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

Comparing CBOR-XS/XS.pm (file contents):
Revision 1.4 by root, Sat Oct 26 22:25:47 2013 UTC vs.
Revision 1.18 by root, Sun Nov 17 05:26:14 2013 UTC

…		…
12	$perl_value = decode_cbor $binary_cbor_data;	12	$perl_value = decode_cbor $binary_cbor_data;
13		13
14	# OO-interface	14	# OO-interface
15		15
16	$coder = CBOR::XS->new;	16	$coder = CBOR::XS->new;
17	#TODO	17	$binary_cbor_data = $coder->encode ($perl_value);
		18	$perl_value = $coder->decode ($binary_cbor_data);
		19
		20	# prefix decoding
		21
		22	my $many_cbor_strings = ...;
		23	while (length $many_cbor_strings) {
		24	my ($data, $length) = $cbor->decode_prefix ($many_cbor_strings);
		25	# data was decoded
		26	substr $many_cbor_strings, 0, $length, ""; # remove decoded cbor string
		27	}
18		28
19	=head1 DESCRIPTION	29	=head1 DESCRIPTION
20		30
21	WARNING! THIS IS A PRE-ALPHA RELEASE! IT WILL CRASH, CORRUPT YOUR DATA AND	31	WARNING! This module is very new, and not very well tested (that's up to
22	EAT YOUR CHILDREN!	32	you to do). Furthermore, details of the implementation might change freely
		33	before version 1.0. And lastly, the object serialisation protocol depends
		34	on a pending IANA assignment, and until that assignment is official, this
		35	implementation is not interoperable with other implementations (even
		36	future versions of this module) until the assignment is done.
23		37
24	This module converts Perl data structures to CBOR and vice versa. Its	38	You are still invited to try out CBOR, and this module.
		39
		40	This module converts Perl data structures to the Concise Binary Object
		41	Representation (CBOR) and vice versa. CBOR is a fast binary serialisation
		42	format that aims to use a superset of the JSON data model, i.e. when you
		43	can represent something in JSON, you should be able to represent it in
		44	CBOR.
		45
		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
		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
25	primary goal is to be I<correct> and its secondary goal is to be	59	The primary goal of this module is to be I<correct> and the secondary goal
26	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.
27		61
28	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
29	vice versa.	63	vice versa.
30		64
31	=cut	65	=cut
32		66
33	package CBOR::XS;	67	package CBOR::XS;
34		68
35	use common::sense;	69	use common::sense;
36		70
37	our $VERSION = 0.02;	71	our $VERSION = 0.08;
38	our @ISA = qw(Exporter);	72	our @ISA = qw(Exporter);
39		73
40	our @EXPORT = qw(encode_cbor decode_cbor);	74	our @EXPORT = qw(encode_cbor decode_cbor);
41		75
42	use Exporter;	76	use Exporter;
43	use XSLoader;	77	use XSLoader;
		78
		79	use Types::Serialiser;
44		80
45	our $MAGIC = "\xd9\xd9\xf7";	81	our $MAGIC = "\xd9\xd9\xf7";
46		82
47	=head1 FUNCTIONAL INTERFACE	83	=head1 FUNCTIONAL INTERFACE
48		84
…		…
186		222
187	CBOR arrays and CBOR maps will be converted into references to a Perl	223	CBOR arrays and CBOR maps will be converted into references to a Perl
188	array or hash, respectively. The keys of the map will be stringified	224	array or hash, respectively. The keys of the map will be stringified
189	during this process.	225	during this process.
190		226
		227	=item null
		228
		229	CBOR null becomes C<undef> in Perl.
		230
191	=item true, false	231	=item true, false, undefined
192		232
193	These CBOR values become C<CBOR::XS::true> and C<CBOR::XS::false>,	233	These CBOR values become C<Types:Serialiser::true>,
		234	C<Types:Serialiser::false> and C<Types::Serialiser::error>,
194	respectively. They are overloaded to act almost exactly like the numbers	235	respectively. They are overloaded to act almost exactly like the numbers
195	C<1> and C<0>. You can check whether a scalar is a CBOR boolean by using	236	C<1> and C<0> (for true and false) or to throw an exception on access (for
196	the C<CBOR::XS::is_bool> function.	237	error). See the L<Types::Serialiser> manpage for details.
