1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
|
// Copyright (c) 2019 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_UTIL_HASHER_H
#define BITCOIN_UTIL_HASHER_H
#include <crypto/siphash.h>
#include <primitives/transaction.h>
#include <uint256.h>
class SaltedTxidHasher
{
private:
/** Salt */
const uint64_t k0, k1;
public:
SaltedTxidHasher();
size_t operator()(const uint256& txid) const {
return SipHashUint256(k0, k1, txid);
}
};
class SaltedOutpointHasher
{
private:
/** Salt */
const uint64_t k0, k1;
public:
SaltedOutpointHasher();
/**
* Having the hash noexcept allows libstdc++'s unordered_map to recalculate
* the hash during rehash, so it does not have to cache the value. This
* reduces node's memory by sizeof(size_t). The required recalculation has
* a slight performance penalty (around 1.6%), but this is compensated by
* memory savings of about 9% which allow for a larger dbcache setting.
*
* @see https://gcc.gnu.org/onlinedocs/gcc-9.2.0/libstdc++/manual/manual/unordered_associative.html
*/
size_t operator()(const COutPoint& id) const noexcept {
return SipHashUint256Extra(k0, k1, id.hash, id.n);
}
};
struct FilterHeaderHasher
{
size_t operator()(const uint256& hash) const { return ReadLE64(hash.begin()); }
};
/**
* We're hashing a nonce into the entries themselves, so we don't need extra
* blinding in the set hash computation.
*
* This may exhibit platform endian dependent behavior but because these are
* nonced hashes (random) and this state is only ever used locally it is safe.
* All that matters is local consistency.
*/
class SignatureCacheHasher
{
public:
template <uint8_t hash_select>
uint32_t operator()(const uint256& key) const
{
static_assert(hash_select <8, "SignatureCacheHasher only has 8 hashes available.");
uint32_t u;
std::memcpy(&u, key.begin()+4*hash_select, 4);
return u;
}
};
struct BlockHasher
{
// this used to call `GetCheapHash()` in uint256, which was later moved; the
// cheap hash function simply calls ReadLE64() however, so the end result is
// identical
size_t operator()(const uint256& hash) const { return ReadLE64(hash.begin()); }
};
class SaltedSipHasher
{
private:
/** Salt */
const uint64_t m_k0, m_k1;
public:
SaltedSipHasher();
size_t operator()(const Span<const unsigned char>& script) const;
};
#endif // BITCOIN_UTIL_HASHER_H
|
