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9e21b3d0 1;# $Id: Storable.pm,v 1.0 2000/09/01 19:40:41 ram Exp $
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2;#
3;# Copyright (c) 1995-2000, Raphael Manfredi
4;#
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5;# You may redistribute only under the same terms as Perl 5, as specified
6;# in the README file that comes with the distribution.
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7;#
8;# $Log: Storable.pm,v $
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9;# Revision 1.0 2000/09/01 19:40:41 ram
10;# Baseline for first official release.
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11;#
12
13require DynaLoader;
14require Exporter;
15package Storable; @ISA = qw(Exporter DynaLoader);
16
17@EXPORT = qw(store retrieve);
18@EXPORT_OK = qw(
9e21b3d0 19 nstore store_fd nstore_fd fd_retrieve
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20 freeze nfreeze thaw
21 dclone
9e21b3d0 22 retrieve_fd
dd19458b 23 lock_store lock_nstore lock_retrieve
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24);
25
26use AutoLoader;
27use vars qw($forgive_me $VERSION);
28
b29b780f 29$VERSION = '1.004';
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30*AUTOLOAD = \&AutoLoader::AUTOLOAD; # Grrr...
31
32#
33# Use of Log::Agent is optional
34#
35
36eval "use Log::Agent";
37
38unless (defined @Log::Agent::EXPORT) {
39 eval q{
40 sub logcroak {
41 require Carp;
42 Carp::croak(@_);
43 }
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44 sub logcarp {
45 require Carp;
46 Carp::carp(@_);
47 }
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48 };
49}
50
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51#
52# They might miss :flock in Fcntl
53#
54
55BEGIN {
56 require Fcntl;
57 if (exists $Fcntl::EXPORT_TAGS{'flock'}) {
58 Fcntl->import(':flock');
59 } else {
60 eval q{
61 sub LOCK_SH () {1}
62 sub LOCK_EX () {2}
63 };
64 }
65}
66
7a6a85bf 67sub logcroak;
b29b780f 68sub logcarp;
7a6a85bf 69
9e21b3d0 70sub retrieve_fd { &fd_retrieve } # Backward compatibility
cb3d9de5 71
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72bootstrap Storable;
731;
74__END__
75
76#
77# store
78#
79# Store target object hierarchy, identified by a reference to its root.
80# The stored object tree may later be retrieved to memory via retrieve.
81# Returns undef if an I/O error occurred, in which case the file is
82# removed.
83#
84sub store {
dd19458b 85 return _store(\&pstore, @_, 0);
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86}
87
88#
89# nstore
90#
91# Same as store, but in network order.
92#
93sub nstore {
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94 return _store(\&net_pstore, @_, 0);
95}
96
97#
98# lock_store
99#
100# Same as store, but flock the file first (advisory locking).
101#
102sub lock_store {
103 return _store(\&pstore, @_, 1);
104}
105
106#
107# lock_nstore
108#
109# Same as nstore, but flock the file first (advisory locking).
110#
111sub lock_nstore {
112 return _store(\&net_pstore, @_, 1);
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113}
114
115# Internal store to file routine
116sub _store {
117 my $xsptr = shift;
118 my $self = shift;
dd19458b 119 my ($file, $use_locking) = @_;
7a6a85bf 120 logcroak "not a reference" unless ref($self);
dd19458b 121 logcroak "too many arguments" unless @_ == 2; # No @foo in arglist
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122 local *FILE;
123 open(FILE, ">$file") || logcroak "can't create $file: $!";
124 binmode FILE; # Archaic systems...
dd19458b 125 if ($use_locking) {
f567092b 126 if ($^O eq 'dos') {
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127 logcarp "Storable::lock_store: fcntl/flock emulation broken on $^O";
128 return undef;
f567092b 129 }
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130 flock(FILE, LOCK_EX) ||
131 logcroak "can't get exclusive lock on $file: $!";
132 truncate FILE, 0;
133 # Unlocking will happen when FILE is closed
134 }
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135 my $da = $@; # Don't mess if called from exception handler
136 my $ret;
137 # Call C routine nstore or pstore, depending on network order
138 eval { $ret = &$xsptr(*FILE, $self) };
139 close(FILE) or $ret = undef;
140 unlink($file) or warn "Can't unlink $file: $!\n" if $@ || !defined $ret;
141 logcroak $@ if $@ =~ s/\.?\n$/,/;
142 $@ = $da;
143 return $ret ? $ret : undef;
144}
145
146#
147# store_fd
148#
149# Same as store, but perform on an already opened file descriptor instead.
