashLen17to32(const char *s, size_t len) {
+uint64 a = UNALIGNED_LOAD64(s) * k1;
+uint64 b = UNALIGNED_LOAD64(s + 8);
+uint64 c = UNALIGNED_LOAD64(s + len - 8) * k2;
+uint64 d = UNALIGNED_LOAD64(s + len - 16) * k0;
+return HashLen16(Rotate(a - b, 43) + Rotate(c, 30) + d,
+a + Rotate(b ^ k3, 20) - c + 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 pair<uint64, uint64> WeakHashLen32WithSeeds(
+uint64 w, uint64 x, uint64 y, uint64 z, uint64 a, uint64 b) {
+a += w;
+b = Rotate(b + a + z, 21);
+uint64 c = a;
+a += x;
+a += y;
+b += Rotate(a, 44);
+return make_pair(a + z, b + c);
+}
+// Return a 16-byte hash for s[0] ... s[31], a, and b.  Quick and dirty.
+static pair<uint64, uint64> WeakHashLen32WithSeeds(
+const char* s, uint64 a, uint64 b) {
+return WeakHashLen32WithSeeds(UNALIGNED_LOAD64(s),
+UNALIGNED_LOAD64(s + 8),
+UNALIGNED_LOAD64(s + 16),
+UNALIGNED_LOAD64(s + 24),
+a,
+b);
+}
+// Return an 8-byte hash for 33 to 64 bytes.
+static uint64 HashLen33to64(const char *s, size_t len) {
+uint64 z = UNALIGNED_LOAD64(s + 24);
+uint64 a = UNALIGNED_LOAD64(s) + (len + UNALIGNED_LOAD64(s + len - 16)) * k0;
+uint64 b = Rotate(a + z, 52);
+uint64 c = Rotate(a, 37);
+a += UNALIGNED_LOAD64(s + 8);
+c += Rotate(a, 7);
+a += UNALIGNED_LOAD64(s + 16);
+uint64 vf = a + z;
+uint64 vs = b + Rotate(a, 31) + c;
+a = UNALIGNED_LOAD64(s + 16) + UNALIGNED_LOAD64(s + len - 32);
+z = UNALIGNED_LOAD64(s + len - 8);
+b = Rotate(a + z, 52);
+c = Rotate(a, 37);
+a += UNALIGNED_LOAD64(s + len - 24);
+c += Rotate(a, 7);
+a += UNALIGNED_LOAD64(s + len - 16);
+uint64 wf = a + z;
+uint64 ws = b + Rotate(a, 31) + c;
+uint64 r = ShiftMix((vf + ws) * k2 + (wf + vs) * k0);
+return ShiftMix(r * k0 + vs) * k2;
+}
+uint64 CityHash64(const char *s, size_t len) {
+if (len <= 32) {
+if (len <= 16) {
+return HashLen0to16(s, len);
+} else {
+return HashLen17to32(s, len);
+}
+} else if (len <= 64) {
+return HashLen33to64(s, len);
+}
+// For strings over 64 bytes we hash the end first, and then as we
+// loop we keep 56 bytes of state: v, w, x, y, and z.
+uint64 x = UNALIGNED_LOAD64(s);
+uint64 y = UNALIGNED_LOAD64(s + len - 16) ^ k1;
+uint64 z = UNALIGNED_LOAD64(s + len - 56) ^ k0;
+pair<uint64, uint64> v = WeakHashLen32WithSeeds(s + len - 64, len, y);
+pair<uint64, uint64> w = WeakHashLen32WithSeeds(s + len - 32, len * k1, k0);
+z += ShiftMix(v.second) * k1;
+x = Rotate(z + x, 39) * k1;
+y = Rotate(y, 33) * k1;
+// Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.
+len = (len - 1) & ~static_cast<size_t>(63);
+do {
+x = Rotate(x + y + v.first + UNALIGNED_LOAD64(s + 16), 37) * k1;
+y = Rotate(y + v.second + UNALIGNED_LOAD64(s + 48), 42) * k1;
+x ^= w.second;
+y ^= v.first;
+z = Rotate(z ^ w.first, 33);
+v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first);
+w = WeakHashLen32WithSeeds(s + 32, z + w.second, y);
+std::swap(z, x);
+s += 64;
+len -= 64;
+} while (len != 0);
+return HashLen16(HashLen16(v.first, w.first) + ShiftMix(y) * k1 + z,
+HashLen16(v.second, w.second) + x);
+}
+uint64 CityHash64WithSeed(const char *s, size_t len, uint64 seed) {
+return CityHash64WithSeeds(s, len, k2, seed);
+}
+uint64 CityHash64WithSeeds(const char *s, size_t len,
+uint64 seed0, uint64 seed1) {
+return HashLen16(CityHash64(s, len) - seed0, seed1);
+}
+// A subroutine for CityHash128().  Returns a decent 128-bit hash for strings
+// of any length representable in ssize_t.  Based on City and Murmur.