197		238
198	=item null, undefined	239	=item CBOR tag 256 (perl object)
199		240
200	CBOR null and undefined values becomes C<undef> in Perl (in the future,	241	The tag value C<256> (TODO: pending iana registration) will be used
201	Undefined may raise an exception or something else).	242	to deserialise a Perl object serialised with C<FREEZE>. See L<OBJECT
		243	SERIALISATION>, below, for details.
202		244
203	=item tags	245	=item CBOR tag 55799 (magic header)
204		246
		247	The tag 55799 is ignored (this tag implements the magic header).
		248
		249	=item other CBOR tags
		250
205	Tagged items consists of a numeric tag and another CBOR value. The tag	251	Tagged items consists of a numeric tag and another CBOR value. Tags not
206	55799 is ignored (this tag implements the magic header).	252	handled internally are currently converted into a L<CBOR::XS::Tagged>
207
208	All other tags are currently converted into a L<CBOR::XS::Tagged> object,
209	which is simply a blessed array reference consistsing of the numeric tag	253	object, which is simply a blessed array reference consisting of the
210	value followed by the (decoded) BOR value.	254	numeric tag value followed by the (decoded) CBOR value.
		255
		256	In the future, support for user-supplied conversions might get added.
211		257
212	=item anything else	258	=item anything else
213		259
214	Anything else (e.g. unsupported simple values) will raise a decoding	260	Anything else (e.g. unsupported simple values) will raise a decoding
215	error.	261	error.
…		…
245	C<1>, which get turned into false and true in CBOR.	291	C<1>, which get turned into false and true in CBOR.
246		292
247	=item CBOR::XS::Tagged objects	293	=item CBOR::XS::Tagged objects
248		294
249	Objects of this type must be arrays consisting of a single C<[tag, value]>	295	Objects of this type must be arrays consisting of a single C<[tag, value]>
250	pair. The (numerical) tag will be encoded as a CBOR tag, the value will be	296	pair. The (numerical) tag will be encoded as a CBOR tag, the value will
251	encoded as appropriate for the value.	297	be encoded as appropriate for the value. You cna use C<CBOR::XS::tag> to
		298	create such objects.
252		299
253	=item CBOR::XS::true, CBOR::XS::false	300	=item Types::Serialiser::true, Types::Serialiser::false, Types::Serialiser::error
254		301
255	These special values become CBOR true and CBOR false values,	302	These special values become CBOR true, CBOR false and CBOR undefined
256	respectively. You can also use C<\1> and C<\0> directly if you want.	303	values, respectively. You can also use C<\1>, C<\0> and C<\undef> directly
		304	if you want.
257		305
258	=item blessed objects	306	=item other blessed objects
259		307
260	Other blessed objects currently need to have a C<TO_CBOR> method. It	308	Other blessed objects are serialised via C<TO_CBOR> or C<FREEZE>. See
261	will be called on every object that is being serialised, and must return	309	L<OBJECT SERIALISATION>, below, for details.
262	something that can be encoded in CBOR.
263		310
264	=item simple scalars	311	=item simple scalars
265		312
266	TODO	313	TODO
267	Simple Perl scalars (any scalar that is not a reference) are the most	314	Simple Perl scalars (any scalar that is not a reference) are the most
…		…
305	represent numerical values are supported, but might suffer loss of	352	represent numerical values are supported, but might suffer loss of
306	precision.	353	precision.
307		354
308	=back	355	=back
309		356
		357	=head2 OBJECT SERIALISATION
310		358
		359	This module knows two way to serialise a Perl object: The CBOR-specific
		360	way, and the generic way.
		361
		362	Whenever the encoder encounters a Perl object that it cnanot serialise
		363	directly (most of them), it will first look up the C<TO_CBOR> method on
		364	it.
		365
		366	If it has a C<TO_CBOR> method, it will call it with the object as only
		367	argument, and expects exactly one return value, which it will then
		368	substitute and encode it in the place of the object.
		369
		370	Otherwise, it will look up the C<FREEZE> method. If it exists, it will
		371	call it with the object as first argument, and the constant string C<CBOR>
		372	as the second argument, to distinguish it from other serialisers.
		373
		374	The C<FREEZE> method can return any number of values (i.e. zero or
		375	more). These will be encoded as CBOR perl object, together with the
		376	classname.
		377
		378	If an object supports neither C<TO_CBOR> nor C<FREEZE>, encoding will fail
		379	with an error.
		380
		381	Objects encoded via C<TO_CBOR> cannot be automatically decoded, but
		382	objects encoded via C<FREEZE> can be decoded using the following protocol:
		383
		384	When an encoded CBOR perl object is encountered by the decoder, it will
		385	look up the C<THAW> method, by using the stored classname, and will fail
		386	if the method cannot be found.
		387
		388	After the lookup it will call the C<THAW> method with the stored classname
		389	as first argument, the constant string C<CBOR> as second argument, and all
		390	values returned by C<FREEZE> as remaining arguments.
