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

Comparing CBOR-XS/XS.pm (file contents):
Revision 1.28 by root, Thu Nov 28 16:09:04 2013 UTC vs.
Revision 1.80 by root, Fri Dec 11 06:05:33 2020 UTC

…		…
38	with the added ability of supporting serialisation of Perl objects. (JSON	38	with the added ability of supporting serialisation of Perl objects. (JSON
39	often compresses better than CBOR though, so if you plan to compress the	39	often compresses better than CBOR though, so if you plan to compress the
40	data later and speed is less important you might want to compare both	40	data later and speed is less important you might want to compare both
41	formats first).	41	formats first).
42		42
		43	The primary goal of this module is to be I<correct> and the secondary goal
		44	is to be I<fast>. To reach the latter goal it was written in C.
		45
43	To give you a general idea about speed, with texts in the megabyte range,	46	To give you a general idea about speed, with texts in the megabyte range,
44	C<CBOR::XS> usually encodes roughly twice as fast as L<Storable> or	47	C<CBOR::XS> usually encodes roughly twice as fast as L<Storable> or
45	L<JSON::XS> and decodes about 15%-30% faster than those. The shorter the	48	L<JSON::XS> and decodes about 15%-30% faster than those. The shorter the
46	data, the worse L<Storable> performs in comparison.	49	data, the worse L<Storable> performs in comparison.
47		50
48	Regarding compactness, C<CBOR::XS>-encoded data structures are usually	51	Regarding compactness, C<CBOR::XS>-encoded data structures are usually
49	about 20% smaller than the same data encoded as (compact) JSON or	52	about 20% smaller than the same data encoded as (compact) JSON or
50	L<Storable>.	53	L<Storable>.
51		54
52	In addition to the core CBOR data format, this module implements a	55	In addition to the core CBOR data format, this module implements a
53	number of extensions, to support cyclic and shared data structures (see	56	number of extensions, to support cyclic and shared data structures
54	C<allow_sharing>), string deduplication (see C<pack_strings>) and scalar	57	(see C<allow_sharing> and C<allow_cycles>), string deduplication (see
55	references (always enabled).	58	C<pack_strings>) and scalar references (always enabled).
56
57	The primary goal of this module is to be I<correct> and the secondary goal
58	is to be I<fast>. To reach the latter goal it was written in C.
59		59
60	See MAPPING, below, on how CBOR::XS maps perl values to CBOR values and	60	See MAPPING, below, on how CBOR::XS maps perl values to CBOR values and
61	vice versa.	61	vice versa.
62		62
63	=cut	63	=cut
64		64
65	package CBOR::XS;	65	package CBOR::XS;
66		66
67	use common::sense;	67	use common::sense;
68		68
69	our $VERSION = '1.0';	69	our $VERSION = 1.83;
70	our @ISA = qw(Exporter);	70	our @ISA = qw(Exporter);
71		71
72	our @EXPORT = qw(encode_cbor decode_cbor);	72	our @EXPORT = qw(encode_cbor decode_cbor);
73		73
74	use Exporter;	74	use Exporter;
…		…
112		112
113	The mutators for flags all return the CBOR object again and thus calls can	113	The mutators for flags all return the CBOR object again and thus calls can
114	be chained:	114	be chained:
115		115
116	my $cbor = CBOR::XS->new->encode ({a => [1,2]});	116	my $cbor = CBOR::XS->new->encode ({a => [1,2]});
		117
		118	=item $cbor = new_safe CBOR::XS
		119
		120	Create a new, safe/secure CBOR::XS object. This is similar to C<new>,
		121	but configures the coder object to be safe to use with untrusted
		122	data. Currently, this is equivalent to:
		123
		124	my $cbor = CBOR::XS
		125	->new
		126	->forbid_objects
		127	->filter (\&CBOR::XS::safe_filter)
		128	->max_size (1e8);
		129
		130	But is more future proof (it is better to crash because of a change than
		131	to be exploited in other ways).
		132
		133	=cut
		134
		135	sub new_safe {
		136	CBOR::XS
		137	->new
		138	->forbid_objects
		139	->filter (\&CBOR::XS::safe_filter)
		140	->max_size (1e8)
		141	}
117		142
118	=item $cbor = $cbor->max_depth ([$maximum_nesting_depth])	143	=item $cbor = $cbor->max_depth ([$maximum_nesting_depth])
119		144
120	=item $max_depth = $cbor->get_max_depth	145	=item $max_depth = $cbor->get_max_depth
121		146
…		…
137		162
138	Note that nesting is implemented by recursion in C. The default value has	163	Note that nesting is implemented by recursion in C. The default value has
139	been chosen to be as large as typical operating systems allow without	164	been chosen to be as large as typical operating systems allow without
140	crashing.	165	crashing.
141		166
142	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.	167	See L<SECURITY CONSIDERATIONS>, below, for more info on why this is useful.
143		168
144	=item $cbor = $cbor->max_size ([$maximum_string_size])	169	=item $cbor = $cbor->max_size ([$maximum_string_size])
145		170
146	=item $max_size = $cbor->get_max_size	171	=item $max_size = $cbor->get_max_size
147		172
…		…
152	effect on C<encode> (yet).	177	effect on C<encode> (yet).
153		178
154	If no argument is given, the limit check will be deactivated (same as when	179	If no argument is given, the limit check will be deactivated (same as when
155	C<0> is specified).	180	C<0> is specified).
156		181
157	See SECURITY CONSIDERATIONS, below, for more info on why this is useful.	182	See L<SECURITY CONSIDERATIONS>, below, for more info on why this is useful.
158		183
159	=item $cbor = $cbor->allow_unknown ([$enable])	184	=item $cbor = $cbor->allow_unknown ([$enable])
160		185
161	=item $enabled = $cbor->get_allow_unknown	186	=item $enabled = $cbor->get_allow_unknown
162		187
…		…
180	reference to the earlier value.	205	reference to the earlier value.
181		206
182	This means that such values will only be encoded once, and will not result	207	This means that such values will only be encoded once, and will not result
183	in a deep cloning of the value on decode, in decoders supporting the value	208	in a deep cloning of the value on decode, in decoders supporting the value
184	sharing extension. This also makes it possible to encode cyclic data	209	sharing extension. This also makes it possible to encode cyclic data
185	structures.	210	structures (which need C<allow_cycles> to be enabled to be decoded by this
		211	module).
186		212
187	It is recommended to leave it off unless you know your	213	It is recommended to leave it off unless you know your
188	communication partner supports the value sharing extensions to CBOR	214	communication partner supports the value sharing extensions to CBOR
189	(L<http://cbor.schmorp.de/value-sharing>), as without decoder support, the	215	(L<http://cbor.schmorp.de/value-sharing>), as without decoder support, the
190	resulting data structure might be unusable.	216	resulting data structure might be unusable.
191		217
192	Detecting shared values incurs a runtime overhead when values are encoded	218	Detecting shared values incurs a runtime overhead when values are encoded
193	that have a reference counter large than one, and might unnecessarily	219	that have a reference counter large than one, and might unnecessarily
194	increase the encoded size, as potentially shared values are encode as	220	increase the encoded size, as potentially shared values are encoded as
195	sharable whether or not they are actually shared.	221	shareable whether or not they are actually shared.
