[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 1.22 by root, Fri Nov 22 15:28:38 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<allow_stringref>) 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.
…		…
171	exception when it encounters anything it cannot encode as CBOR.	176	exception when it encounters anything it cannot encode as CBOR.
172		177
173	This option does not affect C<decode> in any way, and it is recommended to	178	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.	179	leave it off unless you know your communications partner.
175		180
176	=item $cbor = $cbor->allow_sharable ([$enable])	181	=item $cbor = $cbor->allow_sharing ([$enable])
177		182
178	=item $enabled = $cbor->get_allow_sharable	183	=item $enabled = $cbor->get_allow_sharing
179		184
180	If C<$enable> is true (or missing), then C<encode> will not double-encode	185	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	186	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	187	as an array, is referenced multiple times), but instead will emit a
183	the earlier value.	188	reference to the earlier value.
184		189
185	This means that such values will only be encoded once, and will not result	190	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	191	in a deep cloning of the value on decode, in decoders supporting the value
187	sharing extension.	192	sharing extension.
		193
		194	It is recommended to leave it off unless you know your
		195	communication partner supports the value sharing extensions to CBOR
		196	(http://cbor.schmorp.de/value-sharing).
188		197
189	Detecting shared values incurs a runtime overhead when values are encoded	198	Detecting shared values incurs a runtime overhead when values are encoded
190	that have a reference counter large than one, and might unnecessarily	199	that have a reference counter large than one, and might unnecessarily
191	increase the encoded size, as potentially shared values are encode as	200	increase the encoded size, as potentially shared values are encode as
192	sharable whether or not they are actually shared.	201	sharable whether or not they are actually shared.
193		202
194	At the moment, all shared values will be detected, even weird and unusual	203	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,	204	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	205	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	206	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	207	for L<Storable>).
199	references only.
200		208
201	If C<$enable> is false (the default), then C<encode> will encode	209	If C<$enable> is false (the default), then C<encode> will encode
202	exception when it encounters anything it cannot encode as CBOR.	210	exception when it encounters anything it cannot encode as CBOR.
203		211
204	This option does not affect C<decode> in any way - shared values and	212	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	213	references will always be decoded properly if present.
206	to leave it off unless you know your communications partner supports the	214
207	value sharing extensions to CBOR (http://cbor.schmorp.de/value-sharing).	215	=item $cbor = $cbor->allow_stringref ([$enable])
		216
		217	=item $enabled = $cbor->get_allow_stringref
		218
		219	If C<$enable> is true (or missing), then C<encode> will try not to encode
		220	the same string twice, but will instead encode a reference to the string
		221	instead. Depending on your data format. this can save a lot of space, but
		222	also results in a very large runtime overhead (expect encoding times to be
		223	2-4 times as high as without).
		224
		225	It is recommended to leave it off unless you know your
		226	communications partner supports the stringref extension to CBOR
		227	(http://cbor.schmorp.de/stringref).
		228
		229	If C<$enable> is false (the default), then C<encode> will encode
		230	exception when it encounters anything it cannot encode as CBOR.
		231
		232	This option does not affect C<decode> in any way - string references will
		233	always be decoded properly if present.
208		234
209	=item $cbor_data = $cbor->encode ($perl_scalar)	235	=item $cbor_data = $cbor->encode ($perl_scalar)
210		236
211	Converts the given Perl data structure (a scalar value) to its CBOR	237	Converts the given Perl data structure (a scalar value) to its CBOR
212	representation.	238	representation.
…		…
601	CBOR::XS::tag 24,	627	CBOR::XS::tag 24,
602	encode_cbor [1, 2, 3];	628	encode_cbor [1, 2, 3];
603		629
604	=head1 TAG HANDLING AND EXTENSIONS	630	=head1 TAG HANDLING AND EXTENSIONS
605		631
606	This section describes how this module handles specific tagged values and	632	This section describes how this module handles specific tagged values
607	extensions. If a tag is not mentioned here, then the default handling	633	and extensions. If a tag is not mentioned here and no additional filters
		634	are provided for it, then the default handling applies (creating a
608	applies (creating a CBOR::XS::Tagged object on decoding, and only encoding	635	CBOR::XS::Tagged object on decoding, and only encoding the tag when
609	the tag when explicitly requested).	636	explicitly requested).
