大多数文件系统函数使用gzip来压缩文件，本模块可以帮助透明读取gzip压缩文件。
在PHP中Zlib支持默认并没有开启。需要安装配置 PHP的时候使用 --with-zlib[=DIR]。
下面这个例子开启了一个临时文件来写入测试字符串，然后两次打印文件内容。
Example #1 简单的Zlib示例
<?php
$filename = tempnam('/tmp', 'zlibtest') . '.gz';
echo "<html>\n<head></head>\n<body>\n<pre>\n";
$s = "Only a test, test, test, test, test, test, test, test!\n";
// open file for writing with maximum compression
$zp = gzopen($filename, "w9");
// write string to file
gzwrite($zp, $s);
// close file
gzclose($zp);
// open file for reading
$zp = gzopen($filename, "r");
// read 3 char
echo gzread($zp, 3);
// output until end of the file and close it.
gzpassthru($zp);
gzclose($zp);
echo "\n";
// open file and print content (the 2nd time).
if (readgzfile($filename) != strlen($s)) {
echo "Error with zlib functions!";
}
unlink($filename);
echo "</pre>\n</body>\n</html>\n";
?>
相关函数：
gzclose — Close an open gz-file pointer
gzcompress — Compress a string
gzdecode — Decodes a gzip compressed string
gzdeflate — Deflate a string
gzencode — Create a gzip compressed string
gzeof — Test for EOF on a gz-file pointer
gzfile — Read entire gz-file into an array
gzgetc — Get character from gz-file pointer
gzgets — Get line from file pointer
gzgetss — Get line from gz-file pointer and strip HTML tags
gzinflate — Inflate a deflated string
gzopen — Open gz-file
gzpassthru — Output all remaining data on a gz-file pointer
gzputs — 别名 gzwrite
gzread — Binary-safe gz-file read
gzrewind — Rewind the position of a gz-file pointer
gzseek — Seek on a gz-file pointer
gztell — Tell gz-file pointer read/write position
gzuncompress — Uncompress a compressed string
gzwrite — Binary-safe gz-file write
readgzfile — Output a gz-file
zlib_decode — Uncompress any raw/gzip/zlib encoded data
zlib_encode — Compress data with the specified encoding
zlib_get_coding_type — Returns the coding type used for output compression
