Matching substrings between wrappers (with unicode chars in input)

match.php

<?php
function matchStringsBetweenWrappers($string, $start, $end) {
    // preserving symbols from being removed
    $preserveDashPlaceholder = md5($string.'1');
    $string = str_replace('-', $preserveDashPlaceholder, $string);
    $preserveQuotePlaceholder = md5($string.'2');
    $string = str_replace("'", $preserveQuotePlaceholder, $string);
    $preserveWildcardPlaceholder = md5($string.'3');
    $string = str_replace('*', $preserveWildcardPlaceholder, $string);
    $preserveExclamationPlaceholder = md5($string.'4');
    $string = str_replace('!', $preserveExclamationPlaceholder, $string);
    $preserveDQuotePlaceholder = md5($string.'5');
    $string = str_replace('"', $preserveDQuotePlaceholder, $string);
    $preserveQuotPlaceholder = md5($string.'6');
    $string = str_replace('&quot;', $preserveQuotPlaceholder, $string);
    $preserveANDPlaceholder = md5($string.'7');
    $string = str_replace('&', $preserveANDPlaceholder, $string);

    // cleaning string from non alpha numeric chars
    $string = trim(preg_replace('/\W/', ' ', $string));
    // replacing multiple whitespaces with single
    $string = preg_replace(array('/\s{2,}/', '/[\t\n]/'), ' ', $string);

    // putting symbols to placeholder
    $string = str_replace($preserveDashPlaceholder, '-', $string);
    $string = str_replace($preserveQuotePlaceholder, "'", $string);
    $string = str_replace($preserveWildcardPlaceholder, '*', $string);
    $string = str_replace($preserveExclamationPlaceholder, '!', $string);
    $string = str_replace($preserveDQuotePlaceholder, '"', $string);
    $string = str_replace($preserveQuotPlaceholder, '&quot;', $string);
    $string = str_replace($preserveANDPlaceholder, '&', $string);

    // injecting some symbol (any) between words to delimit them
    $string = ' '.implode('  ', explode(' ', $string)).' ';
    //print "\n\nCleaned string: \"".$string."\"\n\n";
    preg_match_all('/ '.$start.'(.*?)'.$end.' /ui', $string, $matches);
    array_walk($matches[0], function(&$item) {
        $item = preg_replace(array('/\s{2,}/', '/[\t\n]/'), ' ', $item);
        $item = trim($item);
    });
    array_walk($matches[1], function(&$item) {
        $item = preg_replace(array('/\s{2,}/', '/[\t\n]/'), ' ', $item);
        $item = trim($item);
    });
    return $matches;
}
$string = 'Some text N_abc_New_New_New_N other text N_ghi_jkl_N and other text:;.#{}()[]N_abc_New_N.!@';
$matches = matchStringsBetweenWrappers($string, 'N_', '_N');
var_dump($matches);
$string = "في الصيف الماضي ، أنشأ N_Lego_N N_Lego_New_N مجموعة ذات سمة N_Friends_n.";
$matches = matchStringsBetweenWrappers($string, 'N_', '_N');
var_dump($matches);
$string = "N_Lego_New_N N_New_Friends_New_N  N_Lego_New_N ";
$matches = matchStringsBetweenWrappers($string, 'N_', '_N');
var_dump($matches);
$string = 'Some N_Mercedes-Benz_N, N_Chick-fil-A_N text N_abc_New_New_New_N other text N_ghi_jkl_N and other text:;.#{}()[]N_McDonald\'s*!&HP_"hey"_&quot;A&quot;_N.!@ N_"Actions Speak Louder Than Words"_N';
$matches = matchStringsBetweenWrappers($string, 'N_', '_N');
var_dump($matches);

stdout

array(2) {
  [0]=>
  array(3) {
    [0]=>
    string(19) "N_abc_New_New_New_N"
    [1]=>
    string(11) "N_ghi_jkl_N"
    [2]=>
    string(11) "N_abc_New_N"
  }
  [1]=>
  array(3) {
    [0]=>
    string(15) "abc_New_New_New"
    [1]=>
    string(7) "ghi_jkl"
    [2]=>
    string(7) "abc_New"
  }
}
array(2) {
  [0]=>
  array(3) {
    [0]=>
    string(8) "N_Lego_N"
    [1]=>
    string(12) "N_Lego_New_N"
    [2]=>
    string(11) "N_Friends_n"
  }
  [1]=>
  array(3) {
    [0]=>
    string(4) "Lego"
    [1]=>
    string(8) "Lego_New"
    [2]=>
    string(7) "Friends"
  }
}
array(2) {
  [0]=>
  array(3) {
    [0]=>
    string(12) "N_Lego_New_N"
    [1]=>
    string(19) "N_New_Friends_New_N"
    [2]=>
    string(12) "N_Lego_New_N"
  }
  [1]=>
  array(3) {
    [0]=>
    string(8) "Lego_New"
    [1]=>
    string(15) "New_Friends_New"
    [2]=>
    string(8) "Lego_New"
  }
}
array(2) {
  [0]=>
  array(6) {
    [0]=>
    string(17) "N_Mercedes-Benz_N"
    [1]=>
    string(15) "N_Chick-fil-A_N"
    [2]=>
    string(19) "N_abc_New_New_New_N"
    [3]=>
    string(11) "N_ghi_jkl_N"
    [4]=>
    string(39) "N_McDonald's*!&HP_"hey"_"A"_N"
    [5]=>
    string(37) "N_"Actions Speak Louder Than Words"_N"
  }
  [1]=>
  array(6) {
    [0]=>
    string(13) "Mercedes-Benz"
    [1]=>
    string(11) "Chick-fil-A"
    [2]=>
    string(15) "abc_New_New_New"
    [3]=>
    string(7) "ghi_jkl"
    [4]=>
    string(35) "McDonald's*!&HP_"hey"_"A""
    [5]=>
    string(33) ""Actions Speak Louder Than Words""
  }
}