<?php

// config -----
$strArr = array(
    'requestInfo',
    'memGet',
    'memGetInfo',
    'apiInfo',
    'memSetInfo',
    'resInfo',
    '012345678901234567890123456789012345678901234567890123456789',
);
$totalLength = 50;
$padChar = '*';
// ----- config


foreach ($strArr as $txt) {
    var_dump(makeCenteringText($txt, $totalLength, $padChar));
}


function makeCenteringText($txt, $totalLength, $padChar) {
    // deny overflow total length? uncomment this.
    //if (strlen((string)$txt) > $totalLength) { return null; }

    $padLengthPre = round((int)$totalLength/2, 0, PHP_ROUND_HALF_DOWN) + round(strlen((string)$txt)/2, 0, PHP_ROUND_HALF_UP);

    return sprintf('%\''.(string)$padChar.'-'.(int)$totalLength.'s', sprintf('%\''.(string)$padChar.(int)$padLengthPre.'s', (string)$txt));
}


// output.
//
// string(50) "********************requestInfo*******************"
// string(50) "**********************memGet**********************"
// string(50) "********************memGetInfo********************"
// string(50) "**********************apiInfo*********************"
// string(50) "********************memSetInfo********************"
// string(50) "**********************resInfo*********************"
// string(60) "012345678901234567890123456789012345678901234567890123456789"