150# Returns undef if an I/O error occurred.
151#
152sub store_fd {
153 return _store_fd(\&pstore, @_);
154}
155
156#
157# nstore_fd
158#
159# Same as store_fd, but in network order.
160#
161sub nstore_fd {
162 my ($self, $file) = @_;
163 return _store_fd(\&net_pstore, @_);
164}
165
166# Internal store routine on opened file descriptor
167sub _store_fd {
168 my $xsptr = shift;
169 my $self = shift;
170 my ($file) = @_;
171 logcroak "not a reference" unless ref($self);
172 logcroak "too many arguments" unless @_ == 1; # No @foo in arglist
173 my $fd = fileno($file);
174 logcroak "not a valid file descriptor" unless defined $fd;
175 my $da = $@; # Don't mess if called from exception handler
176 my $ret;
177 # Call C routine nstore or pstore, depending on network order
178 eval { $ret = &$xsptr($file, $self) };
179 logcroak $@ if $@ =~ s/\.?\n$/,/;
180 $@ = $da;
181 return $ret ? $ret : undef;
182}
183
184#
185# freeze
186#
187# Store oject and its hierarchy in memory and return a scalar
188# containing the result.
189#
190sub freeze {
191 _freeze(\&mstore, @_);
192}
193
194#
195# nfreeze
196#
197# Same as freeze but in network order.
198#
199sub nfreeze {
200 _freeze(\&net_mstore, @_);
201}
202
203# Internal freeze routine
204sub _freeze {
205 my $xsptr = shift;
206 my $self = shift;
207 logcroak "not a reference" unless ref($self);
208 logcroak "too many arguments" unless @_ == 0; # No @foo in arglist
209 my $da = $@; # Don't mess if called from exception handler
210 my $ret;
211 # Call C routine mstore or net_mstore, depending on network order
212 eval { $ret = &$xsptr($self) };
213 logcroak $@ if $@ =~ s/\.?\n$/,/;
214 $@ = $da;
215 return $ret ? $ret : undef;
216}
217
218#
219# retrieve
220#
221# Retrieve object hierarchy from disk, returning a reference to the root
222# object of that tree.
223#
224sub retrieve {
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225 _retrieve($_[0], 0);
226}
227
228#
229# lock_retrieve
230#
231# Same as retrieve, but with advisory locking.
232#
233sub lock_retrieve {
234 _retrieve($_[0], 1);
235}
236
237# Internal retrieve routine
238sub _retrieve {
239 my ($file, $use_locking) = @_;
7a6a85bf 240 local *FILE;
dd19458b 241 open(FILE, $file) || logcroak "can't open $file: $!";
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242 binmode FILE; # Archaic systems...
243 my $self;
244 my $da = $@; # Could be from exception handler
dd19458b 245 if ($use_locking) {
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246 if ($^O eq 'dos') {
247 logcarp "Storable::lock_store: fcntl/flock emulation broken on $^O";
248 return undef;
249 }
250 flock(FILE, LOCK_SH) || logcroak "can't get shared lock on $file: $!";
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251 # Unlocking will happen when FILE is closed
252 }
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253 eval { $self = pretrieve(*FILE) }; # Call C routine
254 close(FILE);
255 logcroak $@ if $@ =~ s/\.?\n$/,/;
256 $@ = $da;
257 return $self;
258}
259
260#
9e21b3d0 261# fd_retrieve
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262#
263# Same as retrieve, but perform from an already opened file descriptor instead.
264#
9e21b3d0 265sub fd_retrieve {
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266 my ($file) = @_;
267 my $fd = fileno($file);
268 logcroak "not a valid file descriptor" unless defined $fd;
269 my $self;
270 my $da = $@; # Could be from exception handler
271 eval { $self = pretrieve($file) }; # Call C routine
272 logcroak $@ if $@ =~ s/\.?\n$/,/;
273 $@ = $da;
274 return $self;
275}
276
277#
278# thaw
279#
280# Recreate objects in memory from an existing frozen image created
281# by freeze. If the frozen image passed is undef, return undef.
