1#ifndef _LINUX_JHASH_H
2#define _LINUX_JHASH_H
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26#include <linux/bitops.h>
27#include <linux/unaligned/packed_struct.h>
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29
30#define jhash_size(n) ((u32)1<<(n))
31
32#define jhash_mask(n) (jhash_size(n)-1)
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34
35#define __jhash_mix(a, b, c) \
36{ \
37 a -= c; a ^= rol32(c, 4); c += b; \
38 b -= a; b ^= rol32(a, 6); a += c; \
39 c -= b; c ^= rol32(b, 8); b += a; \
40 a -= c; a ^= rol32(c, 16); c += b; \
41 b -= a; b ^= rol32(a, 19); a += c; \
42 c -= b; c ^= rol32(b, 4); b += a; \
43}
44
45
46#define __jhash_final(a, b, c) \
47{ \
48 c ^= b; c -= rol32(b, 14); \
49 a ^= c; a -= rol32(c, 11); \
50 b ^= a; b -= rol32(a, 25); \
51 c ^= b; c -= rol32(b, 16); \
52 a ^= c; a -= rol32(c, 4); \
53 b ^= a; b -= rol32(a, 14); \
54 c ^= b; c -= rol32(b, 24); \
55}
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57
58#define JHASH_INITVAL 0xdeadbeef
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70static inline u32 jhash(const void *key, u32 length, u32 initval)
71{
72 u32 a, b, c;
73 const u8 *k = key;
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75
76 a = b = c = JHASH_INITVAL + length + initval;
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78
79 while (length > 12) {
80 a += __get_unaligned_cpu32(k);
81 b += __get_unaligned_cpu32(k + 4);
82 c += __get_unaligned_cpu32(k + 8);
83 __jhash_mix(a, b, c);
84 length -= 12;
85 k += 12;
86 }
87
88 switch (length) {
89 case 12: c += (u32)k[11]<<24; fallthrough;
90 case 11: c += (u32)k[10]<<16; fallthrough;
91 case 10: c += (u32)k[9]<<8; fallthrough;
92 case 9: c += k[8]; fallthrough;
93 case 8: b += (u32)k[7]<<24; fallthrough;
94 case 7: b += (u32)k[6]<<16; fallthrough;
95 case 6: b += (u32)k[5]<<8; fallthrough;
96 case 5: b += k[4]; fallthrough;
97 case 4: a += (u32)k[3]<<24; fallthrough;
98 case 3: a += (u32)k[2]<<16; fallthrough;
99 case 2: a += (u32)k[1]<<8; fallthrough;
100 case 1: a += k[0];
101 __jhash_final(a, b, c);
102 break;
103 case 0:
104 break;
105 }
106
107 return c;
108}
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116
117static inline u32 jhash2(const u32 *k, u32 length, u32 initval)
118{
119 u32 a, b, c;
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122 a = b = c = JHASH_INITVAL + (length<<2) + initval;
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124
125 while (length > 3) {
126 a += k[0];
127 b += k[1];
128 c += k[2];
129 __jhash_mix(a, b, c);
130 length -= 3;
131 k += 3;
132 }
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134
135 switch (length) {
136 case 3: c += k[2]; fallthrough;
137 case 2: b += k[1]; fallthrough;
138 case 1: a += k[0];
139 __jhash_final(a, b, c);
140 break;
141 case 0:
142 break;
143 }
144
145 return c;
146}
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150static inline u32 __jhash_nwords(u32 a, u32 b, u32 c, u32 initval)
151{
152 a += initval;
153 b += initval;
154 c += initval;
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156 __jhash_final(a, b, c);
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158 return c;
159}
160
161static inline u32 jhash_3words(u32 a, u32 b, u32 c, u32 initval)
162{
163 return __jhash_nwords(a, b, c, initval + JHASH_INITVAL + (3 << 2));
164}
165
166static inline u32 jhash_2words(u32 a, u32 b, u32 initval)
167{
168 return __jhash_nwords(a, b, 0, initval + JHASH_INITVAL + (2 << 2));
169}
170
171static inline u32 jhash_1word(u32 a, u32 initval)
172{
173 return __jhash_nwords(a, 0, 0, initval + JHASH_INITVAL + (1 << 2));
174}
175
176#endif
177