[ViewVC] Diff of: cvs/CBOR-XS/XS.pm

Comparing CBOR-XS/XS.pm (file contents):
Revision 1.20 by root, Wed Nov 20 02:03:08 2013 UTC vs.
Revision 1.35 by root, Sun Dec 1 16:40:25 2013 UTC

…		…
26	substr $many_cbor_strings, 0, $length, ""; # remove decoded cbor string	26	substr $many_cbor_strings, 0, $length, ""; # remove decoded cbor string
27	}	27	}
28		28
29	=head1 DESCRIPTION	29	=head1 DESCRIPTION
30		30
31	WARNING! This module is very new, and not very well tested (that's up to
32	you to do). Furthermore, details of the implementation might change freely
33	before version 1.0. And lastly, the object serialisation protocol depends
34	on a pending IANA assignment, and until that assignment is official, this
35	implementation is not interoperable with other implementations (even
36	future versions of this module) until the assignment is done.
37
38	You are still invited to try out CBOR, and this module.
39
40	This module converts Perl data structures to the Concise Binary Object	31	This module converts Perl data structures to the Concise Binary Object
41	Representation (CBOR) and vice versa. CBOR is a fast binary serialisation	32	Representation (CBOR) and vice versa. CBOR is a fast binary serialisation
42	format that aims to use a superset of the JSON data model, i.e. when you	33	format that aims to use an (almost) superset of the JSON data model, i.e.
43	can represent something in JSON, you should be able to represent it in	34	when you can represent something useful in JSON, you should be able to
44	CBOR.	35	represent it in CBOR.
45		36
46	In short, CBOR is a faster and very compact binary alternative to JSON,	37	In short, CBOR is a faster and quite compact binary alternative to JSON,
47	with the added ability of supporting serialisation of Perl objects. (JSON	38	with the added ability of supporting serialisation of Perl objects. (JSON
48	often compresses better than CBOR though, so if you plan to compress the	39	often compresses better than CBOR though, so if you plan to compress the
49	data later you might want to compare both formats first).	40	data later and speed is less important you might want to compare both
		41	formats first).
50		42
51	To give you a general idea about speed, with texts in the megabyte range,	43	To give you a general idea about speed, with texts in the megabyte range,
52	C<CBOR::XS> usually encodes roughly twice as fast as L<Storable> or	44	C<CBOR::XS> usually encodes roughly twice as fast as L<Storable> or
53	L<JSON::XS> and decodes about 15%-30% faster than those. The shorter the	45	L<JSON::XS> and decodes about 15%-30% faster than those. The shorter the
54	data, the worse L<Storable> performs in comparison.	46	data, the worse L<Storable> performs in comparison.
55		47
56	As for compactness, C<CBOR::XS> encoded data structures are usually about	48	Regarding compactness, C<CBOR::XS>-encoded data structures are usually
57	20% smaller than the same data encoded as (compact) JSON or L<Storable>.	49	about 20% smaller than the same data encoded as (compact) JSON or
		50	L<Storable>.
		51
		52	In addition to the core CBOR data format, this module implements a
		53	number of extensions, to support cyclic and shared data structures
		54	(see C<allow_sharing> and C<allow_cycles>), string deduplication (see
		55	C<pack_strings>) and scalar references (always enabled).
58		56
59	The primary goal of this module is to be I<correct> and the secondary goal	57	The primary goal of this module is to be I<correct> and the secondary goal
60	is to be I<fast>. To reach the latter goal it was written in C.	58	is to be I<fast>. To reach the latter goal it was written in C.
61		59
62	See MAPPING, below, on how CBOR::XS maps perl values to CBOR values and	60	See MAPPING, below, on how CBOR::XS maps perl values to CBOR values and
…		…
66		64
67	package CBOR::XS;	65	package CBOR::XS;
68		66
69	use common::sense;	67	use common::sense;
70		68
71	our $VERSION = 0.08;	69	our $VERSION = 1.11;
72	our @ISA = qw(Exporter);	70	our @ISA = qw(Exporter);
73		71
74	our @EXPORT = qw(encode_cbor decode_cbor);	72	our @EXPORT = qw(encode_cbor decode_cbor);
75		73
76	use Exporter;	74	use Exporter;
…		…
113	strings. All boolean flags described below are by default I<disabled>.	111	strings. All boolean flags described below are by default I<disabled>.
114		112
115	The mutators for flags all return the CBOR object again and thus calls can	113	The mutators for flags all return the CBOR object again and thus calls can
116	be chained:	114	be chained:
117		115
118	#TODO
119	my $cbor = CBOR::XS->new->encode ({a => [1,2]});	116	my $cbor = CBOR::XS->new->encode ({a => [1,2]});
120		117
121	=item $cbor = $cbor->max_depth ([$maximum_nesting_depth])	118	=item $cbor = $cbor->max_depth ([$maximum_nesting_depth])
122		119
123	=item $max_depth = $cbor->get_max_depth	120	=item $max_depth = $cbor->get_max_depth
…		…
182	as an array, is referenced multiple times), but instead will emit a	179	as an array, is referenced multiple times), but instead will emit a
183	reference to the earlier value.	180	reference to the earlier value.
