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man : IO::Uncompress::AnyInflate
IO::Uncompress::APerlfProgrammers RIO::Uncompress::AnyInflate(3p)
NAME
IO::Uncompress::AnyInflate - Uncompress zlib-based (zip,
gzip) file/buffer
SYNOPSIS
use IO::Uncompress::AnyInflate qw(anyinflate $AnyInflateError) ;
my $status = anyinflate $input => $output [,OPTS]
or die "anyinflate failed: $AnyInflateError\n";
my $z = new IO::Uncompress::AnyInflate $input [OPTS]
or die "anyinflate failed: $AnyInflateError\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()
$AnyInflateError ;
# IO::File mode
<$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)
DESCRIPTION
This module provides a Perl interface that allows the
reading of files/buffers that have been compressed in a
number of formats that use the zlib compression library.
The formats supported are
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RFC 1950
RFC 1951 (optionally)
gzip (RFC 1952)
zip
The module will auto-detect which, if any, of the
supported compression formats is being used.
Functional Interface
A top-level function, "anyinflate", 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::AnyInflate qw(anyinflate $AnyInflateError) ;
anyinflate $input => $output [,OPTS]
or die "anyinflate failed: $AnyInflateError\n";
The functional interface needs Perl5.005 or better.
anyinflate $input => $output [, OPTS]
"anyinflate" expects at least two parameters, $input and
$output.
The $input parameter
The parameter, $input, is used to define the source of the
compressed data.
It can take one of the following forms:
A filename
If the $input 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.
A filehandle
If the $input parameter is a filehandle, the input
data will be read from it. The string '-' can be
used as an alias for standard input.
A scalar reference
If $input is a scalar reference, the input data will
be read from $$input.
An array reference
If $input is an array reference, each element in the
array must be a filename.
The input data will be read from each file in turn.
The complete array will be walked to ensure that it
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only contains valid filenames before any data is
uncompressed.
An Input FileGlob string
If $input is a string that is delimited by the
characters "<" and ">" "anyinflate" will assume that
it is an input fileglob string. The input is the list
of files that match the fileglob.
If the fileglob does not match any files ...
See File::GlobMapper for more details.
If the $input parameter is any other type, "undef" will be
returned.
The $output parameter
The parameter $output is used to control the destination
of the uncompressed data. This parameter can take one of
these forms.
A filename
If the $output parameter is a simple scalar, it is
assumed to be a filename. This file will be opened
for writing and the uncompressed data will be written
to it.
A filehandle
If the $output parameter is a filehandle, the
uncompressed data will be written to it. The string
'-' can be used as an alias for standard output.
A scalar reference
If $output is a scalar reference, the uncompressed
data will be stored in $$output.
An Array Reference
If $output is an array reference, the uncompressed
data will be pushed onto the array.
An Output FileGlob
If $output is a string that is delimited by the
characters "<" and ">" "anyinflate" will assume that
it is an output fileglob string. The output is the
list of files that match the fileglob.
When $output is an fileglob string, $input must also
be a fileglob string. Anything else is an error.
If the $output parameter is any other type, "undef" will
be returned.
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Notes
When $input maps to multiple compressed files/buffers and
$output is a single file/buffer, after uncompression
$output will contain a concatenation of all the
uncompressed data from each of the input files/buffers.
Optional Parameters
Unless specified below, the optional parameters for
"anyinflate", "OPTS", are the same as those used with the
OO interface defined in the "Constructor Options" section
below.
"AutoClose => 0|1"
This option applies to any input or output data
streams to "anyinflate" 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 "anyinflate" has completed.
This parameter defaults to 0.
"BinModeOut => 0|1"
When writing to a file or filehandle, set "binmode"
before writing to the file.
Defaults to 0.
"Append => 0|1"
TODO
"MultiStream => 0|1"
If the input file/buffer contains multiple compressed
data streams, this option will uncompress the whole
lot as a single data stream.
Defaults to 0.
