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

Comparing CBOR-XS/XS.pm (file contents):
Revision 1.1 by root, Fri Oct 25 23:09:45 2013 UTC vs.
Revision 1.26 by root, Thu Nov 28 12:11:06 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<pack_strings>) 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 = 0.09;
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. This also makes it possible to encode cyclic data
		192	structures.
		193
		194	It is recommended to leave it off unless you know your
		195	communication partner supports the value sharing extensions to CBOR
		196	(L<http://cbor.schmorp.de/value-sharing>), as without decoder support, the
		197	resulting data structure might be unusable.
		198
		199	Detecting shared values incurs a runtime overhead when values are encoded
		200	that have a reference counter large than one, and might unnecessarily
		201	increase the encoded size, as potentially shared values are encode as
		202	sharable whether or not they are actually shared.
		203
		204	At the moment, only targets of references can be shared (e.g. scalars,
		205	arrays or hashes pointed to by a reference). Weirder constructs, such as
		206	an array with multiple "copies" of the I<same> string, which are hard but
		207	not impossible to create in Perl, are not supported (this is the same as
		208	with L<Storable>).
		209
		210	If C<$enable> is false (the default), then C<encode> will encode shared
		211	data structures repeatedly, unsharing them in the process. Cyclic data
		212	structures cannot be encoded in this mode.
		213
		214	This option does not affect C<decode> in any way - shared values and
		215	references will always be decoded properly if present.
		216
		217	=item $cbor = $cbor->pack_strings ([$enable])
		218
		219	=item $enabled = $cbor->get_pack_strings
		220
		221	If C<$enable> is true (or missing), then C<encode> will try not to encode
		222	the same string twice, but will instead encode a reference to the string
		223	instead. Depending on your data format, this can save a lot of space, but
		224	also results in a very large runtime overhead (expect encoding times to be
		225	2-4 times as high as without).
		226
		227	It is recommended to leave it off unless you know your
		228	communications partner supports the stringref extension to CBOR
		229	(L<http://cbor.schmorp.de/stringref>), as without decoder support, the
		230	resulting data structure might not be usable.
		231
		232	If C<$enable> is false (the default), then C<encode> will encode strings
		233	the standard CBOR way.
		234
		235	This option does not affect C<decode> in any way - string references will
		236	always be decoded properly if present.
		237
		238	=item $cbor = $cbor->filter ([$cb->($tag, $value)])
		239
		240	=item $cb_or_undef = $cbor->get_filter
		241
		242	Sets or replaces the tagged value decoding filter (when C<$cb> is
		243	specified) or clears the filter (if no argument or C<undef> is provided).
		244
		245	The filter callback is called only during decoding, when a non-enforced
		246	tagged value has been decoded (see L<TAG HANDLING AND EXTENSIONS> for a
		247	list of enforced tags). For specific tags, it's often better to provide a
		248	default converter using the C<%CBOR::XS::FILTER> hash (see below).
		249
		250	The first argument is the numerical tag, the second is the (decoded) value
		251	that has been tagged.
		252
		253	The filter function should return either exactly one value, which will
		254	replace the tagged value in the decoded data structure, or no values,
		255	which will result in default handling, which currently means the decoder
		256	creates a C<CBOR::XS::Tagged> object to hold the tag and the value.
		257
		258	When the filter is cleared (the default state), the default filter
		259	function, C<CBOR::XS::default_filter>, is used. This function simply looks
		260	up the tag in the C<%CBOR::XS::FILTER> hash. If an entry exists it must be
		261	a code reference that is called with tag and value, and is responsible for
		262	decoding the value. If no entry exists, it returns no values.
		263
		264	Example: decode all tags not handled internally into CBOR::XS::Tagged
		265	objects, with no other special handling (useful when working with
		266	potentially "unsafe" CBOR data).
		267
		268	CBOR::XS->new->filter (sub { })->decode ($cbor_data);
		269
		270	Example: provide a global filter for tag 1347375694, converting the value
		271	into some string form.
