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Revision 1.43 by root, Sun Dec 14 06:12:13 2014 UTC vs.
Revision 1.89 by root, Fri Sep 8 20:03:06 2023 UTC

38with the added ability of supporting serialisation of Perl objects. (JSON 38with the added ability of supporting serialisation of Perl objects. (JSON
39often compresses better than CBOR though, so if you plan to compress the 39often compresses better than CBOR though, so if you plan to compress the
40data later and speed is less important you might want to compare both 40data later and speed is less important you might want to compare both
41formats first). 41formats first).
42 42
43The primary goal of this module is to be I<correct> and the secondary goal
44is to be I<fast>. To reach the latter goal it was written in C.
45
43To give you a general idea about speed, with texts in the megabyte range, 46To give you a general idea about speed, with texts in the megabyte range,
44C<CBOR::XS> usually encodes roughly twice as fast as L<Storable> or 47C<CBOR::XS> usually encodes roughly twice as fast as L<Storable> or
45L<JSON::XS> and decodes about 15%-30% faster than those. The shorter the 48L<JSON::XS> and decodes about 15%-30% faster than those. The shorter the
46data, the worse L<Storable> performs in comparison. 49data, the worse L<Storable> performs in comparison.
47 50
52In addition to the core CBOR data format, this module implements a 55In addition to the core CBOR data format, this module implements a
53number of extensions, to support cyclic and shared data structures 56number of extensions, to support cyclic and shared data structures
54(see C<allow_sharing> and C<allow_cycles>), string deduplication (see 57(see C<allow_sharing> and C<allow_cycles>), string deduplication (see
55C<pack_strings>) and scalar references (always enabled). 58C<pack_strings>) and scalar references (always enabled).
56 59
57The primary goal of this module is to be I<correct> and the secondary goal
58is to be I<fast>. To reach the latter goal it was written in C.
59
60See MAPPING, below, on how CBOR::XS maps perl values to CBOR values and 60See MAPPING, below, on how CBOR::XS maps perl values to CBOR values and
61vice versa. 61vice versa.
62 62
63=cut 63=cut
64 64
65package CBOR::XS; 65package CBOR::XS;
66 66
67use common::sense; 67use common::sense;
68 68
69our $VERSION = 1.26; 69our $VERSION = 1.87;
70our @ISA = qw(Exporter); 70our @ISA = qw(Exporter);
71 71
72our @EXPORT = qw(encode_cbor decode_cbor); 72our @EXPORT = qw(encode_cbor decode_cbor);
73 73
74use Exporter; 74use Exporter;
112 112
113The mutators for flags all return the CBOR object again and thus calls can 113The mutators for flags all return the CBOR object again and thus calls can
114be chained: 114be 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
120Create a new, safe/secure CBOR::XS object. This is similar to C<new>,
121but configures the coder object to be safe to use with untrusted
122data. Currently, this is equivalent to:
123
124 my $cbor = CBOR::XS
125 ->new
126 ->validate_utf8
127 ->forbid_objects
128 ->filter (\&CBOR::XS::safe_filter)
129 ->max_size (1e8);
130
131But is more future proof (it is better to crash because of a change than
132to be exploited in other ways).
133
134=cut
135
136sub new_safe {
137 CBOR::XS
138 ->new
139 ->validate_utf8
140 ->forbid_objects
141 ->filter (\&CBOR::XS::safe_filter)
142 ->max_size (1e8)
143}
117 144
118=item $cbor = $cbor->max_depth ([$maximum_nesting_depth]) 145=item $cbor = $cbor->max_depth ([$maximum_nesting_depth])
119 146
120=item $max_depth = $cbor->get_max_depth 147=item $max_depth = $cbor->get_max_depth
121 148
137 164
138Note that nesting is implemented by recursion in C. The default value has 165Note that nesting is implemented by recursion in C. The default value has
139been chosen to be as large as typical operating systems allow without 166been chosen to be as large as typical operating systems allow without
140crashing. 167crashing.
