gf/text/gstr/gstr_soundex.go
2019-07-29 21:01:19 +08:00

59 lines
1.4 KiB
Go

// Copyright 2018 gf Author(https://github.com/gogf/gf). All Rights Reserved.
//
// This Source Code Form is subject to the terms of the MIT License.
// If a copy of the MIT was not distributed with this file,
// You can obtain one at https://github.com/gogf/gf.
package gstr
// Soundex calculates the soundex key of a string.
// See http://php.net/manual/en/function.soundex.php.
func Soundex(str string) string {
if str == "" {
panic("str: cannot be an empty string")
}
table := [26]rune{
'0', '1', '2', '3', // A, B, C, D
'0', '1', '2', // E, F, G
'0', // H
'0', '2', '2', '4', '5', '5', // I, J, K, L, M, N
'0', '1', '2', '6', '2', '3', // O, P, Q, R, S, T
'0', '1', // U, V
'0', '2', // W, X
'0', '2', // Y, Z
}
last, code, small := -1, 0, 0
sd := make([]rune, 4)
// build soundex string
for i := 0; i < len(str) && small < 4; i++ {
// ToUpper
char := str[i]
if char < '\u007F' && 'a' <= char && char <= 'z' {
code = int(char - 'a' + 'A')
} else {
code = int(char)
}
if code >= 'A' && code <= 'Z' {
if small == 0 {
sd[small] = rune(code)
small++
last = int(table[code-'A'])
} else {
code = int(table[code-'A'])
if code != last {
if code != 0 {
sd[small] = rune(code)
small++
}
last = code
}
}
}
}
// pad with "0"
for ; small < 4; small++ {
sd[small] = '0'
}
return string(sd)
}