107 lines
1.8 KiB
Go
107 lines
1.8 KiB
Go
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package crush
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const (
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MaxVal = uint32(0xFFFFFFFF)
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HashSeed = uint32(1315423911)
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)
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func hash1(a uint32) uint32 {
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hash := HashSeed ^ a
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x := uint32(231232)
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y := uint32(1232)
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b := a
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hashMix(&b, &x, &hash)
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hashMix(&y, &a, &hash)
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return hash
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}
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func hash2(a, b uint32) uint32 {
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hash := HashSeed ^ a ^ b
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var x = uint32(231232)
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var y = uint32(1232)
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hashMix(&a, &b, &hash)
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hashMix(&x, &a, &hash)
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hashMix(&b, &y, &hash)
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return hash
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}
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func hash3(a, b, c uint32) uint32 {
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hash := HashSeed ^ a ^ b ^ c
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x := uint32(231232)
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y := uint32(1232)
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hashMix(&a, &b, &hash)
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hashMix(&c, &x, &hash)
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hashMix(&y, &a, &hash)
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hashMix(&b, &x, &hash)
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hashMix(&y, &c, &hash)
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return hash
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}
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func hash4(a, b, c, d uint32) uint32 {
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hash := HashSeed ^ a ^ b ^ c ^ d
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x := uint32(231232)
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y := uint32(1232)
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hashMix(&a, &b, &hash)
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hashMix(&c, &d, &hash)
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hashMix(&a, &x, &hash)
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hashMix(&y, &b, &hash)
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hashMix(&c, &x, &hash)
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hashMix(&y, &d, &hash)
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return hash
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}
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func hash5(a, b, c, d, e uint32) uint32 {
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hash := HashSeed ^ a ^ b ^ c ^ d ^ e
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x := uint32(231232)
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y := uint32(1232)
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hashMix(&a, &b, &hash)
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hashMix(&c, &d, &hash)
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hashMix(&e, &x, &hash)
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hashMix(&y, &a, &hash)
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hashMix(&b, &x, &hash)
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hashMix(&y, &c, &hash)
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hashMix(&d, &x, &hash)
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hashMix(&y, &e, &hash)
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return hash
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}
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/*
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* Robert Jenkins' function for mixing 32-bit values
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* http://burtleburtle.net/bob/hash/evahash.html
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* a, b = random bits, c = input and output
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*/
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func hashMix(a, b, c *uint32) {
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(*a) -= *b
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(*a) -= *c
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*a = *a ^ (*c >> 13)
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*b -= *c
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*b -= *a
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*b = *b ^ (*a << 8)
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*c -= *a
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*c -= *b
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*c = *c ^ (*b >> 13)
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*a -= *b
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*a -= *c
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*a = *a ^ (*c >> 12)
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*b -= *c
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*b -= *a
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*b = *b ^ (*a << 16)
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*c -= *a
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*c -= *b
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*c = *c ^ (*b >> 5)
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*a -= *b
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*a -= *c
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*a = *a ^ (*c >> 3)
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*b -= *c
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*b -= *a
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*b = *b ^ (*a << 10)
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*c -= *a
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*c -= *b
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*c = *c ^ (*b >> 15)
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}
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