		272
		273	$CBOR::XS::FILTER{1347375694} = sub {
		274	my ($tag, $value);
		275
		276	"tag 1347375694 value $value"
		277	};
		278
124	=item $cbor_data = $cbor->encode ($perl_scalar)	279	=item $cbor_data = $cbor->encode ($perl_scalar)
125		280
126	Converts the given Perl data structure (a scalar value) to its CBOR	281	Converts the given Perl data structure (a scalar value) to its CBOR
127	representation.	282	representation.
128		283
…		…
161		316
162	=head2 CBOR -> PERL	317	=head2 CBOR -> PERL
163		318
164	=over 4	319	=over 4
165		320
166	=item True, False	321	=item integers
167		322
168	These CBOR values become C<CBOR::XS::true> and C<CBOR::XS::false>,	323	CBOR integers become (numeric) perl scalars. On perls without 64 bit
		324	support, 64 bit integers will be truncated or otherwise corrupted.
		325
		326	=item byte strings
		327
		328	Byte strings will become octet strings in Perl (the byte values 0..255
		329	will simply become characters of the same value in Perl).
		330
		331	=item UTF-8 strings
		332
		333	UTF-8 strings in CBOR will be decoded, i.e. the UTF-8 octets will be
		334	decoded into proper Unicode code points. At the moment, the validity of
		335	the UTF-8 octets will not be validated - corrupt input will result in
		336	corrupted Perl strings.
		337
		338	=item arrays, maps
		339
		340	CBOR arrays and CBOR maps will be converted into references to a Perl
		341	array or hash, respectively. The keys of the map will be stringified
		342	during this process.
		343
		344	=item null
		345
		346	CBOR null becomes C<undef> in Perl.
		347
		348	=item true, false, undefined
		349
		350	These CBOR values become C<Types:Serialiser::true>,
		351	C<Types:Serialiser::false> and C<Types::Serialiser::error>,
169	respectively. They are overloaded to act almost exactly like the numbers	352	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	353	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.	354	error). See the L<Types::Serialiser> manpage for details.
172		355
173	=item null	356	=item tagged values
174		357
175	A CBOR Null value becomes C<undef> in Perl.	358	Tagged items consists of a numeric tag and another CBOR value.
		359
		360	See L<TAG HANDLING AND EXTENSIONS> and the description of C<< ->filter >>
		361	for details.
		362
		363	=item anything else
		364
		365	Anything else (e.g. unsupported simple values) will raise a decoding
		366	error.
176		367
177	=back	368	=back
178		369
179		370
180	=head2 PERL -> CBOR	371	=head2 PERL -> CBOR
…		…
185		376
186	=over 4	377	=over 4
187		378
188	=item hash references	379	=item hash references
189		380
190	Perl hash references become CBOR maps. As there is no inherent ordering	381	Perl hash references become CBOR maps. As there is no inherent ordering in
191	in hash keys (or CBOR maps), they will usually be encoded in a	382	hash keys (or CBOR maps), they will usually be encoded in a pseudo-random
192	pseudo-random order.	383	order.
		384
		385	Currently, tied hashes will use the indefinite-length format, while normal
		386	hashes will use the fixed-length format.
193		387
194	=item array references	388	=item array references
195		389
196	Perl array references become CBOR arrays.	390	Perl array references become fixed-length CBOR arrays.
197		391
198	=item other references	392	=item other references
199		393
200	Other unblessed references are generally not allowed and will cause an	394	Other unblessed references are generally not allowed and will cause an
201	exception to be thrown, except for references to the integers C<0> and	395	exception to be thrown, except for references to the integers C<0> and
202	C<1>, which get turned into C<False> and C<True> in CBOR.	396	C<1>, which get turned into false and true in CBOR.
203		397
204	=item CBOR::XS::true, CBOR::XS::false	398	=item CBOR::XS::Tagged objects
205		399
		400	Objects of this type must be arrays consisting of a single C<[tag, value]>
		401	pair. The (numerical) tag will be encoded as a CBOR tag, the value will
		402	be encoded as appropriate for the value. You cna use C<CBOR::XS::tag> to
		403	create such objects.
		404
		405	=item Types::Serialiser::true, Types::Serialiser::false, Types::Serialiser::error
		406
206	These special values become CBOR True and CBOR False values,	407	These special values become CBOR true, CBOR false and CBOR undefined
207	respectively. You can also use C<\1> and C<\0> directly if you want.	408	values, respectively. You can also use C<\1>, C<\0> and C<\undef> directly
		409	if you want.
