<?php
function do_split($name) {
return preg_split('/([A-Z]{2,}|([A-Z][^A-Z]*))/', $name, null, PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_NO_EMPTY);
}
function convert_case($name) {
return implode(
'_',
array_map(
'strtolower',
do_split($name)
)
);
}
function convert_case2($in) {
$len = strlen($in);
if ($len < 2) {
return strtolower($in);
}
// no state
$upper = function ($c) {
return 'A' <= $c && $c <= 'Z';
};
$lower = function ($c) {
return 'a' <= $c && $c <= 'z';
};
$alpha = function ($c) use ($upper, $lower) {
return $upper($c) || $lower($c);
};
$num = function ($c) {
return '0' <= $c && $c <= '9';
};
$alpha_num = function ($c) use ($alpha, $num) {
return $alpha($c) || $num($c);
};
// stream state
$pos = 0;
$char = $in[0];
$peek = function() use ($in, &$pos, $len) {
if ($pos+1 >= $len) {
return null;
}
return $in[$pos+1];
};
$next = function() use ($peek, &$pos, &$char) {
$char = $peek();
$pos++;
return $char !== null;
};
// lex state
$out = array();
$upper_word = null;
$lower_word = null;
$cap_word = null;
$num_word = null;
$find_word = function () use (&$char, $alpha_num, $lower, $upper, $next, $peek, &$lower_word, &$upper_word, &$cap_word, &$num_word) {
while (!$alpha_num($char)) {
if (!$next()) {
return null;
}
}
if ($lower($char)) {
return $lower_word;
}
if ($upper($char)) {
if ($upper($peek())) { // uppercase word
return $upper_word;
}
return $cap_word; // capitalized word
}
return $num_word;
};
$upper_word = function() use (&$out, &$char, $next, $peek, $upper, $lower, $find_word) {
$word = $char;
while ($next() && $upper($char)) {
if ($lower($peek())) { // start of capitalized word (e.g. FOOBar at B)
break;
}
$word .= $char;
}
$out[] = $word;
return $find_word;
};
$lower_word = function() use (&$out, &$char, $next, $lower, $find_word) {
$word = $char;
while ($next() && $lower($char)) {
$word .= $char;
}
$out[] = $word;
return $find_word;
};
$state = $find_word;
while ($state !== null) {
$state = $state();
}
return strtolower(implode('_', $out));
}
convert_case2('FooBARbar0123');
$samples = array(
'FooBar',
'FooBAR',
'FOOBar',
'foo_bar',
'FOO_bar',
'FOO_Bar',
'foo_BAR',
'foo_Bar',
'Foo_bar',
);
print_r(array_map(function ($name) {
return array(
'name' => $name,
'converted' => convert_case2($name),
// 'converted' => convert_case($name),
);
}, $samples));
preferences:
33.75 ms | 402 KiB | 5 Q