184		181
185	This means that such values will only be encoded once, and will not result	182	This means that such values will only be encoded once, and will not result
186	in a deep cloning of the value on decode, in decoders supporting the value	183	in a deep cloning of the value on decode, in decoders supporting the value
187	sharing extension.	184	sharing extension. This also makes it possible to encode cyclic data
		185	structures (which need C<allow_cycles> to ne enabled to be decoded by this
		186	module).
		187
		188	It is recommended to leave it off unless you know your
		189	communication partner supports the value sharing extensions to CBOR
		190	(L<http://cbor.schmorp.de/value-sharing>), as without decoder support, the
		191	resulting data structure might be unusable.
188		192
189	Detecting shared values incurs a runtime overhead when values are encoded	193	Detecting shared values incurs a runtime overhead when values are encoded
190	that have a reference counter large than one, and might unnecessarily	194	that have a reference counter large than one, and might unnecessarily
191	increase the encoded size, as potentially shared values are encode as	195	increase the encoded size, as potentially shared values are encode as
192	sharable whether or not they are actually shared.	196	shareable whether or not they are actually shared.
193		197
194	At the moment, only targets of references can be shared (e.g. scalars,	198	At the moment, only targets of references can be shared (e.g. scalars,
195	arrays or hashes pointed to by a reference). Weirder constructs, such as	199	arrays or hashes pointed to by a reference). Weirder constructs, such as
196	an array with multiple "copies" of the I<same> string, which are hard but	200	an array with multiple "copies" of the I<same> string, which are hard but
197	not impossible to create in Perl, are not supported (this is the same as	201	not impossible to create in Perl, are not supported (this is the same as
198	for L<Storable>).	202	with L<Storable>).
199		203
200	If C<$enable> is false (the default), then C<encode> will encode	204	If C<$enable> is false (the default), then C<encode> will encode shared
201	exception when it encounters anything it cannot encode as CBOR.	205	data structures repeatedly, unsharing them in the process. Cyclic data
		206	structures cannot be encoded in this mode.
202		207
203	This option does not affect C<decode> in any way - shared values and	208	This option does not affect C<decode> in any way - shared values and
204	references will always be decoded properly if present. It is recommended	209	references will always be decoded properly if present.
205	to leave it off unless you know your communications partner supports the	210
206	value sharing extensions to CBOR (http://cbor.schmorp.de/value-sharing).	211	=item $cbor = $cbor->allow_cycles ([$enable])
		212
		213	=item $enabled = $cbor->get_allow_cycles
		214
		215	If C<$enable> is true (or missing), then C<decode> will happily decode
		216	self-referential (cyclic) data structures. By default these will not be
		217	decoded, as they need manual cleanup to avoid memory leaks, so code that
		218	isn't prepared for this will not leak memory.
		219
		220	If C<$enable> is false (the default), then C<decode> will throw an error
		221	when it encounters a self-referential/cyclic data structure.
		222
		223	This option does not affect C<encode> in any way - shared values and
		224	references will always be decoded properly if present.
		225
		226	=item $cbor = $cbor->pack_strings ([$enable])
		227
		228	=item $enabled = $cbor->get_pack_strings
		229
		230	If C<$enable> is true (or missing), then C<encode> will try not to encode
		231	the same string twice, but will instead encode a reference to the string
		232	instead. Depending on your data format, this can save a lot of space, but
		233	also results in a very large runtime overhead (expect encoding times to be
		234	2-4 times as high as without).
		235
		236	It is recommended to leave it off unless you know your
		237	communications partner supports the stringref extension to CBOR
		238	(L<http://cbor.schmorp.de/stringref>), as without decoder support, the
		239	resulting data structure might not be usable.
		240
		241	If C<$enable> is false (the default), then C<encode> will encode strings
		242	the standard CBOR way.
		243
		244	This option does not affect C<decode> in any way - string references will
		245	always be decoded properly if present.
		246
		247	=item $cbor = $cbor->validate_utf8 ([$enable])
		248
		249	=item $enabled = $cbor->get_validate_utf8
		250
		251	If C<$enable> is true (or missing), then C<decode> will validate that
		252	elements (text strings) containing UTF-8 data in fact contain valid UTF-8
		253	data (instead of blindly accepting it). This validation obviously takes
		254	extra time during decoding.
		255
		256	The concept of "valid UTF-8" used is perl's concept, which is a superset
		257	of the official UTF-8.
		258
		259	If C<$enable> is false (the default), then C<decode> will blindly accept
		260	UTF-8 data, marking them as valid UTF-8 in the resulting data structure
		261	regardless of whether thats true or not.
