| IO::Uncompress::Inflate - Read RFC 1950 files/buffers |
IO::Uncompress::Inflate - Read RFC 1950 files/buffers
use IO::Uncompress::Inflate qw(inflate $InflateError) ;
my $status = inflate $input => $output [,OPTS]
or die "inflate failed: $InflateError\n";
my $z = new IO::Uncompress::Inflate $input [OPTS]
or die "inflate failed: $InflateError\n";
$status = $z->read($buffer)
$status = $z->read($buffer, $length)
$status = $z->read($buffer, $length, $offset)
$line = $z->getline()
$char = $z->getc()
$char = $z->ungetc()
$char = $z->opened()
$status = $z->inflateSync()
$data = $z->trailingData()
$status = $z->nextStream()
$data = $z->getHeaderInfo()
$z->tell()
$z->seek($position, $whence)
$z->binmode()
$z->fileno()
$z->eof()
$z->close()
$InflateError ;
# IO::File mode
<$z>
read($z, $buffer);
read($z, $buffer, $length);
read($z, $buffer, $length, $offset);
tell($z)
seek($z, $position, $whence)
binmode($z)
fileno($z)
eof($z)
close($z)
This module provides a Perl interface that allows the reading of files/buffers that conform to RFC 1950.
For writing RFC 1950 files/buffers, see the companion module IO::Compress::Deflate.
A top-level function, inflate, is provided to carry out
``one-shot'' uncompression between buffers and/or files. For finer
control over the uncompression process, see the OO Interface
section.
use IO::Uncompress::Inflate qw(inflate $InflateError) ;
inflate $input_filename_or_reference => $output_filename_or_reference [,OPTS]
or die "inflate failed: $InflateError\n";
The functional interface needs Perl5.005 or better.
inflate expects at least two parameters,
$input_filename_or_reference and $output_filename_or_reference.
$input_filename_or_reference parameterThe parameter, $input_filename_or_reference, is used to define the
source of the compressed data.
It can take one of the following forms:
$input_filename_or_reference parameter is a filehandle, the input
data will be read from it. The string '-' can be used as an alias for
standard input.
$input_filename_or_reference is a scalar reference, the input data
will be read from $$input_filename_or_reference.
$input_filename_or_reference is an array reference, each element in
the array must be a filename.
The input data will be read from each file in turn.
The complete array will be walked to ensure that it only contains valid filenames before any data is uncompressed.
$input_filename_or_reference is a string that is delimited by the
characters ``<'' and ``>'' inflate will assume that it is an
input fileglob string. The input is the list of files that match the
fileglob.
See File::GlobMapper for more details.
If the $input_filename_or_reference parameter is any other type,
undef will be returned.
$output_filename_or_reference parameterThe parameter $output_filename_or_reference is used to control the
destination of the uncompressed data. This parameter can take one of
these forms.
$output_filename_or_reference parameter is a simple scalar, it is
assumed to be a filename. This file will be opened for writing and the
uncompressed data will be written to it.
$output_filename_or_reference parameter is a filehandle, the
uncompressed data will be written to it. The string '-' can be used as
an alias for standard output.
$output_filename_or_reference is a scalar reference, the
uncompressed data will be stored in $$output_filename_or_reference.
$output_filename_or_reference is an array reference,
the uncompressed data will be pushed onto the array.
$output_filename_or_reference is a string that is delimited by the
characters ``<'' and ``>'' inflate will assume that it is an
output fileglob string. The output is the list of files that match the
fileglob.
When $output_filename_or_reference is an fileglob string,
$input_filename_or_reference must also be a fileglob string. Anything
else is an error.
See File::GlobMapper for more details.
If the $output_filename_or_reference parameter is any other type,
undef will be returned.
When $input_filename_or_reference maps to multiple compressed
files/buffers and $output_filename_or_reference is
a single file/buffer, after uncompression $output_filename_or_reference will contain a
concatenation of all the uncompressed data from each of the input
files/buffers.
Unless specified below, the optional parameters for inflate,
OPTS, are the same as those used with the OO interface defined in the
Constructor Options section below.
AutoClose => 0|1inflate that are filehandles.
If AutoClose is specified, and the value is true, it will result in all
input and/or output filehandles being closed once inflate has
completed.
This parameter defaults to 0.