208		410
209	=item blessed objects	411	=item other blessed objects
210		412
211	Blessed objects are not directly representable in CBOR. TODO	413	Other blessed objects are serialised via C<TO_CBOR> or C<FREEZE>. See
212	See the	414	L<TAG HANDLING AND EXTENSIONS> for specific classes handled by this
213	C<allow_blessed> and C<convert_blessed> methods on various options on	415	module, and L<OBJECT SERIALISATION> for generic object serialisation.
214	how to deal with this: basically, you can choose between throwing an
215	exception, encoding the reference as if it weren't blessed, or provide
216	your own serialiser method.
217		416
218	=item simple scalars	417	=item simple scalars
219		418
220	TODO
221	Simple Perl scalars (any scalar that is not a reference) are the most	419	Simple Perl scalars (any scalar that is not a reference) are the most
222	difficult objects to encode: CBOR::XS will encode undefined scalars as	420	difficult objects to encode: CBOR::XS will encode undefined scalars as
223	CBOR C<Null> values, scalars that have last been used in a string context	421	CBOR null values, scalars that have last been used in a string context
224	before encoding as CBOR strings, and anything else as number value:	422	before encoding as CBOR strings, and anything else as number value:
225		423
226	# dump as number	424	# dump as number
227	encode_cbor [2] # yields [2]	425	encode_cbor [2] # yields [2]
228	encode_cbor [-3.0e17] # yields [-3e+17]	426	encode_cbor [-3.0e17] # yields [-3e+17]
…		…
250		448
251	You can not currently force the type in other, less obscure, ways. Tell me	449	You can not currently force the type in other, less obscure, ways. Tell me
252	if you need this capability (but don't forget to explain why it's needed	450	if you need this capability (but don't forget to explain why it's needed
253	:).	451	:).
254		452
255	Note that numerical precision has the same meaning as under Perl (so	453	Perl values that seem to be integers generally use the shortest possible
256	binary to decimal conversion follows the same rules as in Perl, which	454	representation. Floating-point values will use either the IEEE single
257	can differ to other languages). Also, your perl interpreter might expose	455	format if possible without loss of precision, otherwise the IEEE double
258	extensions to the floating point numbers of your platform, such as	456	format will be used. Perls that use formats other than IEEE double to
259	infinities or NaN's - these cannot be represented in CBOR, and it is an	457	represent numerical values are supported, but might suffer loss of
260	error to pass those in.	458	precision.
261		459
262	=back	460	=back
263		461
		462	=head2 OBJECT SERIALISATION
264		463
		464	This module knows two way to serialise a Perl object: The CBOR-specific
		465	way, and the generic way.
		466
		467	Whenever the encoder encounters a Perl object that it cnanot serialise
		468	directly (most of them), it will first look up the C<TO_CBOR> method on
		469	it.
		470
		471	If it has a C<TO_CBOR> method, it will call it with the object as only
		472	argument, and expects exactly one return value, which it will then
		473	substitute and encode it in the place of the object.
		474
		475	Otherwise, it will look up the C<FREEZE> method. If it exists, it will
		476	call it with the object as first argument, and the constant string C<CBOR>
		477	as the second argument, to distinguish it from other serialisers.
		478
		479	The C<FREEZE> method can return any number of values (i.e. zero or
		480	more). These will be encoded as CBOR perl object, together with the
		481	classname.
		482
		483	If an object supports neither C<TO_CBOR> nor C<FREEZE>, encoding will fail
		484	with an error.
		485
		486	Objects encoded via C<TO_CBOR> cannot be automatically decoded, but
		487	objects encoded via C<FREEZE> can be decoded using the following protocol:
		488
		489	When an encoded CBOR perl object is encountered by the decoder, it will
		490	look up the C<THAW> method, by using the stored classname, and will fail
		491	if the method cannot be found.
		492
		493	After the lookup it will call the C<THAW> method with the stored classname
		494	as first argument, the constant string C<CBOR> as second argument, and all
		495	values returned by C<FREEZE> as remaining arguments.
