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 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrBinHashKey_DEFINED
#define GrBinHashKey_DEFINED
#include "GrTypes.h"
/**
* Hash function class that can take a data chunk of any predetermined
* length. The hash function used is the One-at-a-Time Hash
* (http://burtleburtle.net/bob/hash/doobs.html).
*/
template<typename Entry, size_t KeySize>
class GrBinHashKey {
public:
GrBinHashKey()
: fHash(0)
#if GR_DEBUG
, fIsValid(false)
#endif
{}
GrBinHashKey(const GrBinHashKey<Entry, KeySize>& other) {
*this = other;
}
GrBinHashKey<Entry, KeySize>& operator=(const GrBinHashKey<Entry,
KeySize>& other) {
memcpy(this, &other, sizeof(*this));
return *this;
}
~GrBinHashKey() {
}
void setKeyData(const uint32_t* SK_RESTRICT data) {
GrAssert(GrIsALIGN4(KeySize));
memcpy(&fData, data, KeySize);
uint32_t hash = 0;
size_t len = KeySize;
while (len >= 4) {
hash += *data++;
hash += (fHash << 10);
hash ^= (hash >> 6);
len -= 4;
}
hash += (fHash << 3);
hash ^= (fHash >> 11);
hash += (fHash << 15);
#if GR_DEBUG
fIsValid = true;
#endif
fHash = hash;
}
int compare(const GrBinHashKey<Entry, KeySize>& key) const {
GrAssert(fIsValid && key.fIsValid);
return memcmp(fData, key.fData, KeySize);
}
static bool
EQ(const Entry& entry, const GrBinHashKey<Entry, KeySize>& key) {
GrAssert(key.fIsValid);
return 0 == entry.compare(key);
}
static bool
LT(const Entry& entry, const GrBinHashKey<Entry, KeySize>& key) {
GrAssert(key.fIsValid);
return entry.compare(key) < 0;
}
uint32_t getHash() const {
GrAssert(fIsValid);
return fHash;
}
private:
uint32_t fHash;
uint8_t fData[KeySize]; //Buffer for key storage
#if GR_DEBUG
public:
bool fIsValid;
#endif
};
#endif
|
