-
Notifications
You must be signed in to change notification settings - Fork 26
/
phonex.go
128 lines (112 loc) · 2.72 KB
/
phonex.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
package matchr
func preProcess(input []rune) []rune {
output := runestring(make([]rune, 0, len(input)))
// 0. Remove all non-ASCII characters
for _, v := range input {
if v >= 65 && v <= 90 {
output = append(output, v)
}
}
// 1. Remove all trailing 'S' characters at the end of the name
for i := len(output) - 1; i >= 0 && output[i] == 'S'; i-- {
output.Del(i)
}
// 2. Convert leading letter pairs as follows
// KN -> N, PH -> F, WR -> R
switch output.SafeSubstr(0, 2) {
case "KN":
output = output[1:]
case "PH":
output[0] = 'F' // H will be ignored anyway
case "WR":
output = output[1:]
}
// 3a. Convert leading single letters as follows:
// H -> Remove
if output.SafeAt(0) == 'H' {
output = output[1:]
}
// 3a. Convert leading single letters as follows:
// E,I,O,U,Y -> A
// P -> B
// V -> F
// K,Q -> C
// J -> G
// Z -> S
switch output.SafeAt(0) {
case 'E', 'I', 'O', 'U', 'Y':
output[0] = 'A'
case 'P':
output[0] = 'B'
case 'V':
output[0] = 'F'
case 'K', 'Q':
output[0] = 'C'
case 'J':
output[0] = 'G'
case 'Z':
output[0] = 'S'
}
return output
}
// Phonex computes the Phonex phonetic encoding of the input string. Phonex is
// a modification of the venerable Soundex algorithm. It accounts for a few
// more letter combinations to improve accuracy on some data sets.
//
// This implementation is based off of the original C implementation by the
// creator - A. J. Lait - as found in his research paper entitled "An
// Assessment of Name Matching Algorithms."
func Phonex(s1 string) string {
// preprocess
s1 = cleanInput(s1)
input := runestring(preProcess([]rune(s1)))
result := make([]rune, 0, len(input))
last := rune(0)
code := rune(0)
for i := 0; i < len(input) &&
input[i] != ' ' &&
input[i] != ',' &&
len(result) < 4; i++ {
switch input[i] {
case 'B', 'P', 'F', 'V':
code = '1'
case 'C', 'S', 'K', 'G', 'J', 'Q', 'X', 'Z':
code = '2'
case 'D', 'T':
if input.SafeAt(i+1) != 'C' {
code = '3'
}
case 'L':
if isVowel(input.SafeAt(i+1)) || i == len(input)-1 {
code = '4'
}
case 'M', 'N':
nextChar := input.SafeAt(i + 1)
if nextChar == 'D' || nextChar == 'G' {
// ignore next character
i++
}
code = '5'
case 'R':
if isVowel(input.SafeAt(i+1)) || i == len(input)-1 {
code = '6'
}
default:
code = 0
}
if last != code && code != 0 && i != 0 {
result = append(result, code)
}
// special case for 1st character: we use the actual character
if i == 0 {
result = append(result, input[i])
last = code
} else {
last = result[len(result)-1]
}
}
for len(result) < 4 {
result = append(result, '0')
}
return string(result)
}