Edit report at https://bugs.php.net/bug.php?id=36741&edit=1
ID: 36741
Comment by: devendonaldson473 at gmail dot com
Reported by: elliot dot li at gmail dot com
Summary: userstreams testcase have off-by-one error on
fseek()
Status: Closed
Type: Bug
Package: Streams related
Operating System: Linux
PHP Version: 5.1.2
Block user comment: N
Private report: N
New Comment:
Thanks for the information, I will try to figure it out for more.
https://www.mygroundbiz.website/
Previous Comments:
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[2006-03-20 23:09:18] tony2001@php.net
This bug has been fixed in CVS.
Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.
Thank you for the report, and for helping us make PHP better.
------------------------------------------------------------------------
[2006-03-20 01:43:18] elliot dot li at gmail dot com
Well, this is my patch. (sorry, I don't know how to append an attachment)
===== php-5.1.2-userstreams.test.patch FOLLOWS =====
diff -Nur php-5.1.2/ext/standard/tests/file/userstreams.phpt
php-5.1.2.my/ext/standard/tests/file/userstreams.phpt
--- php-5.1.2/ext/standard/tests/file/userstreams.phpt 2003-11-30 21:57:17.000000000 +0800
+++ php-5.1.2.my/ext/standard/tests/file/userstreams.phpt 2006-03-20 08:32:10.000000000 +0800
@@ -211,15 +211,15 @@
$whence = $whence_map[array_rand($whence_map, 1)];
switch($whence) {
case SEEK_SET:
- $offset = rand(0, $DATALEN);
+ $offset = rand(0, $DATALEN-1);
$position = $offset;
break;
case SEEK_END:
- $offset = -rand(0, $DATALEN);
+ $offset = -rand(0, $DATALEN-1);
$position = $DATALEN + $offset;
break;
case SEEK_CUR:
- $offset = rand(0, $DATALEN);
+ $offset = rand(0, $DATALEN-1);
$offset -= $position;
$position += $offset;
break;
===== php-5.1.2-userstreams.test.patch ABOVE =====
------------------------------------------------------------------------
[2006-03-18 21:57:31] tony2001@php.net
Do you have a patch? (unified diff, please)
------------------------------------------------------------------------
[2006-03-15 05:58:13] elliot dot li at gmail dot com
Description:
------------
This case(php-5.1.2/ext/standard/tests/file/userstreams.phpt) generates a bunch of random numbers
and use them as offsets for fseek() test on a userstream. However, the range of these random numbers
is [0, $DATALEN](rand(0, $DATALEN)), which should be [0, $DATALEN).
======== CODE SNIP FOLLOWS ========
/* generate some random seek offsets */
$position = 0;
for ($i = 0; $i < 256; $i++) {
$whence = $whence_map[array_rand($whence_map, 1)];
switch($whence) {
case SEEK_SET:
$offset = rand(0, $DATALEN);
$position = $offset;
break;
case SEEK_END:
$offset = -rand(0, $DATALEN);
$position = $DATALEN + $offset;
break;
case SEEK_CUR:
$offset = rand(0, $DATALEN);
$offset -= $position;
$position += $offset;
break;
}
$seeks[] = array($whence, $offset, $position);
}
======== CODE SNIP ABOVE ========
Reproduce code:
---------------
Run this case on and on for a while, you can encounter this problem. I found this problem during a
regression test, and reproduced it on my PC(Pentium 4 2.6GHz) within one day.
Expected result:
----------------
No error should be reported if everything goes OK.
Actual result:
--------------
========= LOG SNIP FOLLOWS =========
--[34] whence=SEEK_SET offset=32550 line_length=1024 position_should_be=32550 --
REAL: pos=(29175,32550,32550) ret=0 line[0]=`'
USER: pos=(29175,29175,29175) ret=0 line[16]=`zl urnq vf ubzr
'
###################################### FAIL!
========= LOG SNIP ABOVE =========
32550 is the total length of the userstream, so fseek($fp, 32550, SEEK_SET) must fail.
I noticed another problem: mystream.stream_seek() would return a false on this condition, but the
return value of fseek() is still 0! This would lead to the result that the failure of seeking in a
userstream couldn't be noticed by the main program.
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=36741&edit=1