Compress::Zlib - phpMan

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NAME
    Compress::Zlib - Interface to zlib compression library

SYNOPSIS
        use Compress::Zlib ;

        ($d, $status) = deflateInit( [OPT] ) ;
        $status = $d->deflate($input, $output) ;
        $status = $d->flush([$flush_type]) ;
        $d->deflateParams(OPTS) ;
        $d->deflateTune(OPTS) ;
        $d->dict_adler() ;
        $d->crc32() ;
        $d->adler32() ;
        $d->total_in() ;
        $d->total_out() ;
        $d->msg() ;
        $d->get_Strategy();
        $d->get_Level();
        $d->get_BufSize();

        ($i, $status) = inflateInit( [OPT] ) ;
        $status = $i->inflate($input, $output [, $eof]) ;
        $status = $i->inflateSync($input) ;
        $i->dict_adler() ;
        $d->crc32() ;
        $d->adler32() ;
        $i->total_in() ;
        $i->total_out() ;
        $i->msg() ;
        $d->get_BufSize();

        $dest = compress($source) ;
        $dest = uncompress($source) ;

        $gz = gzopen($filename or filehandle, $mode) ;
        $bytesread = $gz->gzread($buffer [,$size]) ;
        $bytesread = $gz->gzreadline($line) ;
        $byteswritten = $gz->gzwrite($buffer) ;
        $status = $gz->gzflush($flush) ;
        $offset = $gz->gztell() ;
        $status = $gz->gzseek($offset, $whence) ;
        $status = $gz->gzclose() ;
        $status = $gz->gzeof() ;
        $status = $gz->gzsetparams($level, $strategy) ;
        $errstring = $gz->gzerror() ;
        $gzerrno

        $dest = Compress::Zlib::memGzip($buffer) ;
        $dest = Compress::Zlib::memGunzip($buffer) ;

        $crc = adler32($buffer [,$crc]) ;
        $crc = crc32($buffer [,$crc]) ;

        $crc = crc32_combine($crc1, $crc2, $len2);
        $adler = adler32_combine($adler1, $adler2, $len2);

        my $version = Compress::Raw::Zlib::zlib_version();

DESCRIPTION
    The *Compress::Zlib* module provides a Perl interface to the *zlib*
    compression library (see "AUTHOR" for details about where to get
    *zlib*).

    The "Compress::Zlib" module can be split into two general areas of
    functionality, namely a simple read/write interface to *gzip* files and
    a low-level in-memory compression/decompression interface.

    Each of these areas will be discussed in the following sections.

  Notes for users of Compress::Zlib version 1
    The main change in "Compress::Zlib" version 2.x is that it does not now
    interface directly to the zlib library. Instead it uses the
    "IO::Compress::Gzip" and "IO::Uncompress::Gunzip" modules for
    reading/writing gzip files, and the "Compress::Raw::Zlib" module for
    some low-level zlib access.

    The interface provided by version 2 of this module should be 100%
    backward compatible with version 1. If you find a difference in the
    expected behaviour please contact the author (See "AUTHOR"). See "GZIP
    INTERFACE"

    With the creation of the "IO::Compress" and "IO::Uncompress" modules no
    new features are planned for "Compress::Zlib" - the new modules do
    everything that "Compress::Zlib" does and then some. Development on
    "Compress::Zlib" will be limited to bug fixes only.

    If you are writing new code, your first port of call should be one of
    the new "IO::Compress" or "IO::Uncompress" modules.

GZIP INTERFACE
    A number of functions are supplied in *zlib* for reading and writing
    *gzip* files that conform to RFC 1952. This module provides an interface
    to most of them.

    If you have previously used "Compress::Zlib" 1.x, the following
    enhancements/changes have been made to the "gzopen" interface:

    1    If you want to open either STDIN or STDOUT with "gzopen", you can
         now optionally use the special filename ""-"" as a synonym for
         "\*STDIN" and "\*STDOUT".

    2    In "Compress::Zlib" version 1.x, "gzopen" used the zlib library to
         open the underlying file. This made things especially tricky when a
         Perl filehandle was passed to "gzopen". Behind the scenes the
         numeric C file descriptor had to be extracted from the Perl
         filehandle and this passed to the zlib library.

         Apart from being non-portable to some operating systems, this made
         it difficult to use "gzopen" in situations where you wanted to
         extract/create a gzip data stream that is embedded in a larger
         file, without having to resort to opening and closing the file
         multiple times.

