[ViewVC] Annotation of: cvs/Convert-UUlib/README

NAME
    Convert::UUlib - Perl interface to the uulib library (a.k.a.
    uudeview/uuenview).

SYNOPSIS
     use Convert::UUlib ':all';
 
     # read all the files named on the commandline and decode them
     # into the CURRENT directory. See below for a longer example.
     LoadFile $_ for @ARGV;

     for my $uu (GetFileList) {
        if ($uu->state & FILE_OK) {
          $uu->decode;
          print $uu->filename, "\n";
        }
     }

DESCRIPTION
    Read the file doc/library.pdf from the distribution for in-depth
    information about the C-library used in this interface, and the rest of
    this document and especially the non-trivial decoder program at the end.

EXPORTED CONSTANTS
  Action code constants
      ACT_IDLE      we don't do anything
      ACT_SCANNING  scanning an input file
      ACT_DECODING  decoding into a temp file
      ACT_COPYING   copying temp to target
      ACT_ENCODING  encoding a file

  Message severity levels
      MSG_MESSAGE   just a message, nothing important
      MSG_NOTE      something that should be noticed
      MSG_WARNING   important msg, processing continues
      MSG_ERROR     processing has been terminated
      MSG_FATAL     decoder cannot process further requests
      MSG_PANIC     recovery impossible, app must terminate

  Options
      OPT_VERSION   version number MAJOR.MINORplPATCH (ro)
      OPT_FAST      assumes only one part per file
      OPT_DUMBNESS  switch off the program's intelligence
      OPT_BRACKPOL  give numbers in [] higher precendence
      OPT_VERBOSE   generate informative messages
      OPT_DESPERATE try to decode incomplete files
      OPT_IGNREPLY  ignore RE:plies (off by default)
      OPT_OVERWRITE whether it's OK to overwrite ex. files
      OPT_SAVEPATH  prefix to save-files on disk
      OPT_IGNMODE   ignore the original file mode
      OPT_DEBUG     print messages with FILE/LINE info
      OPT_ERRNO     get last error code for RET_IOERR (ro)
      OPT_PROGRESS  retrieve progress information
      OPT_USETEXT   handle text messages
      OPT_PREAMB    handle Mime preambles/epilogues
      OPT_TINYB64   detect short B64 outside of Mime
      OPT_ENCEXT    extension for single-part encoded files
      OPT_REMOVE    remove input files after decoding (dangerous)
      OPT_MOREMIME  strict MIME adherence
      OPT_DOTDOT    ".."-unescaping has not yet been done on input files
      OPT_RBUF      set default read I/O buffer size in bytes
      OPT_WBUF      set default write I/O buffer size in bytes
      OPT_AUTOCHECK automatically check file list after every loadfile

  Result/Error codes
      RET_OK        everything went fine
      RET_IOERR     I/O Error - examine errno
      RET_NOMEM     not enough memory
      RET_ILLVAL    illegal value for operation
      RET_NODATA    decoder didn't find any data
      RET_NOEND     encoded data wasn't ended properly
      RET_UNSUP     unsupported function (encoding)
      RET_EXISTS    file exists (decoding)
      RET_CONT      continue -- special from ScanPart
      RET_CANCEL    operation canceled

  File States
     This code is zero, i.e. "false":

      UUFILE_READ   Read in, but not further processed

     The following state codes are or'ed together:

      FILE_MISPART  Missing Part(s) detected
      FILE_NOBEGIN  No 'begin' found
      FILE_NOEND    No 'end' found
      FILE_NODATA   File does not contain valid uudata
      FILE_OK       All Parts found, ready to decode
      FILE_ERROR    Error while decoding
      FILE_DECODED  Successfully decoded
      FILE_TMPFILE  Temporary decoded file exists

  Encoding types
      UU_ENCODED    UUencoded data
      B64_ENCODED   Mime-Base64 data
      XX_ENCODED    XXencoded data
      BH_ENCODED    Binhex encoded
      PT_ENCODED    Plain-Text encoded (MIME)
      QP_ENCODED    Quoted-Printable (MIME)
      YENC_ENCODED  yEnc encoded (non-MIME)

EXPORTED FUNCTIONS
  Initializing and cleanup
    Initialize is automatically called when the module is loaded and
    allocates quite a small amount of memory for todays machines ;) CleanUp
    releases that again.

