github.com/amp-space/amp-sdk-go@v0.7.6/stdlib/bufs/map.go (about) 1 package bufs 2 3 import ( 4 "bytes" 5 "hash/maphash" 6 ) 7 8 type MapEntry interface { 9 MapKey() []byte 10 } 11 12 type BufMap struct { 13 hashMap map[uint64]MapEntry 14 hasher maphash.Hash 15 } 16 17 func NewBufMap() BufMap { 18 return BufMap{ 19 hashMap: make(map[uint64]MapEntry), 20 } 21 } 22 23 // Returns the entry having a matching key (or nil) 24 func (m *BufMap) Get(key []byte) MapEntry { 25 existing, _ := m.get(key) 26 return existing 27 } 28 29 // Returns the entry being replaced (or nil) 30 func (m *BufMap) Put(entry MapEntry) MapEntry { 31 existing, atHash := m.get(entry.MapKey()) 32 33 m.hashMap[atHash] = entry 34 return existing 35 } 36 37 // Removes and returns the entry having a matching key (or nil) 38 func (m *BufMap) Remove(key []byte) MapEntry { 39 existing, atHash := m.get(key) 40 41 if existing != nil { 42 delete(m.hashMap, atHash) 43 } 44 return existing 45 } 46 47 func (m *BufMap) get(key []byte) (entry MapEntry, atHash uint64) { 48 m.hasher.Reset() 49 m.hasher.Write(key) 50 atHash = m.hasher.Sum64() 51 52 var found bool 53 entry, found = m.hashMap[atHash] 54 for found { 55 if bytes.Equal(entry.MapKey(), key) { 56 return 57 } 58 atHash++ 59 entry, found = m.hashMap[atHash] 60 } 61 62 return nil, atHash 63 }