         It also made it impossible to pass a perl filehandle that wasn't
         associated with a real filesystem file, like, say, an "IO::String".

         In "Compress::Zlib" version 2.x, the "gzopen" interface has been
         completely rewritten to use the IO::Compress::Gzip for writing gzip
         files and IO::Uncompress::Gunzip for reading gzip files. None of
         the limitations mentioned above apply.

    3    Addition of "gzseek" to provide a restricted "seek" interface.

    4.   Added "gztell".

    A more complete and flexible interface for reading/writing gzip
    files/buffers is included with the module "IO-Compress-Zlib". See
    IO::Compress::Gzip and IO::Uncompress::Gunzip for more details.

    $gz = gzopen($filename, $mode)
    $gz = gzopen($filehandle, $mode)
         This function opens either the *gzip* file $filename for reading or
         writing or attaches to the opened filehandle, $filehandle. It
         returns an object on success and "undef" on failure.

         When writing a gzip file this interface will *always* create the
         smallest possible gzip header (exactly 10 bytes). If you want
         greater control over what gets stored in the gzip header (like the
         original filename or a comment) use IO::Compress::Gzip instead.
         Similarly if you want to read the contents of the gzip header use
         IO::Uncompress::Gunzip.

         The second parameter, $mode, is used to specify whether the file is
         opened for reading or writing and to optionally specify a
         compression level and compression strategy when writing. The format
         of the $mode parameter is similar to the mode parameter to the 'C'
         function "fopen", so "rb" is used to open for reading, "wb" for
         writing and "ab" for appending (writing at the end of the file).

         To specify a compression level when writing, append a digit between
         0 and 9 to the mode string -- 0 means no compression and 9 means
         maximum compression. If no compression level is specified
         Z_DEFAULT_COMPRESSION is used.

         To specify the compression strategy when writing, append 'f' for
         filtered data, 'h' for Huffman only compression, or 'R' for
         run-length encoding. If no strategy is specified Z_DEFAULT_STRATEGY
         is used.

         So, for example, "wb9" means open for writing with the maximum
         compression using the default strategy and "wb4R" means open for
         writing with compression level 4 and run-length encoding.

         Refer to the *zlib* documentation for the exact format of the $mode
         parameter.

    $bytesread = $gz->gzread($buffer [, $size]) ;
         Reads $size bytes from the compressed file into $buffer. If $size
         is not specified, it will default to 4096. If the scalar $buffer is
         not large enough, it will be extended automatically.

         Returns the number of bytes actually read. On EOF it returns 0 and
         in the case of an error, -1.

    $bytesread = $gz->gzreadline($line) ;
         Reads the next line from the compressed file into $line.

         Returns the number of bytes actually read. On EOF it returns 0 and
         in the case of an error, -1.

         It is legal to intermix calls to "gzread" and "gzreadline".

         To maintain backward compatibility with version 1.x of this module
         "gzreadline" ignores the $/ variable - it *always* uses the string
         "\n" as the line delimiter.

         If you want to read a gzip file a line at a time and have it
         respect the $/ variable (or $INPUT_RECORD_SEPARATOR, or $RS when
         "English" is in use) see IO::Uncompress::Gunzip.

    $byteswritten = $gz->gzwrite($buffer) ;
         Writes the contents of $buffer to the compressed file. Returns the
         number of bytes actually written, or 0 on error.

    $status = $gz->gzflush($flush_type) ;
         Flushes all pending output into the compressed file.

         This method takes an optional parameter, $flush_type, that controls
         how the flushing will be carried out. By default the $flush_type
         used is "Z_FINISH". Other valid values for $flush_type are
         "Z_NO_FLUSH", "Z_SYNC_FLUSH", "Z_FULL_FLUSH" and "Z_BLOCK". It is
         strongly recommended that you only set the "flush_type" parameter
         if you fully understand the implications of what it does - overuse
         of "flush" can seriously degrade the level of compression achieved.
         See the "zlib" documentation for details.

         Returns 0 on success.

    $offset = $gz->gztell() ;
         Returns the uncompressed file offset.

    $status = $gz->gzseek($offset, $whence) ;
         Provides a sub-set of the "seek" functionality, with the
         restriction that it is only legal to seek forward in the compressed
         file. It is a fatal error to attempt to seek backward.