		262
		263	Perl isn't too happy about corrupted UTF-8 in strings, but should
		264	generally not crash or do similarly evil things. Extensions might be not
		265	so forgiving, so it's recommended to turn on this setting if you receive
		266	untrusted CBOR.
		267
		268	This option does not affect C<encode> in any way - strings that are
		269	supposedly valid UTF-8 will simply be dumped into the resulting CBOR
		270	string without checking whether that is, in fact, true or not.
		271
		272	=item $cbor = $cbor->filter ([$cb->($tag, $value)])
		273
		274	=item $cb_or_undef = $cbor->get_filter
		275
		276	Sets or replaces the tagged value decoding filter (when C<$cb> is
		277	specified) or clears the filter (if no argument or C<undef> is provided).
		278
		279	The filter callback is called only during decoding, when a non-enforced
		280	tagged value has been decoded (see L<TAG HANDLING AND EXTENSIONS> for a
		281	list of enforced tags). For specific tags, it's often better to provide a
		282	default converter using the C<%CBOR::XS::FILTER> hash (see below).
		283
		284	The first argument is the numerical tag, the second is the (decoded) value
		285	that has been tagged.
		286
		287	The filter function should return either exactly one value, which will
		288	replace the tagged value in the decoded data structure, or no values,
		289	which will result in default handling, which currently means the decoder
		290	creates a C<CBOR::XS::Tagged> object to hold the tag and the value.
		291
		292	When the filter is cleared (the default state), the default filter
		293	function, C<CBOR::XS::default_filter>, is used. This function simply looks
		294	up the tag in the C<%CBOR::XS::FILTER> hash. If an entry exists it must be
		295	a code reference that is called with tag and value, and is responsible for
		296	decoding the value. If no entry exists, it returns no values.
		297
		298	Example: decode all tags not handled internally into C<CBOR::XS::Tagged>
		299	objects, with no other special handling (useful when working with
		300	potentially "unsafe" CBOR data).
		301
		302	CBOR::XS->new->filter (sub { })->decode ($cbor_data);
		303
		304	Example: provide a global filter for tag 1347375694, converting the value
		305	into some string form.
		306
		307	$CBOR::XS::FILTER{1347375694} = sub {
		308	my ($tag, $value);
		309
		310	"tag 1347375694 value $value"
		311	};
207		312
208	=item $cbor_data = $cbor->encode ($perl_scalar)	313	=item $cbor_data = $cbor->encode ($perl_scalar)
209		314
210	Converts the given Perl data structure (a scalar value) to its CBOR	315	Converts the given Perl data structure (a scalar value) to its CBOR
211	representation.	316	representation.
…		…
252	CBOR integers become (numeric) perl scalars. On perls without 64 bit	357	CBOR integers become (numeric) perl scalars. On perls without 64 bit
253	support, 64 bit integers will be truncated or otherwise corrupted.	358	support, 64 bit integers will be truncated or otherwise corrupted.
254		359
255	=item byte strings	360	=item byte strings
256		361
257	Byte strings will become octet strings in Perl (the byte values 0..255	362	Byte strings will become octet strings in Perl (the Byte values 0..255
258	will simply become characters of the same value in Perl).	363	will simply become characters of the same value in Perl).
259		364
260	=item UTF-8 strings	365	=item UTF-8 strings
261		366
262	UTF-8 strings in CBOR will be decoded, i.e. the UTF-8 octets will be	367	UTF-8 strings in CBOR will be decoded, i.e. the UTF-8 octets will be
…		…
280	C<Types:Serialiser::false> and C<Types::Serialiser::error>,	385	C<Types:Serialiser::false> and C<Types::Serialiser::error>,
281	respectively. They are overloaded to act almost exactly like the numbers	386	respectively. They are overloaded to act almost exactly like the numbers
282	C<1> and C<0> (for true and false) or to throw an exception on access (for	387	C<1> and C<0> (for true and false) or to throw an exception on access (for
283	error). See the L<Types::Serialiser> manpage for details.	388	error). See the L<Types::Serialiser> manpage for details.
284		389
285	=item CBOR tag 256 (perl object)	390	=item tagged values
286		391
287	The tag value C<256> (TODO: pending iana registration) will be used
288	to deserialise a Perl object serialised with C<FREEZE>. See L<OBJECT
289	SERIALISATION>, below, for details.
290
291	=item CBOR tag 55799 (magic header)
292
293	The tag 55799 is ignored (this tag implements the magic header).
294
295	=item other CBOR tags
296
297	Tagged items consists of a numeric tag and another CBOR value. Tags not	392	Tagged items consists of a numeric tag and another CBOR value.
298	handled internally are currently converted into a L<CBOR::XS::Tagged>
299	object, which is simply a blessed array reference consisting of the
300	numeric tag value followed by the (decoded) CBOR value.
