LLVM 17.0.0git
xxhash.cpp
Go to the documentation of this file.
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
43using namespace llvm;
44using namespace support;
45
46static uint64_t rotl64(uint64_t X, size_t R) {
47 return (X << R) | (X >> (64 - R));
48}
49
50static const uint64_t PRIME64_1 = 11400714785074694791ULL;
51static const uint64_t PRIME64_2 = 14029467366897019727ULL;
52static const uint64_t PRIME64_3 = 1609587929392839161ULL;
53static const uint64_t PRIME64_4 = 9650029242287828579ULL;
54static const uint64_t PRIME64_5 = 2870177450012600261ULL;
55
56static 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
64 Val = round(0, Val);
65 Acc ^= Val;
66 Acc = Acc * PRIME64_1 + PRIME64_4;
67 return Acc;
68}
69
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;
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) {
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
136 return xxHash64({(const char *)Data.data(), Data.size()});
137}
static GCMetadataPrinterRegistry::Add< ErlangGCPrinter > X("erlang", "erlang-compatible garbage collector")
#define P(N)
static ManagedStatic< cl::opt< uint64_t >, CreateSeed > Seed
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory),...
Definition: ArrayRef.h:41
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
uint64_t read64le(const void *P)
Definition: Endian.h:382
uint32_t read32le(const void *P)
Definition: Endian.h:381
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
uint64_t xxHash64(llvm::StringRef Data)
Definition: xxhash.cpp:70
static uint64_t mergeRound(uint64_t Acc, uint64_t Val)
Definition: xxhash.cpp:63
static const uint64_t PRIME64_3
Definition: xxhash.cpp:52
static const uint64_t PRIME64_1
Definition: xxhash.cpp:50
static const uint64_t PRIME64_2
Definition: xxhash.cpp:51
static const uint64_t PRIME64_4
Definition: xxhash.cpp:53
static const uint64_t PRIME64_5
Definition: xxhash.cpp:54
static uint64_t rotl64(uint64_t X, size_t R)
Definition: xxhash.cpp:46
static uint64_t round(uint64_t Acc, uint64_t Input)
Definition: xxhash.cpp:56