blob: 728ef932a1accbfe6b2fc33754fdf2a660e00bee (
plain)
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
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
|
#ifndef Py_HASH_H
#define Py_HASH_H
#ifdef __cplusplus
extern "C" {
#endif
/* Helpers for hash functions */
#ifndef Py_LIMITED_API
PyAPI_FUNC(Py_hash_t) _Py_HashDouble(PyObject *, double);
PyAPI_FUNC(Py_hash_t) _Py_HashPointer(const void*);
// Similar to _Py_HashPointer(), but don't replace -1 with -2
PyAPI_FUNC(Py_hash_t) _Py_HashPointerRaw(const void*);
PyAPI_FUNC(Py_hash_t) _Py_HashBytes(const void*, Py_ssize_t);
#endif
/* Prime multiplier used in string and various other hashes. */
#define _PyHASH_MULTIPLIER 1000003UL /* 0xf4243 */
/* Parameters used for the numeric hash implementation. See notes for
_Py_HashDouble in Python/pyhash.c. Numeric hashes are based on
reduction modulo the prime 2**_PyHASH_BITS - 1. */
#if SIZEOF_VOID_P >= 8
# define _PyHASH_BITS 61
#else
# define _PyHASH_BITS 31
#endif
#define _PyHASH_MODULUS (((size_t)1 << _PyHASH_BITS) - 1)
#define _PyHASH_INF 314159
#define _PyHASH_IMAG _PyHASH_MULTIPLIER
/* hash secret
*
* memory layout on 64 bit systems
* cccccccc cccccccc cccccccc uc -- unsigned char[24]
* pppppppp ssssssss ........ fnv -- two Py_hash_t
* k0k0k0k0 k1k1k1k1 ........ siphash -- two uint64_t
* ........ ........ ssssssss djbx33a -- 16 bytes padding + one Py_hash_t
* ........ ........ eeeeeeee pyexpat XML hash salt
*
* memory layout on 32 bit systems
* cccccccc cccccccc cccccccc uc
* ppppssss ........ ........ fnv -- two Py_hash_t
* k0k0k0k0 k1k1k1k1 ........ siphash -- two uint64_t (*)
* ........ ........ ssss.... djbx33a -- 16 bytes padding + one Py_hash_t
* ........ ........ eeee.... pyexpat XML hash salt
*
* (*) The siphash member may not be available on 32 bit platforms without
* an unsigned int64 data type.
*/
#ifndef Py_LIMITED_API
typedef union {
/* ensure 24 bytes */
unsigned char uc[24];
/* two Py_hash_t for FNV */
struct {
Py_hash_t prefix;
Py_hash_t suffix;
} fnv;
/* two uint64 for SipHash24 */
struct {
uint64_t k0;
uint64_t k1;
} siphash;
/* a different (!) Py_hash_t for small string optimization */
struct {
unsigned char padding[16];
Py_hash_t suffix;
} djbx33a;
struct {
unsigned char padding[16];
Py_hash_t hashsalt;
} expat;
} _Py_HashSecret_t;
PyAPI_DATA(_Py_HashSecret_t) _Py_HashSecret;
#endif
#ifdef Py_DEBUG
PyAPI_DATA(int) _Py_HashSecret_Initialized;
#endif
/* hash function definition */
#ifndef Py_LIMITED_API
typedef struct {
Py_hash_t (*const hash)(const void *, Py_ssize_t);
const char *name;
const int hash_bits;
const int seed_bits;
} PyHash_FuncDef;
PyAPI_FUNC(PyHash_FuncDef*) PyHash_GetFuncDef(void);
#endif
/* cutoff for small string DJBX33A optimization in range [1, cutoff).
*
* About 50% of the strings in a typical Python application are smaller than
* 6 to 7 chars. However DJBX33A is vulnerable to hash collision attacks.
* NEVER use DJBX33A for long strings!
*
* A Py_HASH_CUTOFF of 0 disables small string optimization. 32 bit platforms
* should use a smaller cutoff because it is easier to create colliding
* strings. A cutoff of 7 on 64bit platforms and 5 on 32bit platforms should
* provide a decent safety margin.
*/
#ifndef Py_HASH_CUTOFF
# define Py_HASH_CUTOFF 0
#elif (Py_HASH_CUTOFF > 7 || Py_HASH_CUTOFF < 0)
# error Py_HASH_CUTOFF must in range 0...7.
#endif /* Py_HASH_CUTOFF */
/* hash algorithm selection
*
* The values for Py_HASH_SIPHASH24 and Py_HASH_FNV are hard-coded in the
* configure script.
*
* - FNV is available on all platforms and architectures.
* - SIPHASH24 only works on platforms that don't require aligned memory for integers.
* - With EXTERNAL embedders can provide an alternative implementation with::
*
* PyHash_FuncDef PyHash_Func = {...};
*
* XXX: Figure out __declspec() for extern PyHash_FuncDef.
*/
#define Py_HASH_EXTERNAL 0
#define Py_HASH_SIPHASH24 1
#define Py_HASH_FNV 2
#ifndef Py_HASH_ALGORITHM
# ifndef HAVE_ALIGNED_REQUIRED
# define Py_HASH_ALGORITHM Py_HASH_SIPHASH24
# else
# define Py_HASH_ALGORITHM Py_HASH_FNV
# endif /* uint64_t && uint32_t && aligned */
#endif /* Py_HASH_ALGORITHM */
#ifdef __cplusplus
}
#endif
#endif /* !Py_HASH_H */
|
