gzread

(PHP 4, PHP 5)

gzread — Liest aus einer gz-Datei

Beschreibung

string gzread ( resource $zp , int $length )

gzread() liest bis zu length Bytes aus der gegebenen gz-Datei Resource. Wird beim Lesen das Dateiende erreicht können auch weniger Bytes gelesen werden.

Parameter-Liste

zp: Die gz-Datei Resource. Dies muss auf eine gültige, erfolgreich mit gzopen() geöffnete Datei zeigen.
length: Die Anzahl der zu lesenden Bytes.

Rückgabewerte

Die gelesenen Daten.

Beispiele

Beispiel #1 gzread() Beispiel


<?php
// Liest den Inhalt einer gz-Datei in einen String
$filename = "/usr/local/something.txt.gz";
$zd = gzopen($filename, "r");
$contents = gzread($zd, 10000);
gzclose($zd);
?>

Siehe auch

gzrewind

gzputs

Last updated: Fri, 05 Sep 2008

add a note User Contributed Notes
gzread

utku
08-Feb-2008 01:31


I don't think it would be wise to open a whole gzip file (it _is_ compressed for a reason, and likely to be a very big file) into a single string. You would most likely hit the php memory limits. Instead, if you need to process the file, put your gzread calls in a loop, and read incrementally by a setting $length to a constant value.

zaotong at yahoo dot com
07-Mar-2007 03:06


As was shown to me in another forum there is a way to get the uncompressed size of the gz file by viewing the last 4 bytes of the gz file.



Here is a piece of code that will do this

<?php

$FileRead = 'SomeText.txt';

$FileOpen = fopen($FileRead, "rb");

        fseek($FileOpen, -4, SEEK_END);

        $buf = fread($FileOpen, 4);

        $GZFileSize = end(unpack("V", $buf));

        fclose($FileOpen);

        $HandleRead = gzopen($FileRead, "rb");

        $ContentRead = gzread($HandleRead, $GZFileSize);

?>



This will read the last 4 bytes of the gz file and use it as the file int for the gzread.



Thanks to stereofrog for helping me with this code.

methatron at hotmail dot com
27-Sep-2006 12:33


Be aware that gzread's second parameter - length reffers to the file's uncompressed size, therefore using this code:



<?php

$file_name = "/usr/local/something.txt.gz";

if($file_handle = gzopen($file_name, "r"))

{

    $contents = gzread($file_handle, filesize($file_name));

    gzclose($file_name);

}

?>



will probably truncate the content of the file as filesize checks for the file's compressed size.

So either use the actual uncompressed size, if you know it, or use an aribtrary big enough length, as gzreading will stop at the end of the file anyway.

add a note

gzrewind

gzputs

Last updated: Fri, 05 Sep 2008