196		222
197	At the moment, only targets of references can be shared (e.g. scalars,	223	At the moment, only targets of references can be shared (e.g. scalars,
198	arrays or hashes pointed to by a reference). Weirder constructs, such as	224	arrays or hashes pointed to by a reference). Weirder constructs, such as
199	an array with multiple "copies" of the I<same> string, which are hard but	225	an array with multiple "copies" of the I<same> string, which are hard but
200	not impossible to create in Perl, are not supported (this is the same as	226	not impossible to create in Perl, are not supported (this is the same as
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205	structures cannot be encoded in this mode.	231	structures cannot be encoded in this mode.
206		232
207	This option does not affect C<decode> in any way - shared values and	233	This option does not affect C<decode> in any way - shared values and
208	references will always be decoded properly if present.	234	references will always be decoded properly if present.
209		235
		236	=item $cbor = $cbor->allow_cycles ([$enable])
		237
		238	=item $enabled = $cbor->get_allow_cycles
		239
		240	If C<$enable> is true (or missing), then C<decode> will happily decode
		241	self-referential (cyclic) data structures. By default these will not be
		242	decoded, as they need manual cleanup to avoid memory leaks, so code that
		243	isn't prepared for this will not leak memory.
		244
		245	If C<$enable> is false (the default), then C<decode> will throw an error
		246	when it encounters a self-referential/cyclic data structure.
		247
		248	FUTURE DIRECTION: the motivation behind this option is to avoid I<real>
		249	cycles - future versions of this module might chose to decode cyclic data
		250	structures using weak references when this option is off, instead of
		251	throwing an error.
		252
		253	This option does not affect C<encode> in any way - shared values and
		254	references will always be encoded properly if present.
		255
		256	=item $cbor = $cbor->forbid_objects ([$enable])
		257
		258	=item $enabled = $cbor->get_forbid_objects
		259
		260	Disables the use of the object serialiser protocol.
		261
		262	If C<$enable> is true (or missing), then C<encode> will will throw an
		263	exception when it encounters perl objects that would be encoded using the
		264	perl-object tag (26). When C<decode> encounters such tags, it will fall
		265	back to the general filter/tagged logic as if this were an unknown tag (by
		266	default resulting in a C<CBOR::XC::Tagged> object).
		267
		268	If C<$enable> is false (the default), then C<encode> will use the
		269	L<Types::Serialiser> object serialisation protocol to serialise objects
		270	into perl-object tags, and C<decode> will do the same to decode such tags.
		271
		272	See L<SECURITY CONSIDERATIONS>, below, for more info on why forbidding this
		273	protocol can be useful.
		274
210	=item $cbor = $cbor->pack_strings ([$enable])	275	=item $cbor = $cbor->pack_strings ([$enable])
211		276
212	=item $enabled = $cbor->get_pack_strings	277	=item $enabled = $cbor->get_pack_strings
213		278
214	If C<$enable> is true (or missing), then C<encode> will try not to encode	279	If C<$enable> is true (or missing), then C<encode> will try not to encode
…		…
226	the standard CBOR way.	291	the standard CBOR way.
227		292
228	This option does not affect C<decode> in any way - string references will	293	This option does not affect C<decode> in any way - string references will
229	always be decoded properly if present.	294	always be decoded properly if present.
230		295
		296	=item $cbor = $cbor->text_keys ([$enable])
		297
		298	=item $enabled = $cbor->get_text_keys
		299
		300	If C<$enabled> is true (or missing), then C<encode> will encode all
		301	perl hash keys as CBOR text strings/UTF-8 string, upgrading them as needed.
		302
		303	If C<$enable> is false (the default), then C<encode> will encode hash keys
		304	normally - upgraded perl strings (strings internally encoded as UTF-8) as
		305	CBOR text strings, and downgraded perl strings as CBOR byte strings.
		306
		307	This option does not affect C<decode> in any way.
		308
		309	This option is useful for interoperability with CBOR decoders that don't
		310	treat byte strings as a form of text. It is especially useful as Perl
		311	gives very little control over hash keys.
		312
		313	Enabling this option can be slow, as all downgraded hash keys that are
		314	encoded need to be scanned and converted to UTF-8.
		315
		316	=item $cbor = $cbor->text_strings ([$enable])
		317
		318	=item $enabled = $cbor->get_text_strings
		319
		320	This option works similar to C<text_keys>, above, but works on all strings
		321	(including hash keys), so C<text_keys> has no further effect after
		322	enabling C<text_strings>.
		323
		324	If C<$enabled> is true (or missing), then C<encode> will encode all perl
		325	strings as CBOR text strings/UTF-8 strings, upgrading them as needed.
		326
		327	If C<$enable> is false (the default), then C<encode> will encode strings
		328	normally (but see C<text_keys>) - upgraded perl strings (strings
		329	internally encoded as UTF-8) as CBOR text strings, and downgraded perl
		330	strings as CBOR byte strings.
		331
		332	This option does not affect C<decode> in any way.
		333
		334	This option has similar advantages and disadvantages as C<text_keys>. In
		335	addition, this option effectively removes the ability to automatically
		336	encode byte strings, which might break some C<FREEZE> and C<TO_CBOR>
		337	methods that rely on this.
		338
		339	A workaround is to use explicit type casts, which are unaffected by this option.
		340
		341	=item $cbor = $cbor->validate_utf8 ([$enable])
		342
		343	=item $enabled = $cbor->get_validate_utf8
		344
		345	If C<$enable> is true (or missing), then C<decode> will validate that
		346	elements (text strings) containing UTF-8 data in fact contain valid UTF-8
		347	data (instead of blindly accepting it). This validation obviously takes
		348	extra time during decoding.
		349
		350	The concept of "valid UTF-8" used is perl's concept, which is a superset
		351	of the official UTF-8.
		352
		353	If C<$enable> is false (the default), then C<decode> will blindly accept
		354	UTF-8 data, marking them as valid UTF-8 in the resulting data structure
		355	regardless of whether that's true or not.
		356
		357	Perl isn't too happy about corrupted UTF-8 in strings, but should
		358	generally not crash or do similarly evil things. Extensions might be not
		359	so forgiving, so it's recommended to turn on this setting if you receive
		360	untrusted CBOR.
		361
		362	This option does not affect C<encode> in any way - strings that are
		363	supposedly valid UTF-8 will simply be dumped into the resulting CBOR
		364	string without checking whether that is, in fact, true or not.
		365
231	=item $cbor = $cbor->filter ([$cb->($tag, $value)])	366	=item $cbor = $cbor->filter ([$cb->($tag, $value)])
232		367
233	=item $cb_or_undef = $cbor->get_filter	368	=item $cb_or_undef = $cbor->get_filter
234		369
235	Sets or replaces the tagged value decoding filter (when C<$cb> is	370	Sets or replaces the tagged value decoding filter (when C<$cb> is
…		…
247	replace the tagged value in the decoded data structure, or no values,	382	replace the tagged value in the decoded data structure, or no values,
248	which will result in default handling, which currently means the decoder	383	which will result in default handling, which currently means the decoder
249	creates a C<CBOR::XS::Tagged> object to hold the tag and the value.	384	creates a C<CBOR::XS::Tagged> object to hold the tag and the value.
250		385
251	When the filter is cleared (the default state), the default filter	386	When the filter is cleared (the default state), the default filter
252	function, C<CBOR::XS::default_filter>, is used. This function simply looks	387	function, C<CBOR::XS::default_filter>, is used. This function simply
253	up the tag in the C<%CBOR::XS::FILTER> hash. If an entry exists it must be	388	looks up the tag in the C<%CBOR::XS::FILTER> hash. If an entry exists
254	a code reference that is called with tag and value, and is responsible for	389	it must be a code reference that is called with tag and value, and is
255	decoding the value. If no entry exists, it returns no values.	390	responsible for decoding the value. If no entry exists, it returns no
		391	values. C<CBOR::XS> provides a number of default filter functions already,
		392	the the C<%CBOR::XS::FILTER> hash can be freely extended with more.
