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
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
pub struct Metaphone {
vowels: Vec<char>,
iey: Vec<char>,
}
impl Metaphone {
pub fn new() -> Self {
Metaphone {
vowels: vec!['a', 'e', 'i', 'o', 'u'],
iey: vec!['i', 'e', 'y'],
}
}
pub fn encode(&self, val: &str) -> Result<String, String> {
if val.is_empty() || !self.is_alphabetic(val) {
return Err("String is empty or non-alphabetic.".to_string());
}
let deduplicated = self.de_duplicate(&val.to_lowercase());
let first_char_processed = self.transcode_first_character(&deduplicated);
let transcoded = self.transcode(&first_char_processed);
Ok(transcoded)
}
pub fn compare(&self, val1: &str, val2: &str) -> Result<bool, String> {
let s1_is_alphabetic = self.is_alphabetic(val1);
let s2_is_alphabetic = self.is_alphabetic(val2);
if val1.is_empty() || !s1_is_alphabetic || val2.is_empty() || !s2_is_alphabetic {
return Err("Unable to Metaphone compare the two values.".to_string());
}
let phonetic1 = self.encode(val1)?;
let phonetic2 = self.encode(val2)?;
Ok(phonetic1 == phonetic2)
}
fn is_alphabetic(&self, val: &str) -> bool {
val.chars().all(|c| c.is_alphabetic())
}
pub fn de_duplicate(&self, val: &str) -> String {
let mut result = String::with_capacity(val.len());
let mut chars = val.chars().peekable();
while let Some(c) = chars.next() {
if chars.peek() != Some(&c) {
result.push(c);
}
}
result
}
fn transcode_first_character(&self, s: &str) -> String {
let chars: Vec<char> = s.chars().collect();
match chars.len() {
0 => String::new(),
1 => {
let first_letter = chars[0];
match first_letter {
'x' => "s".to_string(),
_ => s.to_string(),
}
}
_ => {
let letter1 = chars[0];
let letter2 = chars[1];
let rest_of_word1: String = chars[1..].iter().collect();
let rest_of_word2: String = if chars.len() > 2 {
chars[2..].iter().collect()
} else {
String::new()
};
match letter1 {
'a' => match letter2 {
'e' => rest_of_word1,
_ => s.to_string(),
},
'g' | 'k' | 'p' => match letter2 {
'n' => rest_of_word1,
_ => s.to_string(),
},
'w' => match letter2 {
'r' => rest_of_word1,
'h' => format!("w{}", rest_of_word2),
_ => s.to_string(),
},
'x' => format!("s{}", rest_of_word1),
_ => s.to_string(),
}
}
}
}
fn transcode(&self, s: &str) -> String {
let characters: Vec<char> = s.chars().collect();
let size = characters.len();
let mut p_count = 0;
let mut output = vec![' '; size * 2];
let mut o_count = 0;
while p_count < size {
let current_char = characters[p_count];
let r_size = if p_count + 1 >= size {
0
} else {
size - (p_count + 1)
};
match current_char {
'a' | 'e' | 'i' | 'o' | 'u' => {
if p_count == 0 {
output[o_count] = current_char;
o_count += 1;
}
p_count += 1;
}
'f' | 'j' | 'l' | 'm' | 'n' | 'r' => {
output[o_count] = current_char;
o_count += 1;
p_count += 1;
}
'b' => {
if p_count >= 1 && p_count + 1 >= size && characters[p_count - 1] == 'm' {
p_count += 1;
} else {
output[o_count] = 'b';
o_count += 1;
p_count += 1;
}
}
'c' => {
if r_size >= 1
&& characters[p_count + 1] == 'h'
&& p_count >= 1
&& characters[p_count - 1] == 's'
{
output[o_count] = 'k';
o_count += 1;
p_count += 1;
} else if r_size >= 2
&& characters[p_count + 1] == 'i'
&& characters[p_count + 2] == 'a'
{
output[o_count] = 'x';
o_count += 1;
p_count += 3;
} else if (r_size >= 1 && characters[p_count + 1] == 'h')
|| (p_count >= 1
