1*6777b538SAndroid Build Coastguard Worker // Copyright (c) 2011 Google, Inc.
2*6777b538SAndroid Build Coastguard Worker //
3*6777b538SAndroid Build Coastguard Worker // Permission is hereby granted, free of charge, to any person obtaining a copy
4*6777b538SAndroid Build Coastguard Worker // of this software and associated documentation files (the "Software"), to deal
5*6777b538SAndroid Build Coastguard Worker // in the Software without restriction, including without limitation the rights
6*6777b538SAndroid Build Coastguard Worker // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
7*6777b538SAndroid Build Coastguard Worker // copies of the Software, and to permit persons to whom the Software is
8*6777b538SAndroid Build Coastguard Worker // furnished to do so, subject to the following conditions:
9*6777b538SAndroid Build Coastguard Worker //
10*6777b538SAndroid Build Coastguard Worker // The above copyright notice and this permission notice shall be included in
11*6777b538SAndroid Build Coastguard Worker // all copies or substantial portions of the Software.
12*6777b538SAndroid Build Coastguard Worker //
13*6777b538SAndroid Build Coastguard Worker // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14*6777b538SAndroid Build Coastguard Worker // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15*6777b538SAndroid Build Coastguard Worker // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16*6777b538SAndroid Build Coastguard Worker // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17*6777b538SAndroid Build Coastguard Worker // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
18*6777b538SAndroid Build Coastguard Worker // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
19*6777b538SAndroid Build Coastguard Worker // THE SOFTWARE.
20*6777b538SAndroid Build Coastguard Worker //
21*6777b538SAndroid Build Coastguard Worker // CityHash, by Geoff Pike and Jyrki Alakuijala
22*6777b538SAndroid Build Coastguard Worker //
23*6777b538SAndroid Build Coastguard Worker // This file provides CityHash64() and related functions.
24*6777b538SAndroid Build Coastguard Worker //
25*6777b538SAndroid Build Coastguard Worker // It's probably possible to create even faster hash functions by
26*6777b538SAndroid Build Coastguard Worker // writing a program that systematically explores some of the space of
27*6777b538SAndroid Build Coastguard Worker // possible hash functions, by using SIMD instructions, or by
28*6777b538SAndroid Build Coastguard Worker // compromising on hash quality.
29*6777b538SAndroid Build Coastguard Worker
30*6777b538SAndroid Build Coastguard Worker #include "city.h"
31*6777b538SAndroid Build Coastguard Worker
32*6777b538SAndroid Build Coastguard Worker #include <string.h> // for memcpy and memset
33*6777b538SAndroid Build Coastguard Worker #include <algorithm>
34*6777b538SAndroid Build Coastguard Worker
35*6777b538SAndroid Build Coastguard Worker using std::make_pair;
36*6777b538SAndroid Build Coastguard Worker using std::pair;
37*6777b538SAndroid Build Coastguard Worker
38*6777b538SAndroid Build Coastguard Worker #if defined(__clang__)
39*6777b538SAndroid Build Coastguard Worker
40*6777b538SAndroid Build Coastguard Worker // Use builtins where possible. On Windows for instance, this may prevent a
41*6777b538SAndroid Build Coastguard Worker // function call instead of emitting a single instruction.
42*6777b538SAndroid Build Coastguard Worker #define bswap_32(x) __builtin_bswap32(x)
43*6777b538SAndroid Build Coastguard Worker #define bswap_64(x) __builtin_bswap64(x)
44*6777b538SAndroid Build Coastguard Worker
45*6777b538SAndroid Build Coastguard Worker #elif _MSC_VER
46*6777b538SAndroid Build Coastguard Worker
47*6777b538SAndroid Build Coastguard Worker #include <stdlib.h>
48*6777b538SAndroid Build Coastguard Worker #define bswap_32(x) _byteswap_ulong(x)
49*6777b538SAndroid Build Coastguard Worker #define bswap_64(x) _byteswap_uint64(x)
50*6777b538SAndroid Build Coastguard Worker
51*6777b538SAndroid Build Coastguard Worker #elif defined(__APPLE__)
52*6777b538SAndroid Build Coastguard Worker
53*6777b538SAndroid Build Coastguard Worker // Mac OS X / Darwin features
54*6777b538SAndroid Build Coastguard Worker #include <libkern/OSByteOrder.h>
55*6777b538SAndroid Build Coastguard Worker #define bswap_32(x) OSSwapInt32(x)
56*6777b538SAndroid Build Coastguard Worker #define bswap_64(x) OSSwapInt64(x)
57*6777b538SAndroid Build Coastguard Worker
58*6777b538SAndroid Build Coastguard Worker #elif defined(__sun) || defined(sun)
59*6777b538SAndroid Build Coastguard Worker
60*6777b538SAndroid Build Coastguard Worker #include <sys/byteorder.h>
61*6777b538SAndroid Build Coastguard Worker #define bswap_32(x) BSWAP_32(x)
62*6777b538SAndroid Build Coastguard Worker #define bswap_64(x) BSWAP_64(x)
63*6777b538SAndroid Build Coastguard Worker
64*6777b538SAndroid Build Coastguard Worker #elif defined(__FreeBSD__)
65*6777b538SAndroid Build Coastguard Worker
66*6777b538SAndroid Build Coastguard Worker #include <sys/endian.h>
67*6777b538SAndroid Build Coastguard Worker #define bswap_32(x) bswap32(x)
68*6777b538SAndroid Build Coastguard Worker #define bswap_64(x) bswap64(x)
69*6777b538SAndroid Build Coastguard Worker
70*6777b538SAndroid Build Coastguard Worker #elif defined(__OpenBSD__)
71*6777b538SAndroid Build Coastguard Worker
72*6777b538SAndroid Build Coastguard Worker #include <sys/types.h>
73*6777b538SAndroid Build Coastguard Worker #define bswap_32(x) swap32(x)
74*6777b538SAndroid Build Coastguard Worker #define bswap_64(x) swap64(x)
75*6777b538SAndroid Build Coastguard Worker
76*6777b538SAndroid Build Coastguard Worker #elif defined(__NetBSD__)
77*6777b538SAndroid Build Coastguard Worker
78*6777b538SAndroid Build Coastguard Worker #include <machine/bswap.h>
79*6777b538SAndroid Build Coastguard Worker #include <sys/types.h>
80*6777b538SAndroid Build Coastguard Worker #if defined(__BSWAP_RENAME) && !defined(__bswap_32)
81*6777b538SAndroid Build Coastguard Worker #define bswap_32(x) bswap32(x)
82*6777b538SAndroid Build Coastguard Worker #define bswap_64(x) bswap64(x)
83*6777b538SAndroid Build Coastguard Worker #endif
84*6777b538SAndroid Build Coastguard Worker
85*6777b538SAndroid Build Coastguard Worker #else
86*6777b538SAndroid Build Coastguard Worker
87*6777b538SAndroid Build Coastguard Worker // XXX(cavalcanti): building 'native_client' fails with this header.