		393
		394	C<CBOR::XS> additionally provides an alternative filter function that is
		395	supposed to be safe to use with untrusted data (which the default filter
		396	might not), called C<CBOR::XS::safe_filter>, which works the same as
		397	the C<default_filter> but uses the C<%CBOR::XS::SAFE_FILTER> variable
		398	instead. It is prepopulated with the tag decoding functions that are
		399	deemed safe (basically the same as C<%CBOR::XS::FILTER> without all
		400	the bignum tags), and can be extended by user code as wlel, although,
		401	obviously, one should be very careful about adding decoding functions
		402	here, since the expectation is that they are safe to use on untrusted
		403	data, after all.
256		404
257	Example: decode all tags not handled internally into C<CBOR::XS::Tagged>	405	Example: decode all tags not handled internally into C<CBOR::XS::Tagged>
258	objects, with no other special handling (useful when working with	406	objects, with no other special handling (useful when working with
259	potentially "unsafe" CBOR data).	407	potentially "unsafe" CBOR data).
260		408
…		…
267	my ($tag, $value);	415	my ($tag, $value);
268		416
269	"tag 1347375694 value $value"	417	"tag 1347375694 value $value"
270	};	418	};
271		419
		420	Example: provide your own filter function that looks up tags in your own
		421	hash:
		422
		423	my %my_filter = (
		424	998347484 => sub {
		425	my ($tag, $value);
		426
		427	"tag 998347484 value $value"
		428	};
		429	);
		430
		431	my $coder = CBOR::XS->new->filter (sub {
		432	&{ $my_filter{$_[0]} or return }
		433	});
		434
		435
		436	Example: use the safe filter function (see L<SECURITY CONSIDERATIONS> for
		437	more considerations on security).
		438
		439	CBOR::XS->new->filter (\&CBOR::XS::safe_filter)->decode ($cbor_data);
		440
272	=item $cbor_data = $cbor->encode ($perl_scalar)	441	=item $cbor_data = $cbor->encode ($perl_scalar)
273		442
274	Converts the given Perl data structure (a scalar value) to its CBOR	443	Converts the given Perl data structure (a scalar value) to its CBOR
275	representation.	444	representation.
276		445
…		…
285	when there is trailing garbage after the CBOR string, it will silently	454	when there is trailing garbage after the CBOR string, it will silently
286	stop parsing there and return the number of characters consumed so far.	455	stop parsing there and return the number of characters consumed so far.
287		456
288	This is useful if your CBOR texts are not delimited by an outer protocol	457	This is useful if your CBOR texts are not delimited by an outer protocol
289	and you need to know where the first CBOR string ends amd the next one	458	and you need to know where the first CBOR string ends amd the next one
290	starts.	459	starts - CBOR strings are self-delimited, so it is possible to concatenate
		460	CBOR strings without any delimiters or size fields and recover their data.
291		461
292	CBOR::XS->new->decode_prefix ("......")	462	CBOR::XS->new->decode_prefix ("......")
293	=> ("...", 3)	463	=> ("...", 3)
		464
		465	=back
		466
		467	=head2 INCREMENTAL PARSING
		468
		469	In some cases, there is the need for incremental parsing of JSON
		470	texts. While this module always has to keep both CBOR text and resulting
		471	Perl data structure in memory at one time, it does allow you to parse a
		472	CBOR stream incrementally, using a similar to using "decode_prefix" to see
		473	if a full CBOR object is available, but is much more efficient.
		474
		475	It basically works by parsing as much of a CBOR string as possible - if
		476	the CBOR data is not complete yet, the pasrer will remember where it was,
		477	to be able to restart when more data has been accumulated. Once enough
		478	data is available to either decode a complete CBOR value or raise an
		479	error, a real decode will be attempted.
		480
		481	A typical use case would be a network protocol that consists of sending
		482	and receiving CBOR-encoded messages. The solution that works with CBOR and
		483	about anything else is by prepending a length to every CBOR value, so the
		484	receiver knows how many octets to read. More compact (and slightly slower)
		485	would be to just send CBOR values back-to-back, as C<CBOR::XS> knows where
		486	a CBOR value ends, and doesn't need an explicit length.
		487
		488	The following methods help with this:
		489
		490	=over 4
		491
		492	=item @decoded = $cbor->incr_parse ($buffer)
		493
		494	This method attempts to decode exactly one CBOR value from the beginning
		495	of the given C<$buffer>. The value is removed from the C<$buffer> on
		496	success. When C<$buffer> doesn't contain a complete value yet, it returns
		497	nothing. Finally, when the C<$buffer> doesn't start with something
		498	that could ever be a valid CBOR value, it raises an exception, just as
		499	C<decode> would. In the latter case the decoder state is undefined and
		500	must be reset before being able to parse further.
		501
		502	This method modifies the C<$buffer> in place. When no CBOR value can be
		503	decoded, the decoder stores the current string offset. On the next call,
		504	continues decoding at the place where it stopped before. For this to make
		505	sense, the C<$buffer> must begin with the same octets as on previous
		506	unsuccessful calls.
		507
		508	You can call this method in scalar context, in which case it either
		509	returns a decoded value or C<undef>. This makes it impossible to
		510	distinguish between CBOR null values (which decode to C<undef>) and an
		511	unsuccessful decode, which is often acceptable.
		512
		513	=item @decoded = $cbor->incr_parse_multiple ($buffer)
		514
		515	Same as C<incr_parse>, but attempts to decode as many CBOR values as
		516	possible in one go, instead of at most one. Calls to C<incr_parse> and
		517	C<incr_parse_multiple> can be interleaved.
		518
		519	=item $cbor->incr_reset
		520
		521	Resets the incremental decoder. This throws away any saved state, so that
		522	subsequent calls to C<incr_parse> or C<incr_parse_multiple> start to parse
		523	a new CBOR value from the beginning of the C<$buffer> again.
		524
		525	This method can be called at any time, but it I<must> be called if you want
		526	to change your C<$buffer> or there was a decoding error and you want to
		527	reuse the C<$cbor> object for future incremental parsings.
294		528
295	=back	529	=back
296		530
297		531
298	=head1 MAPPING	532	=head1 MAPPING
…		…
371		605
372	=item hash references	606	=item hash references
373		607
374	Perl hash references become CBOR maps. As there is no inherent ordering in	608	Perl hash references become CBOR maps. As there is no inherent ordering in
375	hash keys (or CBOR maps), they will usually be encoded in a pseudo-random	609	hash keys (or CBOR maps), they will usually be encoded in a pseudo-random
376	order. This order can be different each time a hahs is encoded.	610	order. This order can be different each time a hash is encoded.
377		611
378	Currently, tied hashes will use the indefinite-length format, while normal	612	Currently, tied hashes will use the indefinite-length format, while normal
379	hashes will use the fixed-length format.	613	hashes will use the fixed-length format.
