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

Comparing CBOR-XS/XS.pm (file contents):
Revision 1.19 by root, Wed Nov 20 01:09:46 2013 UTC vs.
Revision 1.30 by root, Sat Nov 30 16:19:59 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 (see
		54	C<allow_sharing>), string deduplication (see C<pack_strings>) and scalar
		55	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 = '1.0';
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
…		…
171	exception when it encounters anything it cannot encode as CBOR.	168	exception when it encounters anything it cannot encode as CBOR.
172		169
173	This option does not affect C<decode> in any way, and it is recommended to	170	This option does not affect C<decode> in any way, and it is recommended to
174	leave it off unless you know your communications partner.	171	leave it off unless you know your communications partner.
175		172
176	=item $cbor = $cbor->allow_sharable ([$enable])	173	=item $cbor = $cbor->allow_sharing ([$enable])
177		174
178	=item $enabled = $cbor->get_allow_sharable	175	=item $enabled = $cbor->get_allow_sharing
179		176
180	If C<$enable> is true (or missing), then C<encode> will not double-encode	177	If C<$enable> is true (or missing), then C<encode> will not double-encode
181	values that have been seen before (e.g. when the same object, such as an	178	values that have been referenced before (e.g. when the same object, such
182	array, is referenced multiple times), but instead will emit a reference to	179	as an array, is referenced multiple times), but instead will emit a
183	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.
		186
		187	It is recommended to leave it off unless you know your
		188	communication partner supports the value sharing extensions to CBOR
		189	(L<http://cbor.schmorp.de/value-sharing>), as without decoder support, the
		190	resulting data structure might be unusable.
188		191
189	Detecting shared values incurs a runtime overhead when values are encoded	192	Detecting shared values incurs a runtime overhead when values are encoded
190	that have a reference counter large than one, and might unnecessarily	193	that have a reference counter large than one, and might unnecessarily
191	increase the encoded size, as potentially shared values are encode as	194	increase the encoded size, as potentially shared values are encode as
192	sharable whether or not they are actually shared.	195	sharable whether or not they are actually shared.
193		196
194	At the moment, all shared values will be detected, even weird and unusual	197	At the moment, only targets of references can be shared (e.g. scalars,
195	cases, such as an array with multiple "copies" of the I<same> scalar,	198	arrays or hashes pointed to by a reference). Weirder constructs, such as
196	which are hard but not impossible to create in Perl (L<Storable> for	199	an array with multiple "copies" of the I<same> string, which are hard but
197	example doesn't handle these cases). If this turns out ot be a performance	200	not impossible to create in Perl, are not supported (this is the same as
198	issue then future versions might limit the shared value detection to	201	with L<Storable>).
199	references only.
200		202
201	If C<$enable> is false (the default), then C<encode> will encode	203	If C<$enable> is false (the default), then C<encode> will encode shared
202	exception when it encounters anything it cannot encode as CBOR.	204	data structures repeatedly, unsharing them in the process. Cyclic data
		205	structures cannot be encoded in this mode.
203		206
204	This option does not affect C<decode> in any way - shared values and	207	This option does not affect C<decode> in any way - shared values and
205	references will always be decoded properly if present. It is recommended	208	references will always be decoded properly if present.
206	to leave it off unless you know your communications partner supports the	209
207	value sharing extensions to CBOR (http://cbor.schmorp.de/value-sharing).	210	=item $cbor = $cbor->pack_strings ([$enable])
		211
		212	=item $enabled = $cbor->get_pack_strings
		213
		214	If C<$enable> is true (or missing), then C<encode> will try not to encode
		215	the same string twice, but will instead encode a reference to the string
		216	instead. Depending on your data format, this can save a lot of space, but
		217	also results in a very large runtime overhead (expect encoding times to be
		218	2-4 times as high as without).
		219
		220	It is recommended to leave it off unless you know your
		221	communications partner supports the stringref extension to CBOR
		222	(L<http://cbor.schmorp.de/stringref>), as without decoder support, the
		223	resulting data structure might not be usable.
		224
		225	If C<$enable> is false (the default), then C<encode> will encode strings
		226	the standard CBOR way.
		227
		228	This option does not affect C<decode> in any way - string references will
		229	always be decoded properly if present.