301		393
302	In the future, support for user-supplied conversions might get added.	394	See L<TAG HANDLING AND EXTENSIONS> and the description of C<< ->filter >>
		395	for details on which tags are handled how.
303		396
304	=item anything else	397	=item anything else
305		398
306	Anything else (e.g. unsupported simple values) will raise a decoding	399	Anything else (e.g. unsupported simple values) will raise a decoding
307	error.	400	error.
…		…
310		403
311		404
312	=head2 PERL -> CBOR	405	=head2 PERL -> CBOR
313		406
314	The mapping from Perl to CBOR is slightly more difficult, as Perl is a	407	The mapping from Perl to CBOR is slightly more difficult, as Perl is a
315	truly typeless language, so we can only guess which CBOR type is meant by	408	typeless language. That means this module can only guess which CBOR type
316	a Perl value.	409	is meant by a perl value.
317		410
318	=over 4	411	=over 4
319		412
320	=item hash references	413	=item hash references
321		414
322	Perl hash references become CBOR maps. As there is no inherent ordering in	415	Perl hash references become CBOR maps. As there is no inherent ordering in
323	hash keys (or CBOR maps), they will usually be encoded in a pseudo-random	416	hash keys (or CBOR maps), they will usually be encoded in a pseudo-random
324	order.	417	order. This order can be different each time a hahs is encoded.
325		418
326	Currently, tied hashes will use the indefinite-length format, while normal	419	Currently, tied hashes will use the indefinite-length format, while normal
327	hashes will use the fixed-length format.	420	hashes will use the fixed-length format.
328		421
329	=item array references	422	=item array references
330		423
331	Perl array references become fixed-length CBOR arrays.	424	Perl array references become fixed-length CBOR arrays.
332		425
333	=item other references	426	=item other references
334		427
335	Other unblessed references are generally not allowed and will cause an	428	Other unblessed references will be represented using
336	exception to be thrown, except for references to the integers C<0> and	429	the indirection tag extension (tag value C<22098>,
337	C<1>, which get turned into false and true in CBOR.	430	L<http://cbor.schmorp.de/indirection>). CBOR decoders are guaranteed
		431	to be able to decode these values somehow, by either "doing the right
		432	thing", decoding into a generic tagged object, simply ignoring the tag, or
		433	something else.
338		434
339	=item CBOR::XS::Tagged objects	435	=item CBOR::XS::Tagged objects
340		436
341	Objects of this type must be arrays consisting of a single C<[tag, value]>	437	Objects of this type must be arrays consisting of a single C<[tag, value]>
342	pair. The (numerical) tag will be encoded as a CBOR tag, the value will	438	pair. The (numerical) tag will be encoded as a CBOR tag, the value will
343	be encoded as appropriate for the value. You cna use C<CBOR::XS::tag> to	439	be encoded as appropriate for the value. You must use C<CBOR::XS::tag> to
344	create such objects.	440	create such objects.
345		441
346	=item Types::Serialiser::true, Types::Serialiser::false, Types::Serialiser::error	442	=item Types::Serialiser::true, Types::Serialiser::false, Types::Serialiser::error
347		443
348	These special values become CBOR true, CBOR false and CBOR undefined	444	These special values become CBOR true, CBOR false and CBOR undefined
…		…
350	if you want.	446	if you want.
351		447
352	=item other blessed objects	448	=item other blessed objects
353		449
354	Other blessed objects are serialised via C<TO_CBOR> or C<FREEZE>. See	450	Other blessed objects are serialised via C<TO_CBOR> or C<FREEZE>. See
355	L<OBJECT SERIALISATION>, below, for details.	451	L<TAG HANDLING AND EXTENSIONS> for specific classes handled by this
		452	module, and L<OBJECT SERIALISATION> for generic object serialisation.
