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

Comparing CBOR-XS/XS.pm (file contents):
Revision 1.21 by root, Wed Nov 20 16:29:02 2013 UTC vs.
Revision 1.27 by root, Thu Nov 28 15:43:24 2013 UTC

…		…
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	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	60	of extensions, to support cyclic and self-referencing data structures
61	(see C<allow_sharing>), string deduplication (see C<allow_stringref>) and	61	(see C<allow_sharing>), string deduplication (see C<pack_strings>) and
62	scalar references (always enabled).	62	scalar references (always enabled).
63		63
64	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
65	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.
66		66
…		…
71		71
72	package CBOR::XS;	72	package CBOR::XS;
73		73
74	use common::sense;	74	use common::sense;
75		75
76	our $VERSION = 0.08;	76	our $VERSION = 0.09;
77	our @ISA = qw(Exporter);	77	our @ISA = qw(Exporter);
78		78
79	our @EXPORT = qw(encode_cbor decode_cbor);	79	our @EXPORT = qw(encode_cbor decode_cbor);
80		80
81	use Exporter;	81	use Exporter;
…		…
118	strings. All boolean flags described below are by default I<disabled>.	118	strings. All boolean flags described below are by default I<disabled>.
119		119
120	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
121	be chained:	121	be chained:
122		122
123	#TODO
124	my $cbor = CBOR::XS->new->encode ({a => [1,2]});	123	my $cbor = CBOR::XS->new->encode ({a => [1,2]});
125		124
126	=item $cbor = $cbor->max_depth ([$maximum_nesting_depth])	125	=item $cbor = $cbor->max_depth ([$maximum_nesting_depth])
127		126
128	=item $max_depth = $cbor->get_max_depth	127	=item $max_depth = $cbor->get_max_depth
…		…
187	as an array, is referenced multiple times), but instead will emit a	186	as an array, is referenced multiple times), but instead will emit a
188	reference to the earlier value.	187	reference to the earlier value.
189		188
190	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
191	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
192	sharing extension.	191	sharing extension. This also makes it possible to encode cyclic data
		192	structures.
193		193
194	It is recommended to leave it off unless you know your	194	It is recommended to leave it off unless you know your
195	communication partner supports the value sharing extensions to CBOR	195	communication partner supports the value sharing extensions to CBOR
196	(http://cbor.schmorp.de/value-sharing).	196	(L<http://cbor.schmorp.de/value-sharing>), as without decoder support, the
		197	resulting data structure might be unusable.
197		198
198	Detecting shared values incurs a runtime overhead when values are encoded	199	Detecting shared values incurs a runtime overhead when values are encoded
199	that have a reference counter large than one, and might unnecessarily	200	that have a reference counter large than one, and might unnecessarily
200	increase the encoded size, as potentially shared values are encode as	201	increase the encoded size, as potentially shared values are encode as
201	sharable whether or not they are actually shared.	202	sharable whether or not they are actually shared.
202		203
203	At the moment, only targets of references can be shared (e.g. scalars,	204	At the moment, only targets of references can be shared (e.g. scalars,
204	arrays or hashes pointed to by a reference). Weirder constructs, such as	205	arrays or hashes pointed to by a reference). Weirder constructs, such as
205	an array with multiple "copies" of the I<same> string, which are hard but	206	an array with multiple "copies" of the I<same> string, which are hard but
206	not impossible to create in Perl, are not supported (this is the same as	207	not impossible to create in Perl, are not supported (this is the same as
207	for L<Storable>).	208	with L<Storable>).
208		209
209	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
210	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.
211		213
212	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
213	references will always be decoded properly if present.	215	references will always be decoded properly if present.
214		216
215	=item $cbor = $cbor->allow_stringref ([$enable])	217	=item $cbor = $cbor->pack_strings ([$enable])
216		218
217	=item $enabled = $cbor->get_allow_stringref	219	=item $enabled = $cbor->get_pack_strings
218		220
219	If C<$enable> is true (or missing), then C<encode> will try not to encode	221	If C<$enable> is true (or missing), then C<encode> will try not to encode
220	the same string twice, but will instead encode a reference to the string	222	the same string twice, but will instead encode a reference to the string
221	instead. Depending on your data format. this can save a lot of space, but	223	instead. Depending on your data format, this can save a lot of space, but
222	also results in a very large runtime overhead (expect encoding times to be	224	also results in a very large runtime overhead (expect encoding times to be
223	2-4 times as high as without).	225	2-4 times as high as without).