    On my machine, a fairly complete decode with DBI backend needs about
    10MB RSS to decode 20000 files.

    CleanUp
        Release memory, file items and clean up files. Should be called
        after a decoidng run, if you want to start a new one.

  Setting and querying options
    $option = GetOption OPT_xxx
    SetOption OPT_xxx, opt-value

    See the "OPT_xxx" constants above to see which options exist.

  Setting various callbacks
    SetMsgCallback [callback-function]
    SetBusyCallback [callback-function]
    SetFileCallback [callback-function]
    SetFNameFilter [callback-function]

  Call the currently selected FNameFilter
    $file = FNameFilter $file

  Loading sourcefiles, optionally fuzzy merge and start decoding
    ($retval, $count) = LoadFile $fname, [$id, [$delflag, [$partno]]]
        Load the given file and scan it for encoded contents. Optionally tag
        it with the given id, and if $delflag is true, delete the file after
        it is no longer necessary. If you are certain of the part number,
        you can specify it as the last argument.

        A better (usually faster) way of doing this is using the
        "SetFNameFilter" functionality.

    $retval = Smerge $pass
        If you are desperate, try to call "Smerge" with increasing $pass
        values, beginning at 0, to try to merge parts that usually would not
        have been merged.

        Most probably this will result in garbled files, so never do this by
        default, except:

        If the "OPT_AUTOCHECK" option has been disabled (by default it is
        enabled) to speed up file loading, then you *have* to call "Smerge
        -1" after loading all files as an additional pre-pass (which is
        normally done by "LoadFile").

    $item = GetFileListItem $item_number
        Return the $item structure for the $item_number'th found file, or
        "undef" of no file with that number exists.

        The first file has number 0, and the series has no holes, so you can
        iterate over all files by starting with zero and incrementing until
        you hit "undef".

        This function has to walk the linear list of fils on each access, so
        if you want to iterate over all items, it is usually faster to use
        "GetFileList".

    @items = GetFileList
        Similar to "GetFileListItem", but returns all files in one go.

  Decoding files
    $retval = $item->rename ($newname)
        Change the ondisk filename where the decoded file will be saved.

    $retval = $item->decode_temp
        Decode the file into a temporary location, use "$item->infile" to
        retrieve the temporary filename.

    $retval = $item->remove_temp
        Remove the temporarily decoded file again.

    $retval = $item->decode ([$target_path])
        Decode the file to its destination, or the given target path.

    $retval = $item->info (callback-function)

  Querying (and setting) item attributes
    $state = $item->state
    $mode = $item->mode ([newmode])
    $uudet = $item->uudet
    $size = $item->size
    $filename = $item->filename ([newfilename})
    $subfname = $item->subfname
    $mimeid = $item->mimeid
    $mimetype = $item->mimetype
    $binfile = $item->binfile

  Information about source parts
    $parts = $item->parts
        Return information about all parts (source files) used to decode the
        file as a list of hashrefs with the following structure:

         {
           partno   => <integer describing the part number, starting with 1>,
           # the following member sonly exist when they contain useful information
           sfname   => <local pathname of the file where this part is from>,
           filename => <the ondisk filename of the decoded file>,
           subfname => <used to cluster postings, possibly the posting filename>,
           subject  => <the subject of the posting/mail>,
           origin   => <the possible source (From) address>,
           mimetype => <the possible mimetype of the decoded file>,
           mimeid   => <the id part of the Content-Type>,
         }

        Usually you are interested mostly the "sfname" and possibly the
        "partno" and "filename" members.

  Functions below are not documented and not very well tested - feedback welcome
      QuickDecode
      EncodeMulti
      EncodePartial
      EncodeToStream
      EncodeToFile
      E_PrepSingle
      E_PrepPartial

  EXTENSION FUNCTIONS
    Functions found in this module but not documented in the uulib
    documentation:

    $msg = straction ACT_xxx
        Return a human readable string representing the given action code.