356		453
357	=item simple scalars	454	=item simple scalars
358		455
359	TODO
360	Simple Perl scalars (any scalar that is not a reference) are the most	456	Simple Perl scalars (any scalar that is not a reference) are the most
361	difficult objects to encode: CBOR::XS will encode undefined scalars as	457	difficult objects to encode: CBOR::XS will encode undefined scalars as
362	CBOR null values, scalars that have last been used in a string context	458	CBOR null values, scalars that have last been used in a string context
363	before encoding as CBOR strings, and anything else as number value:	459	before encoding as CBOR strings, and anything else as number value:
364		460
365	# dump as number	461	# dump as number
366	encode_cbor [2] # yields [2]	462	encode_cbor [2] # yields [2]
367	encode_cbor [-3.0e17] # yields [-3e+17]	463	encode_cbor [-3.0e17] # yields [-3e+17]
368	my $value = 5; encode_cbor [$value] # yields [5]	464	my $value = 5; encode_cbor [$value] # yields [5]
369		465
370	# used as string, so dump as string	466	# used as string, so dump as string (either byte or text)
371	print $value;	467	print $value;
372	encode_cbor [$value] # yields ["5"]	468	encode_cbor [$value] # yields ["5"]
373		469
374	# undef becomes null	470	# undef becomes null
375	encode_cbor [undef] # yields [null]	471	encode_cbor [undef] # yields [null]
…		…
378		474
379	my $x = 3.1; # some variable containing a number	475	my $x = 3.1; # some variable containing a number
380	"$x"; # stringified	476	"$x"; # stringified
381	$x .= ""; # another, more awkward way to stringify	477	$x .= ""; # another, more awkward way to stringify
382	print $x; # perl does it for you, too, quite often	478	print $x; # perl does it for you, too, quite often
		479
		480	You can force whether a string ie encoded as byte or text string by using
		481	C<utf8::upgrade> and C<utf8::downgrade>):
		482
		483	utf8::upgrade $x; # encode $x as text string
		484	utf8::downgrade $x; # encode $x as byte string
		485
		486	Perl doesn't define what operations up- and downgrade strings, so if the
		487	difference between byte and text is important, you should up- or downgrade
		488	your string as late as possible before encoding.
383		489
384	You can force the type to be a CBOR number by numifying it:	490	You can force the type to be a CBOR number by numifying it:
385		491
386	my $x = "3"; # some variable containing a string	492	my $x = "3"; # some variable containing a string
387	$x += 0; # numify it, ensuring it will be dumped as a number	493	$x += 0; # numify it, ensuring it will be dumped as a number
…		…
400		506
401	=back	507	=back
402		508
403	=head2 OBJECT SERIALISATION	509	=head2 OBJECT SERIALISATION
404		510
		511	This module implements both a CBOR-specific and the generic
		512	L<Types::Serialier> object serialisation protocol. The following
		513	subsections explain both methods.
		514
		515	=head3 ENCODING
		516
405	This module knows two way to serialise a Perl object: The CBOR-specific	517	This module knows two way to serialise a Perl object: The CBOR-specific
406	way, and the generic way.	518	way, and the generic way.
407		519
408	Whenever the encoder encounters a Perl object that it cnanot serialise	520	Whenever the encoder encounters a Perl object that it cannot serialise
409	directly (most of them), it will first look up the C<TO_CBOR> method on	521	directly (most of them), it will first look up the C<TO_CBOR> method on
410	it.	522	it.
411		523
412	If it has a C<TO_CBOR> method, it will call it with the object as only	524	If it has a C<TO_CBOR> method, it will call it with the object as only
413	argument, and expects exactly one return value, which it will then	525	argument, and expects exactly one return value, which it will then
…		…
419		531
420	The C<FREEZE> method can return any number of values (i.e. zero or	532	The C<FREEZE> method can return any number of values (i.e. zero or
421	more). These will be encoded as CBOR perl object, together with the	533	more). These will be encoded as CBOR perl object, together with the
422	classname.	534	classname.
423		535
		536	These methods I<MUST NOT> change the data structure that is being
		537	serialised. Failure to comply to this can result in memory corruption -
		538	and worse.
		539
424	If an object supports neither C<TO_CBOR> nor C<FREEZE>, encoding will fail	540	If an object supports neither C<TO_CBOR> nor C<FREEZE>, encoding will fail
425	with an error.	541	with an error.
426		542
		543	=head3 DECODING
		544
427	Objects encoded via C<TO_CBOR> cannot be automatically decoded, but	545	Objects encoded via C<TO_CBOR> cannot (normally) be automatically decoded,
428	objects encoded via C<FREEZE> can be decoded using the following protocol:	546	but objects encoded via C<FREEZE> can be decoded using the following
		547	protocol:
429		548
430	When an encoded CBOR perl object is encountered by the decoder, it will	549	When an encoded CBOR perl object is encountered by the decoder, it will
431	look up the C<THAW> method, by using the stored classname, and will fail	550	look up the C<THAW> method, by using the stored classname, and will fail
432	if the method cannot be found.	551	if the method cannot be found.
433		552
434	After the lookup it will call the C<THAW> method with the stored classname	553	After the lookup it will call the C<THAW> method with the stored classname
435	as first argument, the constant string C<CBOR> as second argument, and all	554	as first argument, the constant string C<CBOR> as second argument, and all
436	values returned by C<FREEZE> as remaining arguments.	555	values returned by C<FREEZE> as remaining arguments.