		496
		497	=head4 EXAMPLES
		498
		499	Here is an example C<TO_CBOR> method:
		500
		501	sub My::Object::TO_CBOR {
		502	my ($obj) = @_;
		503
		504	["this is a serialised My::Object object", $obj->{id}]
		505	}
		506
		507	When a C<My::Object> is encoded to CBOR, it will instead encode a simple
		508	array with two members: a string, and the "object id". Decoding this CBOR
		509	string will yield a normal perl array reference in place of the object.
		510
		511	A more useful and practical example would be a serialisation method for
		512	the URI module. CBOR has a custom tag value for URIs, namely 32:
		513
		514	sub URI::TO_CBOR {
		515	my ($self) = @_;
		516	my $uri = "$self"; # stringify uri
		517	utf8::upgrade $uri; # make sure it will be encoded as UTF-8 string
		518	CBOR::XS::tagged 32, "$_[0]"
		519	}
		520
		521	This will encode URIs as a UTF-8 string with tag 32, which indicates an
		522	URI.
		523
		524	Decoding such an URI will not (currently) give you an URI object, but
		525	instead a CBOR::XS::Tagged object with tag number 32 and the string -
		526	exactly what was returned by C<TO_CBOR>.
		527
		528	To serialise an object so it can automatically be deserialised, you need
		529	to use C<FREEZE> and C<THAW>. To take the URI module as example, this
		530	would be a possible implementation:
		531
		532	sub URI::FREEZE {
		533	my ($self, $serialiser) = @_;
		534	"$self" # encode url string
		535	}
		536
		537	sub URI::THAW {
		538	my ($class, $serialiser, $uri) = @_;
		539
		540	$class->new ($uri)
		541	}
		542
		543	Unlike C<TO_CBOR>, multiple values can be returned by C<FREEZE>. For
		544	example, a C<FREEZE> method that returns "type", "id" and "variant" values
		545	would cause an invocation of C<THAW> with 5 arguments:
		546
		547	sub My::Object::FREEZE {
		548	my ($self, $serialiser) = @_;
		549
		550	($self->{type}, $self->{id}, $self->{variant})
		551	}
		552
		553	sub My::Object::THAW {
		554	my ($class, $serialiser, $type, $id, $variant) = @_;
		555
		556	$class-<new (type => $type, id => $id, variant => $variant)
		557	}
		558
		559
		560	=head1 MAGIC HEADER
		561
		562	There is no way to distinguish CBOR from other formats
		563	programmatically. To make it easier to distinguish CBOR from other
		564	formats, the CBOR specification has a special "magic string" that can be
		565	prepended to any CBOR string without changing its meaning.
		566
		567	This string is available as C<$CBOR::XS::MAGIC>. This module does not
		568	prepend this string to the CBOR data it generates, but it will ignore it
		569	if present, so users can prepend this string as a "file type" indicator as
		570	required.
		571
		572
		573	=head1 THE CBOR::XS::Tagged CLASS
		574
		575	CBOR has the concept of tagged values - any CBOR value can be tagged with
		576	a numeric 64 bit number, which are centrally administered.
		577
		578	C<CBOR::XS> handles a few tags internally when en- or decoding. You can
		579	also create tags yourself by encoding C<CBOR::XS::Tagged> objects, and the
		580	decoder will create C<CBOR::XS::Tagged> objects itself when it hits an
		581	unknown tag.
		582
		583	These objects are simply blessed array references - the first member of
		584	the array being the numerical tag, the second being the value.
		585
		586	You can interact with C<CBOR::XS::Tagged> objects in the following ways:
		587
		588	=over 4
		589
		590	=item $tagged = CBOR::XS::tag $tag, $value
		591
		592	This function(!) creates a new C<CBOR::XS::Tagged> object using the given
		593	C<$tag> (0..2**64-1) to tag the given C<$value> (which can be any Perl
		594	value that can be encoded in CBOR, including serialisable Perl objects and
		595	C<CBOR::XS::Tagged> objects).
		596
		597	=item $tagged->[0]
		598
		599	=item $tagged->[0] = $new_tag
		600
		601	=item $tag = $tagged->tag
		602
		603	=item $new_tag = $tagged->tag ($new_tag)
