You should benchmark and tell us - anyway, just looking at the code, I'd
say 'is_prefix2()' is faster since there's 1 function call instead of 2
AmirBehzad Eslami wrote:
In case you haven't realized it, I have already written two functions to
check
for a prefix !! The question is: Which function is better? (is_prefix1() or
is_prefix2())
On 12/29/07, Zoltán Németh <znemeth@xxxxxxxxxxxxxx> wrote:
2007. 12. 29, szombat keltezéssel 13.39-kor AmirBehzad Eslami ezt írta:
I want to write a function to check
whether string $A is a prefix for string $B or not.
if (strpos($B, $A) === 0) {
echo '$B begins with $A';
} else {
echo '$B does not begin with $A';
}
greets
Zoltán Németh
I writing this function in order to prevent directory traversal
during a download request. (e.g., download.php?file=..\index.php)
I want to make sure that the realpath() of the requested file is
within the realpath() of the download-directory. Trying to make
sure that the the $download_dir is a prefix for $filepath.
@see: http://en.wikipedia.org/wiki/Directory_traversal
**
*TWO FUNCTIONS:*
function is_prefix1($prefix, $str) {
return (0 == strncasecmp($prefix, $str, strlen($prefix)));
}
function is_prefix2($prefix, $str) {
return (0 === stripos($str, $prefix));
}
*USAGE:*
if (is_prefix1('a', 'abcdef'))
echo 'prefix1 returned True!', '<br />';
if (is_prefix2('a', 'abcdef'))
echo 'prefix2 returned True!', '<br />';
------------------------
Do these functions do the same job?
Which one provides better performance?
-behzad
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