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

Comparing CBOR-XS/XS.pm (file contents):
Revision 1.14 by root, Tue Oct 29 20:59:16 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
…		…
46	In short, CBOR is a faster and very compact binary alternative to JSON,	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	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	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).	49	data later you might want to compare both formats first).
50		50
51	To give you a general idea, with texts in the megabyte range, C<CBOR::XS>	51	To give you a general idea about speed, with texts in the megabyte range,
52	usually encodes roughly twice as fast as L<Storable> or L<JSON::XS> and	52	C<CBOR::XS> usually encodes roughly twice as fast as L<Storable> or
53	decodes about 15%-30% faster than those. The shorter the data, the worse	53	L<JSON::XS> and decodes about 15%-30% faster than those. The shorter the
54	L<Storable> performs in comparison.	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).
55		63
56	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
57	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.
58		66
59	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		71
64	package CBOR::XS;	72	package CBOR::XS;
65		73
66	use common::sense;	74	use common::sense;
67		75
68	our $VERSION = 0.06;	76	our $VERSION = 0.09;
69	our @ISA = qw(Exporter);	77	our @ISA = qw(Exporter);
70		78
71	our @EXPORT = qw(encode_cbor decode_cbor);	79	our @EXPORT = qw(encode_cbor decode_cbor);
72		80
73	use Exporter;	81	use Exporter;
…		…
110	strings. All boolean flags described below are by default I<disabled>.	118	strings. All boolean flags described below are by default I<disabled>.
111		119
112	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
113	be chained:	121	be chained:
114		122
115	#TODO
116	my $cbor = CBOR::XS->new->encode ({a => [1,2]});	123	my $cbor = CBOR::XS->new->encode ({a => [1,2]});
117		124
118	=item $cbor = $cbor->max_depth ([$maximum_nesting_depth])	125	=item $cbor = $cbor->max_depth ([$maximum_nesting_depth])
119		126
120	=item $max_depth = $cbor->get_max_depth	127	=item $max_depth = $cbor->get_max_depth
…		…
154	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
155	C<0> is specified).	162	C<0> is specified).
156		163
157	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.
158		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
159	=item $cbor_data = $cbor->encode ($perl_scalar)	279	=item $cbor_data = $cbor->encode ($perl_scalar)
160		280
161	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
162	representation.	282	representation.
163		283
…		…
231	C<Types:Serialiser::false> and C<Types::Serialiser::error>,	351	C<Types:Serialiser::false> and C<Types::Serialiser::error>,
232	respectively. They are overloaded to act almost exactly like the numbers	352	respectively. They are overloaded to act almost exactly like the numbers
233	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
234	error). See the L<Types::Serialiser> manpage for details.	354	error). See the L<Types::Serialiser> manpage for details.
235		355
236	=item CBOR tag 256 (perl object)	356	=item tagged values
237		357
238	The tag value C<256> (TODO: pending iana registration) will be used
239	to deserialise a Perl object serialised with C<FREEZE>. See L<OBJECT
240	SERIALISATION>, below, for details.
241
242	=item CBOR tag 55799 (magic header)
243
244	The tag 55799 is ignored (this tag implements the magic header).
245
246	=item other CBOR tags
247
248	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.
249	handled internally are currently converted into a L<CBOR::XS::Tagged>
250	object, which is simply a blessed array reference consisting of the
251	numeric tag value followed by the (decoded) CBOR value.
252		359
253	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.
254		362
255	=item anything else	363	=item anything else
256		364
257	Anything else (e.g. unsupported simple values) will raise a decoding	365	Anything else (e.g. unsupported simple values) will raise a decoding
258	error.	366	error.
…		…
301	if you want.	409	if you want.
302		410
303	=item other blessed objects	411	=item other blessed objects
304		412
305	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
306	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.
