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

Comparing CBOR-XS/XS.pm (file contents):
Revision 1.8 by root, Sun Oct 27 22:48:12 2013 UTC vs.
Revision 1.21 by root, Wed Nov 20 16:29:02 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 IS A PRE-ALPHA RELEASE! IT WILL CRASH, CORRUPT YOUR DATA	31	WARNING! This module is very new, and not very well tested (that's up
32	AND EAT YOUR CHILDREN! (Actually, apart from being untested and a bit	32	to you to do). Furthermore, details of the implementation might change
33	feature-limited, it might already be useful).	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.
		37
		38	You are still invited to try out CBOR, and this module.
34		39
35	This module converts Perl data structures to the Concise Binary Object	40	This module converts Perl data structures to the Concise Binary Object
36	Representation (CBOR) and vice versa. CBOR is a fast binary serialisation	41	Representation (CBOR) and vice versa. CBOR is a fast binary serialisation
37	format that aims to use a superset of the JSON data model, i.e. when you	42	format that aims to use a superset of the JSON data model, i.e. when you
38	can represent something in JSON, you should be able to represent it in	43	can represent something in JSON, you should be able to represent it in
39	CBOR.	44	CBOR.
40		45
41	This makes it a faster and more compact binary alternative to JSON, with	46	In short, CBOR is a faster and very compact binary alternative to JSON,
42	the added ability of supporting serialising of perl objects.	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<allow_stringref>) and
		62	scalar references (always enabled).
43		63
44	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
45	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.
46		66
47	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
…		…
51		71
52	package CBOR::XS;	72	package CBOR::XS;
53		73
54	use common::sense;	74	use common::sense;
55		75
56	our $VERSION = 0.04;	76	our $VERSION = 0.08;
57	our @ISA = qw(Exporter);	77	our @ISA = qw(Exporter);
58		78
59	our @EXPORT = qw(encode_cbor decode_cbor);	79	our @EXPORT = qw(encode_cbor decode_cbor);
60		80
61	use Exporter;	81	use Exporter;
…		…
142	If no argument is given, the limit check will be deactivated (same as when	162	If no argument is given, the limit check will be deactivated (same as when
143	C<0> is specified).	163	C<0> is specified).
144		164
145	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.	165	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
146		166
		167	=item $cbor = $cbor->allow_unknown ([$enable])
		168
		169	=item $enabled = $cbor->get_allow_unknown
		170
		171	If C<$enable> is true (or missing), then C<encode> will I<not> throw an
		172	exception when it encounters values it cannot represent in CBOR (for
		173	example, filehandles) but instead will encode a CBOR C<error> value.
		174
		175	If C<$enable> is false (the default), then C<encode> will throw an
		176	exception when it encounters anything it cannot encode as CBOR.
		177
		178	This option does not affect C<decode> in any way, and it is recommended to
		179	leave it off unless you know your communications partner.
		180
		181	=item $cbor = $cbor->allow_sharing ([$enable])
		182
		183	=item $enabled = $cbor->get_allow_sharing
		184
		185	If C<$enable> is true (or missing), then C<encode> will not double-encode
		186	values that have been referenced before (e.g. when the same object, such
		187	as an array, is referenced multiple times), but instead will emit a
		188	reference to the earlier value.
		189
		190	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
		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).
		197
		198	Detecting shared values incurs a runtime overhead when values are encoded
		199	that have a reference counter large than one, and might unnecessarily
		200	increase the encoded size, as potentially shared values are encode as
		201	sharable whether or not they are actually shared.
		202
		203	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	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	for L<Storable>).
		208
		209	If C<$enable> is false (the default), then C<encode> will encode
		210	exception when it encounters anything it cannot encode as CBOR.
		211
		212	This option does not affect C<decode> in any way - shared values and
		213	references will always be decoded properly if present.
		214
		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.
		234
147	=item $cbor_data = $cbor->encode ($perl_scalar)	235	=item $cbor_data = $cbor->encode ($perl_scalar)
148		236
149	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
150	representation.	238	representation.
151		239
…		…
222	error). See the L<Types::Serialiser> manpage for details.	310	error). See the L<Types::Serialiser> manpage for details.
