-
Notifications
You must be signed in to change notification settings - Fork 3
/
index.go
180 lines (148 loc) · 3.47 KB
/
index.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
package structures
import (
"bufio"
"encoding/binary"
"log"
"math/rand"
"os"
)
type Index interface {
Add()
Find()
Write(filename string)
}
type SSIndex struct {
OffsetSize uint
KeySizeNumber uint
DataKeys []string
DataOffset []uint
filename string
}
func CreateIndex(keys []string, offset []uint, filename string) *SSIndex {
// We need to check if data is sorted
index := SSIndex{filename: filename}
for i, key := range keys{
index.Add(key, offset[i])
}
return &index
}
func (index *SSIndex) Add(key string, offset uint) {
index.DataKeys = append(index.DataKeys, key)
index.DataOffset = append(index.DataOffset, offset)
}
func FindIndex(key string, offset int64, filename string) (ok bool, dataOffset int64) {
ok = false
dataOffset = 0
file, err := os.Open(filename)
if err != nil {
panic(err)
}
defer file.Close()
reader := bufio.NewReader(file)
bytes := make([]byte, 8)
_, err = reader.Read(bytes)
if err != nil {
panic(err)
}
fileLen := binary.LittleEndian.Uint64(bytes)
_, err = file.Seek(offset, 0)
if err != nil {
return false, 0
}
reader = bufio.NewReader(file)
var i uint64
for i = 0; i < fileLen; i++ {
bytes := make([]byte, 8)
_, err = reader.Read(bytes)
if err != nil {
panic(err)
}
keyLen := binary.LittleEndian.Uint64(bytes)
bytes = make([]byte, keyLen)
_, err = reader.Read(bytes)
if err != nil {
panic(err)
}
nodeKey := string(bytes[:])
if nodeKey == key {
ok = true
} else if nodeKey > key {
return false, 0
}
bytes = make([]byte, 8)
_, err = reader.Read(bytes)
if err != nil {
panic(err)
}
newOffset := binary.LittleEndian.Uint64(bytes)
if ok {
dataOffset = int64(newOffset)
break
}
}
return
}
func (index *SSIndex) Write() (keys []string, offsets []uint){
currentOffset := uint(0)
file, err := os.Create(index.filename)
if err != nil {
log.Fatal(err)
}
defer file.Close()
writer := bufio.NewWriter(file)
bytesLen := make([]byte, 8)
binary.LittleEndian.PutUint64(bytesLen, uint64(len(index.DataKeys)))
bytesWritten, err := writer.Write(bytesLen)
if err != nil {
log.Fatal(err)
}
currentOffset += uint(bytesWritten)
err = writer.Flush()
if err != nil {
return
}
rangeKeys := make([]string, 0)
rangeOffsets := make([]uint, 0)
sampleKeys := make([]string, 0)
sampleOffsets := make([]uint, 0)
for i := range index.DataKeys {
key := index.DataKeys[i]
offset := index.DataOffset[i]
if i == 0 || i == (len(index.DataKeys) - 1) {
rangeKeys = append(rangeKeys, key)
rangeOffsets = append(rangeOffsets, currentOffset)
} else if rand.Intn(100) > 50 {
sampleKeys = append(sampleKeys, key)
sampleOffsets = append(sampleOffsets, currentOffset)
}
bytes := []byte(key)
keyLen := uint64(len(bytes))
bytesLen := make([]byte, 8)
binary.LittleEndian.PutUint64(bytesLen, keyLen)
bytesWritten, err := writer.Write(bytesLen)
if err != nil {
log.Fatal(err)
}
currentOffset += uint(bytesWritten)
bytesWritten, err = writer.Write(bytes)
if err != nil {
log.Fatal(err)
}
currentOffset += uint(bytesWritten)
bytes = make([]byte, 8)
binary.LittleEndian.PutUint64(bytes, uint64(offset))
bytesWritten, err = writer.Write(bytes)
if err != nil {
log.Fatal(err)
}
currentOffset += uint(bytesWritten)
//log.Printf("Written: %d\n", bytesWritten + bytesWritten1 + bytesWritten2)
}
err = writer.Flush()
if err != nil {
return
}
keys = append(rangeKeys, sampleKeys...)
offsets = append(rangeOffsets, sampleOffsets...)
return
}