		230
		231	=item $cbor = $cbor->filter ([$cb->($tag, $value)])
		232
		233	=item $cb_or_undef = $cbor->get_filter
		234
		235	Sets or replaces the tagged value decoding filter (when C<$cb> is
		236	specified) or clears the filter (if no argument or C<undef> is provided).
		237
		238	The filter callback is called only during decoding, when a non-enforced
		239	tagged value has been decoded (see L<TAG HANDLING AND EXTENSIONS> for a
		240	list of enforced tags). For specific tags, it's often better to provide a
		241	default converter using the C<%CBOR::XS::FILTER> hash (see below).
		242
		243	The first argument is the numerical tag, the second is the (decoded) value
		244	that has been tagged.
		245
		246	The filter function should return either exactly one value, which will
		247	replace the tagged value in the decoded data structure, or no values,
		248	which will result in default handling, which currently means the decoder
		249	creates a C<CBOR::XS::Tagged> object to hold the tag and the value.
		250
		251	When the filter is cleared (the default state), the default filter
		252	function, C<CBOR::XS::default_filter>, is used. This function simply looks
		253	up the tag in the C<%CBOR::XS::FILTER> hash. If an entry exists it must be
		254	a code reference that is called with tag and value, and is responsible for
		255	decoding the value. If no entry exists, it returns no values.
		256
		257	Example: decode all tags not handled internally into C<CBOR::XS::Tagged>
		258	objects, with no other special handling (useful when working with
		259	potentially "unsafe" CBOR data).
		260
		261	CBOR::XS->new->filter (sub { })->decode ($cbor_data);
		262
		263	Example: provide a global filter for tag 1347375694, converting the value
		264	into some string form.
		265
		266	$CBOR::XS::FILTER{1347375694} = sub {
		267	my ($tag, $value);
		268
		269	"tag 1347375694 value $value"
		270	};
208		271
209	=item $cbor_data = $cbor->encode ($perl_scalar)	272	=item $cbor_data = $cbor->encode ($perl_scalar)
210		273
211	Converts the given Perl data structure (a scalar value) to its CBOR	274	Converts the given Perl data structure (a scalar value) to its CBOR
212	representation.	275	representation.
…		…
253	CBOR integers become (numeric) perl scalars. On perls without 64 bit	316	CBOR integers become (numeric) perl scalars. On perls without 64 bit
254	support, 64 bit integers will be truncated or otherwise corrupted.	317	support, 64 bit integers will be truncated or otherwise corrupted.
255		318
256	=item byte strings	319	=item byte strings
257		320
258	Byte strings will become octet strings in Perl (the byte values 0..255	321	Byte strings will become octet strings in Perl (the Byte values 0..255
259	will simply become characters of the same value in Perl).	322	will simply become characters of the same value in Perl).
260		323
261	=item UTF-8 strings	324	=item UTF-8 strings
262		325
263	UTF-8 strings in CBOR will be decoded, i.e. the UTF-8 octets will be	326	UTF-8 strings in CBOR will be decoded, i.e. the UTF-8 octets will be
…		…
281	C<Types:Serialiser::false> and C<Types::Serialiser::error>,	344	C<Types:Serialiser::false> and C<Types::Serialiser::error>,
282	respectively. They are overloaded to act almost exactly like the numbers	345	respectively. They are overloaded to act almost exactly like the numbers
283	C<1> and C<0> (for true and false) or to throw an exception on access (for	346	C<1> and C<0> (for true and false) or to throw an exception on access (for
284	error). See the L<Types::Serialiser> manpage for details.	347	error). See the L<Types::Serialiser> manpage for details.
285		348
286	=item CBOR tag 256 (perl object)	349	=item tagged values
287		350
288	The tag value C<256> (TODO: pending iana registration) will be used
289	to deserialise a Perl object serialised with C<FREEZE>. See L<OBJECT
290	SERIALISATION>, below, for details.
291
292	=item CBOR tag 55799 (magic header)
293
294	The tag 55799 is ignored (this tag implements the magic header).
295
296	=item other CBOR tags
297
298	Tagged items consists of a numeric tag and another CBOR value. Tags not	351	Tagged items consists of a numeric tag and another CBOR value.
299	handled internally are currently converted into a L<CBOR::XS::Tagged>
300	object, which is simply a blessed array reference consisting of the
301	numeric tag value followed by the (decoded) CBOR value.
