1 package match
2
3 import (
4 "fmt"
5 "strings"
6 "unicode/utf8"
7 )
8
9 type Prefix struct {
10 Prefix string
11 }
12
13 func NewPrefix(p string) Prefix {
14 return Prefix{p}
15 }
16
17 func (self Prefix) Index(s string) (int, []int) {
18 idx := strings.Index(s, self.Prefix)
19 if idx == -1 {
20 return -1, nil
21 }
22
23 length := len(self.Prefix)
24 var sub string
25 if len(s) > idx+length {
26 sub = s[idx+length:]
27 } else {
28 sub = ""
29 }
30
31 segments := acquireSegments(len(sub) + 1)
32 segments = append(segments, length)
33 for i, r := range sub {
34 segments = append(segments, length+i+utf8.RuneLen(r))
35 }
36
37 return idx, segments
38 }
39
40 func (self Prefix) Len() int {
41 return lenNo
42 }
43
44 func (self Prefix) Match(s string) bool {
45 return strings.HasPrefix(s, self.Prefix)
46 }
47
48 func (self Prefix) String() string {
49 return fmt.Sprintf("<prefix:%s>", self.Prefix)
50 }
51
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