58 lines
1.5 KiB
Go
58 lines
1.5 KiB
Go
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package murmur3
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import (
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"hash"
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)
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// Make sure interfaces are correctly implemented.
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var (
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_ hash.Hash = new(digest64)
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_ hash.Hash64 = new(digest64)
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_ bmixer = new(digest64)
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)
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// digest64 is half a digest128.
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type digest64 digest128
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// New64 returns a 64-bit hasher
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func New64() hash.Hash64 { return New64WithSeed(0) }
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// New64WithSeed returns a 64-bit hasher set with explicit seed value
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func New64WithSeed(seed uint32) hash.Hash64 {
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d := (*digest64)(New128WithSeed(seed).(*digest128))
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return d
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}
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func (d *digest64) Sum(b []byte) []byte {
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h1 := d.Sum64()
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return append(b,
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byte(h1>>56), byte(h1>>48), byte(h1>>40), byte(h1>>32),
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byte(h1>>24), byte(h1>>16), byte(h1>>8), byte(h1))
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}
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func (d *digest64) Sum64() uint64 {
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h1, _ := (*digest128)(d).Sum128()
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return h1
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}
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// Sum64 returns the MurmurHash3 sum of data. It is equivalent to the
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// following sequence (without the extra burden and the extra allocation):
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// hasher := New64()
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// hasher.Write(data)
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// return hasher.Sum64()
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func Sum64(data []byte) uint64 { return Sum64WithSeed(data, 0) }
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// Sum64WithSeed returns the MurmurHash3 sum of data. It is equivalent to the
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// following sequence (without the extra burden and the extra allocation):
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// hasher := New64WithSeed(seed)
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// hasher.Write(data)
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// return hasher.Sum64()
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func Sum64WithSeed(data []byte, seed uint32) uint64 {
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d := &digest128{h1: uint64(seed), h2: uint64(seed)}
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d.seed = seed
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d.tail = d.bmix(data)
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d.clen = len(data)
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h1, _ := d.Sum128()
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return h1
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}
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