88*6777b538SAndroid Build Coastguard Worker //#include <byteswap.h>
89*6777b538SAndroid Build Coastguard Worker
90*6777b538SAndroid Build Coastguard Worker // Falling back to compiler builtins instead.
91*6777b538SAndroid Build Coastguard Worker #define bswap_32(x) __builtin_bswap32(x)
92*6777b538SAndroid Build Coastguard Worker #define bswap_64(x) __builtin_bswap64(x)
93*6777b538SAndroid Build Coastguard Worker
94*6777b538SAndroid Build Coastguard Worker #endif
95*6777b538SAndroid Build Coastguard Worker
96*6777b538SAndroid Build Coastguard Worker namespace base {
97*6777b538SAndroid Build Coastguard Worker namespace internal {
98*6777b538SAndroid Build Coastguard Worker namespace cityhash_v111 {
99*6777b538SAndroid Build Coastguard Worker
100*6777b538SAndroid Build Coastguard Worker #ifdef WORDS_BIGENDIAN
101*6777b538SAndroid Build Coastguard Worker #define uint32_in_expected_order(x) (bswap_32(x))
102*6777b538SAndroid Build Coastguard Worker #define uint64_in_expected_order(x) (bswap_64(x))
103*6777b538SAndroid Build Coastguard Worker #else
104*6777b538SAndroid Build Coastguard Worker #define uint32_in_expected_order(x) (x)
105*6777b538SAndroid Build Coastguard Worker #define uint64_in_expected_order(x) (x)
106*6777b538SAndroid Build Coastguard Worker #endif
107*6777b538SAndroid Build Coastguard Worker
108*6777b538SAndroid Build Coastguard Worker #if !defined(LIKELY)
109*6777b538SAndroid Build Coastguard Worker #if HAVE_BUILTIN_EXPECT
110*6777b538SAndroid Build Coastguard Worker #define LIKELY(x) (__builtin_expect(!!(x), 1))
111*6777b538SAndroid Build Coastguard Worker #else
112*6777b538SAndroid Build Coastguard Worker #define LIKELY(x) (x)
113*6777b538SAndroid Build Coastguard Worker #endif
114*6777b538SAndroid Build Coastguard Worker #endif
115*6777b538SAndroid Build Coastguard Worker
UNALIGNED_LOAD64(const char * p)116*6777b538SAndroid Build Coastguard Worker static uint64 UNALIGNED_LOAD64(const char* p) {
117*6777b538SAndroid Build Coastguard Worker uint64 result;
118*6777b538SAndroid Build Coastguard Worker memcpy(&result, p, sizeof(result));
119*6777b538SAndroid Build Coastguard Worker return result;
120*6777b538SAndroid Build Coastguard Worker }
121*6777b538SAndroid Build Coastguard Worker
UNALIGNED_LOAD32(const char * p)122*6777b538SAndroid Build Coastguard Worker static uint32 UNALIGNED_LOAD32(const char* p) {
123*6777b538SAndroid Build Coastguard Worker uint32 result;
124*6777b538SAndroid Build Coastguard Worker memcpy(&result, p, sizeof(result));
125*6777b538SAndroid Build Coastguard Worker return result;
126*6777b538SAndroid Build Coastguard Worker }
127*6777b538SAndroid Build Coastguard Worker
Fetch64(const char * p)128*6777b538SAndroid Build Coastguard Worker static uint64 Fetch64(const char* p) {
129*6777b538SAndroid Build Coastguard Worker return uint64_in_expected_order(UNALIGNED_LOAD64(p));
130*6777b538SAndroid Build Coastguard Worker }
131*6777b538SAndroid Build Coastguard Worker
Fetch32(const char * p)132*6777b538SAndroid Build Coastguard Worker static uint32 Fetch32(const char* p) {
133*6777b538SAndroid Build Coastguard Worker return uint32_in_expected_order(UNALIGNED_LOAD32(p));
134*6777b538SAndroid Build Coastguard Worker }
135*6777b538SAndroid Build Coastguard Worker
136*6777b538SAndroid Build Coastguard Worker // Some primes between 2^63 and 2^64 for various uses.
137*6777b538SAndroid Build Coastguard Worker static const uint64 k0 = 0xc3a5c85c97cb3127ULL;
138*6777b538SAndroid Build Coastguard Worker static const uint64 k1 = 0xb492b66fbe98f273ULL;
139*6777b538SAndroid Build Coastguard Worker static const uint64 k2 = 0x9ae16a3b2f90404fULL;
140*6777b538SAndroid Build Coastguard Worker
141*6777b538SAndroid Build Coastguard Worker // Magic numbers for 32-bit hashing. Copied from Murmur3.
142*6777b538SAndroid Build Coastguard Worker static const uint32 c1 = 0xcc9e2d51;
143*6777b538SAndroid Build Coastguard Worker static const uint32 c2 = 0x1b873593;
144*6777b538SAndroid Build Coastguard Worker
145*6777b538SAndroid Build Coastguard Worker // A 32-bit to 32-bit integer hash copied from Murmur3.
fmix(uint32 h)146*6777b538SAndroid Build Coastguard Worker static uint32 fmix(uint32 h) {
147*6777b538SAndroid Build Coastguard Worker h ^= h >> 16;
148*6777b538SAndroid Build Coastguard Worker h *= 0x85ebca6b;
149*6777b538SAndroid Build Coastguard Worker h ^= h >> 13;
150*6777b538SAndroid Build Coastguard Worker h *= 0xc2b2ae35;
151*6777b538SAndroid Build Coastguard Worker h ^= h >> 16;
152*6777b538SAndroid Build Coastguard Worker return h;
153*6777b538SAndroid Build Coastguard Worker }
154*6777b538SAndroid Build Coastguard Worker
Rotate32(uint32 val,int shift)155*6777b538SAndroid Build Coastguard Worker static uint32 Rotate32(uint32 val, int shift) {
156*6777b538SAndroid Build Coastguard Worker // Avoid shifting by 32: doing so yields an undefined result.