223		311
224	=item CBOR tag 256 (perl object)	312	=item CBOR tag 256 (perl object)
225		313
226	The tag value C<256> (TODO: pending iana registration) will be used	314	The tag value C<256> (TODO: pending iana registration) will be used
227	to deserialise a Perl object serialised with C<FREEZE>. See "OBJECT	315	to deserialise a Perl object serialised with C<FREEZE>. See L<OBJECT
228	SERIALISATION", below, for details.	316	SERIALISATION>, below, for details.
229		317
230	=item CBOR tag 55799 (magic header)	318	=item CBOR tag 55799 (magic header)
231		319
232	The tag 55799 is ignored (this tag implements the magic header).	320	The tag 55799 is ignored (this tag implements the magic header).
233		321
…		…
276	C<1>, which get turned into false and true in CBOR.	364	C<1>, which get turned into false and true in CBOR.
277		365
278	=item CBOR::XS::Tagged objects	366	=item CBOR::XS::Tagged objects
279		367
280	Objects of this type must be arrays consisting of a single C<[tag, value]>	368	Objects of this type must be arrays consisting of a single C<[tag, value]>
281	pair. The (numerical) tag will be encoded as a CBOR tag, the value will be	369	pair. The (numerical) tag will be encoded as a CBOR tag, the value will
282	encoded as appropriate for the value.	370	be encoded as appropriate for the value. You cna use C<CBOR::XS::tag> to
		371	create such objects.
283		372
284	=item Types::Serialiser::true, Types::Serialiser::false, Types::Serialiser::error	373	=item Types::Serialiser::true, Types::Serialiser::false, Types::Serialiser::error
285		374
286	These special values become CBOR true, CBOR false and CBOR undefined	375	These special values become CBOR true, CBOR false and CBOR undefined
287	values, respectively. You can also use C<\1>, C<\0> and C<\undef> directly	376	values, respectively. You can also use C<\1>, C<\0> and C<\undef> directly
288	if you want.	377	if you want.
289		378
290	=item other blessed objects	379	=item other blessed objects
291		380
292	Other blessed objects are serialised via C<TO_CBOR> or C<FREEZE>. See	381	Other blessed objects are serialised via C<TO_CBOR> or C<FREEZE>. See
293	"OBJECT SERIALISATION", below, for details.	382	L<OBJECT SERIALISATION>, below, for details.
294		383
295	=item simple scalars	384	=item simple scalars
296		385
297	TODO	386	TODO
298	Simple Perl scalars (any scalar that is not a reference) are the most	387	Simple Perl scalars (any scalar that is not a reference) are the most
…		…
439	=head1 MAGIC HEADER	528	=head1 MAGIC HEADER
440		529
441	There is no way to distinguish CBOR from other formats	530	There is no way to distinguish CBOR from other formats
442	programmatically. To make it easier to distinguish CBOR from other	531	programmatically. To make it easier to distinguish CBOR from other
443	formats, the CBOR specification has a special "magic string" that can be	532	formats, the CBOR specification has a special "magic string" that can be
444	prepended to any CBOR string without changing it's meaning.	533	prepended to any CBOR string without changing its meaning.
445		534
446	This string is available as C<$CBOR::XS::MAGIC>. This module does not	535	This string is available as C<$CBOR::XS::MAGIC>. This module does not
447	prepend this string tot he CBOR data it generates, but it will ignroe it	536	prepend this string to the CBOR data it generates, but it will ignore it
448	if present, so users can prepend this string as a "file type" indicator as	537	if present, so users can prepend this string as a "file type" indicator as
449	required.	538	required.
		539
		540
		541	=head1 THE CBOR::XS::Tagged CLASS
		542
		543	CBOR has the concept of tagged values - any CBOR value can be tagged with
		544	a numeric 64 bit number, which are centrally administered.
		545
		546	C<CBOR::XS> handles a few tags internally when en- or decoding. You can
		547	also create tags yourself by encoding C<CBOR::XS::Tagged> objects, and the
		548	decoder will create C<CBOR::XS::Tagged> objects itself when it hits an
		549	unknown tag.
		550
		551	These objects are simply blessed array references - the first member of
		552	the array being the numerical tag, the second being the value.