282#
283sub thaw {
284 my ($frozen) = @_;
285 return undef unless defined $frozen;
286 my $self;
287 my $da = $@; # Could be from exception handler
288 eval { $self = mretrieve($frozen) }; # Call C routine
289 logcroak $@ if $@ =~ s/\.?\n$/,/;
290 $@ = $da;
291 return $self;
292}
293
294=head1 NAME
295
296Storable - persistency for perl data structures
297
298=head1 SYNOPSIS
299
300 use Storable;
301 store \%table, 'file';
302 $hashref = retrieve('file');
303
304 use Storable qw(nstore store_fd nstore_fd freeze thaw dclone);
305
306 # Network order
307 nstore \%table, 'file';
308 $hashref = retrieve('file'); # There is NO nretrieve()
309
310 # Storing to and retrieving from an already opened file
311 store_fd \@array, \*STDOUT;
312 nstore_fd \%table, \*STDOUT;
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313 $aryref = fd_retrieve(\*SOCKET);
314 $hashref = fd_retrieve(\*SOCKET);
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315
316 # Serializing to memory
317 $serialized = freeze \%table;
318 %table_clone = %{ thaw($serialized) };
319
320 # Deep (recursive) cloning
321 $cloneref = dclone($ref);
322
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323 # Advisory locking
324 use Storable qw(lock_store lock_nstore lock_retrieve)
325 lock_store \%table, 'file';
326 lock_nstore \%table, 'file';
327 $hashref = lock_retrieve('file');
328
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329=head1 DESCRIPTION
330
331The Storable package brings persistency to your perl data structures
332containing SCALAR, ARRAY, HASH or REF objects, i.e. anything that can be
333convenientely stored to disk and retrieved at a later time.
334
335It can be used in the regular procedural way by calling C<store> with
336a reference to the object to be stored, along with the file name where
337the image should be written.
338The routine returns C<undef> for I/O problems or other internal error,
339a true value otherwise. Serious errors are propagated as a C<die> exception.
340
341To retrieve data stored to disk, use C<retrieve> with a file name,
342and the objects stored into that file are recreated into memory for you,
343a I<reference> to the root object being returned. In case an I/O error
344occurs while reading, C<undef> is returned instead. Other serious
345errors are propagated via C<die>.
346
347Since storage is performed recursively, you might want to stuff references
348to objects that share a lot of common data into a single array or hash
349table, and then store that object. That way, when you retrieve back the
350whole thing, the objects will continue to share what they originally shared.
351
352At the cost of a slight header overhead, you may store to an already
353opened file descriptor using the C<store_fd> routine, and retrieve
9e21b3d0 354from a file via C<fd_retrieve>. Those names aren't imported by default,
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355so you will have to do that explicitely if you need those routines.
356The file descriptor you supply must be already opened, for read
357if you're going to retrieve and for write if you wish to store.
358
359 store_fd(\%table, *STDOUT) || die "can't store to stdout\n";
9e21b3d0 360 $hashref = fd_retrieve(*STDIN);
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361
362You can also store data in network order to allow easy sharing across
363multiple platforms, or when storing on a socket known to be remotely
364connected. The routines to call have an initial C<n> prefix for I<network>,
365as in C<nstore> and C<nstore_fd>. At retrieval time, your data will be
366correctly restored so you don't have to know whether you're restoring
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367from native or network ordered data. Double values are stored stringified
368to ensure portability as well, at the slight risk of loosing some precision
369in the last decimals.
7a6a85bf 370
9e21b3d0 371When using C<fd_retrieve>, objects are retrieved in sequence, one
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372object (i.e. one recursive tree) per associated C<store_fd>.
373
374If you're more from the object-oriented camp, you can inherit from
375Storable and directly store your objects by invoking C<store> as
376a method. The fact that the root of the to-be-stored tree is a
377blessed reference (i.e. an object) is special-cased so that the
378retrieve does not provide a reference to that object but rather the
379blessed object reference itself. (Otherwise, you'd get a reference
380to that blessed object).
381
382=head1 MEMORY STORE
383
384The Storable engine can also store data into a Perl scalar instead, to
385later retrieve them. This is mainly used to freeze a complex structure in
386some safe compact memory place (where it can possibly be sent to another
387process via some IPC, since freezing the structure also serializes it in
388effect). Later on, and maybe somewhere else, you can thaw the Perl scalar
389out and recreate the original complex structure in memory.