157*6777b538SAndroid Build Coastguard Worker return shift == 0 ? val : ((val >> shift) | (val << (32 - shift)));
158*6777b538SAndroid Build Coastguard Worker }
159*6777b538SAndroid Build Coastguard Worker
160*6777b538SAndroid Build Coastguard Worker #undef PERMUTE3
161*6777b538SAndroid Build Coastguard Worker #define PERMUTE3(a, b, c) \
162*6777b538SAndroid Build Coastguard Worker do { \
163*6777b538SAndroid Build Coastguard Worker std::swap(a, b); \
164*6777b538SAndroid Build Coastguard Worker std::swap(a, c); \
165*6777b538SAndroid Build Coastguard Worker } while (0)
166*6777b538SAndroid Build Coastguard Worker
Mur(uint32 a,uint32 h)167*6777b538SAndroid Build Coastguard Worker static uint32 Mur(uint32 a, uint32 h) {
168*6777b538SAndroid Build Coastguard Worker // Helper from Murmur3 for combining two 32-bit values.
169*6777b538SAndroid Build Coastguard Worker a *= c1;
170*6777b538SAndroid Build Coastguard Worker a = Rotate32(a, 17);
171*6777b538SAndroid Build Coastguard Worker a *= c2;
172*6777b538SAndroid Build Coastguard Worker h ^= a;
173*6777b538SAndroid Build Coastguard Worker h = Rotate32(h, 19);
174*6777b538SAndroid Build Coastguard Worker return h * 5 + 0xe6546b64;
175*6777b538SAndroid Build Coastguard Worker }
176*6777b538SAndroid Build Coastguard Worker
Hash32Len13to24(const char * s,size_t len)177*6777b538SAndroid Build Coastguard Worker static uint32 Hash32Len13to24(const char* s, size_t len) {
178*6777b538SAndroid Build Coastguard Worker uint32 a = Fetch32(s - 4 + (len >> 1));
179*6777b538SAndroid Build Coastguard Worker uint32 b = Fetch32(s + 4);
180*6777b538SAndroid Build Coastguard Worker uint32 c = Fetch32(s + len - 8);
181*6777b538SAndroid Build Coastguard Worker uint32 d = Fetch32(s + (len >> 1));
182*6777b538SAndroid Build Coastguard Worker uint32 e = Fetch32(s);
183*6777b538SAndroid Build Coastguard Worker uint32 f = Fetch32(s + len - 4);
184*6777b538SAndroid Build Coastguard Worker uint32 h = static_cast<uint32>(len);
185*6777b538SAndroid Build Coastguard Worker
186*6777b538SAndroid Build Coastguard Worker return fmix(Mur(f, Mur(e, Mur(d, Mur(c, Mur(b, Mur(a, h)))))));
187*6777b538SAndroid Build Coastguard Worker }
188*6777b538SAndroid Build Coastguard Worker
Hash32Len0to4(const char * s,size_t len)189*6777b538SAndroid Build Coastguard Worker static uint32 Hash32Len0to4(const char* s, size_t len) {
190*6777b538SAndroid Build Coastguard Worker uint32 b = 0;
191*6777b538SAndroid Build Coastguard Worker uint32 c = 9;
192*6777b538SAndroid Build Coastguard Worker for (size_t i = 0; i < len; i++) {
193*6777b538SAndroid Build Coastguard Worker signed char v = static_cast<signed char>(s[i]);
194*6777b538SAndroid Build Coastguard Worker b = b * c1 + static_cast<uint32>(v);
195*6777b538SAndroid Build Coastguard Worker c ^= b;
196*6777b538SAndroid Build Coastguard Worker }
197*6777b538SAndroid Build Coastguard Worker return fmix(Mur(b, Mur(static_cast<uint32>(len), c)));
198*6777b538SAndroid Build Coastguard Worker }
199*6777b538SAndroid Build Coastguard Worker
Hash32Len5to12(const char * s,size_t len)200*6777b538SAndroid Build Coastguard Worker static uint32 Hash32Len5to12(const char* s, size_t len) {
201*6777b538SAndroid Build Coastguard Worker uint32 a = static_cast<uint32>(len), b = a * 5, c = 9, d = b;
202*6777b538SAndroid Build Coastguard Worker a += Fetch32(s);
203*6777b538SAndroid Build Coastguard Worker b += Fetch32(s + len - 4);
204*6777b538SAndroid Build Coastguard Worker c += Fetch32(s + ((len >> 1) & 4));
205*6777b538SAndroid Build Coastguard Worker return fmix(Mur(c, Mur(b, Mur(a, d))));
206*6777b538SAndroid Build Coastguard Worker }
207*6777b538SAndroid Build Coastguard Worker
CityHash32(const char * s,size_t len)208*6777b538SAndroid Build Coastguard Worker uint32 CityHash32(const char* s, size_t len) {
209*6777b538SAndroid Build Coastguard Worker if (len <= 24) {
210*6777b538SAndroid Build Coastguard Worker return len <= 12
211*6777b538SAndroid Build Coastguard Worker ? (len <= 4 ? Hash32Len0to4(s, len) : Hash32Len5to12(s, len))
212*6777b538SAndroid Build Coastguard Worker : Hash32Len13to24(s, len);
213*6777b538SAndroid Build Coastguard Worker }
214*6777b538SAndroid Build Coastguard Worker
215*6777b538SAndroid Build Coastguard Worker // len > 24
216*6777b538SAndroid Build Coastguard Worker uint32 h = static_cast<uint32>(len), g = c1 * h, f = g;
217*6777b538SAndroid Build Coastguard Worker uint32 a0 = Rotate32(Fetch32(s + len - 4) * c1, 17) * c2;
