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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 = new IO::Uncompress::Inflate $input [OPTS]
               or die "inflate failed: $InflateError\n";

           $status = $z->read($buffer)
           $status = $z->read($buffer, $length)
           $status = $z->read($buffer, $length, $offset)
           $line = $z->getline()
           $char = $z->getc()
           $char = $z->ungetc()
           $char = $z->opened()

           $status = $z->inflateSync()

           $data = $z->trailingData()
           $status = $z->nextStream()
           $data = $z->getHeaderInfo()
           $z->tell()
           $z->seek($position, $whence)
           $z->binmode()
           $z->fileno()
           $z->eof()
           $z->close()

           $InflateError ;

           # IO::File mode

           <$z>
           read($z, $buffer);
           read($z, $buffer, $length);
           read($z, $buffer, $length, $offset);
           tell($z)
           seek($z, $position, $whence)
           binmode($z)
           fileno($z)
           eof($z)
           close($z)

DESCRIPTION

       This module provides a Perl interface that allows the reading of files/buffers that
       conform to RFC 1950.

       For writing RFC 1950 files/buffers, see the companion module IO::Compress::Deflate.

Functional Interface

       A top-level function, "inflate", is provided to carry out "one-shot" uncompression between
       buffers and/or files. For finer control over the uncompression process, see the "OO
       Interface" section.

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

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

       The functional interface needs Perl5.005 or better.

   inflate $input_filename_or_reference => $output_filename_or_reference [, OPTS]
       "inflate" expects at least two parameters, $input_filename_or_reference and
       $output_filename_or_reference.

       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.

   Optional Parameters
       Unless specified below, the optional parameters for "inflate", "OPTS", are the same as
       those used with the OO interface defined in the "Constructor Options" section below.

       "AutoClose => 0|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"
            When writing to a file or filehandle, set "binmode" before writing to the file.

            Defaults to 0.

       "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.

   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 = new IO::File "<file1.txt.1950"
               or die "Cannot open 'file1.txt.1950': $!\n" ;
           my $buffer ;
           inflate $input => \$buffer
               or die "inflate failed: $InflateError\n";

       To uncompress all files in the directory "/my/home" that match "*.txt.1950" and store the
       compressed data in the same directory

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

           inflate '</my/home/*.txt.1950>' => '</my/home/#1.txt>'
               or die "inflate failed: $InflateError\n";

       and if you want to compress each file one at a time, this will do the trick

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

           for my $input ( glob "/my/home/*.txt.1950" )
           {
               my $output = $input;
               $output =~ s/.1950// ;
               inflate $input => $output
                   or die "Error compressing '$input': $InflateError\n";
           }

OO Interface

   Constructor
       The format of the constructor for IO::Uncompress::Inflate is shown below

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

       Returns an "IO::Uncompress::Inflate" object on success and undef on failure.  The variable
       $InflateError will contain an error message on failure.

       If you are running Perl 5.005 or better the object, $z, returned from
       IO::Uncompress::Inflate can be used exactly like an IO::File filehandle.  This means that
       all normal input file operations can be carried out with $z.  For example, to read a line
       from a compressed file/buffer you can use either of these forms

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

       The mandatory parameter $input is used to determine the source of the compressed data.
       This parameter can take one of three forms.

       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.

   Examples
       TODO

Methods

   read
       Usage is

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

       Reads a block of compressed data (the size of the compressed block is determined by the
       "Buffer" option in the constructor), uncompresses it and writes any uncompressed data into
       $buffer. If the "Append" parameter is set in the constructor, the uncompressed data will
       be appended to the $buffer parameter. Otherwise $buffer will be overwritten.

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

   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 the variable $/ (or $INPUT_RECORD_SEPARATOR or $RS
       when "English" is in use) to determine what constitutes an end of line. Paragraph mode,
       record mode and file slurp mode are all supported.

   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);

       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.

       Note that the implementation of "seek" in this module does not provide true random access
       to a compressed file/buffer. It  works by uncompressing data from the current offset in
       the file/buffer until it reaches the uncompressed offset specified in the parameters to
       "seek". For very small files this may be acceptable behaviour. For large files it may
       cause an unacceptable delay.

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

       Returns 1 on success, 0 on failure.

   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.

   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 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.

       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.

       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::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

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::Lzop, IO::Uncompress::UnLzop, IO::Compress::Lzf,
       IO::Uncompress::UnLzf, 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@prep.ai.mit.edu" and
       Mark Adler "madler@alumni.caltech.edu".

       The primary site for the zlib compression library is <http://www.zlib.org>.

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

AUTHOR

       This module was written by Paul Marquess, "pmqs@cpan.org".

MODIFICATION HISTORY

       See the Changes file.

COPYRIGHT AND LICENSE

       Copyright (c) 2005-2017 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.