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

Comparing CBOR-XS/XS.pm (file contents):
Revision 1.2 by root, Sat Oct 26 10:41:12 2013 UTC vs.
Revision 1.23 by root, Fri Nov 22 16:00:30 2013 UTC

…		…
12	$perl_value = decode_cbor $binary_cbor_data;	12	$perl_value = decode_cbor $binary_cbor_data;
13		13
14	# OO-interface	14	# OO-interface
15		15
16	$coder = CBOR::XS->new;	16	$coder = CBOR::XS->new;
17	#TODO	17	$binary_cbor_data = $coder->encode ($perl_value);
		18	$perl_value = $coder->decode ($binary_cbor_data);
		19
		20	# prefix decoding
		21
		22	my $many_cbor_strings = ...;
		23	while (length $many_cbor_strings) {
		24	my ($data, $length) = $cbor->decode_prefix ($many_cbor_strings);
		25	# data was decoded
		26	substr $many_cbor_strings, 0, $length, ""; # remove decoded cbor string
		27	}
18		28
19	=head1 DESCRIPTION	29	=head1 DESCRIPTION
20		30
21	WARNING! THIS IS A PRE-ALPHA RELEASE! IT WILL CRASH, CORRUPT YOUR DATA AND	31	WARNING! This module is very new, and not very well tested (that's up
22	EAT YOUR CHILDREN!	32	to you to do). Furthermore, details of the implementation might change
		33	freely before version 1.0. And lastly, most extensions depend on an IANA
		34	assignment, and until that assignment is official, this implementation is
		35	not interoperable with other implementations (even future versions of this
		36	module) until the assignment is done.
23		37
24	This module converts Perl data structures to CBOR and vice versa. Its	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
		41	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
		43	can represent something in JSON, you should be able to represent it in
		44	CBOR.
		45
		46	In short, CBOR is a faster and very compact binary alternative to JSON,
		47	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
		49	data later you might want to compare both formats first).
		50
		51	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
		53	L<JSON::XS> and decodes about 15%-30% faster than those. The shorter the
		54	data, the worse L<Storable> performs in comparison.
		55
		56	As for compactness, C<CBOR::XS> encoded data structures are usually about
		57	20% smaller than the same data encoded as (compact) JSON or L<Storable>.
		58
		59	In addition to the core CBOR data format, this module implements a number
		60	of extensions, to support cyclic and self-referencing data structures
		61	(see C<allow_sharing>), string deduplication (see C<allow_stringref>) and
		62	scalar references (always enabled).
		63
25	primary goal is to be I<correct> and its secondary goal is to be	64	The primary goal of this module is to be I<correct> and the secondary goal
26	I<fast>. To reach the latter goal it was written in C.	65	is to be I<fast>. To reach the latter goal it was written in C.
27		66
28	See MAPPING, below, on how CBOR::XS maps perl values to CBOR values and	67	See MAPPING, below, on how CBOR::XS maps perl values to CBOR values and
29	vice versa.	68	vice versa.
30		69
31	=cut	70	=cut
32		71
33	package CBOR::XS;	72	package CBOR::XS;
34		73
35	use common::sense;	74	use common::sense;
36		75
37	our $VERSION = 0.01;	76	our $VERSION = 0.08;
38	our @ISA = qw(Exporter);	77	our @ISA = qw(Exporter);
39		78
40	our @EXPORT = qw(encode_cbor decode_cbor);	79	our @EXPORT = qw(encode_cbor decode_cbor);
41		80
42	use Exporter;	81	use Exporter;
43	use XSLoader;	82	use XSLoader;
44		83
		84	use Types::Serialiser;
		85
		86	our $MAGIC = "\xd9\xd9\xf7";
		87
45	=head1 FUNCTIONAL INTERFACE	88	=head1 FUNCTIONAL INTERFACE
46		89
47	The following convenience methods are provided by this module. They are	90	The following convenience methods are provided by this module. They are
48	exported by default:	91	exported by default:
49		92
…		…
75	strings. All boolean flags described below are by default I<disabled>.	118	strings. All boolean flags described below are by default I<disabled>.
