#49874 [NEW]: ftell()/fseek() inconsistency when using stream filters

From: jketterl at chipxonio dot de Operating system: linux (ubuntu) PHP version: 5.2.11 PHP Bug Type: Filesystem function related Bug description: ftell()/fseek() inconsistency when using stream filters Description: ------------ exact php version: PHP 5.2.11-0.dotdeb.1 with Suhosin-Patch 0.9.7 (cli) (built: Sep 20 2009 09:41:43) this bug is also be filter-/stream-related. i just believe it might be easier to fix on the filesystem side, that's why i chose that category. when using a php stream filter to convert input from utf-16 into iso8859 (or most probably from any 2byte-encoded charset into any single-byte-encode charset) the ftell() and fseek() functions start to behave inconsistently. more precisely: fseek() jumps to exact offsets ignoring the 2byte-encoding, whereas ftell() seems to return the number of bytes read *after* the filter has been applied. thus it is not possible to fseek() back to a certain offset that has been stored with ftell() before. the content of the testfile used in the code examples is as follows: Line 01 Line 02 Line 03 Line 04 Reproduce code: --------------- $file = 'test.csv'; $fp = fopen($file, 'r'); stream_filter_append($fp, 'convert.iconv.utf16/iso8859-15'); $line = fgets($fp); var_dump($line); $line = fgets($fp); var_dump($line); fclose($fp); $fp = fopen($file, 'r'); stream_filter_append($fp, 'convert.iconv.utf16/iso8859-15'); $line = fgets($fp); var_dump($line); fseek($fp, ftell($fp)); // this shouldn't move anything - but it does... $line = fgets($fp); var_dump($line); fclose($fp); Expected result: ---------------- string(8) "Line 01 " string(8) "Line 02 " string(8) "Line 01 " string(8) "Line 02 " Actual result: -------------- string(8) "Line 01 " string(8) "Line 02 " string(8) "Line 01 " string(4) " 01 " -- Edit bug report at http://bugs.php.net/?id=49874&edit=1 -- Try a snapshot (PHP 5.2): http://bugs.php.net/fix.php?id=49874&r=trysnapshot52 Try a snapshot (PHP 5.3): http://bugs.php.net/fix.php?id=49874&r=trysnapshot53 Try a snapshot (PHP 6.0): http://bugs.php.net/fix.php?id=49874&r=trysnapshot60 Fixed in SVN: http://bugs.php.net/fix.php?id=49874&r=fixed Fixed in SVN and need be documented: http://bugs.php.net/fix.php?id=49874&r=needdocs Fixed in release: http://bugs.php.net/fix.php?id=49874&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=49874&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=49874&r=needscript Try newer version: http://bugs.php.net/fix.php?id=49874&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=49874&r=support Expected behavior: http://bugs.php.net/fix.php?id=49874&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=49874&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=49874&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=49874&r=globals PHP 4 support discontinued: http://bugs.php.net/fix.php?id=49874&r=php4 Daylight Savings: http://bugs.php.net/fix.php?id=49874&r=dst IIS Stability: http://bugs.php.net/fix.php?id=49874&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=49874&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=49874&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=49874&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=49874&r=mysqlcfg