IO::UNCOMPRESS::INFLATE(3perl)

hey bestie 💖 welcome to the man page for IO::Uncompress::Inflate from section 3perl of the Perl Programmers Reference Guide. it's literally your all-access pass to reading RFC 1950 stuff. let's get into it 🦋

🎀 NAME 🎀

IO::Uncompress::Inflate — read RFC 1950 files/buffers, no cap 💅

---

✨ 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 🌈

so, this module hands you a Perl interface that lets you read files and buffers that conform to RFC 1950. that's the whole vibe 🫶

and if you're trying to write RFC 1950 files/buffers instead? that's a whole different bestie — go check out the companion module IO::Compress::Deflate ✨

🧚 Functional Interface 🧚

there's a top-level function called inflate that does the "one-shot" uncompression thing between buffers and/or files. it's giving grab-and-go. but if you want finer control over the uncompression process, skip on down to the "OO Interface" section, iykyk.

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

    inflate $input_filename_or_reference => $output_filename_or_reference [,OPTS]
        or die "inflate failed: $InflateError\n";

lowkey important: the functional interface needs Perl5.005 or better. no old-perl slander, it's just the rules 💀

💅 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 — plus zero or more optional parameters (peep "Optional Parameters" for those).

The $input_filename_or_reference parameter

this parameter, $input_filename_or_reference, is what tells us where the compressed data is coming from. it can take one of the following forms:

• A filename — if $input_filename_or_reference is a simple scalar, we assume it's a filename. the file gets opened for reading and the input data gets read from it. classic.
• A filehandle — if $input_filename_or_reference is a filehandle, the input data is read from it. and bestie, 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 gets read from $$input_filename_or_reference.
• An array reference — if $input_filename_or_reference is an array reference, every element in the array has to be a filename. the input data gets read from each file in turn. and before anything gets uncompressed, the complete array gets walked to make sure it only contains valid filenames. safety first, no cap 🛡️
• An Input FileGlob string — if $input_filename_or_reference is a string delimited by the characters < and >, then inflate assumes it's an input fileglob string. the input is the list of files that match the fileglob. see File::GlobMapper for more deets.

and if $input_filename_or_reference is literally any other type? then undef gets returned. that's it, that's the whole story 😭

The $output_filename_or_reference parameter

the parameter $output_filename_or_reference controls where the uncompressed data lands. it takes one of these forms:

• A filename — if $output_filename_or_reference is a simple scalar, it's assumed to be a filename. the file gets opened for writing and the uncompressed data gets written to it.
• A filehandle — if $output_filename_or_reference is a filehandle, the uncompressed data gets 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 gets stored in $$output_filename_or_reference.
• An Array Reference — if $output_filename_or_reference is an array reference, the uncompressed data gets pushed onto the array 📚
• An Output FileGlob — if $output_filename_or_reference is a string delimited by the characters < and >, then inflate assumes it's 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, periodt.

see File::GlobMapper for more details.

and if $output_filename_or_reference is any other type, undef will be returned. same energy as before 💀

🍓 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. one big smoothie of data 🥤

👑 Optional Parameters 👑

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

• "AutoClose => 0|1" — this one applies to any input or output data streams handed to inflate that are filehandles. if "AutoClose" is specified and the value is true, it results 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 one depends on the type of output data stream. so, like, three flavours:
  • A Buffer — if "Append" is enabled, all uncompressed data gets appended to the end of the output buffer. otherwise the output buffer gets cleared before any uncompressed data is written to it.
  • A Filename — if "Append" is enabled, the file gets opened in append mode. otherwise the contents of the file, if any, get truncated before any uncompressed data is written to it.
  • A Filehandle — if "Append" is enabled, the filehandle gets 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 appends all uncompressed data to the output data stream. so when the output is a filehandle it carries out a seek to the eof before writing any uncompressed data. if the output is a filename, it gets opened for appending. if the output is a buffer, all uncompressed data gets appended to the existing buffer 🫶

conversely, when "Append" is not specified — or it's present and set to false — it operates like this: when the output is a filename, it truncates the contents of the file before writing any uncompressed data. if the output is a filehandle, its position is not changed. if the output is a buffer, it gets 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 uncompresses the whole lot as a single data stream. defaults to 0.
• "TrailingData => $scalar" — returns the data, if any, that's present immediately after the compressed data stream once uncompression is complete. this option is your girl when there's useful info sitting right after the compressed data stream and you don't know the length of the compressed data stream.