437		556
438	=head4 EXAMPLES	557	=head3 EXAMPLES
439		558
440	Here is an example C<TO_CBOR> method:	559	Here is an example C<TO_CBOR> method:
441		560
442	sub My::Object::TO_CBOR {	561	sub My::Object::TO_CBOR {
443	my ($obj) = @_;	562	my ($obj) = @_;
…		…
454		573
455	sub URI::TO_CBOR {	574	sub URI::TO_CBOR {
456	my ($self) = @_;	575	my ($self) = @_;
457	my $uri = "$self"; # stringify uri	576	my $uri = "$self"; # stringify uri
458	utf8::upgrade $uri; # make sure it will be encoded as UTF-8 string	577	utf8::upgrade $uri; # make sure it will be encoded as UTF-8 string
459	CBOR::XS::tagged 32, "$_[0]"	578	CBOR::XS::tag 32, "$_[0]"
460	}	579	}
461		580
462	This will encode URIs as a UTF-8 string with tag 32, which indicates an	581	This will encode URIs as a UTF-8 string with tag 32, which indicates an
463	URI.	582	URI.
464		583
…		…
600	CBOR::XS::tag 24,	719	CBOR::XS::tag 24,
601	encode_cbor [1, 2, 3];	720	encode_cbor [1, 2, 3];
602		721
603	=head1 TAG HANDLING AND EXTENSIONS	722	=head1 TAG HANDLING AND EXTENSIONS
604		723
605	This section describes how this module handles specific tagged values and	724	This section describes how this module handles specific tagged values
606	extensions. If a tag is not mentioned here, then the default handling	725	and extensions. If a tag is not mentioned here and no additional filters
		726	are provided for it, then the default handling applies (creating a
607	applies (creating a CBOR::XS::Tagged object on decoding, and only encoding	727	CBOR::XS::Tagged object on decoding, and only encoding the tag when
608	the tag when explicitly requested).	728	explicitly requested).
		729
		730	Tags not handled specifically are currently converted into a
		731	L<CBOR::XS::Tagged> object, which is simply a blessed array reference
		732	consisting of the numeric tag value followed by the (decoded) CBOR value.
609		733
610	Future versions of this module reserve the right to special case	734	Future versions of this module reserve the right to special case
611	additional tags (such as bigfloat or base64url).	735	additional tags (such as base64url).
		736
		737	=head2 ENFORCED TAGS
		738
		739	These tags are always handled when decoding, and their handling cannot be
		740	overriden by the user.
612		741
613	=over 4	742	=over 4
614		743
615	=item <unassigned> (perl-object, L<http://cbor.schmorp.de/perl-object>)	744	=item 26 (perl-object, L<http://cbor.schmorp.de/perl-object>)
616		745
617	These tags are automatically created for serialisable objects using the	746	These tags are automatically created (and decoded) for serialisable
618	C<FREEZE/THAW> methods (the L<Types::Serialier> object serialisation	747	objects using the C<FREEZE/THAW> methods (the L<Types::Serialier> object
619	protocol).	748	serialisation protocol). See L<OBJECT SERIALISATION> for details.
620		749
621	=item <unassigned>, <unassigned> (sharable, sharedref, L <http://cbor.schmorp.de/value-sharing>)	750	=item 28, 29 (shareable, sharedref, L <http://cbor.schmorp.de/value-sharing>)
622		751
623	These tags are automatically decoded when encountered, resulting in	752	These tags are automatically decoded when encountered (and they do not
		753	result in a cyclic data structure, see C<allow_cycles>), resulting in
624	shared values in the decoded object. They are only encoded, however, when	754	shared values in the decoded object. They are only encoded, however, when
625	C<allow_sharable> is enabled.	755	C<allow_sharing> is enabled.
		756
		757	Not all shared values can be successfully decoded: values that reference
		758	themselves will I<currently> decode as C<undef> (this is not the same
		759	as a reference pointing to itself, which will be represented as a value
		760	that contains an indirect reference to itself - these will be decoded
		761	properly).
		762
		763	Note that considerably more shared value data structures can be decoded
		764	than will be encoded - currently, only values pointed to by references
		765	will be shared, others will not. While non-reference shared values can be
		766	generated in Perl with some effort, they were considered too unimportant
		767	to be supported in the encoder. The decoder, however, will decode these
		768	values as shared values.
		769
		770	=item 256, 25 (stringref-namespace, stringref, L <http://cbor.schmorp.de/stringref>)
		771
		772	These tags are automatically decoded when encountered. They are only
		773	encoded, however, when C<pack_strings> is enabled.
626		774
627	=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)	775	=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)
628		776
629	This tag is automatically generated when a reference are encountered (with	777	This tag is automatically generated when a reference are encountered (with
630	the exception of hash and array refernces). It is converted to a reference	778	the exception of hash and array refernces). It is converted to a reference
…		…
634		782
635	This value is not generated on encoding (unless explicitly requested by	783	This value is not generated on encoding (unless explicitly requested by
636	the user), and is simply ignored when decoding.	784	the user), and is simply ignored when decoding.
637		785
638	=back	786	=back
		787
		788	=head2 NON-ENFORCED TAGS
		789
		790	These tags have default filters provided when decoding. Their handling can
		791	be overriden by changing the C<%CBOR::XS::FILTER> entry for the tag, or by
		792	providing a custom C<filter> callback when decoding.