218*6777b538SAndroid Build Coastguard Worker uint32 a1 = Rotate32(Fetch32(s + len - 8) * c1, 17) * c2;
219*6777b538SAndroid Build Coastguard Worker uint32 a2 = Rotate32(Fetch32(s + len - 16) * c1, 17) * c2;
220*6777b538SAndroid Build Coastguard Worker uint32 a3 = Rotate32(Fetch32(s + len - 12) * c1, 17) * c2;
221*6777b538SAndroid Build Coastguard Worker uint32 a4 = Rotate32(Fetch32(s + len - 20) * c1, 17) * c2;
222*6777b538SAndroid Build Coastguard Worker h ^= a0;
223*6777b538SAndroid Build Coastguard Worker h = Rotate32(h, 19);
224*6777b538SAndroid Build Coastguard Worker h = h * 5 + 0xe6546b64;
225*6777b538SAndroid Build Coastguard Worker h ^= a2;
226*6777b538SAndroid Build Coastguard Worker h = Rotate32(h, 19);
227*6777b538SAndroid Build Coastguard Worker h = h * 5 + 0xe6546b64;
228*6777b538SAndroid Build Coastguard Worker g ^= a1;
229*6777b538SAndroid Build Coastguard Worker g = Rotate32(g, 19);
230*6777b538SAndroid Build Coastguard Worker g = g * 5 + 0xe6546b64;
231*6777b538SAndroid Build Coastguard Worker g ^= a3;
232*6777b538SAndroid Build Coastguard Worker g = Rotate32(g, 19);
233*6777b538SAndroid Build Coastguard Worker g = g * 5 + 0xe6546b64;
234*6777b538SAndroid Build Coastguard Worker f += a4;
235*6777b538SAndroid Build Coastguard Worker f = Rotate32(f, 19);
236*6777b538SAndroid Build Coastguard Worker f = f * 5 + 0xe6546b64;
237*6777b538SAndroid Build Coastguard Worker size_t iters = (len - 1) / 20;
238*6777b538SAndroid Build Coastguard Worker do {
239*6777b538SAndroid Build Coastguard Worker a0 = Rotate32(Fetch32(s) * c1, 17) * c2;
240*6777b538SAndroid Build Coastguard Worker a1 = Fetch32(s + 4);
241*6777b538SAndroid Build Coastguard Worker a2 = Rotate32(Fetch32(s + 8) * c1, 17) * c2;
242*6777b538SAndroid Build Coastguard Worker a3 = Rotate32(Fetch32(s + 12) * c1, 17) * c2;
243*6777b538SAndroid Build Coastguard Worker a4 = Fetch32(s + 16);
244*6777b538SAndroid Build Coastguard Worker h ^= a0;
245*6777b538SAndroid Build Coastguard Worker h = Rotate32(h, 18);
246*6777b538SAndroid Build Coastguard Worker h = h * 5 + 0xe6546b64;
247*6777b538SAndroid Build Coastguard Worker f += a1;
248*6777b538SAndroid Build Coastguard Worker f = Rotate32(f, 19);
249*6777b538SAndroid Build Coastguard Worker f = f * c1;
250*6777b538SAndroid Build Coastguard Worker g += a2;
251*6777b538SAndroid Build Coastguard Worker g = Rotate32(g, 18);
252*6777b538SAndroid Build Coastguard Worker g = g * 5 + 0xe6546b64;
253*6777b538SAndroid Build Coastguard Worker h ^= a3 + a1;
254*6777b538SAndroid Build Coastguard Worker h = Rotate32(h, 19);
255*6777b538SAndroid Build Coastguard Worker h = h * 5 + 0xe6546b64;
256*6777b538SAndroid Build Coastguard Worker g ^= a4;
257*6777b538SAndroid Build Coastguard Worker g = bswap_32(g) * 5;
258*6777b538SAndroid Build Coastguard Worker h += a4 * 5;
259*6777b538SAndroid Build Coastguard Worker h = bswap_32(h);
260*6777b538SAndroid Build Coastguard Worker f += a0;
261*6777b538SAndroid Build Coastguard Worker PERMUTE3(f, h, g);
262*6777b538SAndroid Build Coastguard Worker s += 20;
263*6777b538SAndroid Build Coastguard Worker } while (--iters != 0);
264*6777b538SAndroid Build Coastguard Worker g = Rotate32(g, 11) * c1;
265*6777b538SAndroid Build Coastguard Worker g = Rotate32(g, 17) * c1;
266*6777b538SAndroid Build Coastguard Worker f = Rotate32(f, 11) * c1;
267*6777b538SAndroid Build Coastguard Worker f = Rotate32(f, 17) * c1;
268*6777b538SAndroid Build Coastguard Worker h = Rotate32(h + g, 19);
269*6777b538SAndroid Build Coastguard Worker h = h * 5 + 0xe6546b64;
270*6777b538SAndroid Build Coastguard Worker h = Rotate32(h, 17) * c1;
271*6777b538SAndroid Build Coastguard Worker h = Rotate32(h + f, 19);
272*6777b538SAndroid Build Coastguard Worker h = h * 5 + 0xe6546b64;
273*6777b538SAndroid Build Coastguard Worker h = Rotate32(h, 17) * c1;
274*6777b538SAndroid Build Coastguard Worker return h;
275*6777b538SAndroid Build Coastguard Worker }
276*6777b538SAndroid Build Coastguard Worker
277*6777b538SAndroid Build Coastguard Worker // Bitwise right rotate. Normally this will compile to a single
278*6777b538SAndroid Build Coastguard Worker // instruction, especially if the shift is a manifest constant.
Rotate(uint64 val,int shift)279*6777b538SAndroid Build Coastguard Worker static uint64 Rotate(uint64 val, int shift) {
280*6777b538SAndroid Build Coastguard Worker // Avoid shifting by 64: doing so yields an undefined result.
