CODEWITHSUNDEEP
phpmemory-leaksaddslashes
Dany Khalife
Dany Khalife

Reputation: 1850

Memory leak in php

I am having a problem understanding why this part of my code is causing a memory leak:

for($i=0; $i<count($values); $i++){
        $values[$i] = addslashes($values[$i]);
}

To put the code in context, i have a previously built array called values, which has all the values to be inserted into a database. all the fields are strings so i need to escape all of them and for this application addslashes or mysql_real_escape_string are a good choice imo.

Now the strange thing is that as soon as i added the part shown above, i get a message like this:

PHP Fatal error:  Allowed memory size of 134217728 bytes exhausted (tried to allocate 24 bytes)

I understood that this generated a memory leak but i don't know why.

Digging in, i commented out the only line in the for loop, leaving the for statement just for curiosity, and the leak is gone. Any ideas what could this possibly mean?

PS: The strings are all UTF8 encoded, could that be a problem?

EDIT:

The array contains something like this :

Array ( 
    [dossier] => 002A 
    [permis] => 
    [adresse] => 18, rue Bellevue
    [ville] => Ste-Anne-des-Lacs (Québec)
    [province] =>
    [code_postal] => J0R 1B0
    [numero_centrale] => N/A
    [routes] => De la Gare, droite chemin Avila jusqu'au bout et droite chemin Ste-Anne-des-lacs sur 1,8 km et droite sur Bellevue.
)

Upvotes: 1

Views: 924

Answers (2)

Trott
Trott

Reputation: 70143

Your array has string keys, but you are checking/assigning numeric keys. As @nickb notes, each time you add a numeric key, count($values) increases by one, so you have an infinite loop. Hence the memory exhaustion.

Check with a debugger, or better yet, switch to a foreach loop or one of the array_* functions (array_walk(), array_map(), etc. depending on what you are trying to do).

@Jeremy correctly points out that you should not be using addslashes() to escape your strings. Look at mysqli_real_escape_string() (as he suggests), or better yet, consider using PDO if you can.

Upvotes: 11

Jeremy
Jeremy

Reputation: 1972

Try using array_walk instead.

Also, do not count on every loop. Get the count before you put it in the loop conditional. Since this is for the database, you should really be using: mysqli_real_escape_string

Upvotes: 2

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