380		614
381	=item array references	615	=item array references
…		…
434	my $x = 3.1; # some variable containing a number	668	my $x = 3.1; # some variable containing a number
435	"$x"; # stringified	669	"$x"; # stringified
436	$x .= ""; # another, more awkward way to stringify	670	$x .= ""; # another, more awkward way to stringify
437	print $x; # perl does it for you, too, quite often	671	print $x; # perl does it for you, too, quite often
438		672
439	You can force whether a string ie encoded as byte or text string by using	673	You can force whether a string is encoded as byte or text string by using
440	C<utf8::upgrade> and C<utf8::downgrade>):	674	C<utf8::upgrade> and C<utf8::downgrade> (if C<text_strings> is disabled).
441		675
442	utf8::upgrade $x; # encode $x as text string	676	utf8::upgrade $x; # encode $x as text string
443	utf8::downgrade $x; # encode $x as byte string	677	utf8::downgrade $x; # encode $x as byte string
444		678
		679	More options are available, see L<TYPE CASTS>, below, and the C<text_keys>
		680	and C<text_strings> options.
		681
445	Perl doesn't define what operations up- and downgrade strings, so if the	682	Perl doesn't define what operations up- and downgrade strings, so if the
446	difference between byte and text is important, you should up- or downgrade	683	difference between byte and text is important, you should up- or downgrade
447	your string as late as possible before encoding.	684	your string as late as possible before encoding. You can also force the
		685	use of CBOR text strings by using C<text_keys> or C<text_strings>.
448		686
449	You can force the type to be a CBOR number by numifying it:	687	You can force the type to be a CBOR number by numifying it:
450		688
451	my $x = "3"; # some variable containing a string	689	my $x = "3"; # some variable containing a string
452	$x += 0; # numify it, ensuring it will be dumped as a number	690	$x += 0; # numify it, ensuring it will be dumped as a number
…		…
463	represent numerical values are supported, but might suffer loss of	701	represent numerical values are supported, but might suffer loss of
464	precision.	702	precision.
465		703
466	=back	704	=back
467		705
		706	=head2 TYPE CASTS
		707
		708	B<EXPERIMENTAL>: As an experimental extension, C<CBOR::XS> allows you to
		709	force specific cbor types to be used when encoding. That allows you to
		710	encode types not normally accessible (e.g. half floats) as well as force
		711	string types even when C<text_strings> is in effect.
		712
		713	Type forcing is done by calling a special "cast" function which keeps a
		714	copy of the value and returns a new value that can be handed over to any
		715	CBOR encoder function.
		716
		717	The following casts are currently available (all of which are unary
		718	operators, that is, have a prototype of C<$>):
		719
		720	=over
		721
		722	=item CBOR::XS::as_int $value
		723
		724	Forces the value to be encoded as some form of (basic, not bignum) integer
		725	type.
		726
		727	=item CBOR::XS::as_text $value
		728
		729	Forces the value to be encoded as (UTF-8) text values.
		730
		731	=item CBOR::XS::as_bytes $value
		732
		733	Forces the value to be encoded as a (binary) string value.
		734
		735	Example: encode a perl string as binary even though C<text_strings> is in
		736	effect.
		737
		738	CBOR::XS->new->text_strings->encode ([4, "text", CBOR::XS::bytes "bytevalue"]);
		739
		740	=item CBOR::XS::as_bool $value
		741
		742	Converts a Perl boolean (which can be any kind of scalar) into a CBOR
		743	boolean. Strictly the same, but shorter to write, than:
		744
		745	$value ? Types::Serialiser::true : Types::Serialiser::false
		746
		747	=item CBOR::XS::as_float16 $value
		748
		749	Forces half-float (IEEE 754 binary16) encoding of the given value.
		750
		751	=item CBOR::XS::as_float32 $value
		752
		753	Forces single-float (IEEE 754 binary32) encoding of the given value.
		754
		755	=item CBOR::XS::as_float64 $value
		756
		757	Forces double-float (IEEE 754 binary64) encoding of the given value.
		758
		759	=item CBOR::XS::as_cbor $cbor_text
		760
		761	Not a type cast per-se, this type cast forces the argument to eb encoded
		762	as-is. This can be used to embed pre-encoded CBOR data.
		763
		764	Note that no checking on the validity of the C<$cbor_text> is done - it's
		765	the callers responsibility to correctly encode values.
		766
		767	=item CBOR::XS::as_map [key => value...]
		768
		769	Treat the array reference as key value pairs and output a CBOR map. This
		770	allows you to generate CBOR maps with arbitrary key types (or, if you
		771	don't care about semantics, duplicate keys or pairs in a custom order),
		772	which is otherwise hard to do with Perl.
		773
		774	The single argument must be an array reference with an even number of
		775	elements.
		776
		777	Note that only the reference to the array is copied, the array itself is
		778	not. Modifications done to the array before calling an encoding fuinction
		779	will be reflected in the encoded output.
		780
		781	Example: encode a CBOR map with a string and an integer as keys.
		782
		783	encode_cbor CBOR::XS::as_map [string => "value", 5 => "value"]
		784
		785	=back
		786
		787	=cut
		788
		789	sub CBOR::XS::as_cbor ($) { bless [$_[0], 0, undef], CBOR::XS::Tagged:: }
		790	sub CBOR::XS::as_int ($) { bless [$_[0], 1, undef], CBOR::XS::Tagged:: }
		791	sub CBOR::XS::as_bytes ($) { bless [$_[0], 2, undef], CBOR::XS::Tagged:: }
		792	sub CBOR::XS::as_text ($) { bless [$_[0], 3, undef], CBOR::XS::Tagged:: }
		793	sub CBOR::XS::as_float16 ($) { bless [$_[0], 4, undef], CBOR::XS::Tagged:: }
		794	sub CBOR::XS::as_float32 ($) { bless [$_[0], 5, undef], CBOR::XS::Tagged:: }
		795	sub CBOR::XS::as_float64 ($) { bless [$_[0], 6, undef], CBOR::XS::Tagged:: }
		796
		797	sub CBOR::XS::as_bool ($) { $_[0] ? $Types::Serialiser::true : $Types::Serialiser::false }
		798
		799	sub CBOR::XS::as_map ($) {
		800	ARRAY:: eq ref $_[0]
		801	and $#{ $_[0] } & 1
		802	or do { require Carp; Carp::croak ("CBOR::XS::as_map only acepts array references with an even number of elements, caught") };
		803
		804	bless [$_[0], 7, undef], CBOR::XS::Tagged::
		805	}
		806
468	=head2 OBJECT SERIALISATION	807	=head2 OBJECT SERIALISATION
		808
		809	This module implements both a CBOR-specific and the generic
		810	L<Types::Serialier> object serialisation protocol. The following
		811	subsections explain both methods.
		812
		813	=head3 ENCODING
469		814
470	This module knows two way to serialise a Perl object: The CBOR-specific	815	This module knows two way to serialise a Perl object: The CBOR-specific
471	way, and the generic way.	816	way, and the generic way.
472		817
473	Whenever the encoder encounters a Perl object that it cnanot serialise	818	Whenever the encoder encounters a Perl object that it cannot serialise
474	directly (most of them), it will first look up the C<TO_CBOR> method on	819	directly (most of them), it will first look up the C<TO_CBOR> method on
475	it.	820	it.
476		821
477	If it has a C<TO_CBOR> method, it will call it with the object as only	822	If it has a C<TO_CBOR> method, it will call it with the object as only
478	argument, and expects exactly one return value, which it will then	823	argument, and expects exactly one return value, which it will then
…		…
484		829
485	The C<FREEZE> method can return any number of values (i.e. zero or	830	The C<FREEZE> method can return any number of values (i.e. zero or
486	more). These will be encoded as CBOR perl object, together with the	831	more). These will be encoded as CBOR perl object, together with the
487	classname.	832	classname.