281*6777b538SAndroid Build Coastguard Worker return shift == 0 ? val : ((val >> shift) | (val << (64 - shift)));
282*6777b538SAndroid Build Coastguard Worker }
283*6777b538SAndroid Build Coastguard Worker
ShiftMix(uint64 val)284*6777b538SAndroid Build Coastguard Worker static uint64 ShiftMix(uint64 val) {
285*6777b538SAndroid Build Coastguard Worker return val ^ (val >> 47);
286*6777b538SAndroid Build Coastguard Worker }
287*6777b538SAndroid Build Coastguard Worker
HashLen16(uint64 u,uint64 v)288*6777b538SAndroid Build Coastguard Worker static uint64 HashLen16(uint64 u, uint64 v) {
289*6777b538SAndroid Build Coastguard Worker return Hash128to64(uint128(u, v));
290*6777b538SAndroid Build Coastguard Worker }
291*6777b538SAndroid Build Coastguard Worker
HashLen16(uint64 u,uint64 v,uint64 mul)292*6777b538SAndroid Build Coastguard Worker static uint64 HashLen16(uint64 u, uint64 v, uint64 mul) {
293*6777b538SAndroid Build Coastguard Worker // Murmur-inspired hashing.
294*6777b538SAndroid Build Coastguard Worker uint64 a = (u ^ v) * mul;
295*6777b538SAndroid Build Coastguard Worker a ^= (a >> 47);
296*6777b538SAndroid Build Coastguard Worker uint64 b = (v ^ a) * mul;
297*6777b538SAndroid Build Coastguard Worker b ^= (b >> 47);
298*6777b538SAndroid Build Coastguard Worker b *= mul;
299*6777b538SAndroid Build Coastguard Worker return b;
300*6777b538SAndroid Build Coastguard Worker }
301*6777b538SAndroid Build Coastguard Worker
HashLen0to16(const char * s,size_t len)302*6777b538SAndroid Build Coastguard Worker static uint64 HashLen0to16(const char* s, size_t len) {
303*6777b538SAndroid Build Coastguard Worker if (len >= 8) {
304*6777b538SAndroid Build Coastguard Worker uint64 mul = k2 + len * 2;
305*6777b538SAndroid Build Coastguard Worker uint64 a = Fetch64(s) + k2;
306*6777b538SAndroid Build Coastguard Worker uint64 b = Fetch64(s + len - 8);
307*6777b538SAndroid Build Coastguard Worker uint64 c = Rotate(b, 37) * mul + a;
308*6777b538SAndroid Build Coastguard Worker uint64 d = (Rotate(a, 25) + b) * mul;
309*6777b538SAndroid Build Coastguard Worker return HashLen16(c, d, mul);
310*6777b538SAndroid Build Coastguard Worker }
311*6777b538SAndroid Build Coastguard Worker if (len >= 4) {
312*6777b538SAndroid Build Coastguard Worker uint64 mul = k2 + len * 2;
313*6777b538SAndroid Build Coastguard Worker uint64 a = Fetch32(s);
314*6777b538SAndroid Build Coastguard Worker return HashLen16(len + (a << 3), Fetch32(s + len - 4), mul);
315*6777b538SAndroid Build Coastguard Worker }
316*6777b538SAndroid Build Coastguard Worker if (len > 0) {
317*6777b538SAndroid Build Coastguard Worker uint8 a = static_cast<uint8>(s[0]);
318*6777b538SAndroid Build Coastguard Worker uint8 b = static_cast<uint8>(s[len >> 1]);
319*6777b538SAndroid Build Coastguard Worker uint8 c = static_cast<uint8>(s[len - 1]);
320*6777b538SAndroid Build Coastguard Worker uint32 y = static_cast<uint32>(a) + (static_cast<uint32>(b) << 8);
321*6777b538SAndroid Build Coastguard Worker uint32 z = static_cast<uint32>(len) + (static_cast<uint32>(c) << 2);
322*6777b538SAndroid Build Coastguard Worker return ShiftMix(y * k2 ^ z * k0) * k2;
323*6777b538SAndroid Build Coastguard Worker }
324*6777b538SAndroid Build Coastguard Worker return k2;
325*6777b538SAndroid Build Coastguard Worker }
326*6777b538SAndroid Build Coastguard Worker
327*6777b538SAndroid Build Coastguard Worker // This probably works well for 16-byte strings as well, but it may be overkill
328*6777b538SAndroid Build Coastguard Worker // in that case.
HashLen17to32(const char * s,size_t len)329*6777b538SAndroid Build Coastguard Worker static uint64 HashLen17to32(const char* s, size_t len) {
330*6777b538SAndroid Build Coastguard Worker uint64 mul = k2 + len * 2;
331*6777b538SAndroid Build Coastguard Worker uint64 a = Fetch64(s) * k1;
332*6777b538SAndroid Build Coastguard Worker uint64 b = Fetch64(s + 8);
333*6777b538SAndroid Build Coastguard Worker uint64 c = Fetch64(s + len - 8) * mul;
334*6777b538SAndroid Build Coastguard Worker uint64 d = Fetch64(s + len - 16) * k2;
335*6777b538SAndroid Build Coastguard Worker return HashLen16(Rotate(a + b, 43) + Rotate(c, 30) + d,
336*6777b538SAndroid Build Coastguard Worker a + Rotate(b + k2, 18) + c, mul);
337*6777b538SAndroid Build Coastguard Worker }
338*6777b538SAndroid Build Coastguard Worker
339*6777b538SAndroid Build Coastguard Worker // Return a 16-byte hash for 48 bytes. Quick and dirty.
340*6777b538SAndroid Build Coastguard Worker // Callers do best to use "random-looking" values for a and b.
WeakHashLen32WithSeeds(uint64 w,uint64 x,uint64 y,uint64 z,uint64 a,uint64 b)341*6777b538SAndroid Build Coastguard Worker static pair<uint64, uint64> WeakHashLen32WithSeeds(uint64 w,
342*6777b538SAndroid Build Coastguard Worker uint64 x,
343*6777b538SAndroid Build Coastguard Worker uint64 y,
344*6777b538SAndroid Build Coastguard Worker uint64 z,
345*6777b538SAndroid Build Coastguard Worker uint64 a,
346*6777b538SAndroid Build Coastguard Worker uint64 b) {
347*6777b538SAndroid Build Coastguard Worker a += w;
348*6777b538SAndroid Build Coastguard Worker b = Rotate(b + a + z, 21);
349*6777b538SAndroid Build Coastguard Worker uint64 c = a;
350*6777b538SAndroid Build Coastguard Worker a += x;
351*6777b538SAndroid Build Coastguard Worker a += y;
352*6777b538SAndroid Build Coastguard Worker b += Rotate(a, 44);
353*6777b538SAndroid Build Coastguard Worker return make_pair(a + z, b + c);
354*6777b538SAndroid Build Coastguard Worker }
355*6777b538SAndroid Build Coastguard Worker
356*6777b538SAndroid Build Coastguard Worker // Return a 16-byte hash for s[0] ... s[31], a, and b. Quick and dirty.
