IO::UNCOMPRESS::INFLATE(3pm)

📦

version 5.42.3 · 17 versions

💖 IO::Uncompress::Inflate(3pm) — Perl Programmers Reference Guide 💖

✨ NAME ✨

IO::Uncompress::Inflate - Read RFC 1950 files/buffers 🦋

🌈 SYNOPSIS 🌈

use IO::Uncompress::Inflate qw(inflate $InflateError) ;

my $status = inflate $input => $output [,OPTS]
    or die "inflate failed: $InflateError\n";

my $z = IO::Uncompress::Inflate->new( $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)

🎀 DESCRIPTION 🎀

Okay so this module gives you a Perl interface that lets you read files/buffers that conform to RFC 1950. That's the whole vibe 💅

For writing RFC 1950 files/buffers, see the companion module IO::Compress::Deflate. Bestie companion behavior, we love to see it 🫶

🌟 Functional Interface 🌟

There's a top-level function called "inflate" that does "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. No cap 🧚

🚀 inflate $input_filename_or_reference => $output_filename_or_reference [, OPTS] 🚀

"inflate" expects at least two parameters, $input_filename_or_reference and $output_filename_or_reference, and zero or more optional parameters (see "Optional Parameters").

The $input_filename_or_reference parameter

The parameter, $input_filename_or_reference, is used to define the source of the compressed data.

It can take one of the following forms:

A filename — If the $input_filename_or_reference 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_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.
A scalar reference — If $input_filename_or_reference is a scalar reference, the input data will be read from $$input_filename_or_reference.
An array reference — If $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.
An Input FileGlob string — If $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.

The $output_filename_or_reference parameter

The parameter $output_filename_or_reference is used to control the destination of the uncompressed data. This parameter can take one of these forms.

A filename — If the $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.
A filehandle — If the $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.
A scalar reference — If $output_filename_or_reference is a scalar reference, the uncompressed data will be stored in $$output_filename_or_reference.
An Array Reference — If $output_filename_or_reference is an array reference, the uncompressed data will be pushed onto the array.
An Output FileGlob — If $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.

📝 Notes 📝

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. It's giving "all the crumbs in one bag" energy 🍓

🎛️ Optional Parameters 🎛️

The optional parameters for the one-shot function "inflate" are (for the most part) identical to those used with the OO interface defined in the "Constructor Options" section. The exceptions are listed below 👑

AutoClose => 0|1 — This option applies to any input or output data streams to "inflate" 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|1 — This option is now a no-op. All files will be written in binmode.
Append => 0|1 — The behaviour of this option is dependent on the type of output data stream.
- A Buffer — If "Append" 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.
- A Filename — If "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.
- A Filehandle — If "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|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. 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.

🧚 OneShot Examples 🧚

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 = IO::File->new( "<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";
}

🦋 OO Interface 🦋

🎀 Constructor 🎀

Okay so the constructor for IO::Uncompress::Inflate looks like this, bestie:

my $z = IO::Uncompress::Inflate->new( $input [OPTS] )
    or die "IO::Uncompress::Inflate failed: $InflateError\n";

It takes one mandatory parameter, $input — defined below — and zero or more OPTS, which are defined in Constructor Options.

It returns an IO::Uncompress::Inflate object on success and undef on failure. If it fails, the variable $InflateError will contain an error message. Periodt.

If you’re running Perl 5.005 or better, the object $z returned from IO::Uncompress::Inflate can be used exactly like an IO::File filehandle. That means 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>;

Below is a simple example of using the OO interface to read the compressed file myfile.1950 and write its contents to stdout. Iconic behavior, honestly:

my $filename = "myfile.1950";
my $z = IO::Uncompress::Inflate->new($filename)
    or die "IO::Uncompress::Inflate failed: $InflateError\n";

while (<$z>) {
    print $_;
}
$z->close();

See EXAMPLES for further examples.

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 $$input.

✨ 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::Inflate 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. Literally so handy.
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/buffer as a single data stream. This option defaults to 1.
BlockSize => $num — When reading the compressed input data, IO::Uncompress::Inflate 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.
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.

Methods 🎀

okay so these are all the things you can actually do with your shiny $z object. buckle up bestie, there's a bunch 💅

`read` (the simple one)

usage goes like this:

$status = $z->read($buffer)

It reads a block of compressed data — the size of that block comes from the Buffer option you set in the constructor, iykyk — uncompresses it, and writes whatever uncompressed data comes out into $buffer. If you set the Append parameter in the constructor, that uncompressed data gets appended to $buffer instead of clobbering it. Otherwise $buffer gets overwritten, no warning, just vibes gone 🌸

Returns the number of uncompressed bytes written to $buffer, 0 if eof, or a negative number on error.

`read` (the ✨fancy✨ one)

usage:

$status = $z->read($buffer, $length)
$status = $z->read($buffer, $length, $offset)

$status = read($z, $buffer, $length)
$status = read($z, $buffer, $length, $offset)

Attempts to read $length bytes of uncompressed data into $buffer.

The main character difference between this form of read and the previous one is that this one will attempt to return exactly $length bytes. The only situations where it won't are if it hits end-of-file or an IO error. otherwise?? it's giving commitment 💖

Returns the number of uncompressed bytes written to $buffer, 0 if eof, or a negative number on error.

