#35859 [Bgs]: fread limited to 8K
| From: | cpuidle at gmx dot de | Date: | Sun, 01 Jan 2006 13:09:59 +0000 |
| Subject: | #35859 [Bgs]: fread limited to 8K | ||
| References: | 1 | Groups: | php.bugs |
| Request: | Send a blank email to php-bugs+get-91322@lists.php.net to get a copy of this message | ||
ID: 35859
User updated by: cpuidle at gmx dot de
Reported By: cpuidle at gmx dot de
Status: Bogus
Bug Type: Filesystem function related
Operating System: WinXP SP2
PHP Version: 5.1.1
New Comment:
OK. I was further looking at the problem (yes, it *is* a problem, at
least in the documentation). I've now found that fread will normally
read the entire (local) file, not limited to 8K. However, as soon as
stream_wrapper_register is used, the 8K limit is effective:
<?php
class VariableStream {
var $position, $varname;
function stream_open($path, $mode, $options, &$opened_path) {
$url = parse_url($path);
$this->varname = $url['host'];
$this->position = 0;
return true;
}
function stream_read($count) {
$ret = substr($GLOBALS[$this->varname], $this->position,
$count);
$this->position += strlen($ret);
return $ret;
}
function stream_eof() {
return $this->position >= strlen($GLOBALS[$this->varname]);
}
function stream_stat() {
return array('size' => strlen($GLOBALS[$this->varname]));
}
function url_stat() {
return array();
}
}
function read($filename) {
if (file_exists($filename) && ($fd = @fopen($filename, 'rb'))) {
$size = filesize($filename);
$contents = fread($fd, $size);
}
echo("\$filename $filename: \$size: $size strlen(\$contents):
".strlen($contents)."<br/>");
}
// local file
$filename = 'templates/elegant/show.tpl';
// will read entire file
read($filename);
stream_wrapper_register('var', 'VariableStream');
// will only read 8K
read($filename);
?>
Previous Comments:
------------------------------------------------------------------------
[2005-12-31 15:40:41] cpuidle at gmx dot de
If Wez says this is the expected behaviour, then fine, but:
a) document it
b) don't change it around inbetween releases
Cheers,
Andi
------------------------------------------------------------------------
[2005-12-31 15:36:16] cpuidle at gmx dot de
The documentation reads:
> fread() reads up to length bytes from the file pointer referenced by
handle. Reading stops when up to length bytes have been read, EOF (end
of file) is reached, or (for network streams) when a packet becomes
available, whichever comes first.
Neither of the conditions is satisfied. The internal 8K limit is *not*
documented?
------------------------------------------------------------------------
[2005-12-31 15:32:09] cpuidle at gmx dot de
Thanks. Could you verify that this behaviour has been changed between
5.0.5 and 5.1.1? Would it be worth to add to the documentation, that
for local files 8K is an internal limit?
------------------------------------------------------------------------
[2005-12-31 15:27:51] sniper@php.net
See comments in bug #30936
------------------------------------------------------------------------
[2005-12-31 14:20:24] cpuidle at gmx dot de
Description:
------------
I'm experiencing a very weird bug where fread is limited to 8K though
the source file (ANSI) is bigger than 8K. I was not able to reproduce
the bug standalone, only inside a complex application.
This does not happen with PHP5.0.5, but with 5.1.1.
Unfortunately the sample code does not reproduce the problem
standalone, but demonstrates the effect.
Reproduce code:
---------------
function _read_file($filename)
{
if ( file_exists($filename) && ($fd = @fopen($filename, 'rb')) ) {
$contents = ($size = filesize($filename)) ? fread($fd, $size) :
'';
echo("_read_file($filename) \$size: $size strlen(\$contents):
".strlen($contents)."<br/>");
fclose($fd);
}
}
_read_file('templates/elegant/\show.tpl');
Expected result:
----------------
Output:
_read_file(templates/elegant/\show.tpl) $size: 9520 strlen($contents):
9520
Actual result:
--------------
Output:
_read_file(templates/elegant/\show.tpl) $size: 9520 strlen($contents):
8192
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=35859&edit=1