WeakHashLen32WithSeeds(const char * s,uint64 a,uint64 b)357*6777b538SAndroid Build Coastguard Worker static pair<uint64, uint64> WeakHashLen32WithSeeds(const char* s,
358*6777b538SAndroid Build Coastguard Worker uint64 a,
359*6777b538SAndroid Build Coastguard Worker uint64 b) {
360*6777b538SAndroid Build Coastguard Worker return WeakHashLen32WithSeeds(Fetch64(s), Fetch64(s + 8), Fetch64(s + 16),
361*6777b538SAndroid Build Coastguard Worker Fetch64(s + 24), a, b);
362*6777b538SAndroid Build Coastguard Worker }
363*6777b538SAndroid Build Coastguard Worker
364*6777b538SAndroid Build Coastguard Worker // Return an 8-byte hash for 33 to 64 bytes.
HashLen33to64(const char * s,size_t len)365*6777b538SAndroid Build Coastguard Worker static uint64 HashLen33to64(const char* s, size_t len) {
366*6777b538SAndroid Build Coastguard Worker uint64 mul = k2 + len * 2;
367*6777b538SAndroid Build Coastguard Worker uint64 a = Fetch64(s) * k2;
368*6777b538SAndroid Build Coastguard Worker uint64 b = Fetch64(s + 8);
369*6777b538SAndroid Build Coastguard Worker uint64 c = Fetch64(s + len - 24);
370*6777b538SAndroid Build Coastguard Worker uint64 d = Fetch64(s + len - 32);
371*6777b538SAndroid Build Coastguard Worker uint64 e = Fetch64(s + 16) * k2;
372*6777b538SAndroid Build Coastguard Worker uint64 f = Fetch64(s + 24) * 9;
373*6777b538SAndroid Build Coastguard Worker uint64 g = Fetch64(s + len - 8);
374*6777b538SAndroid Build Coastguard Worker uint64 h = Fetch64(s + len - 16) * mul;
375*6777b538SAndroid Build Coastguard Worker uint64 u = Rotate(a + g, 43) + (Rotate(b, 30) + c) * 9;
376*6777b538SAndroid Build Coastguard Worker uint64 v = ((a + g) ^ d) + f + 1;
377*6777b538SAndroid Build Coastguard Worker uint64 w = bswap_64((u + v) * mul) + h;
378*6777b538SAndroid Build Coastguard Worker uint64 x = Rotate(e + f, 42) + c;
379*6777b538SAndroid Build Coastguard Worker uint64 y = (bswap_64((v + w) * mul) + g) * mul;
380*6777b538SAndroid Build Coastguard Worker uint64 z = e + f + c;
381*6777b538SAndroid Build Coastguard Worker a = bswap_64((x + z) * mul + y) + b;
382*6777b538SAndroid Build Coastguard Worker b = ShiftMix((z + a) * mul + d + h) * mul;
383*6777b538SAndroid Build Coastguard Worker return b + x;
384*6777b538SAndroid Build Coastguard Worker }
385*6777b538SAndroid Build Coastguard Worker
CityHash64(const char * s,size_t len)386*6777b538SAndroid Build Coastguard Worker uint64 CityHash64(const char* s, size_t len) {
387*6777b538SAndroid Build Coastguard Worker if (len <= 32) {
388*6777b538SAndroid Build Coastguard Worker if (len <= 16) {
389*6777b538SAndroid Build Coastguard Worker return HashLen0to16(s, len);
390*6777b538SAndroid Build Coastguard Worker } else {
391*6777b538SAndroid Build Coastguard Worker return HashLen17to32(s, len);
392*6777b538SAndroid Build Coastguard Worker }
393*6777b538SAndroid Build Coastguard Worker } else if (len <= 64) {
394*6777b538SAndroid Build Coastguard Worker return HashLen33to64(s, len);
395*6777b538SAndroid Build Coastguard Worker }
396*6777b538SAndroid Build Coastguard Worker
397*6777b538SAndroid Build Coastguard Worker // For strings over 64 bytes we hash the end first, and then as we
398*6777b538SAndroid Build Coastguard Worker // loop we keep 56 bytes of state: v, w, x, y, and z.
399*6777b538SAndroid Build Coastguard Worker uint64 x = Fetch64(s + len - 40);
400*6777b538SAndroid Build Coastguard Worker uint64 y = Fetch64(s + len - 16) + Fetch64(s + len - 56);
401*6777b538SAndroid Build Coastguard Worker uint64 z = HashLen16(Fetch64(s + len - 48) + len, Fetch64(s + len - 24));
402*6777b538SAndroid Build Coastguard Worker pair<uint64, uint64> v = WeakHashLen32WithSeeds(s + len - 64, len, z);
403*6777b538SAndroid Build Coastguard Worker pair<uint64, uint64> w = WeakHashLen32WithSeeds(s + len - 32, y + k1, x);
404*6777b538SAndroid Build Coastguard Worker x = x * k1 + Fetch64(s);
405*6777b538SAndroid Build Coastguard Worker
406*6777b538SAndroid Build Coastguard Worker // Decrease len to the nearest multiple of 64, and operate on 64-byte chunks.