		604
		605	Access/mutate the tag.
		606
		607	=item $tagged->[1]
		608
		609	=item $tagged->[1] = $new_value
		610
		611	=item $value = $tagged->value
		612
		613	=item $new_value = $tagged->value ($new_value)
		614
		615	Access/mutate the tagged value.
		616
		617	=back
		618
		619	=cut
		620
		621	sub tag($$) {
		622	bless [@_], CBOR::XS::Tagged::;
		623	}
		624
		625	sub CBOR::XS::Tagged::tag {
		626	$_[0][0] = $_[1] if $#_;
		627	$_[0][0]
		628	}
		629
		630	sub CBOR::XS::Tagged::value {
		631	$_[0][1] = $_[1] if $#_;
		632	$_[0][1]
		633	}
		634
		635	=head2 EXAMPLES
		636
		637	Here are some examples of C<CBOR::XS::Tagged> uses to tag objects.
		638
		639	You can look up CBOR tag value and emanings in the IANA registry at
		640	L<http://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml>.
		641
		642	Prepend a magic header (C<$CBOR::XS::MAGIC>):
		643
		644	my $cbor = encode_cbor CBOR::XS::tag 55799, $value;
		645	# same as:
		646	my $cbor = $CBOR::XS::MAGIC . encode_cbor $value;
		647
		648	Serialise some URIs and a regex in an array:
		649
		650	my $cbor = encode_cbor [
		651	(CBOR::XS::tag 32, "http://www.nethype.de/"),
		652	(CBOR::XS::tag 32, "http://software.schmorp.de/"),
		653	(CBOR::XS::tag 35, "^[Pp][Ee][Rr][lL]\$"),
		654	];
		655
		656	Wrap CBOR data in CBOR:
		657
		658	my $cbor_cbor = encode_cbor
		659	CBOR::XS::tag 24,
		660	encode_cbor [1, 2, 3];
		661
		662	=head1 TAG HANDLING AND EXTENSIONS
		663
		664	This section describes how this module handles specific tagged values
		665	and extensions. If a tag is not mentioned here and no additional filters
		666	are provided for it, then the default handling applies (creating a
		667	CBOR::XS::Tagged object on decoding, and only encoding the tag when
		668	explicitly requested).
		669
		670	Tags not handled specifically are currently converted into a
		671	L<CBOR::XS::Tagged> object, which is simply a blessed array reference
		672	consisting of the numeric tag value followed by the (decoded) CBOR value.
		673
		674	Future versions of this module reserve the right to special case
		675	additional tags (such as base64url).
		676
		677	=head2 ENFORCED TAGS
		678
		679	These tags are always handled when decoding, and their handling cannot be
		680	overriden by the user.
		681
		682	=over 4
		683
		684	=item 26 (perl-object, L<http://cbor.schmorp.de/perl-object>)
		685
		686	These tags are automatically created (and decoded) for serialisable
		687	objects using the C<FREEZE/THAW> methods (the L<Types::Serialier> object
		688	serialisation protocol). See L<OBJECT SERIALISATION> for details.
		689
		690	=item 28, 29 (sharable, sharedref, L <http://cbor.schmorp.de/value-sharing>)
		691
		692	These tags are automatically decoded when encountered, resulting in
		693	shared values in the decoded object. They are only encoded, however, when
		694	C<allow_sharable> is enabled.
		695
		696	=item 256, 25 (stringref-namespace, stringref, L <http://cbor.schmorp.de/stringref>)
		697
		698	These tags are automatically decoded when encountered. They are only
		699	encoded, however, when C<pack_strings> is enabled.
		700
		701	=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)
		702
		703	This tag is automatically generated when a reference are encountered (with
		704	the exception of hash and array refernces). It is converted to a reference
		705	when decoding.
		706
		707	=item 55799 (self-describe CBOR, RFC 7049)
		708
		709	This value is not generated on encoding (unless explicitly requested by
		710	the user), and is simply ignored when decoding.
		711
		712	=back
		713
		714	=head2 NON-ENFORCED TAGS
		715
		716	These tags have default filters provided when decoding. Their handling can
		717	be overriden by changing the C<%CBOR::XS::FILTER> entry for the tag, or by
		718	providing a custom C<filter> callback when decoding.
		719
		720	When they result in decoding into a specific Perl class, the module
		721	usually provides a corresponding C<TO_CBOR> method as well.
