Source file
src/runtime/hash32.go
Documentation: runtime
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11 package runtime
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13 import "unsafe"
14
15 func memhash32Fallback(p unsafe.Pointer, seed uintptr) uintptr {
16 a, b := mix32(uint32(seed), uint32(4^hashkey[0]))
17 t := readUnaligned32(p)
18 a ^= t
19 b ^= t
20 a, b = mix32(a, b)
21 a, b = mix32(a, b)
22 return uintptr(a ^ b)
23 }
24
25 func memhash64Fallback(p unsafe.Pointer, seed uintptr) uintptr {
26 a, b := mix32(uint32(seed), uint32(8^hashkey[0]))
27 a ^= readUnaligned32(p)
28 b ^= readUnaligned32(add(p, 4))
29 a, b = mix32(a, b)
30 a, b = mix32(a, b)
31 return uintptr(a ^ b)
32 }
33
34 func memhashFallback(p unsafe.Pointer, seed, s uintptr) uintptr {
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36 a, b := mix32(uint32(seed), uint32(s^hashkey[0]))
37 if s == 0 {
38 return uintptr(a ^ b)
39 }
40 for ; s > 8; s -= 8 {
41 a ^= readUnaligned32(p)
42 b ^= readUnaligned32(add(p, 4))
43 a, b = mix32(a, b)
44 p = add(p, 8)
45 }
46 if s >= 4 {
47 a ^= readUnaligned32(p)
48 b ^= readUnaligned32(add(p, s-4))
49 } else {
50 t := uint32(*(*byte)(p))
51 t |= uint32(*(*byte)(add(p, s>>1))) << 8
52 t |= uint32(*(*byte)(add(p, s-1))) << 16
53 b ^= t
54 }
55 a, b = mix32(a, b)
56 a, b = mix32(a, b)
57 return uintptr(a ^ b)
58 }
59
60 func mix32(a, b uint32) (uint32, uint32) {
61 c := uint64(a^uint32(hashkey[1])) * uint64(b^uint32(hashkey[2]))
62 return uint32(c), uint32(c >> 32)
63 }
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