    $msg = strerror RET_xxx
        Return a human readable string representing the given error code.

    $str = strencoding xxx_ENCODED
        Return the name of the encoding type as a string.

    $str = strmsglevel MSG_xxx
        Returns the message level as a string.

    SetFileNameCallback $cb
        Sets (or queries) the FileNameCallback, which is called whenever the
        decoding library can't find a filename and wants to extract a
        filename from the subject line of a posting. The callback will be
        called with two arguments, the subject line and the current
        candidate for the filename. The latter argument can be "undef",
        which means that no filename could be found (and likely no one
        exists, so it is safe to also return "undef" in this case). If it
        doesn't return anything (not even "undef"!), then nothing happens,
        so this is a no-op callback:

           sub cb {
              return ();
           }

        If it returns "undef", then this indicates that no filename could be
        found. In all other cases, the return value is taken to be the
        filename.

        This is a slightly more useful callback:

          sub cb {
             return unless $_[1]; # skip "Re:"-plies et al.
             my ($subject, $filename) = @_;
             # if we find some *.rar, take it
             return $1 if $subject =~ /(\w+\.rar)/;
             # otherwise just pass what we have
             return ();
          }

LARGE EXAMPLE DECODER
    The general workflow for decoding is like this:

    1. Configure options with "SetOption" or "SetXXXCallback".
    2. Load all source files with "LoadFile".
    3. Optionally "Smerge".
    4. Iterate over all "GetFileList" items (i.e. result files).
    5. "CleanUp" to delete files and free items.

    What follows is the file "example-decoder" from the distribution that
    illustrates the above worklfow in a non-trivial example.

       #!/usr/bin/perl

       # decode all the files in the directory uusrc/ and copy
       # the resulting files to uudst/

       use Convert::UUlib ':all';

       sub namefilter {
          my ($path) = @_;

          $path=~s/^.*[\/\\]//;

          $path
       }

       sub busycb {
          my ($action, $curfile, $partno, $numparts, $percent, $fsize) = @_;
          $_[0]=straction($action);
          print "busy_callback(", (join ",",@_), ")\n";
          0
       }

       SetOption OPT_RBUF, 128*1024;
       SetOption OPT_WBUF, 1024*1024;
       SetOption OPT_IGNMODE, 1;
       SetOption OPT_IGNMODE, 1;
       SetOption OPT_VERBOSE, 1;

       # show the three ways you can set callback functions. I normally
       # prefer the one with the sub inplace.
       SetFNameFilter \&namefilter;

       SetBusyCallback "busycb", 333;

       SetMsgCallback sub {
          my ($msg, $level) = @_;
          print uc strmsglevel $_[1], ": $msg\n";
       };

       # the following non-trivial FileNameCallback takes care
       # of some subject lines not detected properly by uulib:
       SetFileNameCallback sub {
          return unless $_[1]; # skip "Re:"-plies et al.
          local $_ = $_[0];

          # the following rules are rather effective on some newsgroups,
          # like alt.binaries.games.anime, where non-mime, uuencoded data
          # is very common

          # if we find some *.rar, take it as the filename
          return $1 if /(\S{3,}\.(?:[rstuvwxyz]\d\d|rar))\s/i;

          # one common subject format
          return $1 if /- "(.{2,}?\..+?)" (?:yenc )?\(\d+\/\d+\)/i;

          # - filename.par (04/55)
          return $1 if /- "?(\S{3,}\.\S+?)"? (?:yenc )?\(\d+\/\d+\)/i;

          # - (xxx) No. 1 sayuri81.jpg 756565 bytes
          # - (20 files) No.17 Roseanne.jpg [2/2]
          return $1 if /No\.[ 0-9]+ (\S+\....) (?:\d+ bytes )?\[/;