"TrailingData => $scalar"
Returns the data, if any, that is present immediately
after the compressed data stream once uncompression
is complete.
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.
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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.
Examples
To read the contents of the file "file1.txt.Compressed"
and write the compressed data to the file "file1.txt".
use strict ;
use warnings ;
use IO::Uncompress::AnyInflate qw(anyinflate $AnyInflateError) ;
my $input = "file1.txt.Compressed";
my $output = "file1.txt";
anyinflate $input => $output
or die "anyinflate failed: $AnyInflateError\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::AnyInflate qw(anyinflate $AnyInflateError) ;
use IO::File ;
my $input = new IO::File "<file1.txt.Compressed"
or die "Cannot open 'file1.txt.Compressed': $!\n" ;
my $buffer ;
anyinflate $input => \$buffer
or die "anyinflate failed: $AnyInflateError\n";
To uncompress all files in the directory "/my/home" that
match "*.txt.Compressed" and store the compressed data in
the same directory
use strict ;
use warnings ;
use IO::Uncompress::AnyInflate qw(anyinflate $AnyInflateError) ;
anyinflate '</my/home/*.txt.Compressed>' => '</my/home/#1.txt>'
or die "anyinflate failed: $AnyInflateError\n";
and if you want to compress each file one at a time, this
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will do the trick
use strict ;
use warnings ;
use IO::Uncompress::AnyInflate qw(anyinflate $AnyInflateError) ;
for my $input ( glob "/my/home/*.txt.Compressed" )
{
my $output = $input;
$output =~ s/.Compressed// ;
anyinflate $input => $output
or die "Error compressing '$input': $AnyInflateError\n";
}
OO Interface
Constructor
The format of the constructor for
IO::Uncompress::AnyInflate is shown below
my $z = new IO::Uncompress::AnyInflate $input [OPTS]
or die "IO::Uncompress::AnyInflate failed: $AnyInflateError\n";
Returns an "IO::Uncompress::AnyInflate" object on success
and undef on failure. The variable $AnyInflateError will
contain an error message on failure.
If you are running Perl 5.005 or better the object, $z,
returned from IO::Uncompress::AnyInflate 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.
A filename
If the $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.
A filehandle
If the $input parameter is a filehandle, the
compressed data will be read from it. The string '-'
can be used as an alias for standard input.
A scalar reference
If $input is a scalar reference, the compressed data
will be read from $$output.
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Constructor Options
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"
This option is only valid when the $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::AnyInflate object is destroyed.
This parameter defaults to 0.
"MultiStream => 0|1"
Allows multiple concatenated compressed streams to be
treated as a single compressed stream. Decompression
will stop once either the end of the file/buffer is
reached, an error is encountered (premature eof,
corrupt compressed data) or the end of a stream is
not immediately followed by the start of another
stream.
This parameter defaults to 0.
"Prime => $string"
This option will uncompress the contents of $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|1"
If this option is set and the input file/buffer is
not compressed data, the module will allow reading of
it anyway.
In 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/bufffer as a
single data stream.
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This option defaults to 1.
"BlockSize => $num"
When reading the compressed input data,
IO::Uncompress::AnyInflate will read it in blocks of
$num bytes.
This option defaults to 4096.
"InputLength => $size"
When present this option will limit the number of
compressed bytes read from the input file/buffer to
$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|1"
This option controls what the "read" 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|1"
This option controls whether the extra checks defined
below are used when carrying out the decompression.
When Strict is on, the extra tests are carried out,
when Strict is off they are not.
The default for this option is off.
If the input is an RFC 1950 data stream, the
following will be checked:
1. The ADLER32 checksum field must be present.
2. The value of the ADLER32 field read must match
the adler32 value of the uncompressed data
actually contained in the file.
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If the input is a gzip (RFC 1952) data stream, the
following will be checked:
1. If the FHCRC bit is set in the gzip FLG header
byte, the CRC16 bytes in the header must match
the crc16 value of the gzip header actually
read.
2. If the gzip header contains a name field (FNAME)
it consists solely of ISO 8859-1 characters.
