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Request #52124 [strpos] Limit search inside $haystack by new $length parameter
Submitted: 2010-06-19 12:13 UTC Modified: 2015-07-26 17:53 UTC
Votes:4
Avg. Score:4.0 ± 0.7
Reproduced:4 of 4 (100.0%)
Same Version:3 (75.0%)
Same OS:3 (75.0%)
From: vovan-ve at yandex dot ru Assigned:
Status: Open Package: Strings related
PHP Version: Irrelevant OS:
Private report: No CVE-ID: None
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 [2010-06-19 12:13 UTC] vovan-ve at yandex dot ru
Description:
------------
Why strpos() does not accept $length parameter with addition to $start? It would be very useful to search a $needle inside a part of $haystack sometimes. Now such behaviour can be made by combination with substr():

  $string = 'The big string [with some data here] and with more data there';
  // searh inside substring from offset 16 with length 19
  $tmp = substr($string, 16, 19);
  // now real search
  $pos = strpos($tmp, 'data');
  if (false !== $pos) $pos += 16; // original position
  var_dump($pos);

It work, but not optimal due to redundant copy of substring. I don't need this copy, I just want to reduce searching area.

Test script:
---------------
$string = 'The big string [with some data here] and with more data there';
// search 'data' inside substring from offset 16 with length 19
$pos = strpos($string, 'data', 16, 19);
var_dump($pos);

Expected result:
----------------
int(26)


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 [2015-07-26 17:53 UTC] cmb@php.net
I have some doubts that this functionality is required often
enough to warrant adding it to PHP, considering that it can easily
be implemented in userland (without making a copy of the string):

    function strpos_len($haystack, $needle, $offset, $length) {
        $pos = strpos($haystack, $needle, $offset);
        if ($pos > $offset + $length - strlen($needle)) {
            $pos = false;
        }
        return $pos;
    }
 [2015-07-28 16:01 UTC] vovan-ve at yandex dot ru
Yes, it can be implemented in userland, but in that manner it will scan whole string upto the very end instead of early fail.

It's very rate sutiation where the FR is really needed with respect to tonns of data per millisecond. Just ignore this FR.
 
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