BinModeOut => 0|1Append => 0|1Append is enabled, all uncompressed data will be append to the end of
the output buffer. Otherwise the output buffer will be cleared before any
uncompressed data is written to it.
Append is enabled, the file will be opened in append mode. Otherwise
the contents of the file, if any, will be truncated before any uncompressed
data is written to it.
Append is enabled, the filehandle will be positioned to the end of
the file via a call to seek before any uncompressed data is
written to it. Otherwise the file pointer will not be moved.
When Append is specified, and set to true, it will append all uncompressed
data to the output data stream.
So when the output is a filehandle it will carry out a seek to the eof before writing any uncompressed data. If the output is a filename, it will be opened for appending. If the output is a buffer, all uncompressed data will be appended to the existing buffer.
Conversely when Append is not specified, or it is present and is set to
false, it will operate as follows.
When the output is a filename, it will truncate the contents of the file before writing any uncompressed data. If the output is a filehandle its position will not be changed. If the output is a buffer, it will be wiped before any uncompressed data is output.
Defaults to 0.
MultiStream => 0|1Defaults to 0.
TrailingData => $scalarThis option can be used when there is useful information immediately following the compressed data stream, and you don't know the length of the compressed data stream.
If the input is a buffer, trailingData will return everything from the
end of the compressed data stream to the end of the buffer.
If the input is a filehandle, trailingData will return the data that is
left in the filehandle input buffer once the end of the compressed data
stream has been reached. You can then use the filehandle to read the rest
of the input file.
Don't bother using trailingData if the input is a filename.
If you know the length of the compressed data stream before you start
uncompressing, you can avoid having to use trailingData by setting the
InputLength option.
To read the contents of the file file1.txt.1950 and write the
uncompressed data to the file file1.txt.
use strict ;
use warnings ;
use IO::Uncompress::Inflate qw(inflate $InflateError) ;
my $input = "file1.txt.1950";
my $output = "file1.txt";
inflate $input => $output
or die "inflate failed: $InflateError\n";
To read from an existing Perl filehandle, $input, and write the
uncompressed data to a buffer, $buffer.
use strict ;
use warnings ;
use IO::Uncompress::Inflate qw(inflate $InflateError) ;
use IO::File ;
my $input = new IO::File "<file1.txt.1950"
or die "Cannot open 'file1.txt.1950': $!\n" ;
my $buffer ;
inflate $input => \$buffer
or die "inflate failed: $InflateError\n";
To uncompress all files in the directory ``/my/home'' that match ``*.txt.1950'' and store the compressed data in the same directory
use strict ;
use warnings ;
use IO::Uncompress::Inflate qw(inflate $InflateError) ;
inflate '</my/home/*.txt.1950>' => '</my/home/#1.txt>'
or die "inflate failed: $InflateError\n";
and if you want to compress each file one at a time, this will do the trick
use strict ;
use warnings ;
use IO::Uncompress::Inflate qw(inflate $InflateError) ;
for my $input ( glob "/my/home/*.txt.1950" )
{
my $output = $input;
$output =~ s/.1950// ;
inflate $input => $output
or die "Error compressing '$input': $InflateError\n";
}
The format of the constructor for IO::Uncompress::Inflate is shown below
my $z = new IO::Uncompress::Inflate $input [OPTS]
or die "IO::Uncompress::Inflate failed: $InflateError\n";
Returns an IO::Uncompress::Inflate object on success and undef on failure.
The variable $InflateError will contain an error message on failure.
If you are running Perl 5.005 or better the object, $z, returned from
IO::Uncompress::Inflate can be used exactly like an IO::File filehandle.
This means that all normal input file operations can be carried out with
$z. For example, to read a line from a compressed file/buffer you can
use either of these forms
$line = $z->getline();
$line = <$z>;
The mandatory parameter $input is used to determine the source of the
compressed data. This parameter can take one of three forms.
$input parameter is a scalar, it is assumed to be a filename. This
file will be opened for reading and the compressed data will be read from it.
$input parameter is a filehandle, the compressed data will be
read from it.
The string '-' can be used as an alias for standard input.
$input is a scalar reference, the compressed data will be read from
$$input.