76		119
77	The mutators for flags all return the CBOR object again and thus calls can	120	The mutators for flags all return the CBOR object again and thus calls can
78	be chained:	121	be chained:
79		122
80	#TODO
81	my $cbor = CBOR::XS->new->encode ({a => [1,2]});	123	my $cbor = CBOR::XS->new->encode ({a => [1,2]});
82		124
83	=item $cbor = $cbor->max_depth ([$maximum_nesting_depth])	125	=item $cbor = $cbor->max_depth ([$maximum_nesting_depth])
84		126
85	=item $max_depth = $cbor->get_max_depth	127	=item $max_depth = $cbor->get_max_depth
…		…
119	If no argument is given, the limit check will be deactivated (same as when	161	If no argument is given, the limit check will be deactivated (same as when
120	C<0> is specified).	162	C<0> is specified).
121		163
122	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.	164	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
123		165
		166	=item $cbor = $cbor->allow_unknown ([$enable])
		167
		168	=item $enabled = $cbor->get_allow_unknown
		169
		170	If C<$enable> is true (or missing), then C<encode> will I<not> throw an
		171	exception when it encounters values it cannot represent in CBOR (for
		172	example, filehandles) but instead will encode a CBOR C<error> value.
		173
		174	If C<$enable> is false (the default), then C<encode> will throw an
		175	exception when it encounters anything it cannot encode as CBOR.
		176
		177	This option does not affect C<decode> in any way, and it is recommended to
		178	leave it off unless you know your communications partner.
		179
		180	=item $cbor = $cbor->allow_sharing ([$enable])
		181
		182	=item $enabled = $cbor->get_allow_sharing
		183
		184	If C<$enable> is true (or missing), then C<encode> will not double-encode
		185	values that have been referenced before (e.g. when the same object, such
		186	as an array, is referenced multiple times), but instead will emit a
		187	reference to the earlier value.
		188
		189	This means that such values will only be encoded once, and will not result
		190	in a deep cloning of the value on decode, in decoders supporting the value
		191	sharing extension.
		192
		193	It is recommended to leave it off unless you know your
		194	communication partner supports the value sharing extensions to CBOR
		195	(http://cbor.schmorp.de/value-sharing).
		196
		197	Detecting shared values incurs a runtime overhead when values are encoded
		198	that have a reference counter large than one, and might unnecessarily
		199	increase the encoded size, as potentially shared values are encode as
		200	sharable whether or not they are actually shared.
		201
		202	At the moment, only targets of references can be shared (e.g. scalars,
		203	arrays or hashes pointed to by a reference). Weirder constructs, such as
		204	an array with multiple "copies" of the I<same> string, which are hard but
		205	not impossible to create in Perl, are not supported (this is the same as
		206	for L<Storable>).
		207
		208	If C<$enable> is false (the default), then C<encode> will encode
		209	exception when it encounters anything it cannot encode as CBOR.
		210
		211	This option does not affect C<decode> in any way - shared values and
		212	references will always be decoded properly if present.
		213
		214	=item $cbor = $cbor->allow_stringref ([$enable])
		215
		216	=item $enabled = $cbor->get_allow_stringref
		217
		218	If C<$enable> is true (or missing), then C<encode> will try not to encode
		219	the same string twice, but will instead encode a reference to the string
		220	instead. Depending on your data format. this can save a lot of space, but
		221	also results in a very large runtime overhead (expect encoding times to be
		222	2-4 times as high as without).
		223
		224	It is recommended to leave it off unless you know your
		225	communications partner supports the stringref extension to CBOR
		226	(http://cbor.schmorp.de/stringref).
		227
		228	If C<$enable> is false (the default), then C<encode> will encode
		229	exception when it encounters anything it cannot encode as CBOR.
		230
		231	This option does not affect C<decode> in any way - string references will
		232	always be decoded properly if present.
		233
		234	=item $cbor = $cbor->filter ([$cb->($tag, $value)])
		235
		236	=item $cb_or_undef = $cbor->get_filter
		237
		238	TODO
		239
124	=item $cbor_data = $cbor->encode ($perl_scalar)	240	=item $cbor_data = $cbor->encode ($perl_scalar)
125		241
126	Converts the given Perl data structure (a scalar value) to its CBOR	242	Converts the given Perl data structure (a scalar value) to its CBOR
127	representation.	243	representation.