302		352
303	In the future, support for user-supplied conversions might get added.	353	See L<TAG HANDLING AND EXTENSIONS> and the description of C<< ->filter >>
		354	for details on which tags are handled how.
304		355
305	=item anything else	356	=item anything else
306		357
307	Anything else (e.g. unsupported simple values) will raise a decoding	358	Anything else (e.g. unsupported simple values) will raise a decoding
308	error.	359	error.
…		…
311		362
312		363
313	=head2 PERL -> CBOR	364	=head2 PERL -> CBOR
314		365
315	The mapping from Perl to CBOR is slightly more difficult, as Perl is a	366	The mapping from Perl to CBOR is slightly more difficult, as Perl is a
316	truly typeless language, so we can only guess which CBOR type is meant by	367	typeless language. That means this module can only guess which CBOR type
317	a Perl value.	368	is meant by a perl value.
318		369
319	=over 4	370	=over 4
320		371
321	=item hash references	372	=item hash references
322		373
323	Perl hash references become CBOR maps. As there is no inherent ordering in	374	Perl hash references become CBOR maps. As there is no inherent ordering in
324	hash keys (or CBOR maps), they will usually be encoded in a pseudo-random	375	hash keys (or CBOR maps), they will usually be encoded in a pseudo-random
325	order.	376	order. This order can be different each time a hahs is encoded.
326		377
327	Currently, tied hashes will use the indefinite-length format, while normal	378	Currently, tied hashes will use the indefinite-length format, while normal
328	hashes will use the fixed-length format.	379	hashes will use the fixed-length format.
329		380
330	=item array references	381	=item array references
331		382
332	Perl array references become fixed-length CBOR arrays.	383	Perl array references become fixed-length CBOR arrays.
333		384
334	=item other references	385	=item other references
335		386
336	Other unblessed references are generally not allowed and will cause an	387	Other unblessed references will be represented using
337	exception to be thrown, except for references to the integers C<0> and	388	the indirection tag extension (tag value C<22098>,
338	C<1>, which get turned into false and true in CBOR.	389	L<http://cbor.schmorp.de/indirection>). CBOR decoders are guaranteed
		390	to be able to decode these values somehow, by either "doing the right
		391	thing", decoding into a generic tagged object, simply ignoring the tag, or
		392	something else.
339		393
340	=item CBOR::XS::Tagged objects	394	=item CBOR::XS::Tagged objects
341		395
342	Objects of this type must be arrays consisting of a single C<[tag, value]>	396	Objects of this type must be arrays consisting of a single C<[tag, value]>
343	pair. The (numerical) tag will be encoded as a CBOR tag, the value will	397	pair. The (numerical) tag will be encoded as a CBOR tag, the value will
344	be encoded as appropriate for the value. You cna use C<CBOR::XS::tag> to	398	be encoded as appropriate for the value. You must use C<CBOR::XS::tag> to
345	create such objects.	399	create such objects.
346		400
347	=item Types::Serialiser::true, Types::Serialiser::false, Types::Serialiser::error	401	=item Types::Serialiser::true, Types::Serialiser::false, Types::Serialiser::error
348		402
349	These special values become CBOR true, CBOR false and CBOR undefined	403	These special values become CBOR true, CBOR false and CBOR undefined
…		…
351	if you want.	405	if you want.
352		406
353	=item other blessed objects	407	=item other blessed objects
354		408
355	Other blessed objects are serialised via C<TO_CBOR> or C<FREEZE>. See	409	Other blessed objects are serialised via C<TO_CBOR> or C<FREEZE>. See
356	L<OBJECT SERIALISATION>, below, for details.	410	L<TAG HANDLING AND EXTENSIONS> for specific classes handled by this
		411	module, and L<OBJECT SERIALISATION> for generic object serialisation.