The option names defined below are case insensitive and can be optionally prefixed by a '-'. So all of the following are valid
-AutoClose
-autoclose
AUTOCLOSE
autoclose
OPTS is a combination of the following options:
AutoClose => 0|1$input parameter is a filehandle. If
specified, and the value is true, it will result in the file being closed once
either the close method is called or the IO::Uncompress::Inflate object is
destroyed.
This parameter defaults to 0.
MultiStream => 0|1This parameter defaults to 0.
Prime => $string$string before processing the
input file/buffer.
This option can be useful when the compressed data is embedded in another file/data structure and it is not possible to work out where the compressed data begins without having to read the first few bytes. If this is the case, the uncompression can be primed with these bytes using this option.
Transparent => 0|1In addition, if the input file/buffer does contain compressed data and there is non-compressed data immediately following it, setting this option will make this module treat the whole file/buffer as a single data stream.
This option defaults to 1.
BlockSize => $num$num bytes.
This option defaults to 4096.
InputLength => $size$size. This option can be used in the
situation where there is useful data directly after the compressed data
stream and you know beforehand the exact length of the compressed data
stream.
This option is mostly used when reading from a filehandle, in which case the file pointer will be left pointing to the first byte directly after the compressed data stream.
This option defaults to off.
Append => 0|1read method does with uncompressed data.
If set to 1, all uncompressed data will be appended to the output parameter
of the read method.
If set to 0, the contents of the output parameter of the read method
will be overwritten by the uncompressed data.
Defaults to 0.
Strict => 0|1The default for this option is off.
TODO
Usage is
$status = $z->read($buffer)
Reads a block of compressed data (the size of the compressed block is
determined by the Buffer option in the constructor), uncompresses it and
writes any uncompressed data into $buffer. If the Append parameter is
set in the constructor, the uncompressed data will be appended to the
$buffer parameter. Otherwise $buffer will be overwritten.
Returns the number of uncompressed bytes written to $buffer, zero if eof
or a negative number on error.
Usage is
$status = $z->read($buffer, $length)
$status = $z->read($buffer, $length, $offset)
$status = read($z, $buffer, $length)
$status = read($z, $buffer, $length, $offset)
Attempt to read $length bytes of uncompressed data into $buffer.
The main difference between this form of the read method and the
previous one, is that this one will attempt to return exactly $length
bytes. The only circumstances that this function will not is if end-of-file
or an IO error is encountered.
Returns the number of uncompressed bytes written to $buffer, zero if eof
or a negative number on error.
Usage is
$line = $z->getline()
$line = <$z>
Reads a single line.
This method fully supports the use of the variable $/ (or
$INPUT_RECORD_SEPARATOR or $RS when English is in use) to
determine what constitutes an end of line. Paragraph mode, record mode and
file slurp mode are all supported.
Usage is
$char = $z->getc()
Read a single character.
Usage is
$char = $z->ungetc($string)
Usage is
$status = $z->inflateSync()
TODO
Usage is
$hdr = $z->getHeaderInfo();
@hdrs = $z->getHeaderInfo();
This method returns either a hash reference (in scalar context) or a list or hash references (in array context) that contains information about each of the header fields in the compressed data stream(s).
Usage is
$z->tell()
tell $z
Returns the uncompressed file offset.
Usage is
$z->eof();
eof($z);
Returns true if the end of the compressed input stream has been reached.
$z->seek($position, $whence);
seek($z, $position, $whence);
Provides a sub-set of the seek functionality, with the restriction
that it is only legal to seek forward in the input file/buffer.
It is a fatal error to attempt to seek backward.
Note that the implementation of seek in this module does not provide
true random access to a compressed file/buffer. It works by uncompressing
data from the current offset in the file/buffer until it reaches the
uncompressed offset specified in the parameters to seek. For very small
files this may be acceptable behaviour. For large files it may cause an
unacceptable delay.
The $whence parameter takes one the usual values, namely SEEK_SET,
SEEK_CUR or SEEK_END.
Returns 1 on success, 0 on failure.
Usage is
$z->binmode
binmode $z ;
This is a noop provided for completeness.
$z->opened()
Returns true if the object currently refers to a opened file/buffer.
my $prev = $z->autoflush()
my $prev = $z->autoflush(EXPR)
If the $z object is associated with a file or a filehandle, this method
returns the current autoflush setting for the underlying filehandle. If
EXPR is present, and is non-zero, it will enable flushing after every
write/print operation.
If $z is associated with a buffer, this method has no effect and always
returns undef.