141 168
142See SECURITY CONSIDERATIONS, below, for more info on why this is useful. 169See L<SECURITY CONSIDERATIONS>, below, for more info on why this is useful.
143 170
144=item $cbor = $cbor->max_size ([$maximum_string_size]) 171=item $cbor = $cbor->max_size ([$maximum_string_size])
145 172
146=item $max_size = $cbor->get_max_size 173=item $max_size = $cbor->get_max_size
147 174
152effect on C<encode> (yet). 179effect on C<encode> (yet).
153 180
154If no argument is given, the limit check will be deactivated (same as when 181If no argument is given, the limit check will be deactivated (same as when
155C<0> is specified). 182C<0> is specified).
156 183
157See SECURITY CONSIDERATIONS, below, for more info on why this is useful. 184See L<SECURITY CONSIDERATIONS>, below, for more info on why this is useful.
158 185
159=item $cbor = $cbor->allow_unknown ([$enable]) 186=item $cbor = $cbor->allow_unknown ([$enable])
160 187
161=item $enabled = $cbor->get_allow_unknown 188=item $enabled = $cbor->get_allow_unknown
162 189
180reference to the earlier value. 207reference to the earlier value.
181 208
182This means that such values will only be encoded once, and will not result 209This means that such values will only be encoded once, and will not result
183in a deep cloning of the value on decode, in decoders supporting the value 210in a deep cloning of the value on decode, in decoders supporting the value
184sharing extension. This also makes it possible to encode cyclic data 211sharing extension. This also makes it possible to encode cyclic data
185structures (which need C<allow_cycles> to ne enabled to be decoded by this 212structures (which need C<allow_cycles> to be enabled to be decoded by this
186module). 213module).
187 214
188It is recommended to leave it off unless you know your 215It is recommended to leave it off unless you know your
189communication partner supports the value sharing extensions to CBOR 216communication partner supports the value sharing extensions to CBOR
190(L<http://cbor.schmorp.de/value-sharing>), as without decoder support, the 217(L<http://cbor.schmorp.de/value-sharing>), as without decoder support, the
191resulting data structure might be unusable. 218resulting data structure might be unusable.
192 219
193Detecting shared values incurs a runtime overhead when values are encoded 220Detecting shared values incurs a runtime overhead when values are encoded
194that have a reference counter large than one, and might unnecessarily 221that have a reference counter larger than one, and might unnecessarily
195increase the encoded size, as potentially shared values are encode as 222increase the encoded size, as potentially shared values are encoded as
196shareable whether or not they are actually shared. 223shareable whether or not they are actually shared.
197 224
198At the moment, only targets of references can be shared (e.g. scalars, 225At the moment, only targets of references can be shared (e.g. scalars,
199arrays or hashes pointed to by a reference). Weirder constructs, such as 226arrays or hashes pointed to by a reference). Weirder constructs, such as
200an array with multiple "copies" of the I<same> string, which are hard but 227an array with multiple "copies" of the I<same> string, which are hard but
218isn't prepared for this will not leak memory. 245isn't prepared for this will not leak memory.
219 246
220If C<$enable> is false (the default), then C<decode> will throw an error 247If C<$enable> is false (the default), then C<decode> will throw an error
221when it encounters a self-referential/cyclic data structure. 248when it encounters a self-referential/cyclic data structure.
222 249
223FUTURE DIRECTION: the motivation behind this option is to avoid I<real>
224cycles - future versions of this module might chose to decode cyclic data
225structures using weak references when this option is off, instead of
226throwing an error.
227
228This option does not affect C<encode> in any way - shared values and 250This option does not affect C<encode> in any way - shared values and
229references will always be encoded properly if present. 251references will always be encoded properly if present.
252
253=item $cbor = $cbor->allow_weak_cycles ([$enable])
254
255=item $enabled = $cbor->get_allow_weak_cycles
256
257This works like C<allow_cycles> in that it allows the resulting data
258structures to contain cycles, but unlike C<allow_cycles>, those cyclic
259rreferences will be weak. That means that code that recurrsively walks
260the data structure must be prepared with cycles, but at least not special
261precautions must be implemented to free these data structures.