128		244
…		…
161		277
162	=head2 CBOR -> PERL	278	=head2 CBOR -> PERL
163		279
164	=over 4	280	=over 4
165		281
166	=item True, False	282	=item integers
167		283
168	These CBOR values become C<CBOR::XS::true> and C<CBOR::XS::false>,	284	CBOR integers become (numeric) perl scalars. On perls without 64 bit
		285	support, 64 bit integers will be truncated or otherwise corrupted.
		286
		287	=item byte strings
		288
		289	Byte strings will become octet strings in Perl (the byte values 0..255
		290	will simply become characters of the same value in Perl).
		291
		292	=item UTF-8 strings
		293
		294	UTF-8 strings in CBOR will be decoded, i.e. the UTF-8 octets will be
		295	decoded into proper Unicode code points. At the moment, the validity of
		296	the UTF-8 octets will not be validated - corrupt input will result in
		297	corrupted Perl strings.
		298
		299	=item arrays, maps
		300
		301	CBOR arrays and CBOR maps will be converted into references to a Perl
		302	array or hash, respectively. The keys of the map will be stringified
		303	during this process.
		304
		305	=item null
		306
		307	CBOR null becomes C<undef> in Perl.
		308
		309	=item true, false, undefined
		310
		311	These CBOR values become C<Types:Serialiser::true>,
		312	C<Types:Serialiser::false> and C<Types::Serialiser::error>,
169	respectively. They are overloaded to act almost exactly like the numbers	313	respectively. They are overloaded to act almost exactly like the numbers
170	C<1> and C<0>. You can check whether a scalar is a CBOR boolean by using	314	C<1> and C<0> (for true and false) or to throw an exception on access (for
171	the C<CBOR::XS::is_bool> function.	315	error). See the L<Types::Serialiser> manpage for details.
172		316
173	=item Null, Undefined	317	=item tagged values
174		318
175	CBOR Null and Undefined values becomes C<undef> in Perl (in the future,	319	Tagged items consists of a numeric tag and another CBOR value.
176	Undefined may raise an exception).	320
		321	See L<TAG HANDLING AND EXTENSIONS> and the description of C<< ->filter >>
		322	for details.
		323
		324	=item anything else
		325
		326	Anything else (e.g. unsupported simple values) will raise a decoding
		327	error.
177		328
178	=back	329	=back
179		330
180		331
181	=head2 PERL -> CBOR	332	=head2 PERL -> CBOR
…		…
186		337
187	=over 4	338	=over 4
188		339
189	=item hash references	340	=item hash references
190		341
191	Perl hash references become CBOR maps. As there is no inherent ordering	342	Perl hash references become CBOR maps. As there is no inherent ordering in
192	in hash keys (or CBOR maps), they will usually be encoded in a	343	hash keys (or CBOR maps), they will usually be encoded in a pseudo-random
193	pseudo-random order.	344	order.
		345
		346	Currently, tied hashes will use the indefinite-length format, while normal
		347	hashes will use the fixed-length format.
194		348
195	=item array references	349	=item array references
196		350
197	Perl array references become CBOR arrays.	351	Perl array references become fixed-length CBOR arrays.
198		352
199	=item other references	353	=item other references
200		354
201	Other unblessed references are generally not allowed and will cause an	355	Other unblessed references are generally not allowed and will cause an
202	exception to be thrown, except for references to the integers C<0> and	356	exception to be thrown, except for references to the integers C<0> and
203	C<1>, which get turned into C<False> and C<True> in CBOR.	357	C<1>, which get turned into false and true in CBOR.
204		358
205	=item CBOR::XS::true, CBOR::XS::false	359	=item CBOR::XS::Tagged objects
206		360
		361	Objects of this type must be arrays consisting of a single C<[tag, value]>
		362	pair. The (numerical) tag will be encoded as a CBOR tag, the value will
		363	be encoded as appropriate for the value. You cna use C<CBOR::XS::tag> to
		364	create such objects.
		365
		366	=item Types::Serialiser::true, Types::Serialiser::false, Types::Serialiser::error
		367
207	These special values become CBOR True and CBOR False values,	368	These special values become CBOR true, CBOR false and CBOR undefined
208	respectively. You can also use C<\1> and C<\0> directly if you want.	369	values, respectively. You can also use C<\1>, C<\0> and C<\undef> directly
		370	if you want.
