[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 1.26 by root, Thu Nov 28 12:11:06 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	31	WARNING! This module is very new, and not very well tested (that's up
32	you to do). Furthermore, details of the implementation might change freely	32	to you to do). Furthermore, details of the implementation might change
33	before version 1.0. And lastly, the object serialisation protocol depends	33	freely before version 1.0. And lastly, most extensions depend on an IANA
34	on a pending IANA assignment, and until that assignment is official, this	34	assignment, and until that assignment is official, this implementation is
35	implementation is not interoperable with other implementations (even	35	not interoperable with other implementations (even future versions of this
36	future versions of this module) until the assignment is done.	36	module) until the assignment is done.
37		37
38	You are still invited to try out CBOR, and this module.	38	You are still invited to try out CBOR, and this module.
39		39
40	This module converts Perl data structures to the Concise Binary Object	40	This module converts Perl data structures to the Concise Binary Object
41	Representation (CBOR) and vice versa. CBOR is a fast binary serialisation	41	Representation (CBOR) and vice versa. CBOR is a fast binary serialisation
…		…
54	data, the worse L<Storable> performs in comparison.	54	data, the worse L<Storable> performs in comparison.
55		55
56	As for compactness, C<CBOR::XS> encoded data structures are usually about	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>.	57	20% smaller than the same data encoded as (compact) JSON or L<Storable>.
58		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
59	The primary goal of this module is to be I<correct> and the secondary goal	64	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.	65	is to be I<fast>. To reach the latter goal it was written in C.
61		66
62	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
63	vice versa.	68	vice versa.
…		…
66		71
67	package CBOR::XS;	72	package CBOR::XS;
68		73
69	use common::sense;	74	use common::sense;
70		75
71	our $VERSION = 0.08;	76	our $VERSION = 0.09;
72	our @ISA = qw(Exporter);	77	our @ISA = qw(Exporter);
73		78
74	our @EXPORT = qw(encode_cbor decode_cbor);	79	our @EXPORT = qw(encode_cbor decode_cbor);
75		80
76	use Exporter;	81	use Exporter;
…		…
113	strings. All boolean flags described below are by default I<disabled>.	118	strings. All boolean flags described below are by default I<disabled>.
114		119
115	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
116	be chained:	121	be chained:
117		122
118	#TODO
119	my $cbor = CBOR::XS->new->encode ({a => [1,2]});	123	my $cbor = CBOR::XS->new->encode ({a => [1,2]});
120		124
121	=item $cbor = $cbor->max_depth ([$maximum_nesting_depth])	125	=item $cbor = $cbor->max_depth ([$maximum_nesting_depth])
122		126
123	=item $max_depth = $cbor->get_max_depth	127	=item $max_depth = $cbor->get_max_depth
…		…
171	exception when it encounters anything it cannot encode as CBOR.	175	exception when it encounters anything it cannot encode as CBOR.
172		176
173	This option does not affect C<decode> in any way, and it is recommended to	177	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.	178	leave it off unless you know your communications partner.
175		179
176	=item $cbor = $cbor->allow_sharable ([$enable])	180	=item $cbor = $cbor->allow_sharing ([$enable])
177		181
178	=item $enabled = $cbor->get_allow_sharable	182	=item $enabled = $cbor->get_allow_sharing
179		183
180	If C<$enable> is true (or missing), then C<encode> will not double-encode	184	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	185	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	186	as an array, is referenced multiple times), but instead will emit a
183	the earlier value.	187	reference to the earlier value.
184		188
185	This means that such values will only be encoded once, and will not result	189	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	190	in a deep cloning of the value on decode, in decoders supporting the value
187	sharing extension.	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.
188		198
189	Detecting shared values incurs a runtime overhead when values are encoded	199	Detecting shared values incurs a runtime overhead when values are encoded
190	that have a reference counter large than one, and might unnecessarily	200	that have a reference counter large than one, and might unnecessarily
191	increase the encoded size, as potentially shared values are encode as	201	increase the encoded size, as potentially shared values are encode as
192	sharable whether or not they are actually shared.	202	sharable whether or not they are actually shared.
193		203
194	At the moment, all shared values will be detected, even weird and unusual	204	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,	205	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	206	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	207	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	208	with L<Storable>).
199	references only.
200		209
201	If C<$enable> is false (the default), then C<encode> will encode	210	If C<$enable> is false (the default), then C<encode> will encode shared
202	exception when it encounters anything it cannot encode as CBOR.	211	data structures repeatedly, unsharing them in the process. Cyclic data
		212	structures cannot be encoded in this mode.
203		213
204	This option does not affect C<decode> in any way - shared values and	214	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	215	references will always be decoded properly if present.
206	to leave it off unless you know your communications partner supports the	216
207	value sharing extensions to CBOR (http://cbor.schmorp.de/value-sharing).	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	};
208		278
209	=item $cbor_data = $cbor->encode ($perl_scalar)	279	=item $cbor_data = $cbor->encode ($perl_scalar)
210		280
211	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
212	representation.	282	representation.
…		…
281	C<Types:Serialiser::false> and C<Types::Serialiser::error>,	351	C<Types:Serialiser::false> and C<Types::Serialiser::error>,
282	respectively. They are overloaded to act almost exactly like the numbers	352	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	353	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.	354	error). See the L<Types::Serialiser> manpage for details.
285		355
286	=item CBOR tag 256 (perl object)	356	=item tagged values
287		357
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	358	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		359
303	In the future, support for user-supplied conversions might get added.	360	See L<TAG HANDLING AND EXTENSIONS> and the description of C<< ->filter >>
		361	for details.
