gzread

(PHP 4, PHP 5)

gzread — Lectura segura de archivo binario gz

Descripción

string gzread ( resource $zp , int $longitud )

gzread() lee hasta longitud bytes de el apuntador de archivo gz. La lectura se detiene cuando length en bytes(sin compresión) han sido leídos o se encuentre el fin del archivo EOF, lo que ocurra primero.

Lista de parámetros

zp: El apuntador de archivo gz. Debe ser válido, y debe apuntar a un archivo exitosamente abierto por gzopen().
longitud: El número de bytes a leer.

Valores retornados

Los datos que han sido leídos.

Ejemplos

Example #1 ejemplo de gzread()


<?php
// get contents of a gz-file into a string
$filename = "/usr/local/something.txt.gz";
$zd = gzopen($filename, "r");
$contents = gzread($zd, 10000);
gzclose($zd);
?>

Ver también

gzrewind

gzputs

Last updated: Fri, 22 Aug 2008

add a note User Contributed Notes
gzread

utku
08-Feb-2008 10:31


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
08-Mar-2007 12:06


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 09:33


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, 22 Aug 2008