209		371
210	=item blessed objects	372	=item other blessed objects
211		373
212	Blessed objects are not directly representable in CBOR. TODO	374	Other blessed objects are serialised via C<TO_CBOR> or C<FREEZE>. See
213	See the	375	L<TAG HANDLING AND EXTENSIONS> for specific classes handled by this
214	C<allow_blessed> and C<convert_blessed> methods on various options on	376	module, and L<OBJECT SERIALISATION> for generic object serialisation.
215	how to deal with this: basically, you can choose between throwing an
216	exception, encoding the reference as if it weren't blessed, or provide
217	your own serialiser method.
218		377
219	=item simple scalars	378	=item simple scalars
220		379
221	TODO
222	Simple Perl scalars (any scalar that is not a reference) are the most	380	Simple Perl scalars (any scalar that is not a reference) are the most
223	difficult objects to encode: CBOR::XS will encode undefined scalars as	381	difficult objects to encode: CBOR::XS will encode undefined scalars as
224	CBOR C<Null> values, scalars that have last been used in a string context	382	CBOR null values, scalars that have last been used in a string context
225	before encoding as CBOR strings, and anything else as number value:	383	before encoding as CBOR strings, and anything else as number value:
226		384
227	# dump as number	385	# dump as number
228	encode_cbor [2] # yields [2]	386	encode_cbor [2] # yields [2]
229	encode_cbor [-3.0e17] # yields [-3e+17]	387	encode_cbor [-3.0e17] # yields [-3e+17]
…		…
251		409
252	You can not currently force the type in other, less obscure, ways. Tell me	410	You can not currently force the type in other, less obscure, ways. Tell me
253	if you need this capability (but don't forget to explain why it's needed	411	if you need this capability (but don't forget to explain why it's needed
254	:).	412	:).
255		413
256	Note that numerical precision has the same meaning as under Perl (so	414	Perl values that seem to be integers generally use the shortest possible
257	binary to decimal conversion follows the same rules as in Perl, which	415	representation. Floating-point values will use either the IEEE single
258	can differ to other languages). Also, your perl interpreter might expose	416	format if possible without loss of precision, otherwise the IEEE double
259	extensions to the floating point numbers of your platform, such as	417	format will be used. Perls that use formats other than IEEE double to
260	infinities or NaN's - these cannot be represented in CBOR, and it is an	418	represent numerical values are supported, but might suffer loss of
261	error to pass those in.	419	precision.
262		420
263	=back	421	=back
264		422
		423	=head2 OBJECT SERIALISATION
265		424
		425	This module knows two way to serialise a Perl object: The CBOR-specific
		426	way, and the generic way.
		427
		428	Whenever the encoder encounters a Perl object that it cnanot serialise
		429	directly (most of them), it will first look up the C<TO_CBOR> method on
		430	it.
		431
		432	If it has a C<TO_CBOR> method, it will call it with the object as only
		433	argument, and expects exactly one return value, which it will then
		434	substitute and encode it in the place of the object.
		435
		436	Otherwise, it will look up the C<FREEZE> method. If it exists, it will
		437	call it with the object as first argument, and the constant string C<CBOR>
		438	as the second argument, to distinguish it from other serialisers.
		439
		440	The C<FREEZE> method can return any number of values (i.e. zero or
		441	more). These will be encoded as CBOR perl object, together with the
		442	classname.
		443
		444	If an object supports neither C<TO_CBOR> nor C<FREEZE>, encoding will fail
		445	with an error.
		446
		447	Objects encoded via C<TO_CBOR> cannot be automatically decoded, but
		448	objects encoded via C<FREEZE> can be decoded using the following protocol:
		449
		450	When an encoded CBOR perl object is encountered by the decoder, it will
		451	look up the C<THAW> method, by using the stored classname, and will fail
		452	if the method cannot be found.
		453
		454	After the lookup it will call the C<THAW> method with the stored classname
		455	as first argument, the constant string C<CBOR> as second argument, and all
		456	values returned by C<FREEZE> as remaining arguments.