357		412
358	=item simple scalars	413	=item simple scalars
359		414
360	TODO
361	Simple Perl scalars (any scalar that is not a reference) are the most	415	Simple Perl scalars (any scalar that is not a reference) are the most
362	difficult objects to encode: CBOR::XS will encode undefined scalars as	416	difficult objects to encode: CBOR::XS will encode undefined scalars as
363	CBOR null values, scalars that have last been used in a string context	417	CBOR null values, scalars that have last been used in a string context
364	before encoding as CBOR strings, and anything else as number value:	418	before encoding as CBOR strings, and anything else as number value:
365		419
366	# dump as number	420	# dump as number
367	encode_cbor [2] # yields [2]	421	encode_cbor [2] # yields [2]
368	encode_cbor [-3.0e17] # yields [-3e+17]	422	encode_cbor [-3.0e17] # yields [-3e+17]
369	my $value = 5; encode_cbor [$value] # yields [5]	423	my $value = 5; encode_cbor [$value] # yields [5]
370		424
371	# used as string, so dump as string	425	# used as string, so dump as string (either byte or text)
372	print $value;	426	print $value;
373	encode_cbor [$value] # yields ["5"]	427	encode_cbor [$value] # yields ["5"]
374		428
375	# undef becomes null	429	# undef becomes null
376	encode_cbor [undef] # yields [null]	430	encode_cbor [undef] # yields [null]
…		…
379		433
380	my $x = 3.1; # some variable containing a number	434	my $x = 3.1; # some variable containing a number
381	"$x"; # stringified	435	"$x"; # stringified
382	$x .= ""; # another, more awkward way to stringify	436	$x .= ""; # another, more awkward way to stringify
383	print $x; # perl does it for you, too, quite often	437	print $x; # perl does it for you, too, quite often
		438
		439	You can force whether a string ie encoded as byte or text string by using
		440	C<utf8::upgrade> and C<utf8::downgrade>):
		441
		442	utf8::upgrade $x; # encode $x as text string
		443	utf8::downgrade $x; # encode $x as byte string
		444
		445	Perl doesn't define what operations up- and downgrade strings, so if the
		446	difference between byte and text is important, you should up- or downgrade
		447	your string as late as possible before encoding.
384		448
385	You can force the type to be a CBOR number by numifying it:	449	You can force the type to be a CBOR number by numifying it:
386		450
387	my $x = "3"; # some variable containing a string	451	my $x = "3"; # some variable containing a string
388	$x += 0; # numify it, ensuring it will be dumped as a number	452	$x += 0; # numify it, ensuring it will be dumped as a number
…		…
401		465
402	=back	466	=back
403		467
404	=head2 OBJECT SERIALISATION	468	=head2 OBJECT SERIALISATION
405		469
		470	This module implements both a CBOR-specific and the generic
		471	L<Types::Serialier> object serialisation protocol. The following
		472	subsections explain both methods.
		473
		474	=head3 ENCODING
		475
406	This module knows two way to serialise a Perl object: The CBOR-specific	476	This module knows two way to serialise a Perl object: The CBOR-specific
407	way, and the generic way.	477	way, and the generic way.
408		478
409	Whenever the encoder encounters a Perl object that it cnanot serialise	479	Whenever the encoder encounters a Perl object that it cannot serialise
410	directly (most of them), it will first look up the C<TO_CBOR> method on	480	directly (most of them), it will first look up the C<TO_CBOR> method on
411	it.	481	it.
412		482
413	If it has a C<TO_CBOR> method, it will call it with the object as only	483	If it has a C<TO_CBOR> method, it will call it with the object as only
414	argument, and expects exactly one return value, which it will then	484	argument, and expects exactly one return value, which it will then
…		…
420		490
421	The C<FREEZE> method can return any number of values (i.e. zero or	491	The C<FREEZE> method can return any number of values (i.e. zero or
422	more). These will be encoded as CBOR perl object, together with the	492	more). These will be encoded as CBOR perl object, together with the
423	classname.	493	classname.
424		494
		495	These methods I<MUST NOT> change the data structure that is being
		496	serialised. Failure to comply to this can result in memory corruption -
		497	and worse.
		498
425	If an object supports neither C<TO_CBOR> nor C<FREEZE>, encoding will fail	499	If an object supports neither C<TO_CBOR> nor C<FREEZE>, encoding will fail
426	with an error.	500	with an error.
427		501
		502	=head3 DECODING
		503
428	Objects encoded via C<TO_CBOR> cannot be automatically decoded, but	504	Objects encoded via C<TO_CBOR> cannot (normally) be automatically decoded,
429	objects encoded via C<FREEZE> can be decoded using the following protocol:	505	but objects encoded via C<FREEZE> can be decoded using the following
		506	protocol:
430		507
431	When an encoded CBOR perl object is encountered by the decoder, it will	508	When an encoded CBOR perl object is encountered by the decoder, it will
432	look up the C<THAW> method, by using the stored classname, and will fail	509	look up the C<THAW> method, by using the stored classname, and will fail
433	if the method cannot be found.	510	if the method cannot be found.