		553
		554	You can interact with C<CBOR::XS::Tagged> objects in the following ways:
		555
		556	=over 4
		557
		558	=item $tagged = CBOR::XS::tag $tag, $value
		559
		560	This function(!) creates a new C<CBOR::XS::Tagged> object using the given
		561	C<$tag> (0..2**64-1) to tag the given C<$value> (which can be any Perl
		562	value that can be encoded in CBOR, including serialisable Perl objects and
		563	C<CBOR::XS::Tagged> objects).
		564
		565	=item $tagged->[0]
		566
		567	=item $tagged->[0] = $new_tag
		568
		569	=item $tag = $tagged->tag
		570
		571	=item $new_tag = $tagged->tag ($new_tag)
		572
		573	Access/mutate the tag.
		574
		575	=item $tagged->[1]
		576
		577	=item $tagged->[1] = $new_value
		578
		579	=item $value = $tagged->value
		580
		581	=item $new_value = $tagged->value ($new_value)
		582
		583	Access/mutate the tagged value.
		584
		585	=back
		586
		587	=cut
		588
		589	sub tag($$) {
		590	bless [@_], CBOR::XS::Tagged::;
		591	}
		592
		593	sub CBOR::XS::Tagged::tag {
		594	$_[0][0] = $_[1] if $#_;
		595	$_[0][0]
		596	}
		597
		598	sub CBOR::XS::Tagged::value {
		599	$_[0][1] = $_[1] if $#_;
		600	$_[0][1]
		601	}
		602
		603	=head2 EXAMPLES
		604
		605	Here are some examples of C<CBOR::XS::Tagged> uses to tag objects.
		606
		607	You can look up CBOR tag value and emanings in the IANA registry at
		608	L<http://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml>.
		609
		610	Prepend a magic header (C<$CBOR::XS::MAGIC>):
		611
		612	my $cbor = encode_cbor CBOR::XS::tag 55799, $value;
		613	# same as:
		614	my $cbor = $CBOR::XS::MAGIC . encode_cbor $value;
		615
		616	Serialise some URIs and a regex in an array:
		617
		618	my $cbor = encode_cbor [
		619	(CBOR::XS::tag 32, "http://www.nethype.de/"),
		620	(CBOR::XS::tag 32, "http://software.schmorp.de/"),
		621	(CBOR::XS::tag 35, "^[Pp][Ee][Rr][lL]\$"),
		622	];
		623
		624	Wrap CBOR data in CBOR:
		625
		626	my $cbor_cbor = encode_cbor
		627	CBOR::XS::tag 24,
		628	encode_cbor [1, 2, 3];
		629
		630	=head1 TAG HANDLING AND EXTENSIONS
		631
		632	This section describes how this module handles specific tagged values and
		633	extensions. If a tag is not mentioned here, then the default handling
		634	applies (creating a CBOR::XS::Tagged object on decoding, and only encoding
		635	the tag when explicitly requested).
		636
		637	Future versions of this module reserve the right to special case
		638	additional tags (such as bigfloat or base64url).
		639
		640	=over 4
		641
		642	=item <unassigned> (perl-object, L<http://cbor.schmorp.de/perl-object>)
		643
		644	These tags are automatically created for serialisable objects using the
		645	C<FREEZE/THAW> methods (the L<Types::Serialier> object serialisation
		646	protocol).
		647
		648	=item <unassigned>, <unassigned> (sharable, sharedref, L <http://cbor.schmorp.de/value-sharing>)
		649
		650	These tags are automatically decoded when encountered, resulting in
		651	shared values in the decoded object. They are only encoded, however, when
		652	C<allow_sharable> is enabled.
		653
		654	=item <unassigned>, <unassigned> (stringref-namespace, stringref, L <http://cbor.schmorp.de/stringref>)
		655
		656	These tags are automatically decoded when encountered. They are only
		657	encoded, however, when C<allow_stringref> is enabled.
		658
		659	=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)
		660
		661	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
		663	when decoding.
		664
		665	=item 55799 (self-describe CBOR, RFC 7049)
		666
		667	This value is not generated on encoding (unless explicitly requested by
		668	the user), and is simply ignored when decoding.
		669
		670	=back
450		671
451		672
452	=head1 CBOR and JSON	673	=head1 CBOR and JSON
453		674
454	CBOR is supposed to implement a superset of the JSON data model, and is,	675	CBOR is supposed to implement a superset of the JSON data model, and is,

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Comparing CBOR-XS/XS.pm (file contents): Revision 1.8 by root, Sun Oct 27 22:48:12 2013 UTC vs. Revision 1.21 by root, Wed Nov 20 16:29:02 2013 UTC

Diff Legend

Comparing CBOR-XS/XS.pm (file contents):
Revision 1.8 by root, Sun Oct 27 22:48:12 2013 UTC vs.
Revision 1.21 by root, Wed Nov 20 16:29:02 2013 UTC