		457
		458	=head4 EXAMPLES
		459
		460	Here is an example C<TO_CBOR> method:
		461
		462	sub My::Object::TO_CBOR {
		463	my ($obj) = @_;
		464
		465	["this is a serialised My::Object object", $obj->{id}]
		466	}
		467
		468	When a C<My::Object> is encoded to CBOR, it will instead encode a simple
		469	array with two members: a string, and the "object id". Decoding this CBOR
		470	string will yield a normal perl array reference in place of the object.
		471
		472	A more useful and practical example would be a serialisation method for
		473	the URI module. CBOR has a custom tag value for URIs, namely 32:
		474
		475	sub URI::TO_CBOR {
		476	my ($self) = @_;
		477	my $uri = "$self"; # stringify uri
		478	utf8::upgrade $uri; # make sure it will be encoded as UTF-8 string
		479	CBOR::XS::tagged 32, "$_[0]"
		480	}
		481
		482	This will encode URIs as a UTF-8 string with tag 32, which indicates an
		483	URI.
		484
		485	Decoding such an URI will not (currently) give you an URI object, but
		486	instead a CBOR::XS::Tagged object with tag number 32 and the string -
		487	exactly what was returned by C<TO_CBOR>.
		488
		489	To serialise an object so it can automatically be deserialised, you need
		490	to use C<FREEZE> and C<THAW>. To take the URI module as example, this
		491	would be a possible implementation:
		492
		493	sub URI::FREEZE {
		494	my ($self, $serialiser) = @_;
		495	"$self" # encode url string
		496	}
		497
		498	sub URI::THAW {
		499	my ($class, $serialiser, $uri) = @_;
		500
		501	$class->new ($uri)
		502	}
		503
		504	Unlike C<TO_CBOR>, multiple values can be returned by C<FREEZE>. For
		505	example, a C<FREEZE> method that returns "type", "id" and "variant" values
		506	would cause an invocation of C<THAW> with 5 arguments:
		507
		508	sub My::Object::FREEZE {
		509	my ($self, $serialiser) = @_;
		510
		511	($self->{type}, $self->{id}, $self->{variant})
		512	}
		513
		514	sub My::Object::THAW {
		515	my ($class, $serialiser, $type, $id, $variant) = @_;
		516
		517	$class-<new (type => $type, id => $id, variant => $variant)
		518	}
		519
		520
		521	=head1 MAGIC HEADER
		522
		523	There is no way to distinguish CBOR from other formats
		524	programmatically. To make it easier to distinguish CBOR from other
		525	formats, the CBOR specification has a special "magic string" that can be
		526	prepended to any CBOR string without changing its meaning.
		527
		528	This string is available as C<$CBOR::XS::MAGIC>. This module does not
		529	prepend this string to the CBOR data it generates, but it will ignore it
		530	if present, so users can prepend this string as a "file type" indicator as
		531	required.
		532
		533
		534	=head1 THE CBOR::XS::Tagged CLASS
		535
		536	CBOR has the concept of tagged values - any CBOR value can be tagged with
		537	a numeric 64 bit number, which are centrally administered.
		538
		539	C<CBOR::XS> handles a few tags internally when en- or decoding. You can
		540	also create tags yourself by encoding C<CBOR::XS::Tagged> objects, and the
		541	decoder will create C<CBOR::XS::Tagged> objects itself when it hits an
		542	unknown tag.
		543
		544	These objects are simply blessed array references - the first member of
		545	the array being the numerical tag, the second being the value.
		546
		547	You can interact with C<CBOR::XS::Tagged> objects in the following ways:
		548
		549	=over 4
		550
		551	=item $tagged = CBOR::XS::tag $tag, $value
		552
		553	This function(!) creates a new C<CBOR::XS::Tagged> object using the given
		554	C<$tag> (0..2**64-1) to tag the given C<$value> (which can be any Perl
		555	value that can be encoded in CBOR, including serialisable Perl objects and
		556	C<CBOR::XS::Tagged> objects).
		557
		558	=item $tagged->[0]
		559
		560	=item $tagged->[0] = $new_tag
		561
		562	=item $tag = $tagged->tag
		563
		564	=item $new_tag = $tagged->tag ($new_tag)