          # try to detect some common forms of filenames
          return $1 if /([a-z0-9_\-+.]{3,}\.[a-z]{3,4}(?:.\d+))/i;

          # otherwise just pass what we have
          ()
       };

       # now read all files in the directory uusrc/*
       for (<uusrc/*>) {
          my ($retval, $count) = LoadFile ($_, $_, 1);
          print "file($_), status(", strerror $retval, ") parts($count)\n";
       }

       SetOption OPT_SAVEPATH, "uudst/";

       # now wade through all files and their source parts
       for my $uu (GetFileList) {
          print "file ", $uu->filename, "\n";
          print " state ", $uu->state, "\n";
          print " mode ", $uu->mode, "\n";
          print " uudet ", strencoding $uu->uudet, "\n";
          print " size ", $uu->size, "\n";
          print " subfname ", $uu->subfname, "\n";
          print " mimeid ", $uu->mimeid, "\n";
          print " mimetype ", $uu->mimetype, "\n";

          # print additional info about all parts
          print " parts";
          for ($uu->parts) {
             for my $k (sort keys %$_) {
                print " $k=$_->{$k}";
             }
             print "\n";
          }

          $uu->remove_temp;

          if (my $err = $uu->decode) {
             print " ERROR ", strerror $err, "\n";
          } else {
             print " successfully saved as uudst/", $uu->filename, "\n";
          }
       }

       print "cleanup...\n";

       CleanUp;

PERLMULTICORE SUPPORT
    This module supports the perlmulticore standard (see
    <http://perlmulticore.schmorp.de/> for more info) for the following
    functions - generally these are functions accessing the disk and/or
    using considerable CPU time:

       LoadFile
       $item->decode
       $item->decode_temp
       $item->remove_temp
       $item->info

    The perl interpreter will be reacquired/released on every callback
    invocation, so for performance reasons, callbacks should be avoided if
    that is costly.

    Future versions might enable multicore support for more functions.

BUGS AND LIMITATIONS
    The original uulib library this module uses was written at a time where
    main memory of measured in megabytes and buffer overflows as a security
    thign didn't exist. While a lot of security fixes have been applied over
    the years (includign some defense in depth mechanism that can shield
    against a lot of as-of-yet undetected bugs), using this library for
    security purposes requires care.

    Likewise, file sizes when the uulib library was written were tiny
    compared to today, so do not expect this library to handle files larger
    than 2GB.

    Lastly, this module uses a very "C-like" interface, which means it
    doesn't protect you from invalid points as you might expect from "more
    perlish" modules - for example, accessing a file item object after
    callinbg "CleanUp" will likely result in crashes, memory corruption, or
    worse.

AUTHOR
    Marc Lehmann <schmorp@schmorp.de>, the original uulib library was
    written by Frank Pilhofer <fp@informatik.uni-frankfurt.de>, and later
    heavily bugfixed by Marc Lehmann.

SEE ALSO
    perl(1), uudeview homepage at <http://www.fpx.de/fp/Software/UUDeview/>.