&& r_size >= 1
&& characters[p_count - 1] == 's'
&& characters[p_count + 1] == 'h')
{
output[o_count] = 'x';
o_count += 1;
p_count += 2;
} else if p_count >= 1
&& r_size >= 1
&& characters[p_count - 1] == 's'
&& self.iey.contains(&characters[p_count + 1])
{
p_count += 1;
} else if r_size >= 1 && self.iey.contains(&characters[p_count + 1]) {
output[o_count] = 's';
o_count += 1;
p_count += 1;
} else {
output[o_count] = 'k';
o_count += 1;
p_count += 1;
}
}
'd' => {
if r_size >= 2
&& characters[p_count + 1] == 'g'
&& self.iey.contains(&characters[p_count + 2])
{
output[o_count] = 'j';
o_count += 1;
p_count += 1;
} else {
output[o_count] = 't';
o_count += 1;
p_count += 1;
}
}
'g' => {
if (r_size > 1 && characters[p_count + 1] == 'h')
|| (r_size == 1 && characters[p_count + 1] == 'n')
|| (r_size == 3
&& characters[p_count + 1] == 'n'
&& characters[p_count + 3] == 'd')
{
p_count += 1;
} else if r_size >= 1 && self.iey.contains(&characters[p_count + 1]) {
output[o_count] = 'j';
o_count += 1;
p_count += 2;
} else {
output[o_count] = 'k';
o_count += 1;
p_count += 1;
}
}
'h' => {
if (p_count >= 1
&& self.vowels.contains(&characters[p_count - 1])
&& (r_size == 0 || self.vowels.contains(&characters[p_count + 1])))
|| (p_count >= 2
&& characters[p_count - 1] == 'h'
&& (characters[p_count - 2] == 't' || characters[p_count - 2] == 'g'))
{
p_count += 1;
} else {
output[o_count] = 'h';
o_count += 1;
p_count += 1;
}
}
'k' => {
if p_count >= 1 && characters[p_count - 1] == 'c' {
p_count += 1;
} else {
output[o_count] = 'k';
o_count += 1;
p_count += 1;
}
}
'p' => {
if r_size >= 1 && characters[p_count + 1] == 'h' {
output[o_count] = 'f';
o_count += 1;
p_count += 2;
} else {
output[o_count] = 'p';
o_count += 1;
p_count += 1;
}
}
'q' => {
output[o_count] = 'k';
o_count += 1;
p_count += 1;
}
's' => {
if r_size >= 2
&& characters[p_count + 1] == 'i'
&& ['a', 'o'].contains(&characters[p_count + 2])
{
output[o_count] = 'x';
o_count += 1;
p_count += 3;
} else if r_size >= 1 && characters[p_count + 1] == 'h' {
output[o_count] = 'x';
o_count += 1;
p_count += 2;
} else {
output[o_count] = 's';
o_count += 1;
p_count += 1;
}
}
't' => {
if r_size >= 2
&& characters[p_count + 1] == 'i'
&& ['a', 'o'].contains(&characters[p_count + 2])
{
output[o_count] = 'x';
o_count += 1;
p_count += 3;
} else if r_size >= 1 && characters[p_count + 1] == 'h' {
output[o_count] = '0';
o_count += 1;
p_count += 2;
} else if r_size >= 2
&& characters[p_count + 1] == 'c'
&& characters[p_count + 2] == 'h'
{
p_count += 1;
} else {
output[o_count] = 't';
o_count += 1;
p_count += 1;
}
}
'v' => {
output[o_count] = 'f';
o_count += 1;
p_count += 1;
}
'w' | 'y' => {
if r_size == 0 || !self.vowels.contains(&characters[p_count + 1]) {
p_count += 1;
} else {
output[o_count] = current_char;
o_count += 1;
p_count += 1;
}
}
'x' => {
output[o_count] = 'k';
output[o_count + 1] = 's';
o_count += 2;
p_count += 1;
}
'z' => {
output[o_count] = 's';
o_count += 1;
p_count += 1;
}
_ => {
p_count += 1;
}
}
}
output[0..o_count].iter().collect()
}
}
impl Default for Metaphone {
fn default() -> Self {
Self::new()
}
}
pub mod metaphone {
use super::Metaphone;
pub fn metaphone(val: &str) -> Result<String, String> {
Metaphone::new().encode(val)
}
pub fn metaphone_metric(val1: &str, val2: &str) -> Result<bool, String> {
Metaphone::new().compare(val1, val2)
}
}