gzwrite

(PHP 4, PHP 5, PHP 7, PHP 8)

gzwrite — Binary-safe gz-file write

说明

gzwrite(resource $stream, string $data, ?int $length = null): int|false

gzwrite() writes the contents of data to the given gz-file.

参数

stream: The gz-file pointer. It must be valid, and must point to a file successfully opened by gzopen().
data: The string to write.
length: The number of uncompressed bytes to write. If supplied, writing will stop after length (uncompressed) bytes have been written or the end of data is reached, whichever comes first.

返回值

Returns the number of (uncompressed) bytes written to the given gz-file stream, 或者在失败时返回 false.

更新日志

版本	说明
8.0.0	`length` is nullable now; previously, the default was `0`.
7.4.0	This functions returns `false` on failure now; previously `0` was returned.

示例

示例 #1 gzwrite() example

<?php
$string = 'Some information to compress';
$gz = gzopen('somefile.gz','w9');
gzwrite($gz, $string);
gzclose($gz);
?>

参见

gzread() - Binary-safe gz-file read
gzopen() - Open gz-file

发现了问题？

了解如何改进此页面 • 提交拉取请求 • 报告一个错误

＋添加备注

用户贡献的备注 1 note

down

calmarius at nospam dot atw dot hu ¶

17 years ago

gz compression is often used with tar archives. Building tar archives is quite easy. Here is a code snipplet which can be used for building tar archives before compressing them to tar.gz.

<?php

//\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
// Adds file header to the tar file, it is used before adding file content.
// f: file resource (provided by eg. fopen)
// phisfn: path to file
// archfn: path to file in archive, directory names must be followed by '/'
//\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
function TarAddHeader($f,$phisfn,$archfn)
{
    $info=stat($phisfn);
    $ouid=sprintf("%6s ", decoct($info[4]));
    $ogid=sprintf("%6s ", decoct($info[5]));
    $omode=sprintf("%6s ", decoct(fileperms($phisfn)));
    $omtime=sprintf("%11s", decoct(filemtime($phisfn)));
    if (@is_dir($phisfn))
    {
         $type="5";
         $osize=sprintf("%11s ", decoct(0));
    }
    else
    {
         $type='';
         $osize=sprintf("%11s ", decoct(filesize($phisfn)));
         clearstatcache();
    }
    $dmajor = '';
    $dminor = '';
    $gname = '';
    $linkname = '';
    $magic = '';
    $prefix = '';
    $uname = '';
    $version = '';
    $chunkbeforeCS=pack("a100a8a8a8a12A12",$archfn, $omode, $ouid, $ogid, $osize, $omtime);
    $chunkafterCS=pack("a1a100a6a2a32a32a8a8a155a12", $type, $linkname, $magic, $version, $uname, $gname, $dmajor, $dminor ,$prefix,'');

    $checksum = 0;
    for ($i=0; $i<148; $i++) $checksum+=ord(substr($chunkbeforeCS,$i,1));
    for ($i=148; $i<156; $i++) $checksum+=ord(' ');
    for ($i=156, $j=0; $i<512; $i++, $j++)    $checksum+=ord(substr($chunkafterCS,$j,1));

    fwrite($f,$chunkbeforeCS,148);
    $checksum=sprintf("%6s ",decoct($checksum));
    $bdchecksum=pack("a8", $checksum);
    fwrite($f,$bdchecksum,8);
    fwrite($f,$chunkafterCS,356);
    return true;
}
//\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
// Writes file content to the tar file must be called after a TarAddHeader
// f:file resource provided by fopen
// phisfn: path to file
//\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
function TarWriteContents($f,$phisfn)
{
    if (@is_dir($phisfn))
    {
        return;
    }
    else
    {
        $size=filesize($phisfn);
        $padding=$size % 512 ? 512-$size%512 : 0;
        $f2=fopen($phisfn,"rb");
        while (!feof($f2)) fwrite($f,fread($f2,1024*1024));
        $pstr=sprintf("a%d",$padding);
        fwrite($f,pack($pstr,''));
    }
}
//\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
// Adds 1024 byte footer at the end of the tar file
// f: file resource
//\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/
function TarAddFooter($f)
{
    fwrite($f,pack('a1024',''));
}

?>