Revision:	1.6
Committed:	Sun Mar 1 05:14:55 2020 UTC (4 years, 3 months ago) by root
Branch:	MAIN
CVS Tags:	rel-1_71, rel-1_7
Changes since 1.5:	+81 -37 lines
Log Message:	1.7
#	User	Rev	Content
1	root	1.1	NAME
2			Convert::UUlib - Perl interface to the uulib library (a.k.a.
3			uudeview/uuenview).
4
5			SYNOPSIS
6			use Convert::UUlib ':all';
7	root	1.5
8			# read all the files named on the commandline and decode them
9	root	1.1	# into the CURRENT directory. See below for a longer example.
10			LoadFile $_ for @ARGV;
11	root	1.6
12			for my $uu (GetFileList) {
13	root	1.1	if ($uu->state & FILE_OK) {
14			$uu->decode;
15			print $uu->filename, "\n";
16			}
17			}
18
19			DESCRIPTION
20			Read the file doc/library.pdf from the distribution for in-depth
21			information about the C-library used in this interface, and the rest of
22			this document and especially the non-trivial decoder program at the end.
23
24			EXPORTED CONSTANTS
25			Action code constants
26			ACT_IDLE we don't do anything
27			ACT_SCANNING scanning an input file
28			ACT_DECODING decoding into a temp file
29			ACT_COPYING copying temp to target
30			ACT_ENCODING encoding a file
31
32			Message severity levels
33			MSG_MESSAGE just a message, nothing important
34			MSG_NOTE something that should be noticed
35			MSG_WARNING important msg, processing continues
36			MSG_ERROR processing has been terminated
37			MSG_FATAL decoder cannot process further requests
38			MSG_PANIC recovery impossible, app must terminate
39
40			Options
41			OPT_VERSION version number MAJOR.MINORplPATCH (ro)
42			OPT_FAST assumes only one part per file
43			OPT_DUMBNESS switch off the program's intelligence
44			OPT_BRACKPOL give numbers in [] higher precendence
45			OPT_VERBOSE generate informative messages
46			OPT_DESPERATE try to decode incomplete files
47			OPT_IGNREPLY ignore RE:plies (off by default)
48			OPT_OVERWRITE whether it's OK to overwrite ex. files
49			OPT_SAVEPATH prefix to save-files on disk
50			OPT_IGNMODE ignore the original file mode
51			OPT_DEBUG print messages with FILE/LINE info
52			OPT_ERRNO get last error code for RET_IOERR (ro)
53			OPT_PROGRESS retrieve progress information
54			OPT_USETEXT handle text messages
55			OPT_PREAMB handle Mime preambles/epilogues
56			OPT_TINYB64 detect short B64 outside of Mime
57			OPT_ENCEXT extension for single-part encoded files
58			OPT_REMOVE remove input files after decoding (dangerous)
59			OPT_MOREMIME strict MIME adherence
60			OPT_DOTDOT ".."-unescaping has not yet been done on input files
61	root	1.5	OPT_RBUF set default read I/O buffer size in bytes
62			OPT_WBUF set default write I/O buffer size in bytes
63			OPT_AUTOCHECK automatically check file list after every loadfile
64	root	1.1
65			Result/Error codes
66			RET_OK everything went fine
67			RET_IOERR I/O Error - examine errno
68			RET_NOMEM not enough memory
69			RET_ILLVAL illegal value for operation
70			RET_NODATA decoder didn't find any data
71			RET_NOEND encoded data wasn't ended properly
72			RET_UNSUP unsupported function (encoding)
73			RET_EXISTS file exists (decoding)
74			RET_CONT continue -- special from ScanPart
75			RET_CANCEL operation canceled
76
77			File States
78			This code is zero, i.e. "false":
79
80			UUFILE_READ Read in, but not further processed
81
82			The following state codes are or'ed together:
83
84			FILE_MISPART Missing Part(s) detected
85			FILE_NOBEGIN No 'begin' found
86			FILE_NOEND No 'end' found
87			FILE_NODATA File does not contain valid uudata
88			FILE_OK All Parts found, ready to decode
89			FILE_ERROR Error while decoding
90			FILE_DECODED Successfully decoded
91			FILE_TMPFILE Temporary decoded file exists
92
93			Encoding types
94			UU_ENCODED UUencoded data
95			B64_ENCODED Mime-Base64 data
96			XX_ENCODED XXencoded data
97			BH_ENCODED Binhex encoded
98			PT_ENCODED Plain-Text encoded (MIME)
99			QP_ENCODED Quoted-Printable (MIME)
100			YENC_ENCODED yEnc encoded (non-MIME)
101
102			EXPORTED FUNCTIONS
103			Initializing and cleanup