434		511
435	After the lookup it will call the C<THAW> method with the stored classname	512	After the lookup it will call the C<THAW> method with the stored classname
436	as first argument, the constant string C<CBOR> as second argument, and all	513	as first argument, the constant string C<CBOR> as second argument, and all
437	values returned by C<FREEZE> as remaining arguments.	514	values returned by C<FREEZE> as remaining arguments.
438		515
439	=head4 EXAMPLES	516	=head3 EXAMPLES
440		517
441	Here is an example C<TO_CBOR> method:	518	Here is an example C<TO_CBOR> method:
442		519
443	sub My::Object::TO_CBOR {	520	sub My::Object::TO_CBOR {
444	my ($obj) = @_;	521	my ($obj) = @_;
…		…
455		532
456	sub URI::TO_CBOR {	533	sub URI::TO_CBOR {
457	my ($self) = @_;	534	my ($self) = @_;
458	my $uri = "$self"; # stringify uri	535	my $uri = "$self"; # stringify uri
459	utf8::upgrade $uri; # make sure it will be encoded as UTF-8 string	536	utf8::upgrade $uri; # make sure it will be encoded as UTF-8 string
460	CBOR::XS::tagged 32, "$_[0]"	537	CBOR::XS::tag 32, "$_[0]"
461	}	538	}
462		539
463	This will encode URIs as a UTF-8 string with tag 32, which indicates an	540	This will encode URIs as a UTF-8 string with tag 32, which indicates an
464	URI.	541	URI.
465		542
…		…
601	CBOR::XS::tag 24,	678	CBOR::XS::tag 24,
602	encode_cbor [1, 2, 3];	679	encode_cbor [1, 2, 3];
603		680
604	=head1 TAG HANDLING AND EXTENSIONS	681	=head1 TAG HANDLING AND EXTENSIONS
605		682
606	This section describes how this module handles specific tagged values and	683	This section describes how this module handles specific tagged values
607	extensions. If a tag is not mentioned here, then the default handling	684	and extensions. If a tag is not mentioned here and no additional filters
		685	are provided for it, then the default handling applies (creating a
608	applies (creating a CBOR::XS::Tagged object on decoding, and only encoding	686	CBOR::XS::Tagged object on decoding, and only encoding the tag when
609	the tag when explicitly requested).	687	explicitly requested).
		688
		689	Tags not handled specifically are currently converted into a
		690	L<CBOR::XS::Tagged> object, which is simply a blessed array reference
		691	consisting of the numeric tag value followed by the (decoded) CBOR value.
610		692
611	Future versions of this module reserve the right to special case	693	Future versions of this module reserve the right to special case
612	additional tags (such as bigfloat or base64url).	694	additional tags (such as base64url).
		695
		696	=head2 ENFORCED TAGS
		697
		698	These tags are always handled when decoding, and their handling cannot be
		699	overriden by the user.
613		700
614	=over 4	701	=over 4
615		702
616	=item <unassigned> (perl-object, L<http://cbor.schmorp.de/perl-object>)	703	=item 26 (perl-object, L<http://cbor.schmorp.de/perl-object>)
617		704
618	These tags are automatically created for serialisable objects using the	705	These tags are automatically created (and decoded) for serialisable
619	C<FREEZE/THAW> methods (the L<Types::Serialier> object serialisation	706	objects using the C<FREEZE/THAW> methods (the L<Types::Serialier> object
620	protocol).	707	serialisation protocol). See L<OBJECT SERIALISATION> for details.
621		708
622	=item <unassigned>, <unassigned> (sharable, sharedref, L <http://cbor.schmorp.de/value-sharing>)	709	=item 28, 29 (sharable, sharedref, L <http://cbor.schmorp.de/value-sharing>)
623		710
624	These tags are automatically decoded when encountered, resulting in	711	These tags are automatically decoded when encountered, resulting in
625	shared values in the decoded object. They are only encoded, however, when	712	shared values in the decoded object. They are only encoded, however, when
626	C<allow_sharable> is enabled.	713	C<allow_sharable> is enabled.
627		714
		715	=item 256, 25 (stringref-namespace, stringref, L <http://cbor.schmorp.de/stringref>)
		716
		717	These tags are automatically decoded when encountered. They are only
		718	encoded, however, when C<pack_strings> is enabled.