304		362
305	=item anything else	363	=item anything else
306		364
307	Anything else (e.g. unsupported simple values) will raise a decoding	365	Anything else (e.g. unsupported simple values) will raise a decoding
308	error.	366	error.
…		…
351	if you want.	409	if you want.
352		410
353	=item other blessed objects	411	=item other blessed objects
354		412
355	Other blessed objects are serialised via C<TO_CBOR> or C<FREEZE>. See	413	Other blessed objects are serialised via C<TO_CBOR> or C<FREEZE>. See
356	L<OBJECT SERIALISATION>, below, for details.	414	L<TAG HANDLING AND EXTENSIONS> for specific classes handled by this
		415	module, and L<OBJECT SERIALISATION> for generic object serialisation.
357		416
358	=item simple scalars	417	=item simple scalars
359		418
360	TODO
361	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
362	difficult objects to encode: CBOR::XS will encode undefined scalars as	420	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	421	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:	422	before encoding as CBOR strings, and anything else as number value:
365		423
…		…
601	CBOR::XS::tag 24,	659	CBOR::XS::tag 24,
602	encode_cbor [1, 2, 3];	660	encode_cbor [1, 2, 3];
603		661
604	=head1 TAG HANDLING AND EXTENSIONS	662	=head1 TAG HANDLING AND EXTENSIONS
605		663
606	This section describes how this module handles specific tagged values and	664	This section describes how this module handles specific tagged values
607	extensions. If a tag is not mentioned here, then the default handling	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
608	applies (creating a CBOR::XS::Tagged object on decoding, and only encoding	667	CBOR::XS::Tagged object on decoding, and only encoding the tag when
609	the tag when explicitly requested).	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.
610		673
611	Future versions of this module reserve the right to special case	674	Future versions of this module reserve the right to special case
612	additional tags (such as bigfloat or base64url).	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.
613		681
614	=over 4	682	=over 4
615		683
616	=item <unassigned> (perl-object, L<http://cbor.schmorp.de/perl-object>)	684	=item 26 (perl-object, L<http://cbor.schmorp.de/perl-object>)
617		685
618	These tags are automatically created for serialisable objects using the	686	These tags are automatically created (and decoded) for serialisable
619	C<FREEZE/THAW> methods (the L<Types::Serialier> object serialisation	687	objects using the C<FREEZE/THAW> methods (the L<Types::Serialier> object
620	protocol).	688	serialisation protocol). See L<OBJECT SERIALISATION> for details.
621		689
622	=item <unassigned>, <unassigned> (sharable, sharedref, L <http://cbor.schmorp.de/value-sharing>)	690	=item 28, 29 (sharable, sharedref, L <http://cbor.schmorp.de/value-sharing>)
623		691
624	These tags are automatically decoded when encountered, resulting in	692	These tags are automatically decoded when encountered, resulting in
625	shared values in the decoded object. They are only encoded, however, when	693	shared values in the decoded object. They are only encoded, however, when
626	C<allow_sharable> is enabled.	694	C<allow_sharable> is enabled.
627		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
628	=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)	701	=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)
629		702
630	This tag is automatically generated when a reference are encountered (with	703	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	704	the exception of hash and array refernces). It is converted to a reference
632	when decoding.	705	when decoding.
…		…
635		708
636	This value is not generated on encoding (unless explicitly requested by	709	This value is not generated on encoding (unless explicitly requested by
637	the user), and is simply ignored when decoding.	710	the user), and is simply ignored when decoding.
638		711
639	=back	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 ($_[1][0], 2)
		783	},
		784
		785	21 => sub { pop }, # expected conversion to base64url encoding
		786	22 => sub { pop }, # expected conversion to base64 encoding
		787	23 => sub { pop }, # expected conversion to base16 encoding
		788
		789	# 24 # embedded cbor, byte string
		790
		791	32 => sub {
		792	require URI;
		793	URI->new (pop)
		794	},
		795
		796	# 33 # base64url rfc4648, utf-8
		797	# 34 # base64 rfc46484, utf-8
		798	# 35 # regex pcre/ecma262, utf-8
		799	# 36 # mime message rfc2045, utf-8
		800	);
640		801
641		802
642	=head1 CBOR and JSON	803	=head1 CBOR and JSON
643		804
644	CBOR is supposed to implement a superset of the JSON data model, and is,	805	CBOR is supposed to implement a superset of the JSON data model, and is,
…		…
727	Please refrain from using rt.cpan.org or any other bug reporting	888	Please refrain from using rt.cpan.org or any other bug reporting
728	service. I put the contact address into my modules for a reason.	889	service. I put the contact address into my modules for a reason.
729		890
730	=cut	891	=cut
731		892
		893	our %FILTER = (
		894	# 0 # rfc4287 datetime, utf-8
		895	# 1 # unix timestamp, any
		896
		897	2 => sub { # pos bigint
		898	require Math::BigInt;
		899	Math::BigInt->new ("0x" . unpack "H*", pop)
		900	},
		901
		902	3 => sub { # neg bigint
		903	require Math::BigInt;
		904	-Math::BigInt->new ("0x" . unpack "H*", pop)
		905	},
		906
		907	4 => sub { # decimal fraction, array
		908	require Math::BigFloat;
		909	Math::BigFloat->new ($_[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 }
		936	}
		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
732	XSLoader::load "CBOR::XS", $VERSION;	959	XSLoader::load "CBOR::XS", $VERSION;
733		960
734	=head1 SEE ALSO	961	=head1 SEE ALSO
735		962
736	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,

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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 1.26 by root, Thu Nov 28 12:11:06 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 1.26 by root, Thu Nov 28 12:11:06 2013 UTC