         When opened for writing, empty parts of the file will have NULL
         (0x00) bytes written to them.

         The $whence parameter should be one of SEEK_SET, SEEK_CUR or
         SEEK_END.

         Returns 1 on success, 0 on failure.

    $gz->gzclose
         Closes the compressed file. Any pending data is flushed to the file
         before it is closed.

         Returns 0 on success.

    $gz->gzsetparams($level, $strategy
         Change settings for the deflate stream $gz.

         The list of the valid options is shown below. Options not specified
         will remain unchanged.

         Note: This method is only available if you are running zlib 1.0.6
         or better.

         $level
              Defines the compression level. Valid values are 0 through 9,
              "Z_NO_COMPRESSION", "Z_BEST_SPEED", "Z_BEST_COMPRESSION", and
              "Z_DEFAULT_COMPRESSION".

         $strategy
              Defines the strategy used to tune the compression. The valid
              values are "Z_DEFAULT_STRATEGY", "Z_FILTERED" and
              "Z_HUFFMAN_ONLY".

    $gz->gzerror
         Returns the *zlib* error message or number for the last operation
         associated with $gz. The return value will be the *zlib* error
         number when used in a numeric context and the *zlib* error message
         when used in a string context. The *zlib* error number constants,
         shown below, are available for use.

             Z_OK
             Z_STREAM_END
             Z_ERRNO
             Z_STREAM_ERROR
             Z_DATA_ERROR
             Z_MEM_ERROR
             Z_BUF_ERROR

    $gzerrno
         The $gzerrno scalar holds the error code associated with the most
         recent *gzip* routine. Note that unlike "gzerror()", the error is
         *not* associated with a particular file.

         As with "gzerror()" it returns an error number in numeric context
         and an error message in string context. Unlike "gzerror()" though,
         the error message will correspond to the *zlib* message when the
         error is associated with *zlib* itself, or the UNIX error message
         when it is not (i.e. *zlib* returned "Z_ERRORNO").

         As there is an overlap between the error numbers used by *zlib* and
         UNIX, $gzerrno should only be used to check for the presence of
         *an* error in numeric context. Use "gzerror()" to check for
         specific *zlib* errors. The *gzcat* example below shows how the
         variable can be used safely.

  Examples
    Here is an example script which uses the interface. It implements a
    *gzcat* function.

        use strict ;
        use warnings ;

        use Compress::Zlib ;

        # use stdin if no files supplied
        @ARGV = '-' unless @ARGV ;

        foreach my $file (@ARGV) {
            my $buffer ;

            my $gz = gzopen($file, "rb")
                 or die "Cannot open $file: $gzerrno\n" ;

            print $buffer while $gz->gzread($buffer) > 0 ;

            die "Error reading from $file: $gzerrno" . ($gzerrno+0) . "\n"
                if $gzerrno != Z_STREAM_END ;

            $gz->gzclose() ;
        }

    Below is a script which makes use of "gzreadline". It implements a very
    simple *grep* like script.

        use strict ;
        use warnings ;

        use Compress::Zlib ;

        die "Usage: gzgrep pattern [file...]\n"
            unless @ARGV >= 1;

        my $pattern = shift ;

        # use stdin if no files supplied
        @ARGV = '-' unless @ARGV ;

        foreach my $file (@ARGV) {
            my $gz = gzopen($file, "rb")
                 or die "Cannot open $file: $gzerrno\n" ;

            while ($gz->gzreadline($_) > 0) {
                print if /$pattern/ ;
            }

            die "Error reading from $file: $gzerrno\n"
                if $gzerrno != Z_STREAM_END ;

            $gz->gzclose() ;
        }

    This script, *gzstream*, does the opposite of the *gzcat* script above.
    It reads from standard input and writes a gzip data stream to standard
    output.

        use strict ;
        use warnings ;

        use Compress::Zlib ;

        binmode STDOUT;  # gzopen only sets it on the fd

        my $gz = gzopen(\*STDOUT, "wb")
              or die "Cannot open stdout: $gzerrno\n" ;

        while (<>) {
            $gz->gzwrite($_)
              or die "error writing: $gzerrno\n" ;
        }

        $gz->gzclose ;

  Compress::Zlib::memGzip
    This function is used to create an in-memory gzip file with the minimum
    possible gzip header (exactly 10 bytes).