610		637
611	Future versions of this module reserve the right to special case	638	Future versions of this module reserve the right to special case
612	additional tags (such as bigfloat or base64url).	639	additional tags (such as base64url).
		640
		641	=head2 ENFORCED TAGS
		642
		643	These tags are always handled when decoding, and their handling cannot be
		644	overriden by the user.
613		645
614	=over 4	646	=over 4
615		647
616	=item <unassigned> (perl-object, L<http://cbor.schmorp.de/perl-object>)	648	=item <unassigned> (perl-object, L<http://cbor.schmorp.de/perl-object>)
617		649
…		…
623		655
624	These tags are automatically decoded when encountered, resulting in	656	These tags are automatically decoded when encountered, resulting in
625	shared values in the decoded object. They are only encoded, however, when	657	shared values in the decoded object. They are only encoded, however, when
626	C<allow_sharable> is enabled.	658	C<allow_sharable> is enabled.
627		659
		660	=item <unassigned>, <unassigned> (stringref-namespace, stringref, L <http://cbor.schmorp.de/stringref>)
		661
		662	These tags are automatically decoded when encountered. They are only
		663	encoded, however, when C<allow_stringref> is enabled.
		664
628	=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)	665	=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)
629		666
630	This tag is automatically generated when a reference are encountered (with	667	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	668	the exception of hash and array refernces). It is converted to a reference
632	when decoding.	669	when decoding.
…		…
635		672
636	This value is not generated on encoding (unless explicitly requested by	673	This value is not generated on encoding (unless explicitly requested by
637	the user), and is simply ignored when decoding.	674	the user), and is simply ignored when decoding.
638		675
639	=back	676	=back
		677
		678	=head2 OPTIONAL TAGS
		679
		680	These tags have default filters provided when decoding. Their handling can
		681	be overriden by changing the C<%CBOR::XS::FILTER> entry for the tag, or by
		682	providing a custom C<filter> function when decoding.
		683
		684	When they result in decoding into a specific Perl class, the module
		685	usually provides a corresponding C<TO_CBOR> method as well.
		686
		687	When any of these need to load additional modules that are not part of the
		688	perl core distribution (e.g. L<URI>), it is (currently) up to the user to
		689	provide these modules. The decoding usually fails with an exception if the
		690	required module cannot be loaded.
		691
		692	=over 4
		693
		694	=item 2, 3 (positive/negative bignum)
		695
		696	These tags are decoded into L<Math::BigInt> objects. The corresponding
		697	C<Math::BigInt::TO_CBOR> method encodes "small" bigints into normal CBOR
		698	integers, and others into positive/negative CBOR bignums.
		699
		700	=item 4, 5 (decimal fraction/bigfloat)
		701
		702	Both decimal fractions and bigfloats are decoded into L<Math::BigFloat>
		703	objects. The corresponding C<Math::BigFloat::TO_CBOR> method I<always>
		704	encodes into a decimal fraction.
		705
		706	CBOR cannot represent bigfloats with I<very> large exponents - conversion
		707	of such big float objects is undefined.
		708
		709	Also, NaN and infinities are not encoded properly.
		710
		711	=item 21, 22, 23 (expected later JSON conversion)
		712
		713	CBOR::XS is not a CBOR-to-JSON converter, and will simply ignore these
		714	tags.
		715
		716	=item 32 (URI)
