/
hash.go
124 lines (104 loc) · 2.53 KB
/
hash.go
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package main
import (
"bytes"
"encoding/binary"
"hash/fnv"
"log"
"math"
"os"
"strconv"
)
func (index *Index) GetByHash(key []byte) *Value {
value := new(Value)
var keyHash []byte = make([]byte, 8)
var keyHash4 [8]byte
h := fnv.New64a()
keyHash = []byte{}
h.Write(key)
keyHash = h.Sum(keyHash)
copy(keyHash4[:], keyHash[:8])
tmp := index.IndexHash[keyHash4]
if bytes.Compare(tmp[:], b4null) == 0 {
return nil
} else {
value.Data = index.GetRaw(byte4UInt32(tmp[:]))
}
return value
}
func (index *Index) UpdateByHash(k string, d []byte) *Value {
value := new(Value)
return value
}
func (index *Index) TruncateByHash(k string) *Value {
return index.UpdateByHash(k, []byte{})
}
var hashCollisions = 0
func (index Index) HashAdd(key []byte, val []byte) bool {
var keyHash []byte = make([]byte, 8)
var keyHash4 [8]byte
h := fnv.New64a()
keyHash = []byte{}
h.Write(key)
keyHash = h.Sum(keyHash)
copy(keyHash4[:], keyHash[:8])
tmp := index.IndexHash[keyHash4]
if bytes.Compare(tmp[:], b4null) == 0 {
index.IndexHash[keyHash4] = byteToByte4(val)
index.HashIndex.SetRaw(append(keyHash, val...), 0)
return true
} else {
// Collision
hashCollisions++
//log.Println("Hash Collisions: %s", hashCollisions)
return false
}
}
func (index Index) HashCheck(key []byte) bool {
var keyHash []byte = make([]byte, 8)
var keyHash4 [8]byte
h := fnv.New64a()
keyHash = []byte{}
h.Write(key)
keyHash = h.Sum(keyHash)
copy(keyHash4[:], keyHash[:8])
tmp := index.IndexHash[keyHash4]
if bytes.Compare(tmp[:], b4null) == 0 {
return false
} else {
return true
}
return false
}
func (index *Index) LoadHash() bool {
godaStat := StatStart()
defer StatEnd(godaStat, "LoadHash", index.HashIndex.SegN)
index.IndexHash = make(map[[8]byte][4]byte, index.HashIndex.SegN)
indexNmax := int(math.Ceil(float64(index.HashIndex.SegN) / float64(index.HashIndex.SegL)))
for indexN := 1; indexN <= indexNmax; indexN++ {
f, err := os.OpenFile(index.File+"/.hash/.storage/"+strconv.Itoa(indexN), os.O_RDONLY, 0600)
if err != nil {
log.Fatal(err)
}
defer f.Close()
stat, err := f.Stat()
b := make([]byte, stat.Size())
if _, err = f.Read(b); err != nil {
log.Fatal(err)
}
strokes := bytes.Split(b, bDelimeter)
for _, v := range strokes {
if len(v) <= 5 {
continue
}
size := binary.LittleEndian.Uint32(v[0:4])
if uint32(len(v[4:])) != size {
continue
}
index.IndexHash[byteToByte8(v[4:12])] = byteToByte4(v[12:16])
}
if Config.Performance.FreeMemoryOnLoading {
FreeMemory()
}
}
return true
}