CODEWITHSUNDEEP
phpregexpreg-replace
ilvi
ilvi

Reputation: 3

preg_replace returns empty string when using lot of spaces

I know it is not recommended to parse XML / HTML with a reg-ex, but i am trying to do this simple thing: 

<?php
echo phpversion()."<br><br>";

$test_1 = '<Tag attr="attr_value">Tag_value</Tag>';
$test_2 = $test_1.str_repeat(' ',1000);
$test_3 = $test_1.str_repeat(' ',2000);

$match = '!<(.*?) (.*?)="(.*?)">!';
$replace = '<\\2>\\3</\\2><\\1>';

$output_1 = preg_replace($match, $replace, $test_1);
$output_2 = preg_replace($match, $replace, $test_2);
$output_3 = preg_replace($match, $replace, $test_3);

echo "xml: ".htmlspecialchars($test_1)."<br>";
echo "1: ".htmlspecialchars($output_1)."<br>";
echo "2: ".htmlspecialchars($output_2)."<br>";
echo "3: ".htmlspecialchars($output_3)."<br>";
?>

I mean, putting an attribute and its value out of the container tag. All working fine with test_1 and test_2 examples, but if I add more spaces like in test_3, the return string is empty. Can someone try this code?

In this example it works adding 1411 spaces. One more (1412) and doesn't ...

I have tested on 5.3.8 and 5.3.19 PHP versions.

Thanks.

Upvotes: 0

Views: 669

Answers (2)

Mikhail Vladimirov
Mikhail Vladimirov

Reputation: 13890

Works fine for me on PHP 4.4.8 from command line. You expression seems to be very inefficient. Probably it causes some kind of error, e.g. out of memory, and thus preg_replace returns NULL which means "error". Here is optimized version of your expression:

<(\S*?) (\S*?)="([^"]*?)">

Upvotes: 0

kittycat
kittycat

Reputation: 15045

Use this regex and it will work correctly:

$match = '!<([^ ]+) ([^=]+)="(.*?)">!';

Upvotes: 1

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