		717
		718	These objects decode into L<URI> objects. The corresponding
		719	C<URI::TO_CBOR> method again results in a CBOR URI value.
		720
		721	=back
		722
		723	=cut
		724
		725	our %FILTER = (
		726	# 0 # rfc4287 datetime, utf-8
		727	# 1 # unix timestamp, any
		728
		729	2 => sub { # pos bigint
		730	require Math::BigInt;
		731	Math::BigInt->new ("0x" . unpack "H*", pop)
		732	},
		733
		734	3 => sub { # neg bigint
		735	require Math::BigInt;
		736	-Math::BigInt->new ("0x" . unpack "H*", pop)
		737	},
		738
		739	4 => sub { # decimal fraction, array
		740	require Math::BigFloat;
		741	Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
		742	},
		743
		744	5 => sub { # bigfloat, array
		745	require Math::BigFloat;
		746	scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2)
		747	},
		748
		749	21 => sub { pop }, # expected conversion to base64url encoding
		750	22 => sub { pop }, # expected conversion to base64 encoding
		751	23 => sub { pop }, # expected conversion to base16 encoding
		752
		753	# 24 # embedded cbor, byte string
		754
		755	32 => sub {
		756	require URI;
		757	URI->new (pop)
		758	},
		759
		760	# 33 # base64url rfc4648, utf-8
		761	# 34 # base64 rfc46484, utf-8
		762	# 35 # regex pcre/ecma262, utf-8
		763	# 36 # mime message rfc2045, utf-8
		764	);
640		765
641		766
642	=head1 CBOR and JSON	767	=head1 CBOR and JSON
643		768
644	CBOR is supposed to implement a superset of the JSON data model, and is,	769	CBOR is supposed to implement a superset of the JSON data model, and is,
…		…
727	Please refrain from using rt.cpan.org or any other bug reporting	852	Please refrain from using rt.cpan.org or any other bug reporting
728	service. I put the contact address into my modules for a reason.	853	service. I put the contact address into my modules for a reason.
729		854
730	=cut	855	=cut
731		856
		857	our %FILTER = (
		858	# 0 # rfc4287 datetime, utf-8
		859	# 1 # unix timestamp, any
		860
		861	2 => sub { # pos bigint
		862	require Math::BigInt;
		863	Math::BigInt->new ("0x" . unpack "H*", pop)
		864	},
		865
		866	3 => sub { # neg bigint
		867	require Math::BigInt;
		868	-Math::BigInt->new ("0x" . unpack "H*", pop)
		869	},
		870
		871	4 => sub { # decimal fraction, array
		872	require Math::BigFloat;
		873	Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
		874	},
		875
		876	5 => sub { # bigfloat, array
		877	require Math::BigFloat;
		878	scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2)
		879	},
		880
		881	21 => sub { pop }, # expected conversion to base64url encoding
		882	22 => sub { pop }, # expected conversion to base64 encoding
		883	23 => sub { pop }, # expected conversion to base16 encoding
		884
		885	# 24 # embedded cbor, byte string
		886
		887	32 => sub {
		888	require URI;
		889	URI->new (pop)
		890	},
		891
		892	# 33 # base64url rfc4648, utf-8
		893	# 34 # base64 rfc46484, utf-8
		894	# 35 # regex pcre/ecma262, utf-8
		895	# 36 # mime message rfc2045, utf-8
		896	);
		897
		898	sub CBOR::XS::default_filter {
		899	&{ $FILTER{$_[0]} or return }
		900	}
		901
		902	sub URI::TO_CBOR {
		903	my $uri = $_[0]->as_string;
		904	utf8::upgrade $uri;
		905	CBOR::XS::tag 32, $uri
		906	}
		907
		908	sub Math::BigInt::TO_CBOR {
		909	if ($_[0] >= -2147483648 && $_[0] <= 2147483647) {
		910	$_[0]->numify
		911	} else {
		912	my $hex = substr $_[0]->as_hex, 2;
		913	$hex = "0$hex" if 1 & length $hex; # sigh
		914	CBOR::XS::tag $_[0] >= 0 ? 2 : 3, pack "H*", $hex
		915	}
		916	}
		917
		918	sub Math::BigFloat::TO_CBOR {
		919	my ($m, $e) = $_[0]->parts;
		920	CBOR::XS::tag 4, [$e->numify, $m]
		921	}
		922
732	XSLoader::load "CBOR::XS", $VERSION;	923	XSLoader::load "CBOR::XS", $VERSION;
733		924
734	=head1 SEE ALSO	925	=head1 SEE ALSO
735		926
736	The L<JSON> and L<JSON::XS> modules that do similar, but human-readable,	927	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 1.22 by root, Fri Nov 22 15:28:38 2013 UTC

Diff Legend

Comparing CBOR-XS/XS.pm (file contents):
Revision 1.19 by root, Wed Nov 20 01:09:46 2013 UTC vs.
Revision 1.22 by root, Fri Nov 22 15:28:38 2013 UTC