summaryrefslogtreecommitdiff
path: root/index/index.go
blob: 60c3d9f6362e590570b9e6f8f16389d3c1115b2e (plain)
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
package index

import (
	"searchEngine/analyzer"
	"sync"
)

type Posting struct {
	DocId          int
	BodyCount      int
	TitleCount     int
	BodyPositions  []int
	TitlePositions []int
}
type InvertedIndex struct {
	Mu       sync.RWMutex
	Data     map[string][]Posting
	DocNames map[int]string
}

func New() *InvertedIndex {
	return &InvertedIndex{
		Data:     make(map[string][]Posting),
		DocNames: make(map[int]string),
	}
}

func (idx *InvertedIndex) Add(docID int, title string, bodyTokens []string) {
	titleTokens := analyzer.ProcessText(title)

	type fieldStats struct {
		body           int
		bodyPositions  []int
		title          int
		titlePositions []int
	}
	docStats := make(map[string]fieldStats)

	for position, token := range titleTokens {
		stats := docStats[token]
		stats.title++
		stats.titlePositions = append(stats.titlePositions, position)
		docStats[token] = stats
	}

	for position, token := range bodyTokens {
		stats := docStats[token]
		stats.body++
		stats.bodyPositions = append(stats.bodyPositions, position)
		docStats[token] = stats
	}

	idx.Mu.Lock()
	defer idx.Mu.Unlock()

	idx.DocNames[docID] = title

	for token, stats := range docStats {
		idx.Data[token] = append(idx.Data[token], Posting{
			DocId:          docID,
			BodyCount:      stats.body,
			TitleCount:     stats.title,
			BodyPositions:  stats.bodyPositions,
			TitlePositions: stats.titlePositions,
		})
	}
}