488		833
		834	These methods I<MUST NOT> change the data structure that is being
		835	serialised. Failure to comply to this can result in memory corruption -
		836	and worse.
		837
489	If an object supports neither C<TO_CBOR> nor C<FREEZE>, encoding will fail	838	If an object supports neither C<TO_CBOR> nor C<FREEZE>, encoding will fail
490	with an error.	839	with an error.
491		840
		841	=head3 DECODING
		842
492	Objects encoded via C<TO_CBOR> cannot be automatically decoded, but	843	Objects encoded via C<TO_CBOR> cannot (normally) be automatically decoded,
493	objects encoded via C<FREEZE> can be decoded using the following protocol:	844	but objects encoded via C<FREEZE> can be decoded using the following
		845	protocol:
494		846
495	When an encoded CBOR perl object is encountered by the decoder, it will	847	When an encoded CBOR perl object is encountered by the decoder, it will
496	look up the C<THAW> method, by using the stored classname, and will fail	848	look up the C<THAW> method, by using the stored classname, and will fail
497	if the method cannot be found.	849	if the method cannot be found.
498		850
499	After the lookup it will call the C<THAW> method with the stored classname	851	After the lookup it will call the C<THAW> method with the stored classname
500	as first argument, the constant string C<CBOR> as second argument, and all	852	as first argument, the constant string C<CBOR> as second argument, and all
501	values returned by C<FREEZE> as remaining arguments.	853	values returned by C<FREEZE> as remaining arguments.
502		854
503	=head4 EXAMPLES	855	=head3 EXAMPLES
504		856
505	Here is an example C<TO_CBOR> method:	857	Here is an example C<TO_CBOR> method:
506		858
507	sub My::Object::TO_CBOR {	859	sub My::Object::TO_CBOR {
508	my ($obj) = @_;	860	my ($obj) = @_;
…		…
540	"$self" # encode url string	892	"$self" # encode url string
541	}	893	}
542		894
543	sub URI::THAW {	895	sub URI::THAW {
544	my ($class, $serialiser, $uri) = @_;	896	my ($class, $serialiser, $uri) = @_;
545
546	$class->new ($uri)	897	$class->new ($uri)
547	}	898	}
548		899
549	Unlike C<TO_CBOR>, multiple values can be returned by C<FREEZE>. For	900	Unlike C<TO_CBOR>, multiple values can be returned by C<FREEZE>. For
550	example, a C<FREEZE> method that returns "type", "id" and "variant" values	901	example, a C<FREEZE> method that returns "type", "id" and "variant" values
…		…
681	additional tags (such as base64url).	1032	additional tags (such as base64url).
682		1033
683	=head2 ENFORCED TAGS	1034	=head2 ENFORCED TAGS
684		1035
685	These tags are always handled when decoding, and their handling cannot be	1036	These tags are always handled when decoding, and their handling cannot be
686	overriden by the user.	1037	overridden by the user.
687		1038
688	=over 4	1039	=over 4
689		1040
690	=item 26 (perl-object, L<http://cbor.schmorp.de/perl-object>)	1041	=item 26 (perl-object, L<http://cbor.schmorp.de/perl-object>)
691		1042
692	These tags are automatically created (and decoded) for serialisable	1043	These tags are automatically created (and decoded) for serialisable
693	objects using the C<FREEZE/THAW> methods (the L<Types::Serialier> object	1044	objects using the C<FREEZE/THAW> methods (the L<Types::Serialier> object
694	serialisation protocol). See L<OBJECT SERIALISATION> for details.	1045	serialisation protocol). See L<OBJECT SERIALISATION> for details.
695		1046
696	=item 28, 29 (sharable, sharedref, L <http://cbor.schmorp.de/value-sharing>)	1047	=item 28, 29 (shareable, sharedref, L<http://cbor.schmorp.de/value-sharing>)
697		1048
698	These tags are automatically decoded when encountered, resulting in	1049	These tags are automatically decoded when encountered (and they do not
		1050	result in a cyclic data structure, see C<allow_cycles>), resulting in
699	shared values in the decoded object. They are only encoded, however, when	1051	shared values in the decoded object. They are only encoded, however, when
700	C<allow_sharable> is enabled.	1052	C<allow_sharing> is enabled.
701		1053
		1054	Not all shared values can be successfully decoded: values that reference
		1055	themselves will I<currently> decode as C<undef> (this is not the same
		1056	as a reference pointing to itself, which will be represented as a value
		1057	that contains an indirect reference to itself - these will be decoded
		1058	properly).
		1059
		1060	Note that considerably more shared value data structures can be decoded
		1061	than will be encoded - currently, only values pointed to by references
		1062	will be shared, others will not. While non-reference shared values can be
		1063	generated in Perl with some effort, they were considered too unimportant
		1064	to be supported in the encoder. The decoder, however, will decode these
		1065	values as shared values.
		1066
702	=item 256, 25 (stringref-namespace, stringref, L <http://cbor.schmorp.de/stringref>)	1067	=item 256, 25 (stringref-namespace, stringref, L<http://cbor.schmorp.de/stringref>)
703		1068
704	These tags are automatically decoded when encountered. They are only	1069	These tags are automatically decoded when encountered. They are only
705	encoded, however, when C<pack_strings> is enabled.	1070	encoded, however, when C<pack_strings> is enabled.
706		1071
707	=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)	1072	=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)
708		1073
709	This tag is automatically generated when a reference are encountered (with	1074	This tag is automatically generated when a reference are encountered (with
710	the exception of hash and array refernces). It is converted to a reference	1075	the exception of hash and array references). It is converted to a reference
711	when decoding.	1076	when decoding.
712		1077
713	=item 55799 (self-describe CBOR, RFC 7049)	1078	=item 55799 (self-describe CBOR, RFC 7049)
714		1079
715	This value is not generated on encoding (unless explicitly requested by	1080	This value is not generated on encoding (unless explicitly requested by
…		…
718	=back	1083	=back
719		1084
720	=head2 NON-ENFORCED TAGS	1085	=head2 NON-ENFORCED TAGS
721		1086
722	These tags have default filters provided when decoding. Their handling can	1087	These tags have default filters provided when decoding. Their handling can
723	be overriden by changing the C<%CBOR::XS::FILTER> entry for the tag, or by	1088	be overridden by changing the C<%CBOR::XS::FILTER> entry for the tag, or by
724	providing a custom C<filter> callback when decoding.	1089	providing a custom C<filter> callback when decoding.
725		1090
726	When they result in decoding into a specific Perl class, the module	1091	When they result in decoding into a specific Perl class, the module
727	usually provides a corresponding C<TO_CBOR> method as well.	1092	usually provides a corresponding C<TO_CBOR> method as well.
728		1093
…		…
731	provide these modules. The decoding usually fails with an exception if the	1096	provide these modules. The decoding usually fails with an exception if the
732	required module cannot be loaded.	1097	required module cannot be loaded.
733		1098
734	=over 4	1099	=over 4
735		1100
		1101	=item 0, 1 (date/time string, seconds since the epoch)
		1102
		1103	These tags are decoded into L<Time::Piece> objects. The corresponding
		1104	C<Time::Piece::TO_CBOR> method always encodes into tag 1 values currently.
		1105
		1106	The L<Time::Piece> API is generally surprisingly bad, and fractional
		1107	seconds are only accidentally kept intact, so watch out. On the plus side,
		1108	the module comes with perl since 5.10, which has to count for something.