224		226
225	It is recommended to leave it off unless you know your	227	It is recommended to leave it off unless you know your
226	communications partner supports the stringref extension to CBOR	228	communications partner supports the stringref extension to CBOR
227	(http://cbor.schmorp.de/stringref).	229	(L<http://cbor.schmorp.de/stringref>), as without decoder support, the
		230	resulting data structure might not be usable.
228		231
229	If C<$enable> is false (the default), then C<encode> will encode	232	If C<$enable> is false (the default), then C<encode> will encode strings
230	exception when it encounters anything it cannot encode as CBOR.	233	the standard CBOR way.
231		234
232	This option does not affect C<decode> in any way - string references will	235	This option does not affect C<decode> in any way - string references will
233	always be decoded properly if present.	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	};
234		278
235	=item $cbor_data = $cbor->encode ($perl_scalar)	279	=item $cbor_data = $cbor->encode ($perl_scalar)
236		280
237	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
238	representation.	282	representation.
…		…
279	CBOR integers become (numeric) perl scalars. On perls without 64 bit	323	CBOR integers become (numeric) perl scalars. On perls without 64 bit
280	support, 64 bit integers will be truncated or otherwise corrupted.	324	support, 64 bit integers will be truncated or otherwise corrupted.
281		325
282	=item byte strings	326	=item byte strings
283		327
284	Byte strings will become octet strings in Perl (the byte values 0..255	328	Byte strings will become octet strings in Perl (the Byte values 0..255
285	will simply become characters of the same value in Perl).	329	will simply become characters of the same value in Perl).
286		330
287	=item UTF-8 strings	331	=item UTF-8 strings
288		332
289	UTF-8 strings in CBOR will be decoded, i.e. the UTF-8 octets will be	333	UTF-8 strings in CBOR will be decoded, i.e. the UTF-8 octets will be
…		…
307	C<Types:Serialiser::false> and C<Types::Serialiser::error>,	351	C<Types:Serialiser::false> and C<Types::Serialiser::error>,
308	respectively. They are overloaded to act almost exactly like the numbers	352	respectively. They are overloaded to act almost exactly like the numbers
309	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
310	error). See the L<Types::Serialiser> manpage for details.	354	error). See the L<Types::Serialiser> manpage for details.
311		355
312	=item CBOR tag 256 (perl object)	356	=item tagged values
313		357
314	The tag value C<256> (TODO: pending iana registration) will be used
315	to deserialise a Perl object serialised with C<FREEZE>. See L<OBJECT
316	SERIALISATION>, below, for details.
317
318	=item CBOR tag 55799 (magic header)
319
320	The tag 55799 is ignored (this tag implements the magic header).
321
322	=item other CBOR tags
323
324	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.
325	handled internally are currently converted into a L<CBOR::XS::Tagged>
326	object, which is simply a blessed array reference consisting of the
327	numeric tag value followed by the (decoded) CBOR value.
328		359
329	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.
330		362
331	=item anything else	363	=item anything else
332		364
333	Anything else (e.g. unsupported simple values) will raise a decoding	365	Anything else (e.g. unsupported simple values) will raise a decoding
334	error.	366	error.
…		…
377	if you want.	409	if you want.
378		410
379	=item other blessed objects	411	=item other blessed objects
380		412
381	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
382	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.
