PHP - Manual: gzdeflate

2024-11-15

gzencode »

« gzdecode

gzdeflate

(PHP 4 >= 4.0.4, PHP 5, PHP 7, PHP 8)

gzdeflate — Deflate a string

说明

gzdeflate(string $data, int $level = -1, int $encoding = ZLIB_ENCODING_RAW): string|false

This function compresses the given string using the DEFLATE data format.

For details on the DEFLATE compression algorithm see the document "» DEFLATE Compressed Data Format Specification version 1.3" (RFC 1951).

参数

data: The data to deflate.
level: The level of compression. Can be given as 0 for no compression up to 9 for maximum compression. If not given, the default compression level will be the default compression level of the zlib library.
encoding: One of ZLIB_ENCODING_* constants.

返回值

The deflated string or false if an error occurred.

范例

示例 #1 gzdeflate() example


<?php
$compressed = gzdeflate('Compress me', 9);
echo $compressed;
?>

参见

gzinflate() - Inflate a deflated string
gzcompress() - Compress a string
gzuncompress() - Uncompress a compressed string
gzencode() - Create a gzip compressed string

add a note

User Contributed Notes 9 notes

down

giunta dot gaetano at sea-aeroportimilano dot it ¶

15 years ago


Take care that that "PHP deflate" != "HTTP deflate".

The deflate encoding used in HTTP is actually zlib encoded.

This is what PHP functions return:
gzencode() == gzip
gzcompress() == zlib (aka. HTTP deflate)
gzdeflate()  == *raw* deflate encoding

down

anonymous at php dot net ¶

13 years ago


gzcompress produces longer data because it embeds information about the encoding onto the string. If you are compressing data that will only ever be handled on one machine, then you don't need to worry about which of these functions you use. However, if you are passing data compressed with these functions to a different machine you should use gzcompress.

down

robin ¶

12 years ago


running 50000 repetitions on various content, i found that gzdeflate() and gzcompress() both performed equally fast regardless content and compression level, but gzinflate() was always about twice as fast as gzuncompress().

down

-1

stockton at wowway dot com ¶

8 years ago


After some searching and experimentation I found that the output from this function cannot be 'inflated' with the objective c 'zlibInflate' wrapper for 'zlib' that is available at http://cocoadev.com/wiki/NSDataCategory but the output from gzcompress() can be. Thank you "anonymous at php dot net" and "tomas at slax dot org" for the clues. I hope this saves someone else the searching.

down

-2

banditsmile at qq dot com ¶

7 years ago


start from php5.4.0 gzdeflate has the fastest speed and best zip rate.
http://3v4l.org/K2XAf

down

-4

HUjuice ¶

6 years ago


The HTTP deflate is quite complicated.
The RFC7230, Sec 4.2.2 (https://tools.ietf.org/html/rfc7230#section-4.2.2) says:
«The "deflate" coding is a "zlib" data format [RFC1950] containing a "deflate" compressed data stream [RFC1951] that uses a combination of the Lempel-Ziv (LZ77) compression algorithm and Huffman coding.»
and, also:
«Note: Some non-conformant implementations send the "deflate" compressed data without the zlib wrapper.»

Since this function implements the RFC1951, the compliant encoding of a $payload should be:

gzcompress(gzdeflate($payload));

down

-7

tomas at slax dot org ¶

13 years ago


gzcompress() is the same like gzdefflate(), it produces identical data and its speed is the same as well. The only difference is that gzcompress produces 6 bytes bigger result (2 extra bytes at the beginning and 4 extra bytes at the end).

down

-8

denis dot noessler at red-at dot de ¶

19 years ago


if you have compressed data which is greater than 2 MB (system dependent), you will receive a buffer error by calling the function gzinflate().
be sure to to compress your data by a lower compression level, like 1.
i.e.: gzdeflate($sData, 1);

down

-6

bzbzh ¶

7 years ago


The "One of ZLIB_ENCODING_* constants." seems to be available only from PHP 5.4. 

So I guess that is you are PHP 5.3 you don't use the $encoding parameter...

add a note

官方地址：https://www.php.net/manual/en/function.gzdeflate.php

有任何技术问题请点击这里网站运营推广招聘

IT PHP 编程语言 Linux 开发编程科技 Elasticsearch HTML/CSS/XML 网络 JAVA NoSQL 数据库面试 C/C++ Golang Git 算法操作系统正则表达式 Redis 互联网 MySql JavaScript 运维软件国际架构设计 Mac OS TCP/IP Excel Vim Windows Socket Oracle VR MongoDB Python 运营 MemCache 商业硬件电子娱乐设计 nginx 摄影游戏 WordPress HTTP 团建数码电器

php7 安装fileinfo扩展 preg_split — 通过一个正则表达式分隔字符串 php位值,解决 PHP 中 usort 在值相同时改变原始位置的问题 [PHP] inet_pton/inet_ntop IP地址转换函数 array_multisort() 多字段排序 PHPMailer设置utf8 PHPMailer字符集CharSet ADORecordSet对象 adodb手册 PHP 8.1 [鸟哥]PHP_INT_MIN 和 -9223372036854775808 opcache预加载 Composer的Packagist资源 mysql面试题 [鸟哥]PHP FFI详解 - 一种全新的PHP扩展方式 PHP7添加redis扩展 Packagist / Composer 中国全量镜像 PHP获取指定函数定义在哪个文件中及行号 PHP mkdir()写出来的权限与mode值不符合 adodb连接mysql多个数据库的问题 php扩展开发

略微加速

PHP官方手册 - 互联网笔记

gzdeflate

说明

参数

返回值

范例

参见

User Contributed Notes 9 notes