gzencode(3) [php man page]

GZENCODE(3)								 1							       GZENCODE(3)

gzencode - Create a gzip compressed string

SYNOPSIS

       string gzencode (string	$data, [int  $level = -1], [int  $encoding_mode = FORCE_GZIP])

DESCRIPTION

	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

	      o $data
		- The data to encode.

	      o $level
		-  The	level of compression. Can be given as 0 for no compression up to 9 for maximum compression. If not given, the default com-
		pression level will be the default compression level of the zlib library.

	      o $encoding_mode
		- The encoding mode. Can be FORCE_GZIP (the default) or FORCE_DEFLATE.	Prior to PHP 5.4.0, using FORCE_DEFLATE results in a stan-
		dard zlib deflated string (inclusive zlib headers) after a gzip file header but without the trailing crc32 checksum.  In PHP 5.4.0
		and later, FORCE_DEFLATE generates RFC 1950 compliant output, consisting of a zlib header, the deflated data, and an Adler  check-
		sum.

RETURN VALUES

	The encoded string, or FALSE if an error occurred.

CHANGELOG

       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       | 5.4.0	|						    |
       |	|						    |
       |	|						    |
       |	| FORCE_DEFLATE  now  generates  RFC 1950 compliant |
       |	| output.					    |
       |	|						    |
       +--------+---------------------------------------------------+
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 = implode("", file("bigfile.txt"));
	      $gzdata = gzencode($data, 9);
	      $fp = fopen("bigfile.txt.gz", "w");
	      fwrite($fp, $gzdata);
	      fclose($fp);
	      ?>

SEE ALSO

       gzdecode(3), gzdeflate(3), gzinflate(3), gzuncompress(3), gzcompress(3),  ZLIB Compressed Data Format Specification (RFC 1950) .

PHP Documentation Group 													       GZENCODE(3)

ZLIB(3) 						     Library Functions Manual							   ZLIB(3)

NAME

       zlib - compression/decompression library

SYNOPSIS

       [see zlib.h for full description]

DESCRIPTION

       The zlib library is a general purpose data compression library.	The code is thread safe.  It provides in-memory compression and decompres-
       sion functions, including integrity checks of the uncompressed data.  This version of the library  supports  only  one  compression  method
       (deflation) but other algorithms will be added later and will have the same stream interface.

       Compression  can  be  done  in  a  single step if the buffers are large enough (for example if an input file is mmap'ed), or can be done by
       repeated calls of the compression function.  In the latter case, the application must provide more input and/or consume the output (provid-
       ing more output space) before each call.

       The library also supports reading and writing files in gzip (.gz) format with an interface similar to that of stdio.

       The  library  does  not	install any signal handler. The decoder checks the consistency of the compressed data, so the library should never
       crash even in case of corrupted input.

       All functions of the compression library are documented in the file zlib.h.  The distribution  source  includes	examples  of  use  of  the
       library the files example.c and minigzip.c.

       A Java implementation of zlib is available in the Java Development Kit 1.1

	      http://www.javasoft.com/products/JDK/1.1/docs/api/Package-java.util.zip.html

       A  Perl	interface  to  zlib, written by Paul Marquess (pmarquess@bfsec.bt.co.uk) is available at CPAN (Comprehensive Perl Archive Network)
       sites, such as:

	      ftp://ftp.cis.ufl.edu/pub/perl/CPAN/modules/by-module/Compress/Compress-Zlib*

       A Python interface to zlib written by A.M. Kuchling <amk@magnet.com> is available from the Python Software Association sites, such as:

	      ftp://ftp.python.org/pub/python/contrib/Encoding/zlib*.tar.gz

SEE ALSO

       Questions about zlib should be sent to:

	      zlib@quest.jpl.nasa.gov or, if this fails, to the author addresses given below.  The zlib home page is:

	      http://www.cdrom.com/pub/infozip/zlib/

       The data format used by the zlib library is described by RFC (Request for Comments) 1950 to 1952 in the files:

	      ftp://ds.internic.net/rfc/rfc1950.txt (zlib format)
	      rfc1951.txt (deflate format)
	      rfc1952.txt (gzip format)

       These documents are also available in other formats from:

	      ftp://ftp.uu.net/graphics/png/documents/zlib/zdoc-index.html

AUTHORS

       Version 1.1.4 Copyright (C) 1995-2002 Jean-loup Gailly (jloup@gzip.org) and Mark Adler (madler@alumni.caltech.edu).

       This software is provided "as-is," without any express or implied warranty.  In no event will the authors be held liable  for  any  damages
       arising	from the use of this software.	See the distribution directory with respect to requirements governing redistribution.  The deflate
       format used by zlib was defined by Phil Katz.  The deflate and zlib specifications were written by L. Peter Deutsch.   Thanks  to  all  the
       people who reported problems and suggested various improvements in zlib; who are too numerous to cite here.

       UNIX manual page by R. P. C. Rodgers, U.S. National Library of Medicine (rodgers@nlm.nih.gov).

								   11 March 2002							   ZLIB(3)