pax_global_header00006660000000000000000000000064145133273330014516gustar00rootroot0000000000000052 comment=2fb2d63a2f6afb76af4cd0b7846d1b03c8eb5d7a golang-github-dgryski-go-rendezvous-0.0~git20200823.9f7001d/000077500000000000000000000000001451332733300230775ustar00rootroot00000000000000golang-github-dgryski-go-rendezvous-0.0~git20200823.9f7001d/LICENSE000066400000000000000000000021211451332733300241000ustar00rootroot00000000000000The MIT License (MIT) Copyright (c) 2017-2020 Damian Gryski Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. golang-github-dgryski-go-rendezvous-0.0~git20200823.9f7001d/rdv.go000066400000000000000000000026171451332733300242270ustar00rootroot00000000000000package rendezvous type Rendezvous struct { nodes map[string]int nstr []string nhash []uint64 hash Hasher } type Hasher func(s string) uint64 func New(nodes []string, hash Hasher) *Rendezvous { r := &Rendezvous{ nodes: make(map[string]int, len(nodes)), nstr: make([]string, len(nodes)), nhash: make([]uint64, len(nodes)), hash: hash, } for i, n := range nodes { r.nodes[n] = i r.nstr[i] = n r.nhash[i] = hash(n) } return r } func (r *Rendezvous) Lookup(k string) string { // short-circuit if we're empty if len(r.nodes) == 0 { return "" } khash := r.hash(k) var midx int var mhash = xorshiftMult64(khash ^ r.nhash[0]) for i, nhash := range r.nhash[1:] { if h := xorshiftMult64(khash ^ nhash); h > mhash { midx = i + 1 mhash = h } } return r.nstr[midx] } func (r *Rendezvous) Add(node string) { r.nodes[node] = len(r.nstr) r.nstr = append(r.nstr, node) r.nhash = append(r.nhash, r.hash(node)) } func (r *Rendezvous) Remove(node string) { // find index of node to remove nidx := r.nodes[node] // remove from the slices l := len(r.nstr) r.nstr[nidx] = r.nstr[l] r.nstr = r.nstr[:l] r.nhash[nidx] = r.nhash[l] r.nhash = r.nhash[:l] // update the map delete(r.nodes, node) moved := r.nstr[nidx] r.nodes[moved] = nidx } func xorshiftMult64(x uint64) uint64 { x ^= x >> 12 // a x ^= x << 25 // b x ^= x >> 27 // c return x * 2685821657736338717 } golang-github-dgryski-go-rendezvous-0.0~git20200823.9f7001d/rdv_test.go000066400000000000000000000003551451332733300252630ustar00rootroot00000000000000package rendezvous import ( "hash/fnv" "testing" ) func hashString(s string) uint64 { h := fnv.New64a() h.Write([]byte(s)) return h.Sum64() } func TestEmpty(t *testing.T) { r := New([]string{}, hashString) r.Lookup("hello") }