262
263Only those references leading to actual cycles will be weakened - other
264references, e.g. when the same hash or arrray is referenced multiple times
265in an arrray, will be normal references.
266
267This option does not affect C<encode> in any way - shared values and
268references will always be encoded properly if present.
269
270=item $cbor = $cbor->forbid_objects ([$enable])
271
272=item $enabled = $cbor->get_forbid_objects
273
274Disables the use of the object serialiser protocol.
275
276If C<$enable> is true (or missing), then C<encode> will will throw an
277exception when it encounters perl objects that would be encoded using the
278perl-object tag (26). When C<decode> encounters such tags, it will fall
279back to the general filter/tagged logic as if this were an unknown tag (by
280default resulting in a C<CBOR::XC::Tagged> object).
281
282If C<$enable> is false (the default), then C<encode> will use the
283L<Types::Serialiser> object serialisation protocol to serialise objects
284into perl-object tags, and C<decode> will do the same to decode such tags.
285
286See L<SECURITY CONSIDERATIONS>, below, for more info on why forbidding this
287protocol can be useful.
230 288
231=item $cbor = $cbor->pack_strings ([$enable]) 289=item $cbor = $cbor->pack_strings ([$enable])
232 290
233=item $enabled = $cbor->get_pack_strings 291=item $enabled = $cbor->get_pack_strings
234 292
247the standard CBOR way. 305the standard CBOR way.
248 306
249This option does not affect C<decode> in any way - string references will 307This option does not affect C<decode> in any way - string references will
250always be decoded properly if present. 308always be decoded properly if present.
251 309
310=item $cbor = $cbor->text_keys ([$enable])
311
312=item $enabled = $cbor->get_text_keys
313
314If C<$enabled> is true (or missing), then C<encode> will encode all
315perl hash keys as CBOR text strings/UTF-8 string, upgrading them as needed.
316
317If C<$enable> is false (the default), then C<encode> will encode hash keys
318normally - upgraded perl strings (strings internally encoded as UTF-8) as
319CBOR text strings, and downgraded perl strings as CBOR byte strings.
320
321This option does not affect C<decode> in any way.
322
323This option is useful for interoperability with CBOR decoders that don't
324treat byte strings as a form of text. It is especially useful as Perl
325gives very little control over hash keys.
326
327Enabling this option can be slow, as all downgraded hash keys that are
328encoded need to be scanned and converted to UTF-8.
329
330=item $cbor = $cbor->text_strings ([$enable])
331
332=item $enabled = $cbor->get_text_strings
333
334This option works similar to C<text_keys>, above, but works on all strings
335(including hash keys), so C<text_keys> has no further effect after
336enabling C<text_strings>.
337
338If C<$enabled> is true (or missing), then C<encode> will encode all perl
339strings as CBOR text strings/UTF-8 strings, upgrading them as needed.
340
341If C<$enable> is false (the default), then C<encode> will encode strings
342normally (but see C<text_keys>) - upgraded perl strings (strings
343internally encoded as UTF-8) as CBOR text strings, and downgraded perl
344strings as CBOR byte strings.
345
346This option does not affect C<decode> in any way.
347
348This option has similar advantages and disadvantages as C<text_keys>. In
349addition, this option effectively removes the ability to automatically
350encode byte strings, which might break some C<FREEZE> and C<TO_CBOR>
351methods that rely on this.
352
353A workaround is to use explicit type casts, which are unaffected by this option.
354
252=item $cbor = $cbor->validate_utf8 ([$enable]) 355=item $cbor = $cbor->validate_utf8 ([$enable])
253 356
254=item $enabled = $cbor->get_validate_utf8 357=item $enabled = $cbor->get_validate_utf8
255 358
256If C<$enable> is true (or missing), then C<decode> will validate that 359If C<$enable> is true (or missing), then C<decode> will validate that
261The concept of "valid UTF-8" used is perl's concept, which is a superset 364The concept of "valid UTF-8" used is perl's concept, which is a superset
262of the official UTF-8. 365of the official UTF-8.
