#45311 [Com]: substr works incorrectly with binary data

bugs dot php dot net at jeka dot ru Thu, 31 Jul 2008 10:14:52 -0700

 ID:               45311
 Comment by:       bugs dot php dot net at jeka dot ru
 Reported By:      yar_helg at mail dot ru
 Status:           Open
 Bug Type:         mbstring related
 Operating System: *
 PHP Version:      5.2.6
 New Comment:


&#1058;&#1072;&#1078;&#1077; &#1089;&#1072;&#1084;&#1072;&#1103;
&#1087;&#1088;&#1086;&#1073;&#1083;&#1077;&#1084;&#1072;.
&#1055;&#1088;&#1080;
&#1091;&#1089;&#1090;&#1072;&#1085;&#1086;&#1074;&#1083;&#1077;&#1085;&#1085;&#1086;&#1084;
mb_internal_encoding('UTF-8');

substr($string, 0, 2)
&#1089;&#1083;&#1091;&#1095;&#1072;&#1081;&#1085;&#1099;&#1084;
&#1086;&#1073;&#1088;&#1072;&#1079;&#1086;&#1084;
&#1074;&#1086;&#1079;&#1074;&#1088;&#1072;&#1097;&#1072;&#1077;&#1090;,
&#1090;&#1086; 2 &#1073;&#1072;&#1081;&#1090;&#1072;, &#1090;&#1086; 4.
C&#1090;&#1088;&#1086;&#1082;&#1072; &#1074; utf8.


Linux 2.6.24-gentoo-r4 #2 SMP
PHP 5.2.6-pl2-gentoo 
mbstring.func_overload = 0


Previous Comments:
------------------------------------------------------------------------

[2008-06-19 07:53:31] yar_helg at mail dot ru

Description:
------------
When trying to operate with binary data using substr and
mb_internal_encoding is set to UTF-8 (but no function overloading is
set) substr works wrong - wrong number of bytes is returned after
function call

P.S. emptyfile.xls used in example is an empty MS Excel 2003 file. It
can be downloaded at http://an-best.ru/empty_file.xls (13/5 Kbytes)

P.P.S. IDENTIFIER_OLE constant is taken from Spreadsheet_excel_reader
class.

Reproduce code:
---------------
<?php

echo "function overload = ".ini_get('mbstring.func_overload')."<br
/>\n";

// Uncomment this for demonstration of wrong behaviour
//mb_internal_encoding('UTF-8');


echo "MB_INTERNAL_ENCODING =".mb_internal_encoding()."<br />\n";

define('IDENTIFIER_OLE',
pack("CCCCCCCC",0xd0,0xcf,0x11,0xe0,0xa1,0xb1,0x1a,0xe1));

$data =
file_get_contents($_SERVER['DOCUMENT_ROOT'].'/substr_bug/emptyfile.xls');

echo "Data length = ".strlen($data)."<br />\n";
echo "First 8 symbols  ==>".var_export(substr($data,0,8),1)."<== <br
/>\n";
echo "Compare result (substr(\$data,0,8)==IDENTIFIER_OLE) -
".var_export(substr($data,0,8)==IDENTIFIER_OLE,1)."<br />\n";
echo "Substring length (substr(\$data,0,8)) -
".strlen(substr($data,0,8))."<br />\n";

?>

Expected result:
----------------
function overload = 0
MB_INTERNAL_ENCODING =ISO-8859-1
Data length = 13824
First 8 symbols ==>'&#1087;&#1086;&#1070;&#9553;&#9568;&#1040;'<==
Compare result (substr($data,0,8)==IDENTIFIER_OLE) - true
Substring length (substr($data,0,8)) - 8


Actual result:
--------------
// This result can be seen if mb_internal_encoding is set to UTF-8

function overload = 0
MB_INTERNAL_ENCODING =UTF-8
Data length = 13824
First 8 symbols ==>'&#1087;&#1086;&#1070;&#9553;&#9568;&#1040;' .
"\0"
. '' . "\0" . '' . "\0" . '' . "\0" . '' . "\0" . ''<==
Compare result (substr($data,0,8)==IDENTIFIER_OLE) - false
Substring length (substr($data,0,8)) - 13



------------------------------------------------------------------------


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Edit this bug report at http://bugs.php.net/?id=45311&edit=1

#45311 [Com]: substr works incorrectly with binary data

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