Multibyte String Functions
This function does not check for bad byte sequence(s), it only checks if the byte stream is valid. If you want to verify a encoded string is valid, (IE: does not contain any bad byte sequences do the following...
<?php
/* check a strings encoded value */
function checkEncoding ( $string, $string_encoding )
{
$fs = $string_encoding == 'UTF-8' ? 'UTF-32' : $string_encoding;
$ts = $string_encoding == 'UTF-32' ? 'UTF-8' : $string_encoding;
return $string === mb_convert_encoding ( mb_convert_encoding ( $string, $fs, $ts ), $ts, $fs );
}
/* test 1 variables */
$string = "\x00\x81";
$encoding = "Shift_JIS";
/* test 1 mb_check_encoding (test for bad byte stream) */
if ( true === mb_check_encoding ( $string, $encoding ) )
{
echo 'valid (' . $encoding . ') encoded byte stream!<br />';
}
else
{
echo 'invalid (' . $encoding . ') encoded byte stream!<br />';
}
/* test 1 checkEncoding (test for bad byte sequence(s)) */
if ( true === checkEncoding ( $string, $encoding ) )
{
echo 'valid (' . $encoding . ') encoded byte sequence!<br />';
}
else
{
echo 'invalid (' . $encoding . ') encoded byte sequence!<br />';
}
/* test 2 */
/* test 2 variables */
$string = "\x00\xE3";
$encoding = "UTF-8";
/* test 2 mb_check_encoding (test for bad byte stream) */
if ( true === mb_check_encoding ( $string, $encoding ) )
{
echo 'valid (' . $encoding . ') encoded byte stream!<br />';
}
else
{
echo 'invalid (' . $encoding . ') encoded byte stream!<br />';
}
/* test 2 checkEncoding (test for bad byte sequence(s)) */
if ( true === checkEncoding ( $string, $encoding ) )
{
echo 'valid (' . $encoding . ') encoded byte sequence!<br />';
}
else
{
echo 'invalid (' . $encoding . ') encoded byte sequence!<br />';
}
?>
mb_check_encoding
(PHP 4 >= 4.4.3, PHP 5 >= 5.1.3)
mb_check_encoding — Check if the string is valid for the specified encoding
Description
bool mb_check_encoding
([ string $var = NULL
[, string $encoding = mb_internal_encoding()
]] )
Checks if the specified byte stream is valid for the specified encoding. It is useful to prevent so-called "Invalid Encoding Attack".
Parameters
- var
-
The byte stream to check. If it is omitted, this function checks all the input from the beginning of the request.
- encoding
-
The expected encoding.
Return Values
Returns TRUE on success or FALSE on failure.
add a note
User Contributed Notesmb_check_encoding
jbricci at ya-right dot com
02-Mar-2009 12:52
02-Mar-2009 12:52