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 #include <string.h>
43
44 using namespace llvm;
45 using namespace support;
46
rotl64(uint64_t X,size_t R)47 static uint64_t rotl64(uint64_t X, size_t R) {
48 return (X << R) | (X >> (64 - R));
49 }
50
51 static const uint64_t PRIME64_1 = 11400714785074694791ULL;
52 static const uint64_t PRIME64_2 = 14029467366897019727ULL;
53 static const uint64_t PRIME64_3 = 1609587929392839161ULL;
54 static const uint64_t PRIME64_4 = 9650029242287828579ULL;
55 static const uint64_t PRIME64_5 = 2870177450012600261ULL;
56
round(uint64_t Acc,uint64_t Input)57 static uint64_t round(uint64_t Acc, uint64_t Input) {
58 Acc += Input * PRIME64_2;
59 Acc = rotl64(Acc, 31);
60 Acc *= PRIME64_1;
61 return Acc;
62 }
63
mergeRound(uint64_t Acc,uint64_t Val)64 static uint64_t mergeRound(uint64_t Acc, uint64_t Val) {
65 Val = round(0, Val);
66 Acc ^= Val;
67 Acc = Acc * PRIME64_1 + PRIME64_4;
68 return Acc;
69 }
70
xxHash64(StringRef Data)71 uint64_t llvm::xxHash64(StringRef Data) {
72 size_t Len = Data.size();
73 uint64_t Seed = 0;
74 const unsigned char *P = Data.bytes_begin();
75 const unsigned char *const BEnd = Data.bytes_end();
76 uint64_t H64;
77
78 if (Len >= 32) {
79 const unsigned char *const Limit = BEnd - 32;
80 uint64_t V1 = Seed + PRIME64_1 + PRIME64_2;
81 uint64_t V2 = Seed + PRIME64_2;
82 uint64_t V3 = Seed + 0;
83 uint64_t V4 = Seed - PRIME64_1;
84
85 do {
86 V1 = round(V1, endian::read64le(P));
87 P += 8;
88 V2 = round(V2, endian::read64le(P));
89 P += 8;
90 V3 = round(V3, endian::read64le(P));
91 P += 8;
92 V4 = round(V4, endian::read64le(P));
93 P += 8;
94 } while (P <= Limit);
95
96 H64 = rotl64(V1, 1) + rotl64(V2, 7) + rotl64(V3, 12) + rotl64(V4, 18);
97 H64 = mergeRound(H64, V1);
98 H64 = mergeRound(H64, V2);
99 H64 = mergeRound(H64, V3);
100 H64 = mergeRound(H64, V4);
101
102 } else {
103 H64 = Seed + PRIME64_5;
104 }
105
106 H64 += (uint64_t)Len;
107
108 while (P + 8 <= BEnd) {
109 uint64_t const K1 = round(0, endian::read64le(P));
110 H64 ^= K1;
111 H64 = rotl64(H64, 27) * PRIME64_1 + PRIME64_4;
112 P += 8;
113 }
114
115 if (P + 4 <= BEnd) {
116 H64 ^= (uint64_t)(endian::read32le(P)) * PRIME64_1;
117 H64 = rotl64(H64, 23) * PRIME64_2 + PRIME64_3;
118 P += 4;
119 }
120
121 while (P < BEnd) {
122 H64 ^= (*P) * PRIME64_5;
123 H64 = rotl64(H64, 11) * PRIME64_1;
124 P++;
125 }
126
127 H64 ^= H64 >> 33;
128 H64 *= PRIME64_2;
129 H64 ^= H64 >> 29;
130 H64 *= PRIME64_3;
131 H64 ^= H64 >> 32;
132
133 return H64;
134 }
135
xxHash64(ArrayRef<uint8_t> Data)136 uint64_t llvm::xxHash64(ArrayRef<uint8_t> Data) {
137 return xxHash64({(const char *)Data.data(), Data.size()});
138 }
139