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use crate::common::FastVec;
use unicode_normalization::UnicodeNormalization;
pub fn isvowel(s: char) -> bool {
matches!(s, 'A' | 'E' | 'I' | 'O' | 'U')
}
fn is_iey(s: char) -> bool {
matches!(s, 'I' | 'E' | 'Y')
}
pub fn metaphone(s: &str) -> String {
if s.is_empty() {
return String::from("");
}
let s = &s.to_uppercase()[..];
let mut v = s.nfkd().collect::<FastVec<char>>();
let mut ret = FastVec::new();
// skip first character if s starts with these
if s.starts_with("KN")
|| s.starts_with("GN")
|| s.starts_with("PN")
|| s.starts_with("WR")
|| s.starts_with("AE")
{
v.remove(0);
}
let mut i = 0;
while i < v.len() {
let c = v[i];
let next = if i + 1 < v.len() { v[i + 1] } else { '*' };
let nextnext = if i + 2 < v.len() { v[i + 2] } else { '*' };
// skip doubles except for CC
if c == next && c != 'C' {
i += 1;
continue;
}
match c {
'A' | 'E' | 'I' | 'O' | 'U' => {
if i == 0 || v[i - 1] == ' ' {
ret.push(c);
}
}
'B' => {
if (i == 0 || v[i - 1] != 'M') || next != '*' {
ret.push('B');
}
}
'C' => {
if next == 'I' && nextnext == 'A' || next == 'H' {
i += 1;
ret.push('X');
} else if is_iey(next) {
i += 1;
ret.push('S');
} else {
ret.push('K');
}
}
'D' => {
if next == 'G' && is_iey(nextnext) {
i += 2;
ret.push('J');
} else {
ret.push('T');
}
}
'F' | 'J' | 'L' | 'M' | 'N' | 'R' => {
ret.push(c);
}
'G' => {
if is_iey(next) {
ret.push('J');
} else if (next == 'H' && nextnext != '*' && !isvowel(nextnext))
|| (next == 'N' && nextnext == '*')
{
i += 1;
} else {
ret.push('K');
}
}
'H' => {
if i == 0 || isvowel(next) || !isvowel(v[i - 1]) {
ret.push('H');
}
}
'K' => {
if i == 0 || v[i - 1] != 'C' {
ret.push('K');
}
}
'P' => {
if next == 'H' {
i += 1;
ret.push('F');
} else {
ret.push('P');
}
}
'Q' => {
ret.push('K');
}
'S' => {
if next == 'H' {
i += 1;
ret.push('X');
} else if next == 'I' && (nextnext == 'O' || nextnext == 'A') {
i += 2;
ret.push('X');
} else {
ret.push('S');
}
}
'T' => {
if next == 'I' && (nextnext == 'O' || nextnext == 'A') {
ret.push('X');
} else if next == 'H' {
i += 1;
ret.push('0');
} else if next != 'C' || nextnext != 'H' {
ret.push('T');
}
}
'V' => {
ret.push('F');
}
'W' => {
if i == 0 && next == 'H' {
i += 1;
ret.push('W');
} else if isvowel(next) {
ret.push('W');
}
}
'X' => {
if i == 0 {
if next == 'H' || (next == 'I' && (nextnext == 'O' || nextnext == 'A')) {
ret.push('X');
} else {
ret.push('S');
}
} else {
ret.push('K');
ret.push('S');
}
}
'Y' => {
if isvowel(next) {
ret.push('Y');
}
}
'Z' => {
ret.push('S');
}
' ' => {
if !ret.is_empty() && ret[ret.len() - 1] != ' ' {
ret.push(' ');
}
}
_ => {}
};
i += 1;
}
let mut str_key = String::new();
for k in ret {
str_key.push(k);
}
str_key
}
#[cfg(test)]
mod test {
use super::*;
use crate::testutils::testutils;
#[test]
fn test_metaphone() {
testutils::test_str_func("testdata/metaphone.csv", metaphone);
}
}