390
391Surprisingly, the routines to be called are named C<freeze> and C<thaw>.
392If you wish to send out the frozen scalar to another machine, use
393C<nfreeze> instead to get a portable image.
394
395Note that freezing an object structure and immediately thawing it
396actually achieves a deep cloning of that structure:
397
398 dclone(.) = thaw(freeze(.))
399
400Storable provides you with a C<dclone> interface which does not create
401that intermediary scalar but instead freezes the structure in some
402internal memory space and then immediatly thaws it out.
403
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404=head1 ADVISORY LOCKING
405
406The C<lock_store> and C<lock_nstore> routine are equivalent to C<store>
407and C<nstore>, only they get an exclusive lock on the file before
408writing. Likewise, C<lock_retrieve> performs as C<retrieve>, but also
409gets a shared lock on the file before reading.
410
411Like with any advisory locking scheme, the protection only works if
412you systematically use C<lock_store> and C<lock_retrieve>. If one
413side of your application uses C<store> whilst the other uses C<lock_retrieve>,
414you will get no protection at all.
415
416The internal advisory locking is implemented using Perl's flock() routine.
417If your system does not support any form of flock(), or if you share
418your files across NFS, you might wish to use other forms of locking by
419using modules like LockFile::Simple which lock a file using a filesystem
420entry, instead of locking the file descriptor.
421
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422=head1 SPEED
423
424The heart of Storable is written in C for decent speed. Extra low-level
425optimization have been made when manipulating perl internals, to
426sacrifice encapsulation for the benefit of a greater speed.
427
428=head1 CANONICAL REPRESENTATION
429
430Normally Storable stores elements of hashes in the order they are
431stored internally by Perl, i.e. pseudo-randomly. If you set
432C<$Storable::canonical> to some C<TRUE> value, Storable will store
433hashes with the elements sorted by their key. This allows you to
434compare data structures by comparing their frozen representations (or
435even the compressed frozen representations), which can be useful for
436creating lookup tables for complicated queries.
437
438Canonical order does not imply network order, those are two orthogonal
439settings.
440
441=head1 ERROR REPORTING
442
443Storable uses the "exception" paradigm, in that it does not try to workaround
444failures: if something bad happens, an exception is generated from the
445caller's perspective (see L<Carp> and C<croak()>). Use eval {} to trap
446those exceptions.
447
448When Storable croaks, it tries to report the error via the C<logcroak()>
449routine from the C<Log::Agent> package, if it is available.
450
451=head1 WIZARDS ONLY
452
453=head2 Hooks
454
455Any class may define hooks that will be called during the serialization
456and deserialization process on objects that are instances of that class.
457Those hooks can redefine the way serialization is performed (and therefore,
458how the symetrical deserialization should be conducted).
459
460Since we said earlier:
461
462 dclone(.) = thaw(freeze(.))
463
464everything we say about hooks should also hold for deep cloning. However,
465hooks get to know whether the operation is a mere serialization, or a cloning.
466
467Therefore, when serializing hooks are involved,
468
469 dclone(.) <> thaw(freeze(.))
470
471Well, you could keep them in sync, but there's no guarantee it will always
472hold on classes somebody else wrote. Besides, there is little to gain in
473doing so: a serializing hook could only keep one attribute of an object,
474which is probably not what should happen during a deep cloning of that
475same object.
476
477Here is the hooking interface:
478
479=over
480
481=item C<STORABLE_freeze> I<obj>, I<cloning>
482
483The serializing hook, called on the object during serialization. It can be
484inherited, or defined in the class itself, like any other method.
485
486Arguments: I<obj> is the object to serialize, I<cloning> is a flag indicating
487whether we're in a dclone() or a regular serialization via store() or freeze().
488
489Returned value: A LIST C<($serialized, $ref1, $ref2, ...)> where $serialized
490is the serialized form to be used, and the optional $ref1, $ref2, etc... are
491extra references that you wish to let the Storable engine serialize.
492
493At deserialization time, you will be given back the same LIST, but all the
494extra references will be pointing into the deserialized structure.
495
496The B<first time> the hook is hit in a serialization flow, you may have it
497return an empty list. That will signal the Storable engine to further
498discard that hook for this class and to therefore revert to the default
499serialization of the underlying Perl data. The hook will again be normally
500processed in the next serialization.