        $dest = Compress::Zlib::memGzip($buffer)
            or die "Cannot compress: $gzerrno\n";

    If successful, it returns the in-memory gzip file. Otherwise it returns
    "undef" and the $gzerrno variable will store the zlib error code.

    The $buffer parameter can either be a scalar or a scalar reference.

    See IO::Compress::Gzip for an alternative way to carry out in-memory
    gzip compression.

  Compress::Zlib::memGunzip
    This function is used to uncompress an in-memory gzip file.

        $dest = Compress::Zlib::memGunzip($buffer)
            or die "Cannot uncompress: $gzerrno\n";

    If successful, it returns the uncompressed gzip file. Otherwise it
    returns "undef" and the $gzerrno variable will store the zlib error
    code.

    The $buffer parameter can either be a scalar or a scalar reference. The
    contents of the $buffer parameter are destroyed after calling this
    function.

    If $buffer consists of multiple concatenated gzip data streams only the
    first will be uncompressed. Use "gunzip" with the "MultiStream" option
    in the "IO::Uncompress::Gunzip" module if you need to deal with
    concatenated data streams.

    See IO::Uncompress::Gunzip for an alternative way to carry out in-memory
    gzip uncompression.

COMPRESS/UNCOMPRESS
    Two functions are provided to perform in-memory
    compression/uncompression of RFC 1950 data streams. They are called
    "compress" and "uncompress".

    $dest = compress($source [, $level] ) ;
         Compresses $source. If successful it returns the compressed data.
         Otherwise it returns *undef*.

         The source buffer, $source, can either be a scalar or a scalar
         reference.

         The $level parameter defines the compression level. Valid values
         are 0 through 9, "Z_NO_COMPRESSION", "Z_BEST_SPEED",
         "Z_BEST_COMPRESSION", and "Z_DEFAULT_COMPRESSION". If $level is not
         specified "Z_DEFAULT_COMPRESSION" will be used.

    $dest = uncompress($source) ;
         Uncompresses $source. If successful it returns the uncompressed
         data. Otherwise it returns *undef*.

         The source buffer can either be a scalar or a scalar reference.

    Please note: the two functions defined above are *not* compatible with
    the Unix commands of the same name.

    See IO::Deflate and IO::Inflate included with this distribution for an
    alternative interface for reading/writing RFC 1950 files/buffers.

Deflate Interface
    This section defines an interface that allows in-memory compression
    using the *deflate* interface provided by zlib.

    Here is a definition of the interface available:

  ($d, $status) = deflateInit( [OPT] )
    Initialises a deflation stream.

    It combines the features of the *zlib* functions "deflateInit",
    "deflateInit2" and "deflateSetDictionary".

    If successful, it will return the initialised deflation stream, $d and
    $status of "Z_OK" in a list context. In scalar context it returns the
    deflation stream, $d, only.

    If not successful, the returned deflation stream ($d) will be *undef*
    and $status will hold the exact *zlib* error code.

    The function optionally takes a number of named options specified as
    "-Name=>value" pairs. This allows individual options to be tailored
    without having to specify them all in the parameter list.

    For backward compatibility, it is also possible to pass the parameters
    as a reference to a hash containing the name=>value pairs.

    The function takes one optional parameter, a reference to a hash. The
    contents of the hash allow the deflation interface to be tailored.

    Here is a list of the valid options:

    -Level
         Defines the compression level. Valid values are 0 through 9,
         "Z_NO_COMPRESSION", "Z_BEST_SPEED", "Z_BEST_COMPRESSION", and
         "Z_DEFAULT_COMPRESSION".

         The default is Z_DEFAULT_COMPRESSION.

    -Method
         Defines the compression method. The only valid value at present
         (and the default) is Z_DEFLATED.

    -WindowBits
         To create an RFC 1950 data stream, set "WindowBits" to a positive
         number.

         To create an RFC 1951 data stream, set "WindowBits" to
         "-MAX_WBITS".

         For a full definition of the meaning and valid values for
         "WindowBits" refer to the *zlib* documentation for *deflateInit2*.

         Defaults to MAX_WBITS.

    -MemLevel
         For a definition of the meaning and valid values for "MemLevel"
         refer to the *zlib* documentation for *deflateInit2*.

         Defaults to MAX_MEM_LEVEL.

    -Strategy
         Defines the strategy used to tune the compression. The valid values
         are "Z_DEFAULT_STRATEGY", "Z_FILTERED" and "Z_HUFFMAN_ONLY".