		565
		566	Access/mutate the tag.
		567
		568	=item $tagged->[1]
		569
		570	=item $tagged->[1] = $new_value
		571
		572	=item $value = $tagged->value
		573
		574	=item $new_value = $tagged->value ($new_value)
		575
		576	Access/mutate the tagged value.
		577
		578	=back
		579
		580	=cut
		581
		582	sub tag($$) {
		583	bless [@_], CBOR::XS::Tagged::;
		584	}
		585
		586	sub CBOR::XS::Tagged::tag {
		587	$_[0][0] = $_[1] if $#_;
		588	$_[0][0]
		589	}
		590
		591	sub CBOR::XS::Tagged::value {
		592	$_[0][1] = $_[1] if $#_;
		593	$_[0][1]
		594	}
		595
		596	=head2 EXAMPLES
		597
		598	Here are some examples of C<CBOR::XS::Tagged> uses to tag objects.
		599
		600	You can look up CBOR tag value and emanings in the IANA registry at
		601	L<http://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml>.
		602
		603	Prepend a magic header (C<$CBOR::XS::MAGIC>):
		604
		605	my $cbor = encode_cbor CBOR::XS::tag 55799, $value;
		606	# same as:
		607	my $cbor = $CBOR::XS::MAGIC . encode_cbor $value;
		608
		609	Serialise some URIs and a regex in an array:
		610
		611	my $cbor = encode_cbor [
		612	(CBOR::XS::tag 32, "http://www.nethype.de/"),
		613	(CBOR::XS::tag 32, "http://software.schmorp.de/"),
		614	(CBOR::XS::tag 35, "^[Pp][Ee][Rr][lL]\$"),
		615	];
		616
		617	Wrap CBOR data in CBOR:
		618
		619	my $cbor_cbor = encode_cbor
		620	CBOR::XS::tag 24,
		621	encode_cbor [1, 2, 3];
		622
		623	=head1 TAG HANDLING AND EXTENSIONS
		624
		625	This section describes how this module handles specific tagged values
		626	and extensions. If a tag is not mentioned here and no additional filters
		627	are provided for it, then the default handling applies (creating a
		628	CBOR::XS::Tagged object on decoding, and only encoding the tag when
		629	explicitly requested).
		630
		631	Tags not handled specifically are currently converted into a
		632	L<CBOR::XS::Tagged> object, which is simply a blessed array reference
		633	consisting of the numeric tag value followed by the (decoded) CBOR value.
		634
		635	Future versions of this module reserve the right to special case
		636	additional tags (such as base64url).
		637
		638	=head2 ENFORCED TAGS
		639
		640	These tags are always handled when decoding, and their handling cannot be
		641	overriden by the user.
		642
		643	=over 4
		644
		645	=item <unassigned> (perl-object, L<http://cbor.schmorp.de/perl-object>)
		646
		647	These tags are automatically created (and decoded) for serialisable
		648	objects using the C<FREEZE/THAW> methods (the L<Types::Serialier> object
		649	serialisation protocol). See L<OBJECT SERIALISATION> for details.
		650
		651	=item <unassigned>, <unassigned> (sharable, sharedref, L <http://cbor.schmorp.de/value-sharing>)
		652
		653	These tags are automatically decoded when encountered, resulting in
		654	shared values in the decoded object. They are only encoded, however, when
		655	C<allow_sharable> is enabled.
		656
		657	=item <unassigned>, <unassigned> (stringref-namespace, stringref, L <http://cbor.schmorp.de/stringref>)
		658
		659	These tags are automatically decoded when encountered. They are only
		660	encoded, however, when C<allow_stringref> is enabled.
		661
		662	=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)
		663
		664	This tag is automatically generated when a reference are encountered (with
		665	the exception of hash and array refernces). It is converted to a reference
		666	when decoding.
		667
		668	=item 55799 (self-describe CBOR, RFC 7049)
		669
		670	This value is not generated on encoding (unless explicitly requested by
		671	the user), and is simply ignored when decoding.
		672
		673	=back
		674
		675	=head2 OPTIONAL TAGS
		676
		677	These tags have default filters provided when decoding. Their handling can
		678	be overriden by changing the C<%CBOR::XS::FILTER> entry for the tag, or by
		679	providing a custom C<filter> function when decoding.
		680
		681	When they result in decoding into a specific Perl class, the module
		682	usually provides a corresponding C<TO_CBOR> method as well.