407*6777b538SAndroid Build Coastguard Worker len = (len - 1) & ~static_cast<size_t>(63);
408*6777b538SAndroid Build Coastguard Worker do {
409*6777b538SAndroid Build Coastguard Worker x = Rotate(x + y + v.first + Fetch64(s + 8), 37) * k1;
410*6777b538SAndroid Build Coastguard Worker y = Rotate(y + v.second + Fetch64(s + 48), 42) * k1;
411*6777b538SAndroid Build Coastguard Worker x ^= w.second;
412*6777b538SAndroid Build Coastguard Worker y += v.first + Fetch64(s + 40);
413*6777b538SAndroid Build Coastguard Worker z = Rotate(z + w.first, 33) * k1;
414*6777b538SAndroid Build Coastguard Worker v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first);
415*6777b538SAndroid Build Coastguard Worker w = WeakHashLen32WithSeeds(s + 32, z + w.second, y + Fetch64(s + 16));
416*6777b538SAndroid Build Coastguard Worker std::swap(z, x);
417*6777b538SAndroid Build Coastguard Worker s += 64;
418*6777b538SAndroid Build Coastguard Worker len -= 64;
419*6777b538SAndroid Build Coastguard Worker } while (len != 0);
420*6777b538SAndroid Build Coastguard Worker return HashLen16(HashLen16(v.first, w.first) + ShiftMix(y) * k1 + z,
421*6777b538SAndroid Build Coastguard Worker HashLen16(v.second, w.second) + x);
422*6777b538SAndroid Build Coastguard Worker }
423*6777b538SAndroid Build Coastguard Worker
CityHash64WithSeed(const char * s,size_t len,uint64 seed)424*6777b538SAndroid Build Coastguard Worker uint64 CityHash64WithSeed(const char* s, size_t len, uint64 seed) {
425*6777b538SAndroid Build Coastguard Worker return CityHash64WithSeeds(s, len, k2, seed);
426*6777b538SAndroid Build Coastguard Worker }
427*6777b538SAndroid Build Coastguard Worker
CityHash64WithSeeds(const char * s,size_t len,uint64 seed0,uint64 seed1)428*6777b538SAndroid Build Coastguard Worker uint64 CityHash64WithSeeds(const char* s,
429*6777b538SAndroid Build Coastguard Worker size_t len,
430*6777b538SAndroid Build Coastguard Worker uint64 seed0,
431*6777b538SAndroid Build Coastguard Worker uint64 seed1) {
432*6777b538SAndroid Build Coastguard Worker return HashLen16(CityHash64(s, len) - seed0, seed1);
433*6777b538SAndroid Build Coastguard Worker }
434*6777b538SAndroid Build Coastguard Worker
435*6777b538SAndroid Build Coastguard Worker // A subroutine for CityHash128(). Returns a decent 128-bit hash for strings
436*6777b538SAndroid Build Coastguard Worker // of any length representable in signed long. Based on City and Murmur.
CityMurmur(const char * s,size_t len,uint128 seed)437*6777b538SAndroid Build Coastguard Worker static uint128 CityMurmur(const char* s, size_t len, uint128 seed) {
438*6777b538SAndroid Build Coastguard Worker uint64 a = Uint128Low64(seed);
439*6777b538SAndroid Build Coastguard Worker uint64 b = Uint128High64(seed);
440*6777b538SAndroid Build Coastguard Worker uint64 c = 0;
441*6777b538SAndroid Build Coastguard Worker uint64 d = 0;
442*6777b538SAndroid Build Coastguard Worker if (len <= 16) {
443*6777b538SAndroid Build Coastguard Worker a = ShiftMix(a * k1) * k1;
444*6777b538SAndroid Build Coastguard Worker c = b * k1 + HashLen0to16(s, len);
445*6777b538SAndroid Build Coastguard Worker d = ShiftMix(a + (len >= 8 ? Fetch64(s) : c));
446*6777b538SAndroid Build Coastguard Worker } else {
447*6777b538SAndroid Build Coastguard Worker c = HashLen16(Fetch64(s + len - 8) + k1, a);
448*6777b538SAndroid Build Coastguard Worker d = HashLen16(b + len, c + Fetch64(s + len - 16));
449*6777b538SAndroid Build Coastguard Worker a += d;
450*6777b538SAndroid Build Coastguard Worker // len > 16 here, so do...while is safe
451*6777b538SAndroid Build Coastguard Worker do {
452*6777b538SAndroid Build Coastguard Worker a ^= ShiftMix(Fetch64(s) * k1) * k1;
453*6777b538SAndroid Build Coastguard Worker a *= k1;
454*6777b538SAndroid Build Coastguard Worker b ^= a;
455*6777b538SAndroid Build Coastguard Worker c ^= ShiftMix(Fetch64(s + 8) * k1) * k1;
456*6777b538SAndroid Build Coastguard Worker c *= k1;
457*6777b538SAndroid Build Coastguard Worker d ^= c;
458*6777b538SAndroid Build Coastguard Worker s += 16;
459*6777b538SAndroid Build Coastguard Worker len -= 16;
460*6777b538SAndroid Build Coastguard Worker } while (len > 16);
461*6777b538SAndroid Build Coastguard Worker }
462*6777b538SAndroid Build Coastguard Worker a = HashLen16(a, c);
463*6777b538SAndroid Build Coastguard Worker b = HashLen16(d, b);
464*6777b538SAndroid Build Coastguard Worker return uint128(a ^ b, HashLen16(b, a));
465*6777b538SAndroid Build Coastguard Worker }
466*6777b538SAndroid Build Coastguard Worker
CityHash128WithSeed(const char * s,size_t len,uint128 seed)467*6777b538SAndroid Build Coastguard Worker uint128 CityHash128WithSeed(const char* s, size_t len, uint128 seed) {
468*6777b538SAndroid Build Coastguard Worker if (len < 128) {
469*6777b538SAndroid Build Coastguard Worker return CityMurmur(s, len, seed);
470*6777b538SAndroid Build Coastguard Worker }
471*6777b538SAndroid Build Coastguard Worker
472*6777b538SAndroid Build Coastguard Worker // We expect len >= 128 to be the common case. Keep 56 bytes of state:
473*6777b538SAndroid Build Coastguard Worker // v, w, x, y, and z.