		391
		392	=head4 EXAMPLES
		393
		394	Here is an example C<TO_CBOR> method:
		395
		396	sub My::Object::TO_CBOR {
		397	my ($obj) = @_;
		398
		399	["this is a serialised My::Object object", $obj->{id}]
		400	}
		401
		402	When a C<My::Object> is encoded to CBOR, it will instead encode a simple
		403	array with two members: a string, and the "object id". Decoding this CBOR
		404	string will yield a normal perl array reference in place of the object.
		405
		406	A more useful and practical example would be a serialisation method for
		407	the URI module. CBOR has a custom tag value for URIs, namely 32:
		408
		409	sub URI::TO_CBOR {
		410	my ($self) = @_;
		411	my $uri = "$self"; # stringify uri
		412	utf8::upgrade $uri; # make sure it will be encoded as UTF-8 string
		413	CBOR::XS::tagged 32, "$_[0]"
		414	}
		415
		416	This will encode URIs as a UTF-8 string with tag 32, which indicates an
		417	URI.
		418
		419	Decoding such an URI will not (currently) give you an URI object, but
		420	instead a CBOR::XS::Tagged object with tag number 32 and the string -
		421	exactly what was returned by C<TO_CBOR>.
		422
		423	To serialise an object so it can automatically be deserialised, you need
		424	to use C<FREEZE> and C<THAW>. To take the URI module as example, this
		425	would be a possible implementation:
		426
		427	sub URI::FREEZE {
		428	my ($self, $serialiser) = @_;
		429	"$self" # encode url string
		430	}
		431
		432	sub URI::THAW {
		433	my ($class, $serialiser, $uri) = @_;
		434
		435	$class->new ($uri)
		436	}
		437
		438	Unlike C<TO_CBOR>, multiple values can be returned by C<FREEZE>. For
		439	example, a C<FREEZE> method that returns "type", "id" and "variant" values
		440	would cause an invocation of C<THAW> with 5 arguments:
		441
		442	sub My::Object::FREEZE {
		443	my ($self, $serialiser) = @_;
		444
		445	($self->{type}, $self->{id}, $self->{variant})
		446	}
		447
		448	sub My::Object::THAW {
		449	my ($class, $serialiser, $type, $id, $variant) = @_;
		450
		451	$class-<new (type => $type, id => $id, variant => $variant)
		452	}
		453
		454
311	=head2 MAGIC HEADER	455	=head1 MAGIC HEADER
312		456
313	There is no way to distinguish CBOR from other formats	457	There is no way to distinguish CBOR from other formats
314	programmatically. To make it easier to distinguish CBOR from other	458	programmatically. To make it easier to distinguish CBOR from other
315	formats, the CBOR specification has a special "magic string" that can be	459	formats, the CBOR specification has a special "magic string" that can be
316	prepended to any CBOR string without changing it's meaning.	460	prepended to any CBOR string without changing its meaning.
317		461
318	This string is available as C<$CBOR::XS::MAGIC>. This module does not	462	This string is available as C<$CBOR::XS::MAGIC>. This module does not
319	prepend this string tot he CBOR data it generates, but it will ignroe it	463	prepend this string to the CBOR data it generates, but it will ignore it
320	if present, so users can prepend this string as a "file type" indicator as	464	if present, so users can prepend this string as a "file type" indicator as
321	required.	465	required.
322		466
323		467
		468	=head1 THE CBOR::XS::Tagged CLASS
		469
		470	CBOR has the concept of tagged values - any CBOR value can be tagged with
		471	a numeric 64 bit number, which are centrally administered.
		472
		473	C<CBOR::XS> handles a few tags internally when en- or decoding. You can
		474	also create tags yourself by encoding C<CBOR::XS::Tagged> objects, and the
		475	decoder will create C<CBOR::XS::Tagged> objects itself when it hits an
		476	unknown tag.
		477
		478	These objects are simply blessed array references - the first member of
		479	the array being the numerical tag, the second being the value.
		480
		481	You can interact with C<CBOR::XS::Tagged> objects in the following ways:
		482
		483	=over 4
		484
		485	=item $tagged = CBOR::XS::tag $tag, $value
		486
		487	This function(!) creates a new C<CBOR::XS::Tagged> object using the given
		488	C<$tag> (0..2**64-1) to tag the given C<$value> (which can be any Perl
		489	value that can be encoded in CBOR, including serialisable Perl objects and
		490	C<CBOR::XS::Tagged> objects).
		491
		492	=item $tagged->[0]
		493
		494	=item $tagged->[0] = $new_tag
		495
		496	=item $tag = $tagged->tag
		497
		498	=item $new_tag = $tagged->tag ($new_tag)