		683
		684	When any of these need to load additional modules that are not part of the
		685	perl core distribution (e.g. L<URI>), it is (currently) up to the user to
		686	provide these modules. The decoding usually fails with an exception if the
		687	required module cannot be loaded.
		688
		689	=over 4
		690
		691	=item 2, 3 (positive/negative bignum)
		692
		693	These tags are decoded into L<Math::BigInt> objects. The corresponding
		694	C<Math::BigInt::TO_CBOR> method encodes "small" bigints into normal CBOR
		695	integers, and others into positive/negative CBOR bignums.
		696
		697	=item 4, 5 (decimal fraction/bigfloat)
		698
		699	Both decimal fractions and bigfloats are decoded into L<Math::BigFloat>
		700	objects. The corresponding C<Math::BigFloat::TO_CBOR> method I<always>
		701	encodes into a decimal fraction.
		702
		703	CBOR cannot represent bigfloats with I<very> large exponents - conversion
		704	of such big float objects is undefined.
		705
		706	Also, NaN and infinities are not encoded properly.
		707
		708	=item 21, 22, 23 (expected later JSON conversion)
		709
		710	CBOR::XS is not a CBOR-to-JSON converter, and will simply ignore these
		711	tags.
		712
		713	=item 32 (URI)
		714
		715	These objects decode into L<URI> objects. The corresponding
		716	C<URI::TO_CBOR> method again results in a CBOR URI value.
		717
		718	=back
		719
		720	=cut
		721
		722	our %FILTER = (
		723	# 0 # rfc4287 datetime, utf-8
		724	# 1 # unix timestamp, any
		725
		726	2 => sub { # pos bigint
		727	require Math::BigInt;
		728	Math::BigInt->new ("0x" . unpack "H*", pop)
		729	},
		730
		731	3 => sub { # neg bigint
		732	require Math::BigInt;
		733	-Math::BigInt->new ("0x" . unpack "H*", pop)
		734	},
		735
		736	4 => sub { # decimal fraction, array
		737	require Math::BigFloat;
		738	Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
		739	},
		740
		741	5 => sub { # bigfloat, array
		742	require Math::BigFloat;
		743	scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2)
		744	},
		745
		746	21 => sub { pop }, # expected conversion to base64url encoding
		747	22 => sub { pop }, # expected conversion to base64 encoding
		748	23 => sub { pop }, # expected conversion to base16 encoding
		749
		750	# 24 # embedded cbor, byte string
		751
		752	32 => sub {
		753	require URI;
		754	URI->new (pop)
		755	},
		756
		757	# 33 # base64url rfc4648, utf-8
		758	# 34 # base64 rfc46484, utf-8
		759	# 35 # regex pcre/ecma262, utf-8
		760	# 36 # mime message rfc2045, utf-8
		761	);
		762
		763
266	=head2 CBOR and JSON	764	=head1 CBOR and JSON
267		765
268	TODO	766	CBOR is supposed to implement a superset of the JSON data model, and is,
		767	with some coercion, able to represent all JSON texts (something that other
		768	"binary JSON" formats such as BSON generally do not support).
		769
		770	CBOR implements some extra hints and support for JSON interoperability,
		771	and the spec offers further guidance for conversion between CBOR and
		772	JSON. None of this is currently implemented in CBOR, and the guidelines
		773	in the spec do not result in correct round-tripping of data. If JSON
		774	interoperability is improved in the future, then the goal will be to
		775	ensure that decoded JSON data will round-trip encoding and decoding to
		776	CBOR intact.
269		777
270		778
271	=head1 SECURITY CONSIDERATIONS	779	=head1 SECURITY CONSIDERATIONS
272		780
273	When you are using CBOR in a protocol, talking to untrusted potentially	781	When you are using CBOR in a protocol, talking to untrusted potentially
…		…
341	Please refrain from using rt.cpan.org or any other bug reporting	849	Please refrain from using rt.cpan.org or any other bug reporting
342	service. I put the contact address into my modules for a reason.	850	service. I put the contact address into my modules for a reason.