104			Initialize is automatically called when the module is loaded and
105			allocates quite a small amount of memory for todays machines ;) CleanUp
106			releases that again.
107
108			On my machine, a fairly complete decode with DBI backend needs about
109			10MB RSS to decode 20000 files.
110
111			CleanUp
112	root	1.6	Release memory, file items and clean up files. Should be called
113			after a decoidng run, if you want to start a new one.
114	root	1.1
115			Setting and querying options
116			$option = GetOption OPT_xxx
117			SetOption OPT_xxx, opt-value
118
119			See the "OPT_xxx" constants above to see which options exist.
120
121			Setting various callbacks
122			SetMsgCallback [callback-function]
123			SetBusyCallback [callback-function]
124			SetFileCallback [callback-function]
125			SetFNameFilter [callback-function]
126
127			Call the currently selected FNameFilter
128			$file = FNameFilter $file
129
130			Loading sourcefiles, optionally fuzzy merge and start decoding
131			($retval, $count) = LoadFile $fname, [$id, [$delflag, [$partno]]]
132			Load the given file and scan it for encoded contents. Optionally tag
133			it with the given id, and if $delflag is true, delete the file after
134			it is no longer necessary. If you are certain of the part number,
135			you can specify it as the last argument.
136
137			A better (usually faster) way of doing this is using the
138			"SetFNameFilter" functionality.
139
140			$retval = Smerge $pass
141			If you are desperate, try to call "Smerge" with increasing $pass
142			values, beginning at 0, to try to merge parts that usually would not
143			have been merged.
144
145			Most probably this will result in garbled files, so never do this by
146	root	1.5	default, except:
147
148			If the "OPT_AUTOCHECK" option has been disabled (by default it is
149			enabled) to speed up file loading, then you have to call "Smerge
150			-1" after loading all files as an additional pre-pass (which is
151			normally done by "LoadFile").
152	root	1.1
153			$item = GetFileListItem $item_number
154			Return the $item structure for the $item_number'th found file, or
155			"undef" of no file with that number exists.
156
157			The first file has number 0, and the series has no holes, so you can
158			iterate over all files by starting with zero and incrementing until
159			you hit "undef".
160
161	root	1.6	This function has to walk the linear list of fils on each access, so
162			if you want to iterate over all items, it is usually faster to use
163			"GetFileList".
164
165			@items = GetFileList
166			Similar to "GetFileListItem", but returns all files in one go.
167
168	root	1.1	Decoding files
169	root	1.6	$retval = $item->rename ($newname)
170	root	1.1	Change the ondisk filename where the decoded file will be saved.
171
172			$retval = $item->decode_temp
173			Decode the file into a temporary location, use "$item->infile" to
174			retrieve the temporary filename.
175
176			$retval = $item->remove_temp
177			Remove the temporarily decoded file again.
178
179	root	1.6	$retval = $item->decode ([$target_path])
180			Decode the file to its destination, or the given target path.
181	root	1.1
182	root	1.6	$retval = $item->info (callback-function)
183	root	1.1
184			Querying (and setting) item attributes
185			$state = $item->state
186	root	1.6	$mode = $item->mode ([newmode])
187	root	1.1	$uudet = $item->uudet
188			$size = $item->size
189	root	1.6	$filename = $item->filename ([newfilename})
190	root	1.1	$subfname = $item->subfname
191			$mimeid = $item->mimeid
192			$mimetype = $item->mimetype
193			$binfile = $item->binfile
194
195			Information about source parts
196			$parts = $item->parts
197			Return information about all parts (source files) used to decode the
198			file as a list of hashrefs with the following structure:
199
200			{
201			partno => <integer describing the part number, starting with 1>,
202			# the following member sonly exist when they contain useful information
203			sfname => <local pathname of the file where this part is from>,
204			filename => <the ondisk filename of the decoded file>,