		722
		723	When any of these need to load additional modules that are not part of the
		724	perl core distribution (e.g. L<URI>), it is (currently) up to the user to
		725	provide these modules. The decoding usually fails with an exception if the
		726	required module cannot be loaded.
		727
		728	=over 4
		729
		730	=item 2, 3 (positive/negative bignum)
		731
		732	These tags are decoded into L<Math::BigInt> objects. The corresponding
		733	C<Math::BigInt::TO_CBOR> method encodes "small" bigints into normal CBOR
		734	integers, and others into positive/negative CBOR bignums.
		735
		736	=item 4, 5 (decimal fraction/bigfloat)
		737
		738	Both decimal fractions and bigfloats are decoded into L<Math::BigFloat>
		739	objects. The corresponding C<Math::BigFloat::TO_CBOR> method I<always>
		740	encodes into a decimal fraction.
		741
		742	CBOR cannot represent bigfloats with I<very> large exponents - conversion
		743	of such big float objects is undefined.
		744
		745	Also, NaN and infinities are not encoded properly.
		746
		747	=item 21, 22, 23 (expected later JSON conversion)
		748
		749	CBOR::XS is not a CBOR-to-JSON converter, and will simply ignore these
		750	tags.
		751
		752	=item 32 (URI)
		753
		754	These objects decode into L<URI> objects. The corresponding
		755	C<URI::TO_CBOR> method again results in a CBOR URI value.
		756
		757	=back
		758
		759	=cut
		760
		761	our %FILTER = (
		762	# 0 # rfc4287 datetime, utf-8
		763	# 1 # unix timestamp, any
		764
		765	2 => sub { # pos bigint
		766	require Math::BigInt;
		767	Math::BigInt->new ("0x" . unpack "H*", pop)
		768	},
		769
		770	3 => sub { # neg bigint
		771	require Math::BigInt;
		772	-Math::BigInt->new ("0x" . unpack "H*", pop)
		773	},
		774
		775	4 => sub { # decimal fraction, array
		776	require Math::BigFloat;
		777	Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
		778	},
		779
		780	5 => sub { # bigfloat, array
		781	require Math::BigFloat;
		782	scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2)
		783	},
		784
		785	21 => sub { pop }, # expected conversion to base64url encoding
		786	22 => sub { pop }, # expected conversion to base64 encoding
		787	23 => sub { pop }, # expected conversion to base16 encoding
		788
		789	# 24 # embedded cbor, byte string
		790
		791	32 => sub {
		792	require URI;
		793	URI->new (pop)
		794	},
		795
		796	# 33 # base64url rfc4648, utf-8
		797	# 34 # base64 rfc46484, utf-8
		798	# 35 # regex pcre/ecma262, utf-8
		799	# 36 # mime message rfc2045, utf-8
		800	);
		801
		802
265	=head2 CBOR and JSON	803	=head1 CBOR and JSON
266		804
267	TODO	805	CBOR is supposed to implement a superset of the JSON data model, and is,
		806	with some coercion, able to represent all JSON texts (something that other
		807	"binary JSON" formats such as BSON generally do not support).
		808
		809	CBOR implements some extra hints and support for JSON interoperability,
		810	and the spec offers further guidance for conversion between CBOR and
		811	JSON. None of this is currently implemented in CBOR, and the guidelines
		812	in the spec do not result in correct round-tripping of data. If JSON
		813	interoperability is improved in the future, then the goal will be to
		814	ensure that decoded JSON data will round-trip encoding and decoding to
		815	CBOR intact.
268		816
269		817
270	=head1 SECURITY CONSIDERATIONS	818	=head1 SECURITY CONSIDERATIONS
271		819
272	When you are using CBOR in a protocol, talking to untrusted potentially	820	When you are using CBOR in a protocol, talking to untrusted potentially
…		…
340	Please refrain from using rt.cpan.org or any other bug reporting	888	Please refrain from using rt.cpan.org or any other bug reporting
341	service. I put the contact address into my modules for a reason.	889	service. I put the contact address into my modules for a reason.