343		851
344	=cut	852	=cut
345		853
346	our $true = do { bless \(my $dummy = 1), "CBOR::XS::Boolean" };	854	our %FILTER = (
347	our $false = do { bless \(my $dummy = 0), "CBOR::XS::Boolean" };	855	# 0 # rfc4287 datetime, utf-8
		856	# 1 # unix timestamp, any
348		857
349	sub true() { $true }	858	2 => sub { # pos bigint
350	sub false() { $false }	859	require Math::BigInt;
		860	Math::BigInt->new ("0x" . unpack "H*", pop)
		861	},
351		862
352	sub is_bool($) {	863	3 => sub { # neg bigint
353	UNIVERSAL::isa $_[0], "CBOR::XS::Boolean"	864	require Math::BigInt;
354	# or UNIVERSAL::isa $_[0], "CBOR::Literal"	865	-Math::BigInt->new ("0x" . unpack "H*", pop)
		866	},
		867
		868	4 => sub { # decimal fraction, array
		869	require Math::BigFloat;
		870	Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
		871	},
		872
		873	5 => sub { # bigfloat, array
		874	require Math::BigFloat;
		875	scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2)
		876	},
		877
		878	21 => sub { pop }, # expected conversion to base64url encoding
		879	22 => sub { pop }, # expected conversion to base64 encoding
		880	23 => sub { pop }, # expected conversion to base16 encoding
		881
		882	# 24 # embedded cbor, byte string
		883
		884	32 => sub {
		885	require URI;
		886	URI->new (pop)
		887	},
		888
		889	# 33 # base64url rfc4648, utf-8
		890	# 34 # base64 rfc46484, utf-8
		891	# 35 # regex pcre/ecma262, utf-8
		892	# 36 # mime message rfc2045, utf-8
		893	);
		894
		895	sub CBOR::XS::default_filter {
		896	&{ $FILTER{$_[0]} or return }
355	}	897	}
356		898
		899	sub URI::TO_CBOR {
		900	my $uri = $_[0]->as_string;
		901	utf8::upgrade $uri;
		902	CBOR::XS::tag 32, $uri
		903	}
		904
		905	sub Math::BigInt::TO_CBOR {
		906	if ($_[0] >= -2147483648 && $_[0] <= 2147483647) {
		907	$_[0]->numify
		908	} else {
		909	my $hex = substr $_[0]->as_hex, 2;
		910	$hex = "0$hex" if 1 & length $hex; # sigh
		911	CBOR::XS::tag $_[0] >= 0 ? 2 : 3, pack "H*", $hex
		912	}
		913	}
		914
		915	sub Math::BigFloat::TO_CBOR {
		916	my ($m, $e) = $_[0]->parts;
		917	CBOR::XS::tag 4, [$e->numify, $m]
		918	}
		919
357	XSLoader::load "CBOR::XS", $VERSION;	920	XSLoader::load "CBOR::XS", $VERSION;
358
359	package CBOR::XS::Boolean;
360
361	use overload
362	"0+" => sub { ${$_[0]} },
363	"++" => sub { $_[0] = ${$_[0]} + 1 },
364	"--" => sub { $_[0] = ${$_[0]} - 1 },
365	fallback => 1;
366
367	1;
368		921
369	=head1 SEE ALSO	922	=head1 SEE ALSO
370		923
371	The L<JSON> and L<JSON::XS> modules that do similar, but human-readable,	924	The L<JSON> and L<JSON::XS> modules that do similar, but human-readable,
372	serialisation.	925	serialisation.
373		926
		927	The L<Types::Serialiser> module provides the data model for true, false
		928	and error values.
		929
374	=head1 AUTHOR	930	=head1 AUTHOR
375		931
376	Marc Lehmann <schmorp@schmorp.de>	932	Marc Lehmann <schmorp@schmorp.de>
377	http://home.schmorp.de/	933	http://home.schmorp.de/
378		934
379	=cut	935	=cut
380		936
		937	1
		938

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Comparing CBOR-XS/XS.pm (file contents): Revision 1.2 by root, Sat Oct 26 10:41:12 2013 UTC vs. Revision 1.23 by root, Fri Nov 22 16:00:30 2013 UTC

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Comparing CBOR-XS/XS.pm (file contents):
Revision 1.2 by root, Sat Oct 26 10:41:12 2013 UTC vs.
Revision 1.23 by root, Fri Nov 22 16:00:30 2013 UTC