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

Comparing CBOR-XS/XS.pm (file contents):
Revision 1.11 by root, Tue Oct 29 00:20:26 2013 UTC vs.
Revision 1.20 by root, Wed Nov 20 02:03:08 2013 UTC

…		…
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 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
51	The primary goal of this module is to be I<correct> and the secondary goal	59	The primary goal of this module is to be I<correct> and the secondary goal
52	is to be I<fast>. To reach the latter goal it was written in C.	60	is to be I<fast>. To reach the latter goal it was written in C.
53		61
54	See MAPPING, below, on how CBOR::XS maps perl values to CBOR values and	62	See MAPPING, below, on how CBOR::XS maps perl values to CBOR values and
55	vice versa.	63	vice versa.
…		…
58		66
59	package CBOR::XS;	67	package CBOR::XS;
60		68
61	use common::sense;	69	use common::sense;
62		70
63	our $VERSION = 0.05;	71	our $VERSION = 0.08;
64	our @ISA = qw(Exporter);	72	our @ISA = qw(Exporter);
65		73
66	our @EXPORT = qw(encode_cbor decode_cbor);	74	our @EXPORT = qw(encode_cbor decode_cbor);
67		75
68	use Exporter;	76	use Exporter;
…		…
149	If no argument is given, the limit check will be deactivated (same as when	157	If no argument is given, the limit check will be deactivated (same as when
150	C<0> is specified).	158	C<0> is specified).
151		159
152	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.	160	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.
153		161
		162	=item $cbor = $cbor->allow_unknown ([$enable])
		163
		164	=item $enabled = $cbor->get_allow_unknown
		165
		166	If C<$enable> is true (or missing), then C<encode> will I<not> throw an
		167	exception when it encounters values it cannot represent in CBOR (for
		168	example, filehandles) but instead will encode a CBOR C<error> value.
		169
		170	If C<$enable> is false (the default), then C<encode> will throw an
		171	exception when it encounters anything it cannot encode as CBOR.
		172
		173	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.
		175
		176	=item $cbor = $cbor->allow_sharing ([$enable])
		177
		178	=item $enabled = $cbor->get_allow_sharing
		179
		180	If C<$enable> is true (or missing), then C<encode> will not double-encode
		181	values that have been referenced before (e.g. when the same object, such
		182	as an array, is referenced multiple times), but instead will emit a
		183	reference to the earlier value.
		184
		185	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
		187	sharing extension.
		188
		189	Detecting shared values incurs a runtime overhead when values are encoded
		190	that have a reference counter large than one, and might unnecessarily
		191	increase the encoded size, as potentially shared values are encode as
		192	sharable whether or not they are actually shared.
		193
		194	At the moment, only targets of references can be shared (e.g. scalars,
		195	arrays or hashes pointed to by a reference). Weirder constructs, such as
		196	an array with multiple "copies" of the I<same> string, which are hard but
		197	not impossible to create in Perl, are not supported (this is the same as
		198	for L<Storable>).
		199
		200	If C<$enable> is false (the default), then C<encode> will encode
		201	exception when it encounters anything it cannot encode as CBOR.
		202
		203	This option does not affect C<decode> in any way - shared values and
		204	references will always be decoded properly if present. It is recommended
		205	to leave it off unless you know your communications partner supports the
		206	value sharing extensions to CBOR (http://cbor.schmorp.de/value-sharing).
		207
154	=item $cbor_data = $cbor->encode ($perl_scalar)	208	=item $cbor_data = $cbor->encode ($perl_scalar)
155		209
156	Converts the given Perl data structure (a scalar value) to its CBOR	210	Converts the given Perl data structure (a scalar value) to its CBOR
157	representation.	211	representation.
158		212
…		…
283	C<1>, which get turned into false and true in CBOR.	337	C<1>, which get turned into false and true in CBOR.
284		338
285	=item CBOR::XS::Tagged objects	339	=item CBOR::XS::Tagged objects
286		340
287	Objects of this type must be arrays consisting of a single C<[tag, value]>	341	Objects of this type must be arrays consisting of a single C<[tag, value]>
288	pair. The (numerical) tag will be encoded as a CBOR tag, the value will be	342	pair. The (numerical) tag will be encoded as a CBOR tag, the value will
289	encoded as appropriate for the value.	343	be encoded as appropriate for the value. You cna use C<CBOR::XS::tag> to
		344	create such objects.
290		345
291	=item Types::Serialiser::true, Types::Serialiser::false, Types::Serialiser::error	346	=item Types::Serialiser::true, Types::Serialiser::false, Types::Serialiser::error
292		347
293	These special values become CBOR true, CBOR false and CBOR undefined	348	These special values become CBOR true, CBOR false and CBOR undefined
294	values, respectively. You can also use C<\1>, C<\0> and C<\undef> directly	349	values, respectively. You can also use C<\1>, C<\0> and C<\undef> directly
…		…
446	=head1 MAGIC HEADER	501	=head1 MAGIC HEADER
447		502
448	There is no way to distinguish CBOR from other formats	503	There is no way to distinguish CBOR from other formats
449	programmatically. To make it easier to distinguish CBOR from other	504	programmatically. To make it easier to distinguish CBOR from other
