1 /*
2 * xxHash - Fast Hash algorithm
3 * Copyright (C) 2012-2016, Yann Collet
4 *
5 * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are
9 * met:
10 *
11 * * Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * * Redistributions in binary form must reproduce the above
14 * copyright notice, this list of conditions and the following disclaimer
15 * in the documentation and/or other materials provided with the
16 * distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 *
30 * You can contact the author at :
31 * - xxHash homepage: http://www.xxhash.com
32 * - xxHash source repository : https://github.com/Cyan4973/xxHash
33 */
34
35 /* based on revision d2df04efcbef7d7f6886d345861e5dfda4edacc1 Removed
36 * everything but a simple interface for computing XXh64. */
37
38 #include "llvm/Support/xxhash.h"
39 #include "llvm/Support/Endian.h"
40
41 #include <stdlib.h>
42
43 using namespace llvm;
44 using namespace support;
45
rotl64(uint64_t X,size_t R)46 static uint64_t rotl64(uint64_t X, size_t R) {
47 return (X << R) | (X >> (64 - R));
48 }
49
50 static const uint64_t PRIME64_1 = 11400714785074694791ULL;
51 static const uint64_t PRIME64_2 = 14029467366897019727ULL;
52 static const uint64_t PRIME64_3 = 1609587929392839161ULL;
53 static const uint64_t PRIME64_4 = 9650029242287828579ULL;
54 static const uint64_t PRIME64_5 = 2870177450012600261ULL;
55
round(uint64_t Acc,uint64_t Input)56 static uint64_t round(uint64_t Acc, uint64_t Input) {
57 Acc += Input * PRIME64_2;
58 Acc = rotl64(Acc, 31);
59 Acc *= PRIME64_1;
60 return Acc;
61 }
62
mergeRound(uint64_t Acc,uint64_t Val)63 static uint64_t mergeRound(uint64_t Acc, uint64_t Val) {
64 Val = round(0, Val);
65 Acc ^= Val;
66 Acc = Acc * PRIME64_1 + PRIME64_4;
67 return Acc;
68 }
69
xxHash64(StringRef Data)70 uint64_t llvm::xxHash64(StringRef Data) {
71 size_t Len = Data.size();
72 uint64_t Seed = 0;
73 const unsigned char *P = Data.bytes_begin();
74 const unsigned char *const BEnd = Data.bytes_end();
75 uint64_t H64;
76
77 if (Len >= 32) {
78 const unsigned char *const Limit = BEnd - 32;
79 uint64_t V1 = Seed + PRIME64_1 + PRIME64_2;
80 uint64_t V2 = Seed + PRIME64_2;
81 uint64_t V3 = Seed + 0;
82 uint64_t V4 = Seed - PRIME64_1;
83
84 do {
85 V1 = round(V1, endian::read64le(P));
86 P += 8;
87 V2 = round(V2, endian::read64le(P));
88 P += 8;
89 V3 = round(V3, endian::read64le(P));
90 P += 8;
91 V4 = round(V4, endian::read64le(P));
92 P += 8;
93 } while (P <= Limit);
94
95 H64 = rotl64(V1, 1) + rotl64(V2, 7) + rotl64(V3, 12) + rotl64(V4, 18);
96 H64 = mergeRound(H64, V1);
97 H64 = mergeRound(H64, V2);
98 H64 = mergeRound(H64, V3);
99 H64 = mergeRound(H64, V4);
100
101 } else {
102 H64 = Seed + PRIME64_5;
103 }
104
105 H64 += (uint64_t)Len;
106
107 while (P + 8 <= BEnd) {
108 uint64_t const K1 = round(0, endian::read64le(P));
109 H64 ^= K1;
110 H64 = rotl64(H64, 27) * PRIME64_1 + PRIME64_4;
111 P += 8;
112 }
113
114 if (P + 4 <= BEnd) {
115 H64 ^= (uint64_t)(endian::read32le(P)) * PRIME64_1;
116 H64 = rotl64(H64, 23) * PRIME64_2 + PRIME64_3;
117 P += 4;
118 }
119
120 while (P < BEnd) {
121 H64 ^= (*P) * PRIME64_5;
122 H64 = rotl64(H64, 11) * PRIME64_1;
123 P++;
124 }
125
126 H64 ^= H64 >> 33;
127 H64 *= PRIME64_2;
128 H64 ^= H64 >> 29;
129 H64 *= PRIME64_3;
130 H64 ^= H64 >> 32;
131
132 return H64;
133 }
134
xxHash64(ArrayRef<uint8_t> Data)135 uint64_t llvm::xxHash64(ArrayRef<uint8_t> Data) {
136 return xxHash64({(const char *)Data.data(), Data.size()});
137 }
138