383		416
384	=item simple scalars	417	=item simple scalars
385		418
386	TODO
387	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
388	difficult objects to encode: CBOR::XS will encode undefined scalars as	420	difficult objects to encode: CBOR::XS will encode undefined scalars as
389	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
390	before encoding as CBOR strings, and anything else as number value:	422	before encoding as CBOR strings, and anything else as number value:
391		423
392	# dump as number	424	# dump as number
393	encode_cbor [2] # yields [2]	425	encode_cbor [2] # yields [2]
394	encode_cbor [-3.0e17] # yields [-3e+17]	426	encode_cbor [-3.0e17] # yields [-3e+17]
395	my $value = 5; encode_cbor [$value] # yields [5]	427	my $value = 5; encode_cbor [$value] # yields [5]
396		428
397	# used as string, so dump as string	429	# used as string, so dump as string (either byte or text)
398	print $value;	430	print $value;
399	encode_cbor [$value] # yields ["5"]	431	encode_cbor [$value] # yields ["5"]
400		432
401	# undef becomes null	433	# undef becomes null
402	encode_cbor [undef] # yields [null]	434	encode_cbor [undef] # yields [null]
…		…
405		437
406	my $x = 3.1; # some variable containing a number	438	my $x = 3.1; # some variable containing a number
407	"$x"; # stringified	439	"$x"; # stringified
408	$x .= ""; # another, more awkward way to stringify	440	$x .= ""; # another, more awkward way to stringify
409	print $x; # perl does it for you, too, quite often	441	print $x; # perl does it for you, too, quite often
		442
		443	You can force whether a string ie encoded as byte or text string by using
		444	C<utf8::upgrade> and C<utf8::downgrade>):
		445
		446	utf8::upgrade $x; # encode $x as text string
		447	utf8::downgrade $x; # encode $x as byte string
		448
		449	Perl doesn't define what operations up- and downgrade strings, so if the
		450	difference between byte and text is important, you should up- or downgrade
		451	your string as late as possible before encoding.
410		452
411	You can force the type to be a CBOR number by numifying it:	453	You can force the type to be a CBOR number by numifying it:
412		454
413	my $x = "3"; # some variable containing a string	455	my $x = "3"; # some variable containing a string
414	$x += 0; # numify it, ensuring it will be dumped as a number	456	$x += 0; # numify it, ensuring it will be dumped as a number
…		…
627	CBOR::XS::tag 24,	669	CBOR::XS::tag 24,
628	encode_cbor [1, 2, 3];	670	encode_cbor [1, 2, 3];
629		671
630	=head1 TAG HANDLING AND EXTENSIONS	672	=head1 TAG HANDLING AND EXTENSIONS
631		673
632	This section describes how this module handles specific tagged values and	674	This section describes how this module handles specific tagged values
633	extensions. If a tag is not mentioned here, then the default handling	675	and extensions. If a tag is not mentioned here and no additional filters
		676	are provided for it, then the default handling applies (creating a
634	applies (creating a CBOR::XS::Tagged object on decoding, and only encoding	677	CBOR::XS::Tagged object on decoding, and only encoding the tag when
635	the tag when explicitly requested).	678	explicitly requested).
		679
		680	Tags not handled specifically are currently converted into a
		681	L<CBOR::XS::Tagged> object, which is simply a blessed array reference
		682	consisting of the numeric tag value followed by the (decoded) CBOR value.
636		683
637	Future versions of this module reserve the right to special case	684	Future versions of this module reserve the right to special case
638	additional tags (such as bigfloat or base64url).	685	additional tags (such as base64url).
		686
		687	=head2 ENFORCED TAGS
		688
		689	These tags are always handled when decoding, and their handling cannot be
		690	overriden by the user.
639		691
640	=over 4	692	=over 4
641		693
642	=item <unassigned> (perl-object, L<http://cbor.schmorp.de/perl-object>)	694	=item 26 (perl-object, L<http://cbor.schmorp.de/perl-object>)
643		695
644	These tags are automatically created for serialisable objects using the	696	These tags are automatically created (and decoded) for serialisable
645	C<FREEZE/THAW> methods (the L<Types::Serialier> object serialisation	697	objects using the C<FREEZE/THAW> methods (the L<Types::Serialier> object
646	protocol).	698	serialisation protocol). See L<OBJECT SERIALISATION> for details.
