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'\"
'\" Copyright (c) 2008 Donal K. Fellows
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
'\" RCS: @(#) $Id: zlib.n,v 1.1 2008/12/11 16:50:51 dkf Exp $
'\"
.so man.macros
.TH zlib n 8.6 Tcl "Tcl Built-In Commands"
.BS
'\" Note: do not modify the .SH NAME line immediately below!
.SH NAME
zlib \- compression and decompression operations
.SH SYNOPSIS
.nf
\fBzlib \fIsubcommand arg ...\fR
.fi
.BE
.SH DESCRIPTION
.PP
The \fBzlib\fR command provides access to the compression facilities of the
Zlib library. It has the following subcommands
.TP
\fBzlib adler32\fI string\fR ?\fIinitValue\fR?
.
.TP
\fBzlib compress\fI string\fR ?\fIlevel\fR?
.
.TP
\fBzlib crc32\fI string\fR ?\fIinitValue\fR?
.
.TP
\fBzlib decompress\fI string\fR ?\fIbufferSize\fR?
.
.TP
\fBzlib deflate\fI string\fR ?\fIlevel\fR?
.
.TP
\fBzlib gunzip\fI string\fR ?\fIbufferSize\fR?
.
.TP
\fBzlib gzip\fI string\fR ?\fIlevel\fR?
.
.TP
\fBzlib inflate\fI string\fR ?\fIbufferSize\fR?
.
.TP
\fBzlib stack\fI channel\fR
.
.TP
\fBzlib stream\fI mode\fR ?\fIlevel\fR?
.
Creates a streaming compression or decompression command based on the
\fImode\fR, and return the name of the command. For a description of how that
command works, see \fBSTREAMING COMMAND\fR below. The following modes are
supported:
.RS
.TP
\fBzlib stream compress\fR
.
.TP
\fBzlib stream decompress\fR
.
.TP
\fBzlib stream deflate\fR
.
.TP
\fBzlib stream gunzip\fR
.
.TP
\fBzlib stream gzip\fR
.
.TP
\fBzlib stream inflate\fR
.
.RE
.TP
\fBzlib unstack\fI channel\fR
.
Reverses the effects of \fBzlib stack\fR on the channel called \fIchannel\fR.
.SH EXAMPLES
.PP
To compress a Tcl string, it should be first converted to a particular charset
encoding since the \fBzlib\fR command always operates on binary strings.
.PP
.CS
set compressed [\fBzlib deflate\fR [encoding convertto utf8 $string]]
.CE
.PP
When converting back, it is also important to reverse the charset encoding:
.PP
.CS
set string [encoding convertfrom utf8 [\fBzlib inflate\fR $compressed]]
.CE
.SH "SEE ALSO"
binary(n), chan(n), encoding(n)
.SH "KEYWORDS"
compress, decompress, deflate, gzip, inflate
'\" Local Variables:
'\" mode: nroff
'\" End:
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