         The default is Z_DEFAULT_STRATEGY.

    -Dictionary
         When a dictionary is specified *Compress::Zlib* will automatically
         call "deflateSetDictionary" directly after calling "deflateInit".
         The Adler32 value for the dictionary can be obtained by calling the
         method "$d->dict_adler()".

         The default is no dictionary.

    -Bufsize
         Sets the initial size for the deflation buffer. If the buffer has
         to be reallocated to increase the size, it will grow in increments
         of "Bufsize".

         The default is 4096.

    Here is an example of using the "deflateInit" optional parameter list to
    override the default buffer size and compression level. All other
    options will take their default values.

        deflateInit( -Bufsize => 300,
                     -Level => Z_BEST_SPEED  ) ;

  ($out, $status) = $d->deflate($buffer)
    Deflates the contents of $buffer. The buffer can either be a scalar or a
    scalar reference. When finished, $buffer will be completely processed
    (assuming there were no errors). If the deflation was successful it
    returns the deflated output, $out, and a status value, $status, of
    "Z_OK".

    On error, $out will be *undef* and $status will contain the *zlib* error
    code.

    In a scalar context "deflate" will return $out only.

    As with the *deflate* function in *zlib*, it is not necessarily the case
    that any output will be produced by this method. So don't rely on the
    fact that $out is empty for an error test.

  ($out, $status) = $d->flush()
=head2 ($out, $status) = $d->flush($flush_type)
    Typically used to finish the deflation. Any pending output will be
    returned via $out. $status will have a value "Z_OK" if successful.

    In a scalar context "flush" will return $out only.

    Note that flushing can seriously degrade the compression ratio, so it
    should only be used to terminate a decompression (using "Z_FINISH") or
    when you want to create a *full flush point* (using "Z_FULL_FLUSH").

    By default the "flush_type" used is "Z_FINISH". Other valid values for
    "flush_type" are "Z_NO_FLUSH", "Z_PARTIAL_FLUSH", "Z_SYNC_FLUSH" and
    "Z_FULL_FLUSH". It is strongly recommended that you only set the
    "flush_type" parameter if you fully understand the implications of what
    it does. See the "zlib" documentation for details.

  $status = $d->deflateParams([OPT])
    Change settings for the deflate stream $d.

    The list of the valid options is shown below. Options not specified will
    remain unchanged.

    -Level
         Defines the compression level. Valid values are 0 through 9,
         "Z_NO_COMPRESSION", "Z_BEST_SPEED", "Z_BEST_COMPRESSION", and
         "Z_DEFAULT_COMPRESSION".

    -Strategy
         Defines the strategy used to tune the compression. The valid values
         are "Z_DEFAULT_STRATEGY", "Z_FILTERED" and "Z_HUFFMAN_ONLY".

  $d->dict_adler()
    Returns the adler32 value for the dictionary.

  $d->msg()
    Returns the last error message generated by zlib.

  $d->total_in()
    Returns the total number of bytes uncompressed bytes input to deflate.

  $d->total_out()
    Returns the total number of compressed bytes output from deflate.

  Example
    Here is a trivial example of using "deflate". It simply reads standard
    input, deflates it and writes it to standard output.

        use strict ;
        use warnings ;

        use Compress::Zlib ;

        binmode STDIN;
        binmode STDOUT;
        my $x = deflateInit()
           or die "Cannot create a deflation stream\n" ;

        my ($output, $status) ;
        while (<>)
        {
            ($output, $status) = $x->deflate($_) ;

            $status == Z_OK
                or die "deflation failed\n" ;

            print $output ;
        }

        ($output, $status) = $x->flush() ;

        $status == Z_OK
            or die "deflation failed\n" ;

        print $output ;

Inflate Interface
    This section defines the interface available that allows in-memory
    uncompression using the *deflate* interface provided by zlib.

    Here is a definition of the interface:

  ($i, $status) = inflateInit()
    Initialises an inflation stream.

    In a list context it returns the inflation stream, $i, and the *zlib*
    status code in $status. In a scalar context it returns the inflation
    stream only.

    If successful, $i will hold the inflation stream and $status will be
    "Z_OK".

    If not successful, $i will be *undef* and $status will hold the *zlib*
    error code.

    The function optionally takes a number of named options specified as
    "-Name=>value" pairs. This allows individual options to be tailored
    without having to specify them all in the parameter list.