342		890
343	=cut	891	=cut
344		892
345	our $true = do { bless \(my $dummy = 1), "CBOR::XS::Boolean" };	893	our %FILTER = (
346	our $false = do { bless \(my $dummy = 0), "CBOR::XS::Boolean" };	894	# 0 # rfc4287 datetime, utf-8
		895	# 1 # unix timestamp, any
347		896
348	sub true() { $true }	897	2 => sub { # pos bigint
349	sub false() { $false }	898	require Math::BigInt;
		899	Math::BigInt->new ("0x" . unpack "H*", pop)
		900	},
350		901
351	sub is_bool($) {	902	3 => sub { # neg bigint
352	UNIVERSAL::isa $_[0], "CBOR::XS::Boolean"	903	require Math::BigInt;
353	# or UNIVERSAL::isa $_[0], "CBOR::Literal"	904	-Math::BigInt->new ("0x" . unpack "H*", pop)
		905	},
		906
		907	4 => sub { # decimal fraction, array
		908	require Math::BigFloat;
		909	Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
		910	},
		911
		912	5 => sub { # bigfloat, array
		913	require Math::BigFloat;
		914	scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2)
		915	},
		916
		917	21 => sub { pop }, # expected conversion to base64url encoding
		918	22 => sub { pop }, # expected conversion to base64 encoding
		919	23 => sub { pop }, # expected conversion to base16 encoding
		920
		921	# 24 # embedded cbor, byte string
		922
		923	32 => sub {
		924	require URI;
		925	URI->new (pop)
		926	},
		927
		928	# 33 # base64url rfc4648, utf-8
		929	# 34 # base64 rfc46484, utf-8
		930	# 35 # regex pcre/ecma262, utf-8
		931	# 36 # mime message rfc2045, utf-8
		932	);
		933
		934	sub CBOR::XS::default_filter {
		935	&{ $FILTER{$_[0]} or return }
354	}	936	}
355		937
		938	sub URI::TO_CBOR {
		939	my $uri = $_[0]->as_string;
		940	utf8::upgrade $uri;
		941	CBOR::XS::tag 32, $uri
		942	}
		943
		944	sub Math::BigInt::TO_CBOR {
		945	if ($_[0] >= -2147483648 && $_[0] <= 2147483647) {
		946	$_[0]->numify
		947	} else {
		948	my $hex = substr $_[0]->as_hex, 2;
		949	$hex = "0$hex" if 1 & length $hex; # sigh
		950	CBOR::XS::tag $_[0] >= 0 ? 2 : 3, pack "H*", $hex
		951	}
		952	}
		953
		954	sub Math::BigFloat::TO_CBOR {
		955	my ($m, $e) = $_[0]->parts;
		956	CBOR::XS::tag 4, [$e->numify, $m]
		957	}
		958
356	XSLoader::load "CBOR::XS", $VERSION;	959	XSLoader::load "CBOR::XS", $VERSION;
357
358	package CBOR::XS::Boolean;
359
360	use overload
361	"0+" => sub { ${$_[0]} },
362	"++" => sub { $_[0] = ${$_[0]} + 1 },
363	"--" => sub { $_[0] = ${$_[0]} - 1 },
364	fallback => 1;
365
366	1;
367		960
368	=head1 SEE ALSO	961	=head1 SEE ALSO
369		962
370	The L<JSON> and L<JSON::XS> modules that do similar, but human-readable,	963	The L<JSON> and L<JSON::XS> modules that do similar, but human-readable,
371	serialisation.	964	serialisation.
372		965
		966	The L<Types::Serialiser> module provides the data model for true, false
		967	and error values.
		968
373	=head1 AUTHOR	969	=head1 AUTHOR
374		970
375	Marc Lehmann <schmorp@schmorp.de>	971	Marc Lehmann <schmorp@schmorp.de>
376	http://home.schmorp.de/	972	http://home.schmorp.de/
377		973
378	=cut	974	=cut
379		975
		976	1
		977

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Comparing CBOR-XS/XS.pm (file contents): Revision 1.1 by root, Fri Oct 25 23:09:45 2013 UTC vs. Revision 1.26 by root, Thu Nov 28 12:11:06 2013 UTC

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Comparing CBOR-XS/XS.pm (file contents):
Revision 1.1 by root, Fri Oct 25 23:09:45 2013 UTC vs.
Revision 1.26 by root, Thu Nov 28 12:11:06 2013 UTC