450	formats, the CBOR specification has a special "magic string" that can be	505	formats, the CBOR specification has a special "magic string" that can be
451	prepended to any CBOR string without changing it's meaning.	506	prepended to any CBOR string without changing its meaning.
452		507
453	This string is available as C<$CBOR::XS::MAGIC>. This module does not	508	This string is available as C<$CBOR::XS::MAGIC>. This module does not
454	prepend this string tot he CBOR data it generates, but it will ignroe it	509	prepend this string to the CBOR data it generates, but it will ignore it
455	if present, so users can prepend this string as a "file type" indicator as	510	if present, so users can prepend this string as a "file type" indicator as
456	required.	511	required.
		512
		513
		514	=head1 THE CBOR::XS::Tagged CLASS
		515
		516	CBOR has the concept of tagged values - any CBOR value can be tagged with
		517	a numeric 64 bit number, which are centrally administered.
		518
		519	C<CBOR::XS> handles a few tags internally when en- or decoding. You can
		520	also create tags yourself by encoding C<CBOR::XS::Tagged> objects, and the
		521	decoder will create C<CBOR::XS::Tagged> objects itself when it hits an
		522	unknown tag.
		523
		524	These objects are simply blessed array references - the first member of
		525	the array being the numerical tag, the second being the value.
		526
		527	You can interact with C<CBOR::XS::Tagged> objects in the following ways:
		528
		529	=over 4
		530
		531	=item $tagged = CBOR::XS::tag $tag, $value
		532
		533	This function(!) creates a new C<CBOR::XS::Tagged> object using the given
		534	C<$tag> (0..2**64-1) to tag the given C<$value> (which can be any Perl
		535	value that can be encoded in CBOR, including serialisable Perl objects and
		536	C<CBOR::XS::Tagged> objects).
		537
		538	=item $tagged->[0]
		539
		540	=item $tagged->[0] = $new_tag
		541
		542	=item $tag = $tagged->tag
		543
		544	=item $new_tag = $tagged->tag ($new_tag)
		545
		546	Access/mutate the tag.
		547
		548	=item $tagged->[1]
		549
		550	=item $tagged->[1] = $new_value
		551
		552	=item $value = $tagged->value
		553
		554	=item $new_value = $tagged->value ($new_value)
		555
		556	Access/mutate the tagged value.
		557
		558	=back
		559
		560	=cut
		561
		562	sub tag($$) {
		563	bless [@_], CBOR::XS::Tagged::;
		564	}
		565
		566	sub CBOR::XS::Tagged::tag {
		567	$_[0][0] = $_[1] if $#_;
		568	$_[0][0]
		569	}
		570
		571	sub CBOR::XS::Tagged::value {
		572	$_[0][1] = $_[1] if $#_;
		573	$_[0][1]
		574	}
		575
		576	=head2 EXAMPLES
		577
		578	Here are some examples of C<CBOR::XS::Tagged> uses to tag objects.
		579
		580	You can look up CBOR tag value and emanings in the IANA registry at
		581	L<http://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml>.
		582
		583	Prepend a magic header (C<$CBOR::XS::MAGIC>):
		584
		585	my $cbor = encode_cbor CBOR::XS::tag 55799, $value;
		586	# same as:
		587	my $cbor = $CBOR::XS::MAGIC . encode_cbor $value;
		588
		589	Serialise some URIs and a regex in an array:
		590
		591	my $cbor = encode_cbor [
		592	(CBOR::XS::tag 32, "http://www.nethype.de/"),
		593	(CBOR::XS::tag 32, "http://software.schmorp.de/"),
		594	(CBOR::XS::tag 35, "^[Pp][Ee][Rr][lL]\$"),
		595	];
		596
		597	Wrap CBOR data in CBOR:
		598
		599	my $cbor_cbor = encode_cbor
		600	CBOR::XS::tag 24,
		601	encode_cbor [1, 2, 3];
		602
		603	=head1 TAG HANDLING AND EXTENSIONS
		604
		605	This section describes how this module handles specific tagged values and
		606	extensions. If a tag is not mentioned here, then the default handling
		607	applies (creating a CBOR::XS::Tagged object on decoding, and only encoding
		608	the tag when explicitly requested).
		609
		610	Future versions of this module reserve the right to special case
		611	additional tags (such as bigfloat or base64url).
		612
		613	=over 4
		614
		615	=item <unassigned> (perl-object, L<http://cbor.schmorp.de/perl-object>)
		616
		617	These tags are automatically created for serialisable objects using the
		618	C<FREEZE/THAW> methods (the L<Types::Serialier> object serialisation
		619	protocol).
		620
		621	=item <unassigned>, <unassigned> (sharable, sharedref, L <http://cbor.schmorp.de/value-sharing>)
		622
		623	These tags are automatically decoded when encountered, resulting in
		624	shared values in the decoded object. They are only encoded, however, when
		625	C<allow_sharable> is enabled.
		626
		627	=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)
		628
		629	This tag is automatically generated when a reference are encountered (with
		630	the exception of hash and array refernces). It is converted to a reference
		631	when decoding.
		632
		633	=item 55799 (self-describe CBOR, RFC 7049)
		634
		635	This value is not generated on encoding (unless explicitly requested by
		636	the user), and is simply ignored when decoding.
		637
		638	=back
457		639
458		640
459	=head1 CBOR and JSON	641	=head1 CBOR and JSON
460		642
461	CBOR is supposed to implement a superset of the JSON data model, and is,	643	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 1.11 by root, Tue Oct 29 00:20:26 2013 UTC vs. Revision 1.20 by root, Wed Nov 20 02:03:08 2013 UTC

Diff Legend

Comparing CBOR-XS/XS.pm (file contents):
Revision 1.11 by root, Tue Oct 29 00:20:26 2013 UTC vs.
Revision 1.20 by root, Wed Nov 20 02:03:08 2013 UTC