263 366
264If C<$enable> is false (the default), then C<decode> will blindly accept 367If C<$enable> is false (the default), then C<decode> will blindly accept
265UTF-8 data, marking them as valid UTF-8 in the resulting data structure 368UTF-8 data, marking them as valid UTF-8 in the resulting data structure
266regardless of whether thats true or not. 369regardless of whether that's true or not.
267 370
268Perl isn't too happy about corrupted UTF-8 in strings, but should 371Perl isn't too happy about corrupted UTF-8 in strings, but should
269generally not crash or do similarly evil things. Extensions might be not 372generally not crash or do similarly evil things. Extensions might be not
270so forgiving, so it's recommended to turn on this setting if you receive 373so forgiving, so it's recommended to turn on this setting if you receive
271untrusted CBOR. 374untrusted CBOR.
293replace the tagged value in the decoded data structure, or no values, 396replace the tagged value in the decoded data structure, or no values,
294which will result in default handling, which currently means the decoder 397which will result in default handling, which currently means the decoder
295creates a C<CBOR::XS::Tagged> object to hold the tag and the value. 398creates a C<CBOR::XS::Tagged> object to hold the tag and the value.
296 399
297When the filter is cleared (the default state), the default filter 400When the filter is cleared (the default state), the default filter
298function, C<CBOR::XS::default_filter>, is used. This function simply looks 401function, C<CBOR::XS::default_filter>, is used. This function simply
299up the tag in the C<%CBOR::XS::FILTER> hash. If an entry exists it must be 402looks up the tag in the C<%CBOR::XS::FILTER> hash. If an entry exists
300a code reference that is called with tag and value, and is responsible for 403it must be a code reference that is called with tag and value, and is
301decoding the value. If no entry exists, it returns no values. 404responsible for decoding the value. If no entry exists, it returns no
405values. C<CBOR::XS> provides a number of default filter functions already,
406the the C<%CBOR::XS::FILTER> hash can be freely extended with more.
407
408C<CBOR::XS> additionally provides an alternative filter function that is
409supposed to be safe to use with untrusted data (which the default filter
410might not), called C<CBOR::XS::safe_filter>, which works the same as
411the C<default_filter> but uses the C<%CBOR::XS::SAFE_FILTER> variable
412instead. It is prepopulated with the tag decoding functions that are
413deemed safe (basically the same as C<%CBOR::XS::FILTER> without all
414the bignum tags), and can be extended by user code as wlel, although,
415obviously, one should be very careful about adding decoding functions
416here, since the expectation is that they are safe to use on untrusted
417data, after all.
302 418
303Example: decode all tags not handled internally into C<CBOR::XS::Tagged> 419Example: decode all tags not handled internally into C<CBOR::XS::Tagged>
304objects, with no other special handling (useful when working with 420objects, with no other special handling (useful when working with
305potentially "unsafe" CBOR data). 421potentially "unsafe" CBOR data).
306 422
313 my ($tag, $value); 429 my ($tag, $value);
314 430
315 "tag 1347375694 value $value" 431 "tag 1347375694 value $value"
316 }; 432 };
317 433
434Example: provide your own filter function that looks up tags in your own
435hash:
436
437 my %my_filter = (
438 998347484 => sub {
439 my ($tag, $value);
440
441 "tag 998347484 value $value"
442 };
443 );
444
445 my $coder = CBOR::XS->new->filter (sub {
446 &{ $my_filter{$_[0]} or return }
447 });
448
449
450Example: use the safe filter function (see L<SECURITY CONSIDERATIONS> for
451more considerations on security).
452
453 CBOR::XS->new->filter (\&CBOR::XS::safe_filter)->decode ($cbor_data);
454
318=item $cbor_data = $cbor->encode ($perl_scalar) 455=item $cbor_data = $cbor->encode ($perl_scalar)
319 456
320Converts the given Perl data structure (a scalar value) to its CBOR 457Converts the given Perl data structure (a scalar value) to its CBOR
321representation. 458representation.