205			subfname => <used to cluster postings, possibly the posting filename>,
206			subject => <the subject of the posting/mail>,
207			origin => <the possible source (From) address>,
208			mimetype => <the possible mimetype of the decoded file>,
209			mimeid => <the id part of the Content-Type>,
210			}
211
212			Usually you are interested mostly the "sfname" and possibly the
213			"partno" and "filename" members.
214
215	root	1.6	Functions below are not documented and not very well tested - feedback welcome
216	root	1.1	QuickDecode
217			EncodeMulti
218			EncodePartial
219			EncodeToStream
220			EncodeToFile
221			E_PrepSingle
222			E_PrepPartial
223
224			EXTENSION FUNCTIONS
225			Functions found in this module but not documented in the uulib
226			documentation:
227
228			$msg = straction ACT_xxx
229			Return a human readable string representing the given action code.
230
231			$msg = strerror RET_xxx
232			Return a human readable string representing the given error code.
233
234			$str = strencoding xxx_ENCODED
235			Return the name of the encoding type as a string.
236
237			$str = strmsglevel MSG_xxx
238			Returns the message level as a string.
239
240			SetFileNameCallback $cb
241			Sets (or queries) the FileNameCallback, which is called whenever the
242			decoding library can't find a filename and wants to extract a
243			filename from the subject line of a posting. The callback will be
244			called with two arguments, the subject line and the current
245			candidate for the filename. The latter argument can be "undef",
246			which means that no filename could be found (and likely no one
247			exists, so it is safe to also return "undef" in this case). If it
248			doesn't return anything (not even "undef"!), then nothing happens,
249			so this is a no-op callback:
250
251			sub cb {
252			return ();
253			}
254
255			If it returns "undef", then this indicates that no filename could be
256			found. In all other cases, the return value is taken to be the
257			filename.
258
259			This is a slightly more useful callback:
260
261			sub cb {
262			return unless $_[1]; # skip "Re:"-plies et al.
263			my ($subject, $filename) = @_;
264			# if we find some *.rar, take it
265			return $1 if $subject =~ /(\w+\.rar)/;
266			# otherwise just pass what we have
267			return ();
268			}
269
270			LARGE EXAMPLE DECODER
271	root	1.6	The general workflow for decoding is like this:
272
273			1. Configure options with "SetOption" or "SetXXXCallback".
274			2. Load all source files with "LoadFile".
275			3. Optionally "Smerge".
276			4. Iterate over all "GetFileList" items (i.e. result files).
277			5. "CleanUp" to delete files and free items.
278
279			What follows is the file "example-decoder" from the distribution that
280			illustrates the above worklfow in a non-trivial example.
281	root	1.1
282	root	1.4	#!/usr/bin/perl
283	root	1.1
284	root	1.4	# decode all the files in the directory uusrc/ and copy
285			# the resulting files to uudst/
286	root	1.1
287	root	1.4	use Convert::UUlib ':all';
288	root	1.1
289	root	1.4	sub namefilter {
290			my ($path) = @_;
291
292			$path=~s/^.*[\/\\]//;
293
294			$path
295			}
296
297			sub busycb {
298			my ($action, $curfile, $partno, $numparts, $percent, $fsize) = @_;
299			$_[0]=straction($action);
300			print "busy_callback(", (join ",",@_), ")\n";
301			0
302			}
303
304			SetOption OPT_RBUF, 128*1024;
305			SetOption OPT_WBUF, 1024*1024;
306			SetOption OPT_IGNMODE, 1;
307			SetOption OPT_IGNMODE, 1;
308			SetOption OPT_VERBOSE, 1;
309
310			# show the three ways you can set callback functions. I normally
311			# prefer the one with the sub inplace.
312			SetFNameFilter \&namefilter;
313
314			SetBusyCallback "busycb", 333;
315
316			SetMsgCallback sub {
317			my ($msg, $level) = @_;
318			print uc strmsglevel $_[1], ": $msg\n";
319			};
320
321			# the following non-trivial FileNameCallback takes care
322			# of some subject lines not detected properly by uulib:
323			SetFileNameCallback sub {
324			return unless $_[1]; # skip "Re:"-plies et al.