		719
628	=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)	720	=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)
629		721
630	This tag is automatically generated when a reference are encountered (with	722	This tag is automatically generated when a reference are encountered (with
631	the exception of hash and array refernces). It is converted to a reference	723	the exception of hash and array refernces). It is converted to a reference
632	when decoding.	724	when decoding.
…		…
635		727
636	This value is not generated on encoding (unless explicitly requested by	728	This value is not generated on encoding (unless explicitly requested by
637	the user), and is simply ignored when decoding.	729	the user), and is simply ignored when decoding.
638		730
639	=back	731	=back
		732
		733	=head2 NON-ENFORCED TAGS
		734
		735	These tags have default filters provided when decoding. Their handling can
		736	be overriden by changing the C<%CBOR::XS::FILTER> entry for the tag, or by
		737	providing a custom C<filter> callback when decoding.
		738
		739	When they result in decoding into a specific Perl class, the module
		740	usually provides a corresponding C<TO_CBOR> method as well.
		741
		742	When any of these need to load additional modules that are not part of the
		743	perl core distribution (e.g. L<URI>), it is (currently) up to the user to
		744	provide these modules. The decoding usually fails with an exception if the
		745	required module cannot be loaded.
		746
		747	=over 4
		748
		749	=item 2, 3 (positive/negative bignum)
		750
		751	These tags are decoded into L<Math::BigInt> objects. The corresponding
		752	C<Math::BigInt::TO_CBOR> method encodes "small" bigints into normal CBOR
		753	integers, and others into positive/negative CBOR bignums.
		754
		755	=item 4, 5 (decimal fraction/bigfloat)
		756
		757	Both decimal fractions and bigfloats are decoded into L<Math::BigFloat>
		758	objects. The corresponding C<Math::BigFloat::TO_CBOR> method I<always>
		759	encodes into a decimal fraction.
		760
		761	CBOR cannot represent bigfloats with I<very> large exponents - conversion
		762	of such big float objects is undefined.
		763
		764	Also, NaN and infinities are not encoded properly.
		765
		766	=item 21, 22, 23 (expected later JSON conversion)
		767
		768	CBOR::XS is not a CBOR-to-JSON converter, and will simply ignore these
		769	tags.
		770
		771	=item 32 (URI)
		772
		773	These objects decode into L<URI> objects. The corresponding
		774	C<URI::TO_CBOR> method again results in a CBOR URI value.
		775
		776	=back
		777
		778	=cut
		779
		780	our %FILTER = (
		781	# 0 # rfc4287 datetime, utf-8
		782	# 1 # unix timestamp, any
		783
		784	2 => sub { # pos bigint
		785	require Math::BigInt;
		786	Math::BigInt->new ("0x" . unpack "H*", pop)
		787	},
		788
		789	3 => sub { # neg bigint
		790	require Math::BigInt;
		791	-Math::BigInt->new ("0x" . unpack "H*", pop)
		792	},
		793
		794	4 => sub { # decimal fraction, array
		795	require Math::BigFloat;
		796	Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
		797	},
		798
		799	5 => sub { # bigfloat, array
		800	require Math::BigFloat;
		801	scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2)
		802	},
		803
		804	21 => sub { pop }, # expected conversion to base64url encoding
		805	22 => sub { pop }, # expected conversion to base64 encoding
		806	23 => sub { pop }, # expected conversion to base16 encoding
		807
		808	# 24 # embedded cbor, byte string
		809
		810	32 => sub {
		811	require URI;
		812	URI->new (pop)
		813	},
		814
		815	# 33 # base64url rfc4648, utf-8
		816	# 34 # base64 rfc46484, utf-8
		817	# 35 # regex pcre/ecma262, utf-8
		818	# 36 # mime message rfc2045, utf-8
		819	);
640		820
641		821
642	=head1 CBOR and JSON	822	=head1 CBOR and JSON
643		823
644	CBOR is supposed to implement a superset of the JSON data model, and is,	824	CBOR is supposed to implement a superset of the JSON data model, and is,
…		…
706	properly. Half precision types are accepted, but not encoded.	886	properly. Half precision types are accepted, but not encoded.