647		699
648	=item <unassigned>, <unassigned> (sharable, sharedref, L <http://cbor.schmorp.de/value-sharing>)	700	=item 28, 29 (sharable, sharedref, L <http://cbor.schmorp.de/value-sharing>)
649		701
650	These tags are automatically decoded when encountered, resulting in	702	These tags are automatically decoded when encountered, resulting in
651	shared values in the decoded object. They are only encoded, however, when	703	shared values in the decoded object. They are only encoded, however, when
652	C<allow_sharable> is enabled.	704	C<allow_sharable> is enabled.
653		705
654	=item <unassigned>, <unassigned> (stringref-namespace, stringref, L <http://cbor.schmorp.de/stringref>)	706	=item 256, 25 (stringref-namespace, stringref, L <http://cbor.schmorp.de/stringref>)
655		707
656	These tags are automatically decoded when encountered. They are only	708	These tags are automatically decoded when encountered. They are only
657	encoded, however, when C<allow_stringref> is enabled.	709	encoded, however, when C<pack_strings> is enabled.
658		710
659	=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)	711	=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)
660		712
661	This tag is automatically generated when a reference are encountered (with	713	This tag is automatically generated when a reference are encountered (with
662	the exception of hash and array refernces). It is converted to a reference	714	the exception of hash and array refernces). It is converted to a reference
…		…
666		718
667	This value is not generated on encoding (unless explicitly requested by	719	This value is not generated on encoding (unless explicitly requested by
668	the user), and is simply ignored when decoding.	720	the user), and is simply ignored when decoding.
669		721
670	=back	722	=back
		723
		724	=head2 NON-ENFORCED TAGS
		725
		726	These tags have default filters provided when decoding. Their handling can
		727	be overriden by changing the C<%CBOR::XS::FILTER> entry for the tag, or by
		728	providing a custom C<filter> callback when decoding.
		729
		730	When they result in decoding into a specific Perl class, the module
		731	usually provides a corresponding C<TO_CBOR> method as well.
		732
		733	When any of these need to load additional modules that are not part of the
		734	perl core distribution (e.g. L<URI>), it is (currently) up to the user to
		735	provide these modules. The decoding usually fails with an exception if the
		736	required module cannot be loaded.
		737
		738	=over 4
		739
		740	=item 2, 3 (positive/negative bignum)
		741
		742	These tags are decoded into L<Math::BigInt> objects. The corresponding
		743	C<Math::BigInt::TO_CBOR> method encodes "small" bigints into normal CBOR
		744	integers, and others into positive/negative CBOR bignums.
		745
		746	=item 4, 5 (decimal fraction/bigfloat)
		747
		748	Both decimal fractions and bigfloats are decoded into L<Math::BigFloat>
		749	objects. The corresponding C<Math::BigFloat::TO_CBOR> method I<always>
		750	encodes into a decimal fraction.
		751
		752	CBOR cannot represent bigfloats with I<very> large exponents - conversion
		753	of such big float objects is undefined.
		754
		755	Also, NaN and infinities are not encoded properly.
		756
		757	=item 21, 22, 23 (expected later JSON conversion)
		758
		759	CBOR::XS is not a CBOR-to-JSON converter, and will simply ignore these
		760	tags.
		761
		762	=item 32 (URI)
