#47152 [Com]: gzseek/fseek using SEEK_END produces strange results

ID: 47152 Comment by: d_kelsey at uk dot ibm dot com Reported By: d_kelsey at uk dot ibm dot com Status: Open Bug Type: Zlib Related Operating System: Windows XP PHP Version: 5.2.8 New Comment: There is also a problem using SEEK_END when opening a file for write mode. for example <?php $file = "test.txt.gz"; $h = gzopen($file, 'w'); gzwrite($h, "first sentence."); gzseek($h, 0, SEEK_END); var_dump(gztell($h)); gzwrite($h, "second sentence."); var_dump(gztell($h)); gzclose($h); $h = gzopen($file, 'r'); gzpassthru($h); gzclose($h); unlink($file) ?> results in: bool(false) int(15) first sentence.second sentence. So the gztell results of bool(false)and then int(15) are both incorrect. Yet the file did get written correctly. Previous Comments: ------------------------------------------------------------------------ [2009-01-19 18:31:59] d_kelsey at uk dot ibm dot com Description: ------------ I have opened a .gz file using gzopen for reading. I can pass SEEK_END with offset of 0 (which would seek to the end of the file) using either fseek or gzseek as a whence. This returns -1 (a failure), but a subsequent gztell/ftell returns false, but I can still read the stream from the position it was last in. The issue is 1. is a whence of SEEK_END supported for a zlib stream ? If it is then SEEK_END is very broken as it doesn't move it to the end of the stream. 2. if not supported, I should get a warning saying invalid parameter. Also a subsequent call to gztell/ftell returns false.a further read and gztell/ftell returns an incorrect value I couldn't find any information to say it was not a valid value so assumed that it was valid. Reproduce code: --------------- <?php //004.txt.gz taken from zlib test directory //first 20 bytes are: "When you're taught t" $f = dirname(__FILE__)."/004.txt.gz"; $h = gzopen($f, 'r'); //read the first 10 var_dump(gzread($h, 10)); echo "move to the end\n"; echo "gzseek="; var_dump(gzseek( $h, 0, SEEK_END ) ); echo "tell="; var_dump(gztell($h)); echo "eof="; var_dump(gzeof($h)); //read the next 10 var_dump(gzread($h, 10)); echo "tell="; var_dump(gztell($h)); ?> Expected result: ---------------- If SEEK_END is not valid: string(10) "When you'r" move to the end gzseek= Warning: gzseek() SEEK_END not supported tell=int(10) eof=bool(false) string(10) "e taught t" tell=int(20) if SEEK_END is valid: string(10) "When you'r" move to the end gzseek=int(0) tell=int(176) eof=bool(true) string(0) "" tell=int(176) Actual result: -------------- string(10) "When you'r" move to the end gzseek=int(-1) tell=bool(false) eof=bool(false) string(10) "e taught t" tell=int(9) ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=47152&edit=1