#43841 [Asn]: mb_strrpos offset is byte count for negative values

ID: 43841 Updated by: jmessa@php.net Reported By: jmessa@php.net Status: Assigned Bug Type: mbstring related Operating System: Windows XP PHP Version: 5.2CVS-2008-01-14 (snap) Assigned To: hirokawa New Comment: Here is the entire mbstring section of my php.ini file, I haven't changed it from the default that comes when you download PHP. [mbstring] ; language for internal character representation. ;mbstring.language = Japanese ; internal/script encoding. ; Some encoding cannot work as internal encoding. ; (e.g. SJIS, BIG5, ISO-2022-*) ;mbstring.internal_encoding = EUC-JP ; http input encoding. ;mbstring.http_input = auto ; http output encoding. mb_output_handler must be ; registered as output buffer to function ;mbstring.http_output = SJIS ; enable automatic encoding translation according to ; mbstring.internal_encoding setting. Input chars are ; converted to internal encoding by setting this to On. ; Note: Do _not_ use automatic encoding translation for ; portable libs/applications. ;mbstring.encoding_translation = Off ; automatic encoding detection order. ; auto means ;mbstring.detect_order = auto ; substitute_character used when character cannot be converted ; one from another ;mbstring.substitute_character = none; ; overload(replace) single byte functions by mbstring functions. ; mail(), ereg(), etc are overloaded by mb_send_mail(), mb_ereg(), ; etc. Possible values are 0,1,2,4 or combination of them. ; For example, 7 for overload everything. ; 0: No overload ; 1: Overload mail() function ; 2: Overload str*() functions ; 4: Overload ereg*() functions ;mbstring.func_overload = 0 Thanks Previous Comments: ------------------------------------------------------------------------ [2008-02-10 00:31:11] hirokawa@php.net Could you show me the mbstring related setting (mbstring.*) in your php.ini ? ------------------------------------------------------------------------ [2008-01-30 15:58:56] nicholsr@php.net assigning to maintainer ------------------------------------------------------------------------ [2008-01-14 16:38:46] jmessa@php.net Description: ------------ The offset argument appears to do a byte count for negative values of offset. In the example below, $string_ascii is 21 characters long and $string_mb is 21 characters (53 bytes) long. In both cases the needle appears twice, first at position 9 and secondly at position 20. When the offset is -24, beyond the character length of the string, it finds $needle at position 9, when $needle would be expected to be found when offest is -12 (i.e. behave the same as the ASCII example). It's also worth noting that strrpos returns a notice when the offset is outside the boundary of the string whereas mb_strrpos does not. This may be linked to this bug: http://bugs.php.net/43840. Reproduce code: --------------- <?php $offsets = array(-25, -24, -13, -12); $string_mb = base64_decode('5pel5pys6Kqe44OG44Kt44K544OI44Gn44GZ44CCMDEyMzTvvJXvvJbvvJfvvJjvvJnjgII='); $needle = base64_decode('44CC'); foreach ($offsets as $i) { echo "\n-- Offset is $i --\n"; echo "Multibyte String:\t"; var_dump( mb_strrpos($string_mb, $needle, $i, 'UTF-8') ); echo "ASCII String:\n"; echo "mb_strrpos:\t\t"; var_dump(mb_strrpos('This is na English ta', 'a', $i)); echo "strrpos:\t\t"; var_dump(strrpos('This is na English ta', 'a', $i)); } ?> Expected result: ---------------- -- Offset is -25 -- Multibyte String: Notice: mb_strrpos(): Offset is greater than the length of haystack string in ...\mb_strrpos.php on line 9 bool(false) ASCII String: mb_strrpos: Notice: mb_strrpos(): Offset is greater than the length of haystack string in ...\mb_strrpos.php on line 14 bool(false) strrpos: Notice: strrpos(): Offset is greater than the length of haystack string in ...\mb_strrpos.php on line 14 bool(false) -- Offset is -24 -- Multibyte String: Notice: mb_strrpos(): Offset is greater than the length of haystack string in ...\mb_strrpos.php on line 9 bool(false) ASCII String: mb_strrpos: Notice: mb_strrpos(): Offset is greater than the length of haystack string in ...\mb_strrpos.php on line 14 bool(false) strrpos: Notice: strrpos(): Offset is greater than the length of haystack string in ...\mb_strrpos.php on line 14 bool(false) -- Offset is -13 -- Multibyte String: bool(false) ASCII String: mb_strrpos: bool(false) strrpos: bool(false) -- Offset is -12 -- Multibyte String: int(9) ASCII String: mb_strrpos: int(9) strrpos: int(9) Actual result: -------------- -- Offset is -25 -- Multibyte String: bool(false) ASCII String: mb_strrpos: bool(false) strrpos: Notice: strrpos(): Offset is greater than the length of haystack string in ...\mb_strrpos.php on line 14 bool(false) -- Offset is -24 -- Multibyte String: int(9) ASCII String: mb_strrpos: bool(false) strrpos: Notice: strrpos(): Offset is greater than the length of haystack string in ...\mb_strrpos.php on line 14 bool(false) -- Offset is -13 -- Multibyte String: int(9) ASCII String: mb_strrpos: bool(false) strrpos: bool(false) -- Offset is -12 -- Multibyte String: int(9) ASCII String: mb_strrpos: int(9) strrpos: int(9) ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=43841&edit=1