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comparison CSP2/CSP2_env/env-d9b9114564458d9d-741b3de822f2aaca6c6caa4325c4afce/include/python3.8/pyhash.h @ 69:33d812a61356

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planemo upload commit 2e9511a184a1ca667c7be0c6321a36dc4e3d116d
author jpayne
date Tue, 18 Mar 2025 17:55:14 -0400
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67:0e9998148a16 69:33d812a61356
1 #ifndef Py_HASH_H
2
3 #define Py_HASH_H
4 #ifdef __cplusplus
5 extern "C" {
6 #endif
7
8 /* Helpers for hash functions */
9 #ifndef Py_LIMITED_API
10 PyAPI_FUNC(Py_hash_t) _Py_HashDouble(double);
11 PyAPI_FUNC(Py_hash_t) _Py_HashPointer(void*);
12 PyAPI_FUNC(Py_hash_t) _Py_HashBytes(const void*, Py_ssize_t);
13 #endif
14
15 /* Prime multiplier used in string and various other hashes. */
16 #define _PyHASH_MULTIPLIER 1000003UL /* 0xf4243 */
17
18 /* Parameters used for the numeric hash implementation. See notes for
19 _Py_HashDouble in Python/pyhash.c. Numeric hashes are based on
20 reduction modulo the prime 2**_PyHASH_BITS - 1. */
21
22 #if SIZEOF_VOID_P >= 8
23 # define _PyHASH_BITS 61
24 #else
25 # define _PyHASH_BITS 31
26 #endif
27
28 #define _PyHASH_MODULUS (((size_t)1 << _PyHASH_BITS) - 1)
29 #define _PyHASH_INF 314159
30 #define _PyHASH_NAN 0
31 #define _PyHASH_IMAG _PyHASH_MULTIPLIER
32
33
34 /* hash secret
35 *
36 * memory layout on 64 bit systems
37 * cccccccc cccccccc cccccccc uc -- unsigned char[24]
38 * pppppppp ssssssss ........ fnv -- two Py_hash_t
39 * k0k0k0k0 k1k1k1k1 ........ siphash -- two uint64_t
40 * ........ ........ ssssssss djbx33a -- 16 bytes padding + one Py_hash_t
41 * ........ ........ eeeeeeee pyexpat XML hash salt
42 *
43 * memory layout on 32 bit systems
44 * cccccccc cccccccc cccccccc uc
45 * ppppssss ........ ........ fnv -- two Py_hash_t
46 * k0k0k0k0 k1k1k1k1 ........ siphash -- two uint64_t (*)
47 * ........ ........ ssss.... djbx33a -- 16 bytes padding + one Py_hash_t
48 * ........ ........ eeee.... pyexpat XML hash salt
49 *
50 * (*) The siphash member may not be available on 32 bit platforms without
51 * an unsigned int64 data type.
52 */
53 #ifndef Py_LIMITED_API
54 typedef union {
55 /* ensure 24 bytes */
56 unsigned char uc[24];
57 /* two Py_hash_t for FNV */
58 struct {
59 Py_hash_t prefix;
60 Py_hash_t suffix;
61 } fnv;
62 /* two uint64 for SipHash24 */
63 struct {
64 uint64_t k0;
65 uint64_t k1;
66 } siphash;
67 /* a different (!) Py_hash_t for small string optimization */
68 struct {
69 unsigned char padding[16];
70 Py_hash_t suffix;
71 } djbx33a;
72 struct {
73 unsigned char padding[16];
74 Py_hash_t hashsalt;
75 } expat;
76 } _Py_HashSecret_t;
77 PyAPI_DATA(_Py_HashSecret_t) _Py_HashSecret;
78 #endif
79
80 #ifdef Py_DEBUG
81 PyAPI_DATA(int) _Py_HashSecret_Initialized;
82 #endif
83
84
85 /* hash function definition */
86 #ifndef Py_LIMITED_API
87 typedef struct {
88 Py_hash_t (*const hash)(const void *, Py_ssize_t);
89 const char *name;
90 const int hash_bits;
91 const int seed_bits;
92 } PyHash_FuncDef;
93
94 PyAPI_FUNC(PyHash_FuncDef*) PyHash_GetFuncDef(void);
95 #endif
96
97
98 /* cutoff for small string DJBX33A optimization in range [1, cutoff).
99 *
100 * About 50% of the strings in a typical Python application are smaller than
101 * 6 to 7 chars. However DJBX33A is vulnerable to hash collision attacks.
102 * NEVER use DJBX33A for long strings!
103 *
104 * A Py_HASH_CUTOFF of 0 disables small string optimization. 32 bit platforms
105 * should use a smaller cutoff because it is easier to create colliding
106 * strings. A cutoff of 7 on 64bit platforms and 5 on 32bit platforms should
107 * provide a decent safety margin.
108 */
109 #ifndef Py_HASH_CUTOFF
110 # define Py_HASH_CUTOFF 0
111 #elif (Py_HASH_CUTOFF > 7 || Py_HASH_CUTOFF < 0)
112 # error Py_HASH_CUTOFF must in range 0...7.
113 #endif /* Py_HASH_CUTOFF */
114
115
116 /* hash algorithm selection
117 *
118 * The values for Py_HASH_SIPHASH24 and Py_HASH_FNV are hard-coded in the
119 * configure script.
120 *
121 * - FNV is available on all platforms and architectures.
122 * - SIPHASH24 only works on platforms that don't require aligned memory for integers.
123 * - With EXTERNAL embedders can provide an alternative implementation with::
124 *
125 * PyHash_FuncDef PyHash_Func = {...};
126 *
127 * XXX: Figure out __declspec() for extern PyHash_FuncDef.
128 */
129 #define Py_HASH_EXTERNAL 0
130 #define Py_HASH_SIPHASH24 1
131 #define Py_HASH_FNV 2
132
133 #ifndef Py_HASH_ALGORITHM
134 # ifndef HAVE_ALIGNED_REQUIRED
135 # define Py_HASH_ALGORITHM Py_HASH_SIPHASH24
136 # else
137 # define Py_HASH_ALGORITHM Py_HASH_FNV
138 # endif /* uint64_t && uint32_t && aligned */
139 #endif /* Py_HASH_ALGORITHM */
140
141 #ifdef __cplusplus
142 }
143 #endif
144
145 #endif /* !Py_HASH_H */