		793
		794	When they result in decoding into a specific Perl class, the module
		795	usually provides a corresponding C<TO_CBOR> method as well.
		796
		797	When any of these need to load additional modules that are not part of the
		798	perl core distribution (e.g. L<URI>), it is (currently) up to the user to
		799	provide these modules. The decoding usually fails with an exception if the
		800	required module cannot be loaded.
		801
		802	=over 4
		803
		804	=item 0, 1 (date/time string, seconds since the epoch)
		805
		806	These tags are decoded into L<Time::Piece> objects. The corresponding
		807	C<Time::Piece::TO_CBOR> method always encodes into tag 1 values currently.
		808
		809	The L<Time::Piece> API is generally surprisingly bad, and fractional
		810	seconds are only accidentally kept intact, so watch out. On the plus side,
		811	the module comes with perl since 5.10, which has to count for something.
		812
		813	=item 2, 3 (positive/negative bignum)
		814
		815	These tags are decoded into L<Math::BigInt> objects. The corresponding
		816	C<Math::BigInt::TO_CBOR> method encodes "small" bigints into normal CBOR
		817	integers, and others into positive/negative CBOR bignums.
		818
		819	=item 4, 5 (decimal fraction/bigfloat)
		820
		821	Both decimal fractions and bigfloats are decoded into L<Math::BigFloat>
		822	objects. The corresponding C<Math::BigFloat::TO_CBOR> method I<always>
		823	encodes into a decimal fraction.
		824
		825	CBOR cannot represent bigfloats with I<very> large exponents - conversion
		826	of such big float objects is undefined.
		827
		828	Also, NaN and infinities are not encoded properly.
		829
		830	=item 21, 22, 23 (expected later JSON conversion)
		831
		832	CBOR::XS is not a CBOR-to-JSON converter, and will simply ignore these
		833	tags.
		834
		835	=item 32 (URI)
		836
		837	These objects decode into L<URI> objects. The corresponding
		838	C<URI::TO_CBOR> method again results in a CBOR URI value.
		839
		840	=back
		841
		842	=cut
		843
		844	our %FILTER = (
		845	# 0 # rfc4287 datetime, utf-8
		846	# 1 # unix timestamp, any
		847
		848	2 => sub { # pos bigint
		849	require Math::BigInt;
		850	Math::BigInt->new ("0x" . unpack "H*", pop)
		851	},
		852
		853	3 => sub { # neg bigint
		854	require Math::BigInt;
		855	-Math::BigInt->new ("0x" . unpack "H*", pop)
		856	},
		857
		858	4 => sub { # decimal fraction, array
		859	require Math::BigFloat;
		860	Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
		861	},
		862
		863	5 => sub { # bigfloat, array
		864	require Math::BigFloat;
		865	scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2)
		866	},
		867
		868	21 => sub { pop }, # expected conversion to base64url encoding
		869	22 => sub { pop }, # expected conversion to base64 encoding
		870	23 => sub { pop }, # expected conversion to base16 encoding
		871
		872	# 24 # embedded cbor, byte string
		873
		874	32 => sub {
		875	require URI;
		876	URI->new (pop)
		877	},
		878
		879	# 33 # base64url rfc4648, utf-8
		880	# 34 # base64 rfc46484, utf-8
		881	# 35 # regex pcre/ecma262, utf-8
		882	# 36 # mime message rfc2045, utf-8
		883	);
639		884
640		885
641	=head1 CBOR and JSON	886	=head1 CBOR and JSON
642		887
643	CBOR is supposed to implement a superset of the JSON data model, and is,	888	CBOR is supposed to implement a superset of the JSON data model, and is,
…		…
705	properly. Half precision types are accepted, but not encoded.	950	properly. Half precision types are accepted, but not encoded.
706		951
707	Strict mode and canonical mode are not implemented.	952	Strict mode and canonical mode are not implemented.
708		953
709		954
		955	=head1 LIMITATIONS ON PERLS WITHOUT 64-BIT INTEGER SUPPORT
		956
		957	On perls that were built without 64 bit integer support (these are rare
		958	nowadays, even on 32 bit architectures), support for any kind of 64 bit
		959	integer in CBOR is very limited - most likely, these 64 bit values will
		960	be truncated, corrupted, or otherwise not decoded correctly. This also
		961	includes string, array and map sizes that are stored as 64 bit integers.
		962
		963
710	=head1 THREADS	964	=head1 THREADS
711		965
712	This module is I<not> guaranteed to be thread safe and there are no	966	This module is I<not> guaranteed to be thread safe and there are no
713	plans to change this until Perl gets thread support (as opposed to the	967	plans to change this until Perl gets thread support (as opposed to the
714	horribly slow so-called "threads" which are simply slow and bloated	968	horribly slow so-called "threads" which are simply slow and bloated
…		…
726	Please refrain from using rt.cpan.org or any other bug reporting	980	Please refrain from using rt.cpan.org or any other bug reporting
727	service. I put the contact address into my modules for a reason.	981	service. I put the contact address into my modules for a reason.
