gzencode

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

gzencode — Create a gzip compressed string

Description

gzencode(string $data, int $level = -1, int $encoding = ZLIB_ENCODING_GZIP ): string |false

This function returns a compressed version of the input data compatible with the output of the gzip program.

For more information on the GZIP file format, see the document: » GZIP file format specification version 4.3 (RFC 1952).

Parameters

data

The data to encode.

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

The encoding mode. Can be FORCE_GZIP (the default) or FORCE_DEFLATE .

FORCE_DEFLATE generates RFC 1950 compliant output, consisting of a zlib header, the deflated data, and an Adler checksum.

Return Values

The encoded string, or false if an error occurred.

Examples

The resulting data contains the appropriate headers and data structure to make a standard .gz file, e.g.:

Example #1 Creating a gzip file

<?php
$data = file_get_contents("bigfile.txt");
$gzdata = gzencode($data, 9);
file_put_contents("bigfile.txt.gz", $gzdata);
?>

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User Contributed Notes 2 notes

down

Sam Dowling ¶

14 years ago

this is a benchmark test of gzencode (.txt file)
----------------------------------------------
original file size = 3.29 MB (3,459,978 bytes)
compress lvl 1 = 1.09 MB (1,144,006 bytes)
compress lvl 2 = 1.06 MB (1,119,518 bytes)
compress lvl 3 = 1.03 MB (1,085,567 bytes)
compress lvl 4 = 953 KB (976,538 bytes)
compress lvl 5 = 909 KB (931,486 bytes)
compress lvl 6 = 910 KB (932,516 bytes)
compress lvl 7 = 910 KB (932,608 bytes)
compress lvl 8 = 910 KB (932,646 bytes)
compress lvl 9 = 910 KB (932,652 bytes)
----------------------------------------------