Note that the special variable $| cannot be used to set or
retrieve the autoflush setting.
$z->input_line_number()
$z->input_line_number(EXPR)
Returns the current uncompressed line number. If EXPR is present it has
the effect of setting the line number. Note that setting the line number
does not change the current position within the file/buffer being read.
The contents of $/ are used to determine what constitutes a line
terminator.
$z->fileno()
fileno($z)
If the $z object is associated with a file or a filehandle, fileno
will return the underlying file descriptor. Once the close method is
called fileno will return undef.
If the $z object is associated with a buffer, this method will return
undef.
$z->close() ;
close $z ;
Closes the output file/buffer.
For most versions of Perl this method will be automatically invoked if
the IO::Uncompress::Inflate object is destroyed (either explicitly or by the
variable with the reference to the object going out of scope). The
exceptions are Perl versions 5.005 through 5.00504 and 5.8.0. In
these cases, the close method will be called automatically, but
not until global destruction of all live objects when the program is
terminating.
Therefore, if you want your scripts to be able to run on all versions
of Perl, you should call close explicitly and not rely on automatic
closing.
Returns true on success, otherwise 0.
If the AutoClose option has been enabled when the IO::Uncompress::Inflate
object was created, and the object is associated with a file, the
underlying file will also be closed.
Usage is
my $status = $z->nextStream();
Skips to the next compressed data stream in the input file/buffer. If a new
compressed data stream is found, the eof marker will be cleared and $.
will be reset to 0.
Returns 1 if a new stream was found, 0 if none was found, and -1 if an error was encountered.
Usage is
my $data = $z->trailingData();
Returns the data, if any, that is present immediately after the compressed data stream once uncompression is complete. It only makes sense to call this method once the end of the compressed data stream has been encountered.
This option can be used when there is useful information immediately following the compressed data stream, and you don't know the length of the compressed data stream.
If the input is a buffer, trailingData will return everything from the
end of the compressed data stream to the end of the buffer.
If the input is a filehandle, trailingData will return the data that is
left in the filehandle input buffer once the end of the compressed data
stream has been reached. You can then use the filehandle to read the rest
of the input file.
Don't bother using trailingData if the input is a filename.
If you know the length of the compressed data stream before you start
uncompressing, you can avoid having to use trailingData by setting the
InputLength option in the constructor.
No symbolic constants are required by this IO::Uncompress::Inflate at present.
inflate and $InflateError.
Same as doing this
use IO::Uncompress::Inflate qw(inflate $InflateError) ;
the Compress::Zlib manpage, the IO::Compress::Gzip manpage, the IO::Uncompress::Gunzip manpage, the IO::Compress::Deflate manpage, the IO::Compress::RawDeflate manpage, the IO::Uncompress::RawInflate manpage, the IO::Compress::Bzip2 manpage, the IO::Uncompress::Bunzip2 manpage, the IO::Compress::Lzma manpage, the IO::Uncompress::UnLzma manpage, the IO::Compress::Xz manpage, the IO::Uncompress::UnXz manpage, the IO::Compress::Lzip manpage, the IO::Uncompress::UnLzip manpage, the IO::Compress::Lzop manpage, the IO::Uncompress::UnLzop manpage, the IO::Compress::Lzf manpage, the IO::Uncompress::UnLzf manpage, the IO::Compress::Zstd manpage, the IO::Uncompress::UnZstd manpage, the IO::Uncompress::AnyInflate manpage, the IO::Uncompress::AnyUncompress manpage
File::GlobMapper, Archive::Zip, Archive::Tar, IO::Zlib
For RFC 1950, 1951 and 1952 see http://www.faqs.org/rfcs/rfc1950.html, http://www.faqs.org/rfcs/rfc1951.html and http://www.faqs.org/rfcs/rfc1952.html
The zlib compression library was written by Jean-loup Gailly
gzip@prep.ai.mit.edu and Mark Adler madler@alumni.caltech.edu.
The primary site for the zlib compression library is http://www.zlib.org.
The primary site for gzip is http://www.gzip.org.
This module was written by Paul Marquess, pmqs@cpan.org.
See the Changes file.
Copyright (c) 2005-2019 Paul Marquess. All rights reserved.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
| IO::Uncompress::Inflate - Read RFC 1950 files/buffers |