		1109
736	=item 2, 3 (positive/negative bignum)	1110	=item 2, 3 (positive/negative bignum)
737		1111
738	These tags are decoded into L<Math::BigInt> objects. The corresponding	1112	These tags are decoded into L<Math::BigInt> objects. The corresponding
739	C<Math::BigInt::TO_CBOR> method encodes "small" bigints into normal CBOR	1113	C<Math::BigInt::TO_CBOR> method encodes "small" bigints into normal CBOR
740	integers, and others into positive/negative CBOR bignums.	1114	integers, and others into positive/negative CBOR bignums.
741		1115
742	=item 4, 5 (decimal fraction/bigfloat)	1116	=item 4, 5, 264, 265 (decimal fraction/bigfloat)
743		1117
744	Both decimal fractions and bigfloats are decoded into L<Math::BigFloat>	1118	Both decimal fractions and bigfloats are decoded into L<Math::BigFloat>
745	objects. The corresponding C<Math::BigFloat::TO_CBOR> method I<always>	1119	objects. The corresponding C<Math::BigFloat::TO_CBOR> method I<always>
746	encodes into a decimal fraction.	1120	encodes into a decimal fraction (either tag 4 or 264).
747		1121
748	CBOR cannot represent bigfloats with I<very> large exponents - conversion	1122	NaN and infinities are not encoded properly, as they cannot be represented
749	of such big float objects is undefined.	1123	in CBOR.
750		1124
751	Also, NaN and infinities are not encoded properly.	1125	See L<BIGNUM SECURITY CONSIDERATIONS> for more info.
		1126
		1127	=item 30 (rational numbers)
		1128
		1129	These tags are decoded into L<Math::BigRat> objects. The corresponding
		1130	C<Math::BigRat::TO_CBOR> method encodes rational numbers with denominator
		1131	C<1> via their numerator only, i.e., they become normal integers or
		1132	C<bignums>.
		1133
		1134	See L<BIGNUM SECURITY CONSIDERATIONS> for more info.
752		1135
753	=item 21, 22, 23 (expected later JSON conversion)	1136	=item 21, 22, 23 (expected later JSON conversion)
754		1137
755	CBOR::XS is not a CBOR-to-JSON converter, and will simply ignore these	1138	CBOR::XS is not a CBOR-to-JSON converter, and will simply ignore these
756	tags.	1139	tags.
…		…
761	C<URI::TO_CBOR> method again results in a CBOR URI value.	1144	C<URI::TO_CBOR> method again results in a CBOR URI value.
762		1145
763	=back	1146	=back
764		1147
765	=cut	1148	=cut
766
767	our %FILTER = (
768	# 0 # rfc4287 datetime, utf-8
769	# 1 # unix timestamp, any
770
771	2 => sub { # pos bigint
772	require Math::BigInt;
773	Math::BigInt->new ("0x" . unpack "H*", pop)
774	},
775
776	3 => sub { # neg bigint
777	require Math::BigInt;
778	-Math::BigInt->new ("0x" . unpack "H*", pop)
779	},
780
781	4 => sub { # decimal fraction, array
782	require Math::BigFloat;
783	Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
784	},
785
786	5 => sub { # bigfloat, array
787	require Math::BigFloat;
788	scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2)
789	},
790
791	21 => sub { pop }, # expected conversion to base64url encoding
792	22 => sub { pop }, # expected conversion to base64 encoding
793	23 => sub { pop }, # expected conversion to base16 encoding
794
795	# 24 # embedded cbor, byte string
796
797	32 => sub {
798	require URI;
799	URI->new (pop)
800	},
801
802	# 33 # base64url rfc4648, utf-8
803	# 34 # base64 rfc46484, utf-8
804	# 35 # regex pcre/ecma262, utf-8
805	# 36 # mime message rfc2045, utf-8
806	);
807
808		1149
809	=head1 CBOR and JSON	1150	=head1 CBOR and JSON
810		1151
811	CBOR is supposed to implement a superset of the JSON data model, and is,	1152	CBOR is supposed to implement a superset of the JSON data model, and is,
812	with some coercion, able to represent all JSON texts (something that other	1153	with some coercion, able to represent all JSON texts (something that other
…		…
821	CBOR intact.	1162	CBOR intact.
822		1163
823		1164
824	=head1 SECURITY CONSIDERATIONS	1165	=head1 SECURITY CONSIDERATIONS
825		1166
826	When you are using CBOR in a protocol, talking to untrusted potentially	1167	Tl;dr... if you want to decode or encode CBOR from untrusted sources, you
827	hostile creatures requires relatively few measures.	1168	should start with a coder object created via C<new_safe> (which implements
		1169	the mitigations explained below):
828		1170
		1171	my $coder = CBOR::XS->new_safe;
		1172
		1173	my $data = $coder->decode ($cbor_text);
		1174	my $cbor = $coder->encode ($data);
		1175
		1176	Longer version: When you are using CBOR in a protocol, talking to
		1177	untrusted potentially hostile creatures requires some thought:
		1178
		1179	=over 4
		1180
		1181	=item Security of the CBOR decoder itself
		1182
829	First of all, your CBOR decoder should be secure, that is, should not have	1183	First and foremost, your CBOR decoder should be secure, that is, should
		1184	not have any buffer overflows or similar bugs that could potentially be
830	any buffer overflows. Obviously, this module should ensure that and I am	1185	exploited. Obviously, this module should ensure that and I am trying hard
831	trying hard on making that true, but you never know.	1186	on making that true, but you never know.
832		1187
		1188	=item CBOR::XS can invoke almost arbitrary callbacks during decoding
		1189
		1190	CBOR::XS supports object serialisation - decoding CBOR can cause calls
		1191	to I<any> C<THAW> method in I<any> package that exists in your process
		1192	(that is, CBOR::XS will not try to load modules, but any existing C<THAW>
		1193	method or function can be called, so they all have to be secure).
		1194
		1195	Less obviously, it will also invoke C<TO_CBOR> and C<FREEZE> methods -
		1196	even if all your C<THAW> methods are secure, encoding data structures from
		1197	untrusted sources can invoke those and trigger bugs in those.
		1198
		1199	So, if you are not sure about the security of all the modules you
		1200	have loaded (you shouldn't), you should disable this part using
		1201	C<forbid_objects> or using C<new_safe>.
		1202
		1203	=item CBOR can be extended with tags that call library code
		1204
		1205	CBOR can be extended with tags, and C<CBOR::XS> has a registry of
		1206	conversion functions for many existing tags that can be extended via
		1207	third-party modules (see the C<filter> method).
		1208
		1209	If you don't trust these, you should configure the "safe" filter function,
		1210	C<CBOR::XS::safe_filter> (C<new_safe> does this), which by default only
		1211	includes conversion functions that are considered "safe" by the author
		1212	(but again, they can be extended by third party modules).
		1213
		1214	Depending on your level of paranoia, you can use the "safe" filter:
		1215
		1216	$cbor->filter (\&CBOR::XS::safe_filter);
		1217
		1218	... your own filter...