		763
		764	These objects decode into L<URI> objects. The corresponding
		765	C<URI::TO_CBOR> method again results in a CBOR URI value.
		766
		767	=back
		768
		769	=cut
		770
		771	our %FILTER = (
		772	# 0 # rfc4287 datetime, utf-8
		773	# 1 # unix timestamp, any
		774
		775	2 => sub { # pos bigint
		776	require Math::BigInt;
		777	Math::BigInt->new ("0x" . unpack "H*", pop)
		778	},
		779
		780	3 => sub { # neg bigint
		781	require Math::BigInt;
		782	-Math::BigInt->new ("0x" . unpack "H*", pop)
		783	},
		784
		785	4 => sub { # decimal fraction, array
		786	require Math::BigFloat;
		787	Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
		788	},
		789
		790	5 => sub { # bigfloat, array
		791	require Math::BigFloat;
		792	scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2)
		793	},
		794
		795	21 => sub { pop }, # expected conversion to base64url encoding
		796	22 => sub { pop }, # expected conversion to base64 encoding
		797	23 => sub { pop }, # expected conversion to base16 encoding
		798
		799	# 24 # embedded cbor, byte string
		800
		801	32 => sub {
		802	require URI;
		803	URI->new (pop)
		804	},
		805
		806	# 33 # base64url rfc4648, utf-8
		807	# 34 # base64 rfc46484, utf-8
		808	# 35 # regex pcre/ecma262, utf-8
		809	# 36 # mime message rfc2045, utf-8
		810	);
671		811
672		812
673	=head1 CBOR and JSON	813	=head1 CBOR and JSON
674		814
675	CBOR is supposed to implement a superset of the JSON data model, and is,	815	CBOR is supposed to implement a superset of the JSON data model, and is,
…		…
758	Please refrain from using rt.cpan.org or any other bug reporting	898	Please refrain from using rt.cpan.org or any other bug reporting
759	service. I put the contact address into my modules for a reason.	899	service. I put the contact address into my modules for a reason.
760		900
761	=cut	901	=cut
762		902
		903	our %FILTER = (
		904	# 0 # rfc4287 datetime, utf-8
		905	# 1 # unix timestamp, any
		906
		907	2 => sub { # pos bigint
		908	require Math::BigInt;
		909	Math::BigInt->new ("0x" . unpack "H*", pop)
		910	},
		911
		912	3 => sub { # neg bigint
		913	require Math::BigInt;
		914	-Math::BigInt->new ("0x" . unpack "H*", pop)
		915	},
		916
		917	4 => sub { # decimal fraction, array
		918	require Math::BigFloat;
		919	Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
		920	},
		921
		922	5 => sub { # bigfloat, array
		923	require Math::BigFloat;
		924	scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2)
		925	},
		926
		927	21 => sub { pop }, # expected conversion to base64url encoding
		928	22 => sub { pop }, # expected conversion to base64 encoding
		929	23 => sub { pop }, # expected conversion to base16 encoding
		930
		931	# 24 # embedded cbor, byte string
		932
		933	32 => sub {
		934	require URI;
		935	URI->new (pop)
		936	},
		937
		938	# 33 # base64url rfc4648, utf-8
		939	# 34 # base64 rfc46484, utf-8
		940	# 35 # regex pcre/ecma262, utf-8
		941	# 36 # mime message rfc2045, utf-8
		942	);
		943
		944	sub CBOR::XS::default_filter {
		945	&{ $FILTER{$_[0]} or return }
		946	}
		947
		948	sub URI::TO_CBOR {
		949	my $uri = $_[0]->as_string;
		950	utf8::upgrade $uri;
		951	CBOR::XS::tag 32, $uri
		952	}
		953
		954	sub Math::BigInt::TO_CBOR {
		955	if ($_[0] >= -2147483648 && $_[0] <= 2147483647) {
		956	$_[0]->numify
		957	} else {
		958	my $hex = substr $_[0]->as_hex, 2;
		959	$hex = "0$hex" if 1 & length $hex; # sigh
		960	CBOR::XS::tag $_[0] >= 0 ? 2 : 3, pack "H*", $hex
		961	}
		962	}
		963
		964	sub Math::BigFloat::TO_CBOR {
		965	my ($m, $e) = $_[0]->parts;
		966	CBOR::XS::tag 4, [$e->numify, $m]
		967	}
		968
763	XSLoader::load "CBOR::XS", $VERSION;	969	XSLoader::load "CBOR::XS", $VERSION;
764		970
765	=head1 SEE ALSO	971	=head1 SEE ALSO
766		972
767	The L<JSON> and L<JSON::XS> modules that do similar, but human-readable,	973	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 1.21 by root, Wed Nov 20 16:29:02 2013 UTC vs. Revision 1.27 by root, Thu Nov 28 15:43:24 2013 UTC

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Comparing CBOR-XS/XS.pm (file contents):
Revision 1.21 by root, Wed Nov 20 16:29:02 2013 UTC vs.
Revision 1.27 by root, Thu Nov 28 15:43:24 2013 UTC