728		982
729	=cut	983	=cut
730		984
		985	our %FILTER = (
		986	0 => sub { # rfc4287 datetime, utf-8
		987	require Time::Piece;
		988	# Time::Piece::Strptime uses the "incredibly flexible date parsing routine"
		989	# from FreeBSD, which can't parse ISO 8601, RFC3339, RFC4287 or much of anything
		990	# else either. Whats incredibe over standard strptime totally escapes me.
		991	# doesn't do fractional times, either. sigh.
		992	scalar eval {
		993	my $s = $_[1];
		994
		995	$s =~ s/Z$/+00:00/;
		996	$s =~ s/(\.[0-9]+)?([+-][0-9][0-9]):([0-9][0-9])/$2$3/
		997	or die;
		998
		999	my $f = $1; # fractional part. hopefully
		1000
		1001	my $d = Time::Piece->strptime ($s, "%Y-%m-%dT%H:%M:%S%z");
		1002
		1003	Time::Piece::gmtime ($d->epoch + $f)
		1004	} \|\| die "corrupted CBOR date/time string ($_[0])";
		1005	},
		1006
		1007	1 => sub { # seconds since the epoch, possibly fractional
		1008	require Time::Piece;
		1009	scalar Time::Piece::gmtime (pop)
		1010	},
		1011
		1012	2 => sub { # pos bigint
		1013	require Math::BigInt;
		1014	Math::BigInt->new ("0x" . unpack "H*", pop)
		1015	},
		1016
		1017	3 => sub { # neg bigint
		1018	require Math::BigInt;
		1019	-Math::BigInt->new ("0x" . unpack "H*", pop)
		1020	},
		1021
		1022	4 => sub { # decimal fraction, array
		1023	require Math::BigFloat;
		1024	Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
		1025	},
		1026
		1027	5 => sub { # bigfloat, array
		1028	require Math::BigFloat;
		1029	scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2)
		1030	},
		1031
		1032	21 => sub { pop }, # expected conversion to base64url encoding
		1033	22 => sub { pop }, # expected conversion to base64 encoding
		1034	23 => sub { pop }, # expected conversion to base16 encoding
		1035
		1036	# 24 # embedded cbor, byte string
		1037
		1038	32 => sub {
		1039	require URI;
		1040	URI->new (pop)
		1041	},
		1042
		1043	# 33 # base64url rfc4648, utf-8
		1044	# 34 # base64 rfc46484, utf-8
		1045	# 35 # regex pcre/ecma262, utf-8
		1046	# 36 # mime message rfc2045, utf-8
		1047	);
		1048
		1049	sub CBOR::XS::default_filter {
		1050	&{ $FILTER{$_[0]} or return }
		1051	}
		1052
		1053	sub URI::TO_CBOR {
		1054	my $uri = $_[0]->as_string;
		1055	utf8::upgrade $uri;
		1056	tag 32, $uri
		1057	}
		1058
		1059	sub Math::BigInt::TO_CBOR {
		1060	if ($_[0] >= -2147483648 && $_[0] <= 2147483647) {
		1061	$_[0]->numify
		1062	} else {
		1063	my $hex = substr $_[0]->as_hex, 2;
		1064	$hex = "0$hex" if 1 & length $hex; # sigh
		1065	tag $_[0] >= 0 ? 2 : 3, pack "H*", $hex
		1066	}
		1067	}
		1068
		1069	sub Math::BigFloat::TO_CBOR {
		1070	my ($m, $e) = $_[0]->parts;
		1071	tag 4, [$e->numify, $m]
		1072	}
		1073
		1074	sub Time::Piece::TO_CBOR {
		1075	tag 1, $_[0]->epoch
		1076	}
		1077
731	XSLoader::load "CBOR::XS", $VERSION;	1078	XSLoader::load "CBOR::XS", $VERSION;
732		1079
733	=head1 SEE ALSO	1080	=head1 SEE ALSO
734		1081
735	The L<JSON> and L<JSON::XS> modules that do similar, but human-readable,	1082	The L<JSON> and L<JSON::XS> modules that do similar, but human-readable,

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Comparing CBOR-XS/XS.pm (file contents): Revision 1.20 by root, Wed Nov 20 02:03:08 2013 UTC vs. Revision 1.35 by root, Sun Dec 1 16:40:25 2013 UTC

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Comparing CBOR-XS/XS.pm (file contents):
Revision 1.20 by root, Wed Nov 20 02:03:08 2013 UTC vs.
Revision 1.35 by root, Sun Dec 1 16:40:25 2013 UTC