307		416
308	=item simple scalars	417	=item simple scalars
309		418
310	TODO
311	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
312	difficult objects to encode: CBOR::XS will encode undefined scalars as	420	difficult objects to encode: CBOR::XS will encode undefined scalars as
313	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
314	before encoding as CBOR strings, and anything else as number value:	422	before encoding as CBOR strings, and anything else as number value:
315		423
…		…
452	=head1 MAGIC HEADER	560	=head1 MAGIC HEADER
453		561
454	There is no way to distinguish CBOR from other formats	562	There is no way to distinguish CBOR from other formats
455	programmatically. To make it easier to distinguish CBOR from other	563	programmatically. To make it easier to distinguish CBOR from other
456	formats, the CBOR specification has a special "magic string" that can be	564	formats, the CBOR specification has a special "magic string" that can be
457	prepended to any CBOR string without changing it's meaning.	565	prepended to any CBOR string without changing its meaning.
458		566
459	This string is available as C<$CBOR::XS::MAGIC>. This module does not	567	This string is available as C<$CBOR::XS::MAGIC>. This module does not
460	prepend this string tot he CBOR data it generates, but it will ignroe it	568	prepend this string to the CBOR data it generates, but it will ignore it
461	if present, so users can prepend this string as a "file type" indicator as	569	if present, so users can prepend this string as a "file type" indicator as
462	required.	570	required.
463		571
464		572
465	=head1 THE CBOR::XS::Tagged CLASS	573	=head1 THE CBOR::XS::Tagged CLASS
…		…
548	Wrap CBOR data in CBOR:	656	Wrap CBOR data in CBOR:
549		657
550	my $cbor_cbor = encode_cbor	658	my $cbor_cbor = encode_cbor
551	CBOR::XS::tag 24,	659	CBOR::XS::tag 24,
552	encode_cbor [1, 2, 3];	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 ($_[1][0], 2)
		783	},
		784
		785	21 => sub { pop }, # expected conversion to base64url encoding
		786	22 => sub { pop }, # expected conversion to base64 encoding
		787	23 => sub { pop }, # expected conversion to base16 encoding
		788
		789	# 24 # embedded cbor, byte string
		790
		791	32 => sub {
		792	require URI;
		793	URI->new (pop)
		794	},
		795
		796	# 33 # base64url rfc4648, utf-8
		797	# 34 # base64 rfc46484, utf-8
		798	# 35 # regex pcre/ecma262, utf-8
		799	# 36 # mime message rfc2045, utf-8
		800	);
		801
553		802
554	=head1 CBOR and JSON	803	=head1 CBOR and JSON
555		804
556	CBOR is supposed to implement a superset of the JSON data model, and is,	805	CBOR is supposed to implement a superset of the JSON data model, and is,
557	with some coercion, able to represent all JSON texts (something that other	806	with some coercion, able to represent all JSON texts (something that other
…		…
639	Please refrain from using rt.cpan.org or any other bug reporting	888	Please refrain from using rt.cpan.org or any other bug reporting
640	service. I put the contact address into my modules for a reason.	889	service. I put the contact address into my modules for a reason.
641		890
642	=cut	891	=cut
643		892
		893	our %FILTER = (
		894	# 0 # rfc4287 datetime, utf-8
		895	# 1 # unix timestamp, any
		896
		897	2 => sub { # pos bigint
		898	require Math::BigInt;
		899	Math::BigInt->new ("0x" . unpack "H*", pop)
		900	},
		901
		902	3 => sub { # neg bigint
		903	require Math::BigInt;
		904	-Math::BigInt->new ("0x" . unpack "H*", pop)
		905	},
		906
		907	4 => sub { # decimal fraction, array
		908	require Math::BigFloat;
		909	Math::BigFloat->new ($_[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
644	XSLoader::load "CBOR::XS", $VERSION;	959	XSLoader::load "CBOR::XS", $VERSION;
645		960
646	=head1 SEE ALSO	961	=head1 SEE ALSO
647		962
648	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 1.14 by root, Tue Oct 29 20:59:16 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 1.14 by root, Tue Oct 29 20:59:16 2013 UTC vs.
Revision 1.26 by root, Thu Nov 28 12:11:06 2013 UTC