707		887
708	Strict mode and canonical mode are not implemented.	888	Strict mode and canonical mode are not implemented.
709		889
710		890
		891	=head1 LIMITATIONS ON PERLS WITHOUT 64-BIT INTEGER SUPPORT
		892
		893	On perls that were built without 64 bit integer support (these are rare
		894	nowadays, even on 32 bit architectures), support for any kind of 64 bit
		895	integer in CBOR is very limited - most likely, these 64 bit values will
		896	be truncated, corrupted, or otherwise not decoded correctly. This also
		897	includes string, array and map sizes that are stored as 64 bit integers.
		898
		899
711	=head1 THREADS	900	=head1 THREADS
712		901
713	This module is I<not> guaranteed to be thread safe and there are no	902	This module is I<not> guaranteed to be thread safe and there are no
714	plans to change this until Perl gets thread support (as opposed to the	903	plans to change this until Perl gets thread support (as opposed to the
715	horribly slow so-called "threads" which are simply slow and bloated	904	horribly slow so-called "threads" which are simply slow and bloated
…		…
727	Please refrain from using rt.cpan.org or any other bug reporting	916	Please refrain from using rt.cpan.org or any other bug reporting
728	service. I put the contact address into my modules for a reason.	917	service. I put the contact address into my modules for a reason.
729		918
730	=cut	919	=cut
731		920
		921	our %FILTER = (
		922	# 0 # rfc4287 datetime, utf-8
		923	# 1 # unix timestamp, any
		924
		925	2 => sub { # pos bigint
		926	require Math::BigInt;
		927	Math::BigInt->new ("0x" . unpack "H*", pop)
		928	},
		929
		930	3 => sub { # neg bigint
		931	require Math::BigInt;
		932	-Math::BigInt->new ("0x" . unpack "H*", pop)
		933	},
		934
		935	4 => sub { # decimal fraction, array
		936	require Math::BigFloat;
		937	Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
		938	},
		939
		940	5 => sub { # bigfloat, array
		941	require Math::BigFloat;
		942	scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2)
		943	},
		944
		945	21 => sub { pop }, # expected conversion to base64url encoding
		946	22 => sub { pop }, # expected conversion to base64 encoding
		947	23 => sub { pop }, # expected conversion to base16 encoding
		948
		949	# 24 # embedded cbor, byte string
		950
		951	32 => sub {
		952	require URI;
		953	URI->new (pop)
		954	},
		955
		956	# 33 # base64url rfc4648, utf-8
		957	# 34 # base64 rfc46484, utf-8
		958	# 35 # regex pcre/ecma262, utf-8
		959	# 36 # mime message rfc2045, utf-8
		960	);
		961
		962	sub CBOR::XS::default_filter {
		963	&{ $FILTER{$_[0]} or return }
		964	}
		965
		966	sub URI::TO_CBOR {
		967	my $uri = $_[0]->as_string;
		968	utf8::upgrade $uri;
		969	CBOR::XS::tag 32, $uri
		970	}
		971
		972	sub Math::BigInt::TO_CBOR {
		973	if ($_[0] >= -2147483648 && $_[0] <= 2147483647) {
		974	$_[0]->numify
		975	} else {
		976	my $hex = substr $_[0]->as_hex, 2;
		977	$hex = "0$hex" if 1 & length $hex; # sigh
		978	CBOR::XS::tag $_[0] >= 0 ? 2 : 3, pack "H*", $hex
		979	}
		980	}
		981
		982	sub Math::BigFloat::TO_CBOR {
		983	my ($m, $e) = $_[0]->parts;
		984	CBOR::XS::tag 4, [$e->numify, $m]
		985	}
		986
732	XSLoader::load "CBOR::XS", $VERSION;	987	XSLoader::load "CBOR::XS", $VERSION;
733		988
734	=head1 SEE ALSO	989	=head1 SEE ALSO
735		990
736	The L<JSON> and L<JSON::XS> modules that do similar, but human-readable,	991	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 1.19 by root, Wed Nov 20 01:09:46 2013 UTC vs. Revision 1.30 by root, Sat Nov 30 16:19:59 2013 UTC

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Comparing CBOR-XS/XS.pm (file contents):
Revision 1.19 by root, Wed Nov 20 01:09:46 2013 UTC vs.
Revision 1.30 by root, Sat Nov 30 16:19:59 2013 UTC