    For backward compatibility, it is also possible to pass the parameters
    as a reference to a hash containing the name=>value pairs.

    The function takes one optional parameter, a reference to a hash. The
    contents of the hash allow the deflation interface to be tailored.

    Here is a list of the valid options:

    -WindowBits
         To uncompress an RFC 1950 data stream, set "WindowBits" to a
         positive number.

         To uncompress an RFC 1951 data stream, set "WindowBits" to
         "-MAX_WBITS".

         For a full definition of the meaning and valid values for
         "WindowBits" refer to the *zlib* documentation for *inflateInit2*.

         Defaults to MAX_WBITS.

    -Bufsize
         Sets the initial size for the inflation buffer. If the buffer has
         to be reallocated to increase the size, it will grow in increments
         of "Bufsize".

         Default is 4096.

    -Dictionary
         The default is no dictionary.

    Here is an example of using the "inflateInit" optional parameter to
    override the default buffer size.

        inflateInit( -Bufsize => 300 ) ;

  ($out, $status) = $i->inflate($buffer)
    Inflates the complete contents of $buffer. The buffer can either be a
    scalar or a scalar reference.

    Returns "Z_OK" if successful and "Z_STREAM_END" if the end of the
    compressed data has been successfully reached. If not successful, $out
    will be *undef* and $status will hold the *zlib* error code.

    The $buffer parameter is modified by "inflate". On completion it will
    contain what remains of the input buffer after inflation. This means
    that $buffer will be an empty string when the return status is "Z_OK".
    When the return status is "Z_STREAM_END" the $buffer parameter will
    contains what (if anything) was stored in the input buffer after the
    deflated data stream.

    This feature is useful when processing a file format that encapsulates a
    compressed data stream (e.g. gzip, zip).

  $status = $i->inflateSync($buffer)
    Scans $buffer until it reaches either a *full flush point* or the end of
    the buffer.

    If a *full flush point* is found, "Z_OK" is returned and $buffer will be
    have all data up to the flush point removed. This can then be passed to
    the "deflate" method.

    Any other return code means that a flush point was not found. If more
    data is available, "inflateSync" can be called repeatedly with more
    compressed data until the flush point is found.

  $i->dict_adler()
    Returns the adler32 value for the dictionary.

  $i->msg()
    Returns the last error message generated by zlib.

  $i->total_in()
    Returns the total number of bytes compressed bytes input to inflate.

  $i->total_out()
    Returns the total number of uncompressed bytes output from inflate.

  Example
    Here is an example of using "inflate".

        use strict ;
        use warnings ;

        use Compress::Zlib ;

        my $x = inflateInit()
           or die "Cannot create a inflation stream\n" ;

        my $input = '' ;
        binmode STDIN;
        binmode STDOUT;

        my ($output, $status) ;
        while (read(STDIN, $input, 4096))
        {
            ($output, $status) = $x->inflate(\$input) ;

            print $output
                if $status == Z_OK or $status == Z_STREAM_END ;

            last if $status != Z_OK ;
        }

        die "inflation failed\n"
            unless $status == Z_STREAM_END ;

CHECKSUM FUNCTIONS
    Two functions are provided by *zlib* to calculate checksums. For the
    Perl interface, the order of the two parameters in both functions has
    been reversed. This allows both running checksums and one off
    calculations to be done.

        $crc = adler32($buffer [,$crc]) ;
        $crc = crc32($buffer [,$crc]) ;

    The buffer parameters can either be a scalar or a scalar reference.

    If the $crc parameters is "undef", the crc value will be reset.

    If you have built this module with zlib 1.2.3 or better, two more
    CRC-related functions are available.

        $crc = crc32_combine($crc1, $crc2, $len2);
        $adler = adler32_combine($adler1, $adler2, $len2);

    These functions allow checksums to be merged. Refer to the *zlib*
    documentation for more details.

Misc
  my $version = Compress::Zlib::zlib_version();
    Returns the version of the zlib library.

CONSTANTS
    All the *zlib* constants are automatically imported when you make use of
    *Compress::Zlib*.

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>.

SEE ALSO
    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::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 <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 AT prep.edu" and Mark Adler "madler AT alumni.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, "pmqs AT cpan.org".

MODIFICATION HISTORY
    See the Changes file.

COPYRIGHT AND LICENSE
    Copyright (c) 1995-2021 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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