io::compress::gzip.3

视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.

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.\" ========================================================================
.\"
.IX Title "IO::Compress::Gzip 3"
.TH IO::Compress::Gzip 3 "2007-12-18" "perl v5.10.0" "Perl Programmers Reference Guide"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
IO::Compress::Gzip \- Write RFC 1952 files/buffers
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\&    use IO::Compress::Gzip qw(gzip $GzipError) ;
\&
\&
\&    my $status = gzip $input => $output [,OPTS] 
\&        or die "gzip failed: $GzipError\en";
\&
\&    my $z = new IO::Compress::Gzip $output [,OPTS]
\&        or die "gzip failed: $GzipError\en";
\&
\&    $z\->print($string);
\&    $z\->printf($format, $string);
\&    $z\->write($string);
\&    $z\->syswrite($string [, $length, $offset]);
\&    $z\->flush();
\&    $z\->tell();
\&    $z\->eof();
\&    $z\->seek($position, $whence);
\&    $z\->binmode();
\&    $z\->fileno();
\&    $z\->opened();
\&    $z\->autoflush();
\&    $z\->input_line_number();
\&    $z\->newStream( [OPTS] );
\&    
\&    $z\->deflateParams();
\&    
\&    $z\->close() ;
\&
\&    $GzipError ;
\&
\&    # IO::File mode
\&
\&    print $z $string;
\&    printf $z $format, $string;
\&    tell $z
\&    eof $z
\&    seek $z, $position, $whence
\&    binmode $z
\&    fileno $z
\&    close $z ;
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This module provides a Perl interface that allows writing compressed
data to files or buffer as defined in \s-1RFC\s0 1952.
.PP
All the gzip headers defined in \s-1RFC\s0 1952 can be created using
this module.
.PP
For reading \s-1RFC\s0 1952 files/buffers, see the companion module 
IO::Uncompress::Gunzip.
.SH "Functional Interface"
.IX Header "Functional Interface"
A top-level function, \f(CW\*(C`gzip\*(C'\fR, is provided to carry out
\&\*(L"one-shot\*(R" compression between buffers and/or files. For finer
control over the compression process, see the \*(L"\s-1OO\s0 Interface\*(R"
section.
.PP
.Vb 1
\&    use IO::Compress::Gzip qw(gzip $GzipError) ;
\&
\&    gzip $input => $output [,OPTS] 
\&        or die "gzip failed: $GzipError\en";
.Ve
.PP
The functional interface needs Perl5.005 or better.
.ie n .Sh "gzip $input\fP => \f(CW$output [, \s-1OPTS\s0]"
.el .Sh "gzip \f(CW$input\fP => \f(CW$output\fP [, \s-1OPTS\s0]"
.IX Subsection "gzip $input => $output [, OPTS]"
\&\f(CW\*(C`gzip\*(C'\fR expects at least two parameters, \f(CW$input\fR and \f(CW$output\fR.
.PP
\fIThe \f(CI$input\fI parameter\fR
.IX Subsection "The $input parameter"
.PP
The parameter, \f(CW$input\fR, is used to define the source of
the uncompressed data.
.PP
It can take one of the following forms:
.IP "A filename" 5
.IX Item "A filename"
If the \f(CW$input\fR parameter is a simple scalar, it is assumed to be a
filename. This file will be opened for reading and the input data
will be read from it.
.IP "A filehandle" 5
.IX Item "A filehandle"
If the \f(CW$input\fR parameter is a filehandle, the input data will be
read from it.
The string '\-' can be used as an alias for standard input.
.IP "A scalar reference" 5
.IX Item "A scalar reference"
If \f(CW$input\fR is a scalar reference, the input data will be read
from \f(CW$$input\fR.
.IP "An array reference" 5
.IX Item "An array reference"
If \f(CW$input\fR is an array reference, each element in the array must be a
filename.
.Sp
The input data will be read from each file in turn.
.Sp
The complete array will be walked to ensure that it only
contains valid filenames before any data is compressed.
.IP "An Input FileGlob string" 5
.IX Item "An Input FileGlob string"
If \f(CW$input\fR is a string that is delimited by the characters \*(L"<\*(R" and \*(L">\*(R"
\&\f(CW\*(C`gzip\*(C'\fR will assume that it is an \fIinput fileglob string\fR. The
input is the list of files that match the fileglob.
.Sp
If the fileglob does not match any files ...