+static uint128 CityMurmur(const char *s, size_t len, uint128 seed) {
+uint64 a = Uint128Low64(seed);
+uint64 b = Uint128High64(seed);
+uint64 c = 0;
+uint64 d = 0;
+ssize_t l = len - 16;
+if (l <= 0) {  // len <= 16
+c = b * k1 + HashLen0to16(s, len);
+d = Rotate(a + (len >= 8 ? UNALIGNED_LOAD64(s) : c), 32);
+} else {  // len > 16
+c = HashLen16(UNALIGNED_LOAD64(s + len - 8) + k1, a);
+d = HashLen16(b + len, c + UNALIGNED_LOAD64(s + len - 16));
+a += d;
+do {
+a ^= ShiftMix(UNALIGNED_LOAD64(s) * k1) * k1;
+a *= k1;
+b ^= a;
+c ^= ShiftMix(UNALIGNED_LOAD64(s + 8) * k1) * k1;
+c *= k1;
+d ^= c;
+s += 16;
+l -= 16;
+} while (l > 0);
+}
+a = HashLen16(a, c);
+b = HashLen16(d, b);
+return uint128(a ^ b, HashLen16(b, a));
+}
+uint128 CityHash128WithSeed(const char *s, size_t len, uint128 seed) {
+if (len < 128) {
+return CityMurmur(s, len, seed);
+}
+// We expect len >= 128 to be the common case.  Keep 56 bytes of state:
+// v, w, x, y, and z.
+pair<uint64, uint64> v, w;
+uint64 x = Uint128Low64(seed);
+uint64 y = Uint128High64(seed);
+uint64 z = len * k1;
+v.first = Rotate(y ^ k1, 49) * k1 + UNALIGNED_LOAD64(s);
+v.second = Rotate(v.first, 42) * k1 + UNALIGNED_LOAD64(s + 8);
+w.first = Rotate(y + z, 35) * k1 + x;
+w.second = Rotate(x + UNALIGNED_LOAD64(s + 88), 53) * k1;
+// This is the same inner loop as CityHash64(), manually unrolled.
+do {
+x = Rotate(x + y + v.first + UNALIGNED_LOAD64(s + 16), 37) * k1;
+y = Rotate(y + v.second + UNALIGNED_LOAD64(s + 48), 42) * k1;
+x ^= w.second;
+y ^= v.first;
+z = Rotate(z ^ w.first, 33);
+v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first);
+w = WeakHashLen32WithSeeds(s + 32, z + w.second, y);
+std::swap(z, x);
+s += 64;
+x = Rotate(x + y + v.first + UNALIGNED_LOAD64(s + 16), 37) * k1;
+y = Rotate(y + v.second + UNALIGNED_LOAD64(s + 48), 42) * k1;
+x ^= w.second;
+y ^= v.first;
+z = Rotate(z ^ w.first, 33);
+v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first);
+w = WeakHashLen32WithSeeds(s + 32, z + w.second, y);
+std::swap(z, x);
+s += 64;
+len -= 128;
+} while (LIKELY(len >= 128));
+y += Rotate(w.first, 37) * k0 + z;
+x += Rotate(v.first + z, 49) * k0;
+// If 0 < len < 128, hash up to 4 chunks of 32 bytes each from the end of s.
+for (size_t tail_done = 0; tail_done < len; ) {
+tail_done += 32;
+y = Rotate(y - x, 42) * k0 + v.second;
+w.first += UNALIGNED_LOAD64(s + len - tail_done + 16);
+x = Rotate(x, 49) * k0 + w.first;
+w.first += v.first;
+v = WeakHashLen32WithSeeds(s + len - tail_done, v.first, v.second);
+}
+// At this point our 48 bytes of state should contain more than
+// enough information for a strong 128-bit hash.  We use two
+// different 48-byte-to-8-byte hashes to get a 16-byte final result.
+x = HashLen16(x, v.first);
+y = HashLen16(y, w.first);
+return uint128(HashLen16(x + v.second, w.second) + y,
+HashLen16(x + w.second, y + v.second));
+}
+uint128 CityHash128(const char *s, size_t len) {
+if (len >= 16) {
+return CityHash128WithSeed(s + 16,
+len - 16,
+uint128(UNALIGNED_LOAD64(s) ^ k3,
+UNALIGNED_LOAD64(s + 8)));
+} else if (len >= 8) {
+return CityHash128WithSeed(NULL,
+0,
+uint128(UNALIGNED_LOAD64(s) ^ (len * k0),
+UNALIGNED_LOAD64(s + len - 8) ^ k1));
+} else {
+return CityHash128WithSeed(s, len, uint128(k0, k1));
+}
+}

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comparison: other-licenses/nsis/Contrib/CityHash/cityhash/city.cpp

other-licenses/nsis/Contrib/CityHash/cityhash/city.cpp