Modified Version of anagram-finder that reduces duplicate string operations

gistfile1.aw

<?php

    public function lineByLineImproved($anagramSeed) {
        
        $fileinfo = new \SplFileInfo(RESOURCE.'wordlist.txt');
        $file = $fileinfo->openFile('r');
                
        $matchedWords = array();
        
        $anagramSeedLength = strlen($anagramSeed); //do this once
        $anagramSeedAsArray = str_split($anagramSeed); //do this once

        foreach($file as $line):
            $line = trim($line);
            
            if(strlen($line) == 0 || strlen($line) > $anagramSeedLength || $line == $anagramSeed){
                continue;
            }
        
            $word = str_split($line);           
            $matchedLetters = 0;
            $letterPool = $anagramSeedAsArray;
            
            foreach($word as $key=>$letter):
                
                $foundLetterKey = array_search($letter, $letterPool); 
                
                if($foundLetterKey !== FALSE){
                    unset($letterPool[$foundLetterKey]);
                    $matchedLetters++;
                }
            endforeach;
            
            if($matchedLetters == count($word)){
                $matchedWords[] = implode("", $word);
            }
        endforeach;     
        
        return $matchedWords;
    }