325			local $_ = $_[0];
326
327			# the following rules are rather effective on some newsgroups,
328			# like alt.binaries.games.anime, where non-mime, uuencoded data
329			# is very common
330
331			# if we find some *.rar, take it as the filename
332			return $1 if /(\S{3,}\.(?:[rstuvwxyz]\d\d\|rar))\s/i;
333
334			# one common subject format
335			return $1 if /- "(.{2,}?\..+?)" (?:yenc )?\(\d+\/\d+\)/i;
336
337			# - filename.par (04/55)
338			return $1 if /- "?(\S{3,}\.\S+?)"? (?:yenc )?\(\d+\/\d+\)/i;
339
340			# - (xxx) No. 1 sayuri81.jpg 756565 bytes
341			# - (20 files) No.17 Roseanne.jpg [2/2]
342			return $1 if /No\.[ 0-9]+ (\S+\....) (?:\d+ bytes )?\[/;
343
344			# try to detect some common forms of filenames
345			return $1 if /([a-z0-9_\-+.]{3,}\.[a-z]{3,4}(?:.\d+))/i;
346
347			# otherwise just pass what we have
348			()
349			};
350
351			# now read all files in the directory uusrc/*
352	root	1.6	for (<uusrc/*>) {
353	root	1.4	my ($retval, $count) = LoadFile ($_, $_, 1);
354			print "file($_), status(", strerror $retval, ") parts($count)\n";
355			}
356
357			SetOption OPT_SAVEPATH, "uudst/";
358
359			# now wade through all files and their source parts
360	root	1.6	for my $uu (GetFileList) {
361			print "file ", $uu->filename, "\n";
362			print " state ", $uu->state, "\n";
363			print " mode ", $uu->mode, "\n";
364			print " uudet ", strencoding $uu->uudet, "\n";
365			print " size ", $uu->size, "\n";
366			print " subfname ", $uu->subfname, "\n";
367			print " mimeid ", $uu->mimeid, "\n";
368			print " mimetype ", $uu->mimetype, "\n";
369	root	1.4
370			# print additional info about all parts
371	root	1.6	print " parts";
372	root	1.4	for ($uu->parts) {
373	root	1.6	for my $k (sort keys %$_) {
374			print " $k=$_->{$k}";
375	root	1.4	}
376			print "\n";
377			}
378
379			$uu->remove_temp;
380
381	root	1.6	if (my $err = $uu->decode) {
382			print " ERROR ", strerror $err, "\n";
383	root	1.4	} else {
384	root	1.6	print " successfully saved as uudst/", $uu->filename, "\n";
385	root	1.4	}
386			}
387	root	1.1
388	root	1.4	print "cleanup...\n";
389
390			CleanUp;
391	root	1.1
392	root	1.6	PERLMULTICORE SUPPORT
393			This module supports the perlmulticore standard (see
394			<http://perlmulticore.schmorp.de/> for more info) for the following
395			functions - generally these are functions accessing the disk and/or
396			using considerable CPU time:
397
398			LoadFile
399			$item->decode
400			$item->decode_temp
401			$item->remove_temp
402			$item->info
403
404			The perl interpreter will be reacquired/released on every callback
405			invocation, so for performance reasons, callbacks should be avoided if
406			that is costly.
407
408			Future versions might enable multicore support for more functions.
409
410			BUGS AND LIMITATIONS
411			The original uulib library this module uses was written at a time where
412			main memory of measured in megabytes and buffer overflows as a security
413			thign didn't exist. While a lot of security fixes have been applied over
414			the years (includign some defense in depth mechanism that can shield
415			against a lot of as-of-yet undetected bugs), using this library for
416			security purposes requires care.
417
418			Likewise, file sizes when the uulib library was written were tiny
419			compared to today, so do not expect this library to handle files larger
420			than 2GB.
421
422			Lastly, this module uses a very "C-like" interface, which means it
423			doesn't protect you from invalid points as you might expect from "more
424			perlish" modules - for example, accessing a file item object after
425			callinbg "CleanUp" will likely result in crashes, memory corruption, or
426			worse.
427
428	root	1.1	AUTHOR
429			Marc Lehmann <schmorp@schmorp.de>, the original uulib library was
430			written by Frank Pilhofer <fp@informatik.uni-frankfurt.de>, and later
431			heavily bugfixed by Marc Lehmann.
432
433			SEE ALSO
434	root	1.6	perl(1), uudeview homepage at <http://www.fpx.de/fp/Software/UUDeview/>.
435	root	1.1