`getline`

usage:

$line = $z->getline()
$line = <$z>

Reads a single line 🦋

This method fully supports the variable $/ (or $INPUT_RECORD_SEPARATOR, or $RS when English is in use) to decide what counts as an end of line. Paragraph mode, record mode and file slurp mode are all supported — all of them, periodt 👑

`getc`

usage:

$char = $z->getc()

Reads a single character. one. singular. iconic 🌈

`ungetc`

usage:

$char = $z->ungetc($string)

(yep, that's the whole entry — go off, mysterious little method 🫶)

`inflateSync`

usage:

$status = $z->inflateSync()

TODO

not me leaving this as a TODO 😭 that's literally all the docs say, bestie — no embellishment from me, no cap

`getHeaderInfo`

usage:

$hdr  = $z->getHeaderInfo();
@hdrs = $z->getHeaderInfo();

This one returns either a hash reference (if you're in scalar context) or a list of hash references (if you're in array context) containing info about each of the header fields in the compressed data stream(s) 👑 header lore fr fr

`tell`

usage:

$z->tell()
tell $z

Returns the uncompressed file offset ⭐

`eof`

usage:

$z->eof();
eof($z);

Returns true if the end of the compressed input stream has been reached. that's it, that's the vibe check 💀

`seek`

$z->seek($position, $whence);
seek($z, $position, $whence);

Gives you a sub-set of seek functionality, with one big restriction: it is only legal to seek forward in the input file/buffer. Attempting to seek backward is a fatal error. like, dead. don't do it 🚫

⚠️ Heads up, this matters: the implementation of seek in this module does not provide true random access to a compressed file/buffer. What it actually does is uncompress data from the current offset in the file/buffer until it reaches the uncompressed offset you specified in the seek parameters. For very small files that's fine, lowkey acceptable behaviour. For large files it may cause an unacceptable delay 😭 you've been warned.

The $whence parameter takes one of the usual values, namely SEEK_SET, SEEK_CUR or SEEK_END.

Returns 1 on success, 0 on failure.

`binmode`

usage:

$z->binmode
binmode $z ;

This is a noop, provided for completeness. it does nothing but it is there and that's what counts 🎀

`opened`

$z->opened()

Returns true if the object currently refers to an 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'll enable flushing after every write/print operation.

If $z is associated with a buffer, this method has no effect and always returns undef. sorry bestie 🙈

Note that the special variable $| cannot be used to set or retrieve the autoflush setting. nope. not here. not today 💅

`input_line_number`

$z->input_line_number()
$z->input_line_number(EXPR)

Returns the current uncompressed line number. If EXPR is present, it sets 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 counts as a line terminator.

`fileno`

$z->fileno()
fileno($z)

If the $z object is associated with a file or filehandle, fileno returns the underlying file descriptor. Once the close method gets called, fileno will return undef ⭐

If the $z object is associated with a buffer, this method returns 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::Inflate object is destroyed — either explicitly, or by the variable holding the reference to the object going out of scope. The exceptions are Perl versions 5.005 through 5.00504 and 5.8.0. In those cases close will be called automatically, but not until global destruction of all live objects when the program is terminating 💀

So if you want your scripts to run on all versions of Perl, you should call close explicitly and not rely on automatic closing. fr fr, just call it.

Returns true on success, otherwise 0.

If the AutoClose option was enabled when the IO::Uncompress::Inflate object was created, and the object is associated with a file, the underlying file will also be closed 👑

`nextStream`

usage:

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 gets cleared and $. gets 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:

my $data = $z->trailingData();

Returns the data, if any, sitting immediately after the compressed data stream once uncompression is done. It only makes sense to call this method once you've hit the end of the compressed data stream 🌸

This option is useful when there's useful info immediately following the compressed data stream and you don't know the length of that stream. iykyk 🫶

If the input is a buffer, trailingData returns everything from the end of the compressed data stream to the end of the buffer.
If the input is a filehandle, trailingData returns the data 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. just don't 🙈

If you already know the length of the compressed data stream before you start uncompressing, you can skip trailingData entirely by setting the InputLength option in the constructor 💅

Importing 💖

No symbolic constants are required by IO::Uncompress::Inflate at present 🎀

:all — imports inflate and $InflateError. Same as doing this:

use IO::Uncompress::Inflate qw(inflate $InflateError) ;

EXAMPLES 🌟

Working with Net::FTP

See IO::Compress::FAQ 📚

SUPPORT 🫶

General feedback, questions and bug reports should be sent to <https://github.com/pmqs/IO-Compress/issues> (preferred) or <https://rt.cpan.org/Public/Dist/Display.html?Name=IO-Compress> 💌

AUTHOR 🎀

This module was written by Paul Marquess, "pmqs@cpan.org". absolute legend, we stan 💜

MODIFICATION HISTORY 📝

See the Changes file.

COPYRIGHT AND LICENSE ⚖️

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

and that's the whole page, bestie!! 🦋✨ this one's perl v5.42.3, dated 2026-11-03, and it's the IO::Unc...:Inflate(3pm) page — go uncompress something iconic 💅💖

📦 where this page comes from

alpine 3.24: perl-doc 5.42.3-r0 · Artistic-1.0-Perl OR GPL-1.0-or-later
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash-1017 on 2026-11-04: a language model's rewrite of the original, under its terms

IO::UNCOMPRESS::INFLATE(3pm)