Description:
------------
After using stream_wrapper_register on php 5.1.1, fread is suddenly limited to 8K block size when reading local(!) files.

This behaviour is
a) not documentated
b) does not happen with PHP 5.0.5
c) not consistent (depending on use of stream_wrapper_register)

I had previously opened bug 35859, but did not receive an answer after the details had been discovered.

Thanks,
Andi

Reproduce code:
---------------
<?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);
?>

Expected result:
----------------
$filename templates/elegant/show.tpl: $size: 9520 strlen($contents): 9520
$filename templates/elegant/show.tpl: $size: 9520 strlen($contents): 9520 (!!)

Actual result:
--------------
$filename templates/elegant/show.tpl: $size: 9520 strlen($contents): 9520
$filename templates/elegant/show.tpl: $size: 9520 strlen($contents): 8192 (!!)