.Sp
See File::GlobMapper for more details.
.PP
If the \f(CW$input\fR parameter is any other type, \f(CW\*(C`undef\*(C'\fR will be returned.
.PP
In addition, if \f(CW$input\fR is a simple filename, the default values for
the \f(CW\*(C`Name\*(C'\fR and \f(CW\*(C`Time\*(C'\fR options will be sourced from that file.
.PP
If you do not want to use these defaults they can be overridden by
explicitly setting the \f(CW\*(C`Name\*(C'\fR and \f(CW\*(C`Time\*(C'\fR options or by setting the
\&\f(CW\*(C`Minimal\*(C'\fR parameter.
.PP
\fIThe \f(CI$output\fI parameter\fR
.IX Subsection "The $output parameter"
.PP
The parameter \f(CW$output\fR is used to control the destination of the
compressed data. This parameter can take one of these forms.
.IP "A filename" 5
.IX Item "A filename"
If the \f(CW$output\fR parameter is a simple scalar, it is assumed to be a
filename.  This file will be opened for writing and the compressed
data will be written to it.
.IP "A filehandle" 5
.IX Item "A filehandle"
If the \f(CW$output\fR parameter is a filehandle, the compressed data
will be written to it.
The string '\-' can be used as an alias for standard output.
.IP "A scalar reference" 5
.IX Item "A scalar reference"
If \f(CW$output\fR is a scalar reference, the compressed data will be
stored in \f(CW$$output\fR.
.IP "An Array Reference" 5
.IX Item "An Array Reference"
If \f(CW$output\fR is an array reference, the compressed data will be
pushed onto the array.
.IP "An Output FileGlob" 5
.IX Item "An Output FileGlob"
If \f(CW$output\fR is a string that is delimited by the characters \*(L"<\*(R" and \*(L">\*(R"
\&\f(CW\*(C`gzip\*(C'\fR will assume that it is an \fIoutput fileglob string\fR. The
output is the list of files that match the fileglob.
.Sp
When \f(CW$output\fR is an fileglob string, \f(CW$input\fR must also be a fileglob
string. Anything else is an error.
.PP
If the \f(CW$output\fR parameter is any other type, \f(CW\*(C`undef\*(C'\fR will be returned.
.Sh "Notes"
.IX Subsection "Notes"
When \f(CW$input\fR maps to multiple files/buffers and \f(CW$output\fR is a single
file/buffer the input files/buffers will be stored
in \f(CW$output\fR as a concatenated series of compressed data streams.
.Sh "Optional Parameters"
.IX Subsection "Optional Parameters"
Unless specified below, the optional parameters for \f(CW\*(C`gzip\*(C'\fR,
\&\f(CW\*(C`OPTS\*(C'\fR, are the same as those used with the \s-1OO\s0 interface defined in the
\&\*(L"Constructor Options\*(R" section below.
.ie n .IP """AutoClose => 0|1""" 5
.el .IP "\f(CWAutoClose => 0|1\fR" 5
.IX Item "AutoClose => 0|1"
This option applies to any input or output data streams to 
\&\f(CW\*(C`gzip\*(C'\fR that are filehandles.
.Sp
If \f(CW\*(C`AutoClose\*(C'\fR is specified, and the value is true, it will result in all
input and/or output filehandles being closed once \f(CW\*(C`gzip\*(C'\fR has
completed.
.Sp
This parameter defaults to 0.
.ie n .IP """BinModeIn => 0|1""" 5
.el .IP "\f(CWBinModeIn => 0|1\fR" 5
.IX Item "BinModeIn => 0|1"
When reading from a file or filehandle, set \f(CW\*(C`binmode\*(C'\fR before reading.
.Sp
Defaults to 0.
.ie n .IP """Append => 0|1""" 5
.el .IP "\f(CWAppend => 0|1\fR" 5
.IX Item "Append => 0|1"
\&\s-1TODO\s0
.Sh "Examples"
.IX Subsection "Examples"
To read the contents of the file \f(CW\*(C`file1.txt\*(C'\fR and write the compressed
data to the file \f(CW\*(C`file1.txt.gz\*(C'\fR.
.PP
.Vb 3
\&    use strict ;
\&    use warnings ;
\&    use IO::Compress::Gzip qw(gzip $GzipError) ;
\&
\&    my $input = "file1.txt";
\&    gzip $input => "$input.gz"
\&        or die "gzip failed: $GzipError\en";