474*6777b538SAndroid Build Coastguard Worker pair<uint64, uint64> v, w;
475*6777b538SAndroid Build Coastguard Worker uint64 x = Uint128Low64(seed);
476*6777b538SAndroid Build Coastguard Worker uint64 y = Uint128High64(seed);
477*6777b538SAndroid Build Coastguard Worker uint64 z = len * k1;
478*6777b538SAndroid Build Coastguard Worker v.first = Rotate(y ^ k1, 49) * k1 + Fetch64(s);
479*6777b538SAndroid Build Coastguard Worker v.second = Rotate(v.first, 42) * k1 + Fetch64(s + 8);
480*6777b538SAndroid Build Coastguard Worker w.first = Rotate(y + z, 35) * k1 + x;
481*6777b538SAndroid Build Coastguard Worker w.second = Rotate(x + Fetch64(s + 88), 53) * k1;
482*6777b538SAndroid Build Coastguard Worker
483*6777b538SAndroid Build Coastguard Worker // This is the same inner loop as CityHash64(), manually unrolled.
484*6777b538SAndroid Build Coastguard Worker do {
485*6777b538SAndroid Build Coastguard Worker x = Rotate(x + y + v.first + Fetch64(s + 8), 37) * k1;
486*6777b538SAndroid Build Coastguard Worker y = Rotate(y + v.second + Fetch64(s + 48), 42) * k1;
487*6777b538SAndroid Build Coastguard Worker x ^= w.second;
488*6777b538SAndroid Build Coastguard Worker y += v.first + Fetch64(s + 40);
489*6777b538SAndroid Build Coastguard Worker z = Rotate(z + w.first, 33) * k1;
490*6777b538SAndroid Build Coastguard Worker v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first);
491*6777b538SAndroid Build Coastguard Worker w = WeakHashLen32WithSeeds(s + 32, z + w.second, y + Fetch64(s + 16));
492*6777b538SAndroid Build Coastguard Worker std::swap(z, x);
493*6777b538SAndroid Build Coastguard Worker s += 64;
494*6777b538SAndroid Build Coastguard Worker x = Rotate(x + y + v.first + Fetch64(s + 8), 37) * k1;
495*6777b538SAndroid Build Coastguard Worker y = Rotate(y + v.second + Fetch64(s + 48), 42) * k1;
496*6777b538SAndroid Build Coastguard Worker x ^= w.second;
497*6777b538SAndroid Build Coastguard Worker y += v.first + Fetch64(s + 40);
498*6777b538SAndroid Build Coastguard Worker z = Rotate(z + w.first, 33) * k1;
499*6777b538SAndroid Build Coastguard Worker v = WeakHashLen32WithSeeds(s, v.second * k1, x + w.first);
500*6777b538SAndroid Build Coastguard Worker w = WeakHashLen32WithSeeds(s + 32, z + w.second, y + Fetch64(s + 16));
501*6777b538SAndroid Build Coastguard Worker std::swap(z, x);
502*6777b538SAndroid Build Coastguard Worker s += 64;
503*6777b538SAndroid Build Coastguard Worker len -= 128;
504*6777b538SAndroid Build Coastguard Worker } while (LIKELY(len >= 128));
505*6777b538SAndroid Build Coastguard Worker x += Rotate(v.first + z, 49) * k0;
506*6777b538SAndroid Build Coastguard Worker y = y * k0 + Rotate(w.second, 37);
507*6777b538SAndroid Build Coastguard Worker z = z * k0 + Rotate(w.first, 27);
508*6777b538SAndroid Build Coastguard Worker w.first *= 9;
509*6777b538SAndroid Build Coastguard Worker v.first *= k0;
510*6777b538SAndroid Build Coastguard Worker // If 0 < len < 128, hash up to 4 chunks of 32 bytes each from the end of s.
511*6777b538SAndroid Build Coastguard Worker for (size_t tail_done = 0; tail_done < len;) {
512*6777b538SAndroid Build Coastguard Worker tail_done += 32;
513*6777b538SAndroid Build Coastguard Worker y = Rotate(x + y, 42) * k0 + v.second;
514*6777b538SAndroid Build Coastguard Worker w.first += Fetch64(s + len - tail_done + 16);
515*6777b538SAndroid Build Coastguard Worker x = x * k0 + w.first;
516*6777b538SAndroid Build Coastguard Worker z += w.second + Fetch64(s + len - tail_done);
517*6777b538SAndroid Build Coastguard Worker w.second += v.first;
518*6777b538SAndroid Build Coastguard Worker v = WeakHashLen32WithSeeds(s + len - tail_done, v.first + z, v.second);
519*6777b538SAndroid Build Coastguard Worker v.first *= k0;
520*6777b538SAndroid Build Coastguard Worker }
521*6777b538SAndroid Build Coastguard Worker // At this point our 56 bytes of state should contain more than
522*6777b538SAndroid Build Coastguard Worker // enough information for a strong 128-bit hash. We use two
523*6777b538SAndroid Build Coastguard Worker // different 56-byte-to-8-byte hashes to get a 16-byte final result.
524*6777b538SAndroid Build Coastguard Worker x = HashLen16(x, v.first);
525*6777b538SAndroid Build Coastguard Worker y = HashLen16(y + z, w.first);
526*6777b538SAndroid Build Coastguard Worker return uint128(HashLen16(x + v.second, w.second) + y,
527*6777b538SAndroid Build Coastguard Worker HashLen16(x + w.second, y + v.second));
528*6777b538SAndroid Build Coastguard Worker }
529*6777b538SAndroid Build Coastguard Worker
CityHash128(const char * s,size_t len)530*6777b538SAndroid Build Coastguard Worker uint128 CityHash128(const char* s, size_t len) {
531*6777b538SAndroid Build Coastguard Worker return len >= 16
532*6777b538SAndroid Build Coastguard Worker ? CityHash128WithSeed(s + 16, len - 16,
533*6777b538SAndroid Build Coastguard Worker uint128(Fetch64(s), Fetch64(s + 8) + k0))
534*6777b538SAndroid Build Coastguard Worker : CityHash128WithSeed(s, len, uint128(k0, k1));
535*6777b538SAndroid Build Coastguard Worker }
536*6777b538SAndroid Build Coastguard Worker
537*6777b538SAndroid Build Coastguard Worker } // namespace cityhash_v111
538*6777b538SAndroid Build Coastguard Worker } // namespace internal
539*6777b538SAndroid Build Coastguard Worker } // namespace base
540