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 that's 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 know the length of the compressed data stream before you start uncompressing, you can dodge having to use "trailingData" by setting the "InputLength" option. work smarter 💅

🌟 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 💅

okay bestie, now we're doing the object-oriented era. same module, but make it fashion. ✨

Constructor 🧚

Here's the format of the constructor for IO::Uncompress::Inflate, and yes, it's giving main character:

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

The constructor takes one mandatory parameter, $input, defined below, and zero or more OPTS, defined in "Constructor Options".

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. 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.

           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.

• 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 bestie, this is the main event — the actual methods you'll be calling on your $z object. buckle up 🎀

read

Usage is

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

So this one reads a block of compressed data — and the size of that block is determined by the Buffer option you set back in the constructor, remember? — then it uncompresses it and writes any uncompressed data into $buffer. If you set the Append parameter in the constructor, that uncompressed data gets appended to whatever's already in $buffer. Otherwise $buffer gets overwritten. no cap. 💖

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)

Yep, there are two read forms — iconic of it honestly. This one attempts 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 where it won't are 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. simple as that, and yet so powerful ✨

This method fully supports using the variable $/ (or $INPUT_RECORD_SEPARATOR, or $RS when English is in use) to determine what counts as an end of line. Paragraph mode, record mode and file slurp mode are all supported. she does it all 💅

---

getc

Usage is

$char = $z->getc()

Read a single character. one (1) character. that's the whole vibe. 🎀

---

getc

wait no, that was getc, this one's the sequel:

ungetc

Usage is

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

yeah that's it, that's the whole entry. i'm not gonna invent lore for it bestie 🙈

---

inflateSync

Usage is

$status = $z->inflateSync()

TODO — literally, that's what the docs say. TODO. iconic documentation moment ngl 😭💀

---

getHeaderInfo

Usage is

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

This method returns either a hash reference (in scalar context) or a list of hash references (in array context) that contains info about each of the header fields in the compressed data stream(s). so if you're a nosy bestie who wants the receipts on the headers, this is your girl 📋✨

---

tell

Usage is

$z->tell()
tell $z

Returns the uncompressed file offset. where are you in the *un*compressed world? this tells you. 🧚

---

eof

Usage is

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

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. 💀 so don't. seriously.

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 of 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. she's just standing there. serving looks. contributing nothing. still valid. 💅

---

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 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. just so you know. iykyk.

---

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. (yes, those are two different things, she contains multitudes 🦋)

The contents of $/ are used to determine what constitutes a line terminator.

---

fileno

$z->fileno()
fileno($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.

---

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 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. do it yourself bestie, be your own safety net 🫶

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.

---

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. like, timing matters, okay? ⏰✨

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. just don't 🙈

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 IO::Uncompress::Inflate at present. (she's low maintenance 💅)

• :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 📚 (go read it, it's good for you)

---

🫶 SUPPORT

General feedback/questions/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>.

they want to hear from you fr fr, don't be shy 💖

---

👑 SEE ALSO

Compress::Zlib, IO::Compress::Gzip, IO::Uncompress::Gunzip, IO::Compress::Deflate, IO::Compress::RawDeflate, IO::Uncompress::RawInflate, IO::Compress::Bzip2, IO::Uncompress::Bunzip2, IO::Compress::Lzma, IO::Uncompress::UnLzma, IO::Compress::Xz, IO::Uncompress::UnXz, IO::Compress::Lzip, IO::Uncompress::UnLzip, IO::Compress::Lzop, IO::Uncompress::UnLzop, IO::Compress::Lzf, IO::Uncompress::UnLzf, IO::Compress::Zstd, IO::Uncompress::UnZstd, IO::Uncompress::AnyInflate, IO::Uncompress::AnyUncompress

IO::Compress::FAQ

File::GlobMapper, Archive::Zip, Archive::Tar, IO::Zlib

For RFC 1950, 1951 and 1952 see <https://datatracker.ietf.org/doc/html/rfc1950>, <https://datatracker.ietf.org/doc/html/rfc1951> and <https://datatracker.ietf.org/doc/html/rfc1952>

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 the zlib-ng compression library is <https://github.com/zlib-ng/zlib-ng>.

The primary site for gzip is <http://www.gzip.org>.

---

🌸 AUTHOR

This module was written by Paul Marquess, pmqs@cpan.org. 🫡 absolute icon, thank you for your service

---

📜 MODIFICATION HISTORY

See the Changes file. 📝

---

💜 COPYRIGHT AND LICENSE

Copyright (c) 2005-2026 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.

---

and that's a wrap bestie!! 🎀✨ this was perl v5.44.0, dated 2026-10-17, serving IO::Un...Inflate(3perl) realness. go forth and inflate your little heart out, you've got this 💖🦋💅