		1219
		1220	$cbor->filter (sub { ... do your stuffs here ... });
		1221
		1222	... or even no filter at all, disabling all tag decoding:
		1223
		1224	$cbor->filter (sub { });
		1225
		1226	This is never a problem for encoding, as the tag mechanism only exists in
		1227	CBOR texts.
		1228
		1229	=item Resource-starving attacks: object memory usage
		1230
833	Second, you need to avoid resource-starving attacks. That means you should	1231	You need to avoid resource-starving attacks. That means you should limit
834	limit the size of CBOR data you accept, or make sure then when your	1232	the size of CBOR data you accept, or make sure then when your resources
835	resources run out, that's just fine (e.g. by using a separate process that	1233	run out, that's just fine (e.g. by using a separate process that can
836	can crash safely). The size of a CBOR string in octets is usually a good	1234	crash safely). The size of a CBOR string in octets is usually a good
837	indication of the size of the resources required to decode it into a Perl	1235	indication of the size of the resources required to decode it into a Perl
838	structure. While CBOR::XS can check the size of the CBOR text, it might be	1236	structure. While CBOR::XS can check the size of the CBOR text (using
839	too late when you already have it in memory, so you might want to check	1237	C<max_size> - done by C<new_safe>), it might be too late when you already
840	the size before you accept the string.	1238	have it in memory, so you might want to check the size before you accept
		1239	the string.
841		1240
		1241	As for encoding, it is possible to construct data structures that are
		1242	relatively small but result in large CBOR texts (for example by having an
		1243	array full of references to the same big data structure, which will all be
		1244	deep-cloned during encoding by default). This is rarely an actual issue
		1245	(and the worst case is still just running out of memory), but you can
		1246	reduce this risk by using C<allow_sharing>.
		1247
		1248	=item Resource-starving attacks: stack overflows
		1249
842	Third, CBOR::XS recurses using the C stack when decoding objects and	1250	CBOR::XS recurses using the C stack when decoding objects and arrays. The
843	arrays. The C stack is a limited resource: for instance, on my amd64	1251	C stack is a limited resource: for instance, on my amd64 machine with 8MB
844	machine with 8MB of stack size I can decode around 180k nested arrays but	1252	of stack size I can decode around 180k nested arrays but only 14k nested
845	only 14k nested CBOR objects (due to perl itself recursing deeply on croak	1253	CBOR objects (due to perl itself recursing deeply on croak to free the
846	to free the temporary). If that is exceeded, the program crashes. To be	1254	temporary). If that is exceeded, the program crashes. To be conservative,
847	conservative, the default nesting limit is set to 512. If your process	1255	the default nesting limit is set to 512. If your process has a smaller
848	has a smaller stack, you should adjust this setting accordingly with the	1256	stack, you should adjust this setting accordingly with the C<max_depth>
849	C<max_depth> method.	1257	method.
		1258
		1259	=item Resource-starving attacks: CPU en-/decoding complexity
		1260
		1261	CBOR::XS will use the L<Math::BigInt>, L<Math::BigFloat> and
		1262	L<Math::BigRat> libraries to represent encode/decode bignums. These can be
		1263	very slow (as in, centuries of CPU time) and can even crash your program
		1264	(and are generally not very trustworthy). See the next section on bignum
		1265	security for details.
		1266
		1267	=item Data breaches: leaking information in error messages
		1268
		1269	CBOR::XS might leak contents of your Perl data structures in its error
		1270	messages, so when you serialise sensitive information you might want to
		1271	make sure that exceptions thrown by CBOR::XS will not end up in front of
		1272	untrusted eyes.
		1273
		1274	=item Something else...
850		1275
851	Something else could bomb you, too, that I forgot to think of. In that	1276	Something else could bomb you, too, that I forgot to think of. In that
852	case, you get to keep the pieces. I am always open for hints, though...	1277	case, you get to keep the pieces. I am always open for hints, though...
853		1278
854	Also keep in mind that CBOR::XS might leak contents of your Perl data	1279	=back
855	structures in its error messages, so when you serialise sensitive	1280
856	information you might want to make sure that exceptions thrown by CBOR::XS	1281
857	will not end up in front of untrusted eyes.	1282	=head1 BIGNUM SECURITY CONSIDERATIONS
		1283
		1284	CBOR::XS provides a C<TO_CBOR> method for both L<Math::BigInt> and
		1285	L<Math::BigFloat> that tries to encode the number in the simplest possible
		1286	way, that is, either a CBOR integer, a CBOR bigint/decimal fraction (tag
		1287	4) or an arbitrary-exponent decimal fraction (tag 264). Rational numbers
		1288	(L<Math::BigRat>, tag 30) can also contain bignums as members.
		1289
		1290	CBOR::XS will also understand base-2 bigfloat or arbitrary-exponent
		1291	bigfloats (tags 5 and 265), but it will never generate these on its own.
		1292
		1293	Using the built-in L<Math::BigInt::Calc> support, encoding and decoding
		1294	decimal fractions is generally fast. Decoding bigints can be slow for very
		1295	big numbers (tens of thousands of digits, something that could potentially
		1296	be caught by limiting the size of CBOR texts), and decoding bigfloats or
		1297	arbitrary-exponent bigfloats can be I<extremely> slow (minutes, decades)
		1298	for large exponents (roughly 40 bit and longer).
		1299
		1300	Additionally, L<Math::BigInt> can take advantage of other bignum
		1301	libraries, such as L<Math::GMP>, which cannot handle big floats with large
		1302	exponents, and might simply abort or crash your program, due to their code
		1303	quality.
		1304
		1305	This can be a concern if you want to parse untrusted CBOR. If it is, you
		1306	might want to disable decoding of tag 2 (bigint) and 3 (negative bigint)
		1307	types. You should also disable types 5 and 265, as these can be slow even
		1308	without bigints.
		1309
		1310	Disabling bigints will also partially or fully disable types that rely on
		1311	them, e.g. rational numbers that use bignums.
		1312
858		1313
859	=head1 CBOR IMPLEMENTATION NOTES	1314	=head1 CBOR IMPLEMENTATION NOTES
860		1315
861	This section contains some random implementation notes. They do not	1316	This section contains some random implementation notes. They do not
862	describe guaranteed behaviour, but merely behaviour as-is implemented	1317	describe guaranteed behaviour, but merely behaviour as-is implemented
…		…
871	Only the double data type is supported for NV data types - when Perl uses	1326	Only the double data type is supported for NV data types - when Perl uses
872	long double to represent floating point values, they might not be encoded	1327	long double to represent floating point values, they might not be encoded
873	properly. Half precision types are accepted, but not encoded.	1328	properly. Half precision types are accepted, but not encoded.
874		1329
875	Strict mode and canonical mode are not implemented.	1330	Strict mode and canonical mode are not implemented.
		1331
		1332
		1333	=head1 LIMITATIONS ON PERLS WITHOUT 64-BIT INTEGER SUPPORT
		1334
		1335	On perls that were built without 64 bit integer support (these are rare
		1336	nowadays, even on 32 bit architectures, as all major Perl distributions
		1337	are built with 64 bit integer support), support for any kind of 64 bit
		1338	value in CBOR is very limited - most likely, these 64 bit values will
		1339	be truncated, corrupted, or otherwise not decoded correctly. This also
		1340	includes string, float, array and map sizes that are stored as 64 bit
		1341	integers.
876		1342
877		1343
878	=head1 THREADS	1344	=head1 THREADS
879		1345
880	This module is I<not> guaranteed to be thread safe and there are no	1346	This module is I<not> guaranteed to be thread safe and there are no
…		…
894	Please refrain from using rt.cpan.org or any other bug reporting	1360	Please refrain from using rt.cpan.org or any other bug reporting
895	service. I put the contact address into my modules for a reason.	1361	service. I put the contact address into my modules for a reason.