501
502Unless you know better, serializing hook should always say:
503
504 sub STORABLE_freeze {
505 my ($self, $cloning) = @_;
506 return if $cloning; # Regular default serialization
507 ....
508 }
509
510in order to keep reasonable dclone() semantics.
511
512=item C<STORABLE_thaw> I<obj>, I<cloning>, I<serialized>, ...
513
514The deserializing hook called on the object during deserialization.
515But wait. If we're deserializing, there's no object yet... right?
516
517Wrong: the Storable engine creates an empty one for you. If you know Eiffel,
518you can view C<STORABLE_thaw> as an alternate creation routine.
519
520This means the hook can be inherited like any other method, and that
521I<obj> is your blessed reference for this particular instance.
522
523The other arguments should look familiar if you know C<STORABLE_freeze>:
524I<cloning> is true when we're part of a deep clone operation, I<serialized>
525is the serialized string you returned to the engine in C<STORABLE_freeze>,
526and there may be an optional list of references, in the same order you gave
527them at serialization time, pointing to the deserialized objects (which
528have been processed courtesy of the Storable engine).
529
530It is up to you to use these information to populate I<obj> the way you want.
531
532Returned value: none.
533
534=back
535
536=head2 Predicates
537
538Predicates are not exportable. They must be called by explicitely prefixing
539them with the Storable package name.
540
541=over
542
543=item C<Storable::last_op_in_netorder>
544
545The C<Storable::last_op_in_netorder()> predicate will tell you whether
546network order was used in the last store or retrieve operation. If you
547don't know how to use this, just forget about it.
548
549=item C<Storable::is_storing>
550
551Returns true if within a store operation (via STORABLE_freeze hook).
552
553=item C<Storable::is_retrieving>
554
555Returns true if within a retrieve operation, (via STORABLE_thaw hook).
556
557=back
558
559=head2 Recursion
560
561With hooks comes the ability to recurse back to the Storable engine. Indeed,
562hooks are regular Perl code, and Storable is convenient when it comes to
563serialize and deserialize things, so why not use it to handle the
564serialization string?
565
566There are a few things you need to know however:
567
568=over
569
570=item *
571
572You can create endless loops if the things you serialize via freeze()
573(for instance) point back to the object we're trying to serialize in the hook.
574
575=item *
576
577Shared references among objects will not stay shared: if we're serializing
578the list of object [A, C] where both object A and C refer to the SAME object
579B, and if there is a serializing hook in A that says freeze(B), then when
580deserializing, we'll get [A', C'] where A' refers to B', but C' refers to D,
581a deep clone of B'. The topology was not preserved.
582
583=back
584
585That's why C<STORABLE_freeze> lets you provide a list of references
586to serialize. The engine guarantees that those will be serialized in the
587same context as the other objects, and therefore that shared objects will
588stay shared.
589
590In the above [A, C] example, the C<STORABLE_freeze> hook could return:
591
592 ("something", $self->{B})
593
594and the B part would be serialized by the engine. In C<STORABLE_thaw>, you
595would get back the reference to the B' object, deserialized for you.
596
597Therefore, recursion should normally be avoided, but is nonetheless supported.
598
599=head2 Deep Cloning
600
601There is a new Clone module available on CPAN which implements deep cloning
602natively, i.e. without freezing to memory and thawing the result. It is
603aimed to replace Storable's dclone() some day. However, it does not currently
604support Storable hooks to redefine the way deep cloning is performed.
605
606=head1 EXAMPLES
607
608Here are some code samples showing a possible usage of Storable:
609
610 use Storable qw(store retrieve freeze thaw dclone);
611
612 %color = ('Blue' => 0.1, 'Red' => 0.8, 'Black' => 0, 'White' => 1);
613
614 store(\%color, '/tmp/colors') or die "Can't store %a in /tmp/colors!\n";
615
616 $colref = retrieve('/tmp/colors');
617 die "Unable to retrieve from /tmp/colors!\n" unless defined $colref;
618 printf "Blue is still %lf\n", $colref->{'Blue'};
619
620 $colref2 = dclone(\%color);
621
622 $str = freeze(\%color);
623 printf "Serialization of %%color is %d bytes long.\n", length($str);
624 $colref3 = thaw($str);
625
626which prints (on my machine):
627
628 Blue is still 0.100000
629 Serialization of %color is 102 bytes long.
630
631=head1 WARNING
632
633If you're using references as keys within your hash tables, you're bound
634to disapointment when retrieving your data. Indeed, Perl stringifies
635references used as hash table keys. If you later wish to access the
636items via another reference stringification (i.e. using the same
637reference that was used for the key originally to record the value into
638the hash table), it will work because both references stringify to the
639same string.