		499
		500	Access/mutate the tag.
		501
		502	=item $tagged->[1]
		503
		504	=item $tagged->[1] = $new_value
		505
		506	=item $value = $tagged->value
		507
		508	=item $new_value = $tagged->value ($new_value)
		509
		510	Access/mutate the tagged value.
		511
		512	=back
		513
		514	=cut
		515
		516	sub tag($$) {
		517	bless [@_], CBOR::XS::Tagged::;
		518	}
		519
		520	sub CBOR::XS::Tagged::tag {
		521	$_[0][0] = $_[1] if $#_;
		522	$_[0][0]
		523	}
		524
		525	sub CBOR::XS::Tagged::value {
		526	$_[0][1] = $_[1] if $#_;
		527	$_[0][1]
		528	}
		529
		530	=head2 EXAMPLES
		531
		532	Here are some examples of C<CBOR::XS::Tagged> uses to tag objects.
		533
		534	You can look up CBOR tag value and emanings in the IANA registry at
		535	L<http://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml>.
		536
		537	Prepend a magic header (C<$CBOR::XS::MAGIC>):
		538
		539	my $cbor = encode_cbor CBOR::XS::tag 55799, $value;
		540	# same as:
		541	my $cbor = $CBOR::XS::MAGIC . encode_cbor $value;
		542
		543	Serialise some URIs and a regex in an array:
		544
		545	my $cbor = encode_cbor [
		546	(CBOR::XS::tag 32, "http://www.nethype.de/"),
		547	(CBOR::XS::tag 32, "http://software.schmorp.de/"),
		548	(CBOR::XS::tag 35, "^[Pp][Ee][Rr][lL]\$"),
		549	];
		550
		551	Wrap CBOR data in CBOR:
		552
		553	my $cbor_cbor = encode_cbor
		554	CBOR::XS::tag 24,
		555	encode_cbor [1, 2, 3];
		556
324	=head2 CBOR and JSON	557	=head1 CBOR and JSON
325		558
326	CBOR is supposed to implement a superset of the JSON data model, and is,	559	CBOR is supposed to implement a superset of the JSON data model, and is,
327	with some coercion, able to represent all JSON texts (something that other	560	with some coercion, able to represent all JSON texts (something that other
328	"binary JSON" formats such as BSON generally do not support).	561	"binary JSON" formats such as BSON generally do not support).
329		562
…		…
409	Please refrain from using rt.cpan.org or any other bug reporting	642	Please refrain from using rt.cpan.org or any other bug reporting
410	service. I put the contact address into my modules for a reason.	643	service. I put the contact address into my modules for a reason.
411		644
412	=cut	645	=cut
413		646
414	our $true = do { bless \(my $dummy = 1), "CBOR::XS::Boolean" };
415	our $false = do { bless \(my $dummy = 0), "CBOR::XS::Boolean" };
416
417	sub true() { $true }
418	sub false() { $false }
419
420	sub is_bool($) {
421	UNIVERSAL::isa $_[0], "CBOR::XS::Boolean"
422	# or UNIVERSAL::isa $_[0], "CBOR::Literal"
423	}
424
425	XSLoader::load "CBOR::XS", $VERSION;	647	XSLoader::load "CBOR::XS", $VERSION;
426
427	package CBOR::XS::Boolean;
428
429	use overload
430	"0+" => sub { ${$_[0]} },
431	"++" => sub { $_[0] = ${$_[0]} + 1 },
432	"--" => sub { $_[0] = ${$_[0]} - 1 },
433	fallback => 1;
434
435	1;
436		648
437	=head1 SEE ALSO	649	=head1 SEE ALSO
438		650
439	The L<JSON> and L<JSON::XS> modules that do similar, but human-readable,	651	The L<JSON> and L<JSON::XS> modules that do similar, but human-readable,
440	serialisation.	652	serialisation.
441		653
		654	The L<Types::Serialiser> module provides the data model for true, false
		655	and error values.
		656
442	=head1 AUTHOR	657	=head1 AUTHOR
443		658
444	Marc Lehmann <schmorp@schmorp.de>	659	Marc Lehmann <schmorp@schmorp.de>
445	http://home.schmorp.de/	660	http://home.schmorp.de/
446		661
447	=cut	662	=cut
448		663
		664	1
		665

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Comparing CBOR-XS/XS.pm (file contents): Revision 1.4 by root, Sat Oct 26 22:25:47 2013 UTC vs. Revision 1.18 by root, Sun Nov 17 05:26:14 2013 UTC

Diff Legend

Comparing CBOR-XS/XS.pm (file contents):
Revision 1.4 by root, Sat Oct 26 22:25:47 2013 UTC vs.
Revision 1.18 by root, Sun Nov 17 05:26:14 2013 UTC