896		1362
897	=cut	1363	=cut
898		1364
		1365	# clumsy and slow hv_store-in-hash helper function
		1366	sub _hv_store {
		1367	$_[0]{$_[1]} = $_[2];
		1368	}
		1369
899	our %FILTER = (	1370	our %FILTER = (
900	# 0 # rfc4287 datetime, utf-8	1371	0 => sub { # rfc4287 datetime, utf-8
901	# 1 # unix timestamp, any	1372	require Time::Piece;
		1373	# Time::Piece::Strptime uses the "incredibly flexible date parsing routine"
		1374	# from FreeBSD, which can't parse ISO 8601, RFC3339, RFC4287 or much of anything
		1375	# else either. Whats incredibe over standard strptime totally escapes me.
		1376	# doesn't do fractional times, either. sigh.
		1377	# In fact, it's all a lie, it uses whatever strptime it wants, and of course,
		1378	# they are all incompatible. The openbsd one simply ignores %z (but according to the
		1379	# docs, it would be much more incredibly flexible indeed. If it worked, that is.).
		1380	scalar eval {
		1381	my $s = $_[1];
		1382
		1383	$s =~ s/Z$/+00:00/;
		1384	$s =~ s/(\.[0-9]+)?([+-][0-9][0-9]):([0-9][0-9])$//
		1385	or die;
		1386
		1387	my $b = $1 - ($2 * 60 + $3) * 60; # fractional part + offset. hopefully
		1388	my $d = Time::Piece->strptime ($s, "%Y-%m-%dT%H:%M:%S");
		1389
		1390	Time::Piece::gmtime ($d->epoch + $b)
		1391	} \|\| die "corrupted CBOR date/time string ($_[0])";
		1392	},
		1393
		1394	1 => sub { # seconds since the epoch, possibly fractional
		1395	require Time::Piece;
		1396	scalar Time::Piece::gmtime (pop)
		1397	},
902		1398
903	2 => sub { # pos bigint	1399	2 => sub { # pos bigint
904	require Math::BigInt;	1400	require Math::BigInt;
905	Math::BigInt->new ("0x" . unpack "H*", pop)	1401	Math::BigInt->new ("0x" . unpack "H*", pop)
906	},	1402	},
…		…
913	4 => sub { # decimal fraction, array	1409	4 => sub { # decimal fraction, array
914	require Math::BigFloat;	1410	require Math::BigFloat;
915	Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])	1411	Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
916	},	1412	},
917		1413
		1414	264 => sub { # decimal fraction with arbitrary exponent
		1415	require Math::BigFloat;
		1416	Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
		1417	},
		1418
918	5 => sub { # bigfloat, array	1419	5 => sub { # bigfloat, array
919	require Math::BigFloat;	1420	require Math::BigFloat;
920	scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2)	1421	scalar Math::BigFloat->new ($_[1][1]) * Math::BigFloat->new (2)->bpow ($_[1][0])
		1422	},
		1423
		1424	265 => sub { # bigfloat with arbitrary exponent
		1425	require Math::BigFloat;
		1426	scalar Math::BigFloat->new ($_[1][1]) * Math::BigFloat->new (2)->bpow ($_[1][0])
		1427	},
		1428
		1429	30 => sub { # rational number
		1430	require Math::BigRat;
		1431	Math::BigRat->new ("$_[1][0]/$_[1][1]") # separate parameters only work in recent versons
921	},	1432	},
922		1433
923	21 => sub { pop }, # expected conversion to base64url encoding	1434	21 => sub { pop }, # expected conversion to base64url encoding
924	22 => sub { pop }, # expected conversion to base64 encoding	1435	22 => sub { pop }, # expected conversion to base64 encoding
925	23 => sub { pop }, # expected conversion to base16 encoding	1436	23 => sub { pop }, # expected conversion to base16 encoding
…		…
935	# 34 # base64 rfc46484, utf-8	1446	# 34 # base64 rfc46484, utf-8
936	# 35 # regex pcre/ecma262, utf-8	1447	# 35 # regex pcre/ecma262, utf-8
937	# 36 # mime message rfc2045, utf-8	1448	# 36 # mime message rfc2045, utf-8
938	);	1449	);
939		1450
940	sub CBOR::XS::default_filter {	1451	sub default_filter {
941	&{ $FILTER{$_[0]} or return }	1452	&{ $FILTER{$_[0]} or return }
		1453	}
		1454
		1455	our %SAFE_FILTER = map { $_ => $FILTER{$_} } 0, 1, 21, 22, 23, 32;
		1456
		1457	sub safe_filter {
		1458	&{ $SAFE_FILTER{$_[0]} or return }
942	}	1459	}
943		1460
944	sub URI::TO_CBOR {	1461	sub URI::TO_CBOR {
945	my $uri = $_[0]->as_string;	1462	my $uri = $_[0]->as_string;
946	utf8::upgrade $uri;	1463	utf8::upgrade $uri;
947	CBOR::XS::tag 32, $uri	1464	tag 32, $uri
948	}	1465	}
949		1466
950	sub Math::BigInt::TO_CBOR {	1467	sub Math::BigInt::TO_CBOR {
951	if ($_[0] >= -2147483648 && $_[0] <= 2147483647) {	1468	if (-2147483648 <= $_[0] && $_[0] <= 2147483647) {
952	$_[0]->numify	1469	$_[0]->numify
953	} else {	1470	} else {
954	my $hex = substr $_[0]->as_hex, 2;	1471	my $hex = substr $_[0]->as_hex, 2;
955	$hex = "0$hex" if 1 & length $hex; # sigh	1472	$hex = "0$hex" if 1 & length $hex; # sigh
956	CBOR::XS::tag $_[0] >= 0 ? 2 : 3, pack "H*", $hex	1473	tag $_[0] >= 0 ? 2 : 3, pack "H*", $hex
957	}	1474	}
958	}	1475	}
959		1476
960	sub Math::BigFloat::TO_CBOR {	1477	sub Math::BigFloat::TO_CBOR {
961	my ($m, $e) = $_[0]->parts;	1478	my ($m, $e) = $_[0]->parts;
		1479
		1480	-9223372036854775808 <= $e && $e <= 18446744073709551615
962	CBOR::XS::tag 4, [$e->numify, $m]	1481	? tag 4, [$e->numify, $m]
		1482	: tag 264, [$e, $m]
		1483	}
		1484
		1485	sub Math::BigRat::TO_CBOR {
		1486	my ($n, $d) = $_[0]->parts;
		1487
		1488	# older versions of BigRat need *1, as they not always return numbers
		1489
		1490	$d*1 == 1
		1491	? $n*1
		1492	: tag 30, [$n1, $d1]
		1493	}
		1494
		1495	sub Time::Piece::TO_CBOR {
		1496	tag 1, 0 + $_[0]->epoch
963	}	1497	}
964		1498
965	XSLoader::load "CBOR::XS", $VERSION;	1499	XSLoader::load "CBOR::XS", $VERSION;
966		1500
967	=head1 SEE ALSO	1501	=head1 SEE ALSO

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Comparing CBOR-XS/XS.pm (file contents): Revision 1.28 by root, Thu Nov 28 16:09:04 2013 UTC vs. Revision 1.80 by root, Fri Dec 11 06:05:33 2020 UTC

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Comparing CBOR-XS/XS.pm (file contents):
Revision 1.28 by root, Thu Nov 28 16:09:04 2013 UTC vs.
Revision 1.80 by root, Fri Dec 11 06:05:33 2020 UTC