640
641It won't work across a C<store> and C<retrieve> operations however, because
642the addresses in the retrieved objects, which are part of the stringified
643references, will probably differ from the original addresses. The
644topology of your structure is preserved, but not hidden semantics
645like those.
646
647On platforms where it matters, be sure to call C<binmode()> on the
648descriptors that you pass to Storable functions.
649
650Storing data canonically that contains large hashes can be
651significantly slower than storing the same data normally, as
652temprorary arrays to hold the keys for each hash have to be allocated,
653populated, sorted and freed. Some tests have shown a halving of the
654speed of storing -- the exact penalty will depend on the complexity of
655your data. There is no slowdown on retrieval.
656
657=head1 BUGS
658
659You can't store GLOB, CODE, FORMLINE, etc... If you can define
660semantics for those operations, feel free to enhance Storable so that
661it can deal with them.
662
663The store functions will C<croak> if they run into such references
664unless you set C<$Storable::forgive_me> to some C<TRUE> value. In that
665case, the fatal message is turned in a warning and some
666meaningless string is stored instead.
667
668Setting C<$Storable::canonical> may not yield frozen strings that
669compare equal due to possible stringification of numbers. When the
670string version of a scalar exists, it is the form stored, therefore
671if you happen to use your numbers as strings between two freezing
672operations on the same data structures, you will get different
673results.
674
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675When storing doubles in network order, their value is stored as text.
676However, you should also not expect non-numeric floating-point values
677such as infinity and "not a number" to pass successfully through a
678nstore()/retrieve() pair.
679
680As Storable neither knows nor cares about character sets (although it
681does know that characters may be more than eight bits wide), any difference
682in the interpretation of character codes between a host and a target
683system is your problem. In particular, if host and target use different
684code points to represent the characters used in the text representation
685of floating-point numbers, you will not be able be able to exchange
686floating-point data, even with nstore().
687
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688=head1 CREDITS
689
690Thank you to (in chronological order):
691
692 Jarkko Hietaniemi <jhi@iki.fi>
693 Ulrich Pfeifer <pfeifer@charly.informatik.uni-dortmund.de>
694 Benjamin A. Holzman <bah@ecnvantage.com>
695 Andrew Ford <A.Ford@ford-mason.co.uk>
696 Gisle Aas <gisle@aas.no>
697 Jeff Gresham <gresham_jeffrey@jpmorgan.com>
698 Murray Nesbitt <murray@activestate.com>
699 Marc Lehmann <pcg@opengroup.org>
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700 Justin Banks <justinb@wamnet.com>
701 Jarkko Hietaniemi <jhi@iki.fi> (AGAIN, as perl 5.7.0 Pumpkin!)
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702 Salvador Ortiz Garcia <sog@msg.com.mx>
703 Dominic Dunlop <domo@computer.org>
704 Erik Haugan <erik@solbors.no>
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705
706for their bug reports, suggestions and contributions.
707
708Benjamin Holzman contributed the tied variable support, Andrew Ford
709contributed the canonical order for hashes, and Gisle Aas fixed
710a few misunderstandings of mine regarding the Perl internals,
711and optimized the emission of "tags" in the output streams by
712simply counting the objects instead of tagging them (leading to
713a binary incompatibility for the Storable image starting at version
7140.6--older images are of course still properly understood).
715Murray Nesbitt made Storable thread-safe. Marc Lehmann added overloading
716and reference to tied items support.
717
718=head1 TRANSLATIONS
719
720There is a Japanese translation of this man page available at
721http://member.nifty.ne.jp/hippo2000/perltips/storable.htm ,
722courtesy of Kawai, Takanori <kawai@nippon-rad.co.jp>.
723
724=head1 AUTHOR
725
726Raphael Manfredi F<E<lt>Raphael_Manfredi@pobox.comE<gt>>
727
728=head1 SEE ALSO
729
730Clone(3).
731
732=cut
733