3. If the gzip header contains a comment field
(FCOMMENT) it consists solely of ISO 8859-1
characters plus line-feed.
4. If the gzip FEXTRA header field is present it
must conform to the sub-field structure as
defined in RFC 1952.
5. The CRC32 and ISIZE trailer fields must be
present.
6. The value of the CRC32 field read must match the
crc32 value of the uncompressed data actually
contained in the gzip file.
7. The value of the ISIZE fields read must match
the length of the uncompressed data actually
read from the file.
"RawInflate => 0|1"
When auto-detecting the compressed format, try to
test for raw-deflate (RFC 1951) content using the
"IO::Uncompress::RawInflate" module.
The reason this is not default behaviour is because
RFC 1951 content can only be detected by attempting
to uncompress it. This process is error prone and can
result is false positives.
Defaults to 0.
"ParseExtra => 0|1" If the gzip FEXTRA header field is
present and this option is set, it will force the module
to check that it conforms to the sub-field structure as
defined in RFC 1952.
If the "Strict" is on it will automatically enable
this option.
Defaults to 0.
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Examples
TODO
Methods
read
Usage is
$status = $z->read($buffer)
Reads a block of compressed data (the size the 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.
read
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.
getline
Usage is
$line = $z->getline()
$line = <$z>
Reads a single line.
This method fully supports the use of of the variable $/
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(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.
getc
Usage is
$char = $z->getc()
Read a single character.
ungetc
Usage is
$char = $z->ungetc($string)
inflateSync
Usage is
$status = $z->inflateSync()
TODO
getHeaderInfo
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).
tell
Usage is
$z->tell()
tell $z
Returns the uncompressed file offset.
eof
Usage is
$z->eof();
eof($z);
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Returns true if the end of the compressed input stream has
been reached.
seek
$z->seek($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.
The $whence parameter takes one the usual values, namely
SEEK_SET, SEEK_CUR or SEEK_END.
Returns 1 on success, 0 on failure.
binmode
Usage is
$z->binmode
binmode $z ;
This is a noop provided for completeness.
opened
$z->opened()
Returns true if the object currently refers to a opened
file/buffer.
autoflush
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.
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input_line_number
$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 to determine what
constitutes a line terminator.
fileno
$z->fileno()
fileno($z)
If the $z object is associated with a file or a
filehandle, this method will return the underlying file
descriptor.
If the $z object is is associated with a buffer, this
method will return undef.
close
$z->close() ;
close $z ;
Closes the output file/buffer.
For most versions of Perl this method will be
automatically invoked if the IO::Uncompress::AnyInflate
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::AnyInflate object was created, and the
object is associated with a file, the underlying file will
also be closed.
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nextStream
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.
trailingData
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.
Importing
No symbolic constants are required by this
IO::Uncompress::AnyInflate at present.
:all Imports "anyinflate" and $AnyInflateError. Same as
doing this
use IO::Uncompress::AnyInflate qw(anyinflate $AnyInflateError) ;
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EXAMPLES
SEE ALSO
Compress::Zlib, IO::Compress::Gzip,
IO::Uncompress::Gunzip, IO::Compress::Deflate,
IO::Uncompress::Inflate, IO::Compress::RawDeflate,
IO::Uncompress::RawInflate, IO::Compress::Bzip2,
IO::Uncompress::Bunzip2, IO::Compress::Lzop,
IO::Uncompress::UnLzop, IO::Compress::Lzf,
IO::Uncompress::UnLzf, IO::Uncompress::AnyUncompress
Compress::Zlib::FAQ
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 gzipATprep.edu and Mark Adler
madlerATalumni.edu.
The primary site for the zlib compression library is
http://www.zlib.org.
The primary site for gzip is http://www.gzip.org.
AUTHOR
This module was written by Paul Marquess, pmqsATcpan.org.
MODIFICATION HISTORY
See the Changes file.
COPYRIGHT AND LICENSE
Copyright (c) 2005-2007 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.
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