322 459
331when there is trailing garbage after the CBOR string, it will silently 468when there is trailing garbage after the CBOR string, it will silently
332stop parsing there and return the number of characters consumed so far. 469stop parsing there and return the number of characters consumed so far.
333 470
334This is useful if your CBOR texts are not delimited by an outer protocol 471This is useful if your CBOR texts are not delimited by an outer protocol
335and you need to know where the first CBOR string ends amd the next one 472and you need to know where the first CBOR string ends amd the next one
336starts. 473starts - CBOR strings are self-delimited, so it is possible to concatenate
474CBOR strings without any delimiters or size fields and recover their data.
337 475
338 CBOR::XS->new->decode_prefix ("......") 476 CBOR::XS->new->decode_prefix ("......")
339 => ("...", 3) 477 => ("...", 3)
340 478
341=back 479=back
347Perl data structure in memory at one time, it does allow you to parse a 485Perl data structure in memory at one time, it does allow you to parse a
348CBOR stream incrementally, using a similar to using "decode_prefix" to see 486CBOR stream incrementally, using a similar to using "decode_prefix" to see
349if a full CBOR object is available, but is much more efficient. 487if a full CBOR object is available, but is much more efficient.
350 488
351It basically works by parsing as much of a CBOR string as possible - if 489It basically works by parsing as much of a CBOR string as possible - if
352the CBOR data is not complete yet, the pasrer will remember where it was, 490the CBOR data is not complete yet, the parser will remember where it was,
353to be able to restart when more data has been accumulated. Once enough 491to be able to restart when more data has been accumulated. Once enough
354data is available to either decode a complete CBOR value or raise an 492data is available to either decode a complete CBOR value or raise an
355error, a real decode will be attempted. 493error, a real decode will be attempted.
356 494
357A typical use case would be a network protocol that consists of sending 495A typical use case would be a network protocol that consists of sending
396 534
397Resets the incremental decoder. This throws away any saved state, so that 535Resets the incremental decoder. This throws away any saved state, so that
398subsequent calls to C<incr_parse> or C<incr_parse_multiple> start to parse 536subsequent calls to C<incr_parse> or C<incr_parse_multiple> start to parse
399a new CBOR value from the beginning of the C<$buffer> again. 537a new CBOR value from the beginning of the C<$buffer> again.
400 538
401This method can be caled at any time, but it I<must> be called if you want 539This method can be called at any time, but it I<must> be called if you want
402to change your C<$buffer> or there was a decoding error and you want to 540to change your C<$buffer> or there was a decoding error and you want to
403reuse the C<$cbor> object for future incremental parsings. 541reuse the C<$cbor> object for future incremental parsings.
404 542
405=back 543=back
406 544
481 619
482=item hash references 620=item hash references
483 621
484Perl hash references become CBOR maps. As there is no inherent ordering in 622Perl hash references become CBOR maps. As there is no inherent ordering in
485hash keys (or CBOR maps), they will usually be encoded in a pseudo-random 623hash keys (or CBOR maps), they will usually be encoded in a pseudo-random
486order. This order can be different each time a hahs is encoded. 624order. This order can be different each time a hash is encoded.
487 625
488Currently, tied hashes will use the indefinite-length format, while normal 626Currently, tied hashes will use the indefinite-length format, while normal
489hashes will use the fixed-length format. 627hashes will use the fixed-length format.
490 628
491=item array references 629=item array references
509create such objects. 647create such objects.
510 648
511=item Types::Serialiser::true, Types::Serialiser::false, Types::Serialiser::error 649=item Types::Serialiser::true, Types::Serialiser::false, Types::Serialiser::error
512 650
513These special values become CBOR true, CBOR false and CBOR undefined 651These special values become CBOR true, CBOR false and CBOR undefined
514values, respectively. You can also use C<\1>, C<\0> and C<\undef> directly 652values, respectively.
515if you want.
516 653
517=item other blessed objects 654=item other blessed objects
518 655
519Other blessed objects are serialised via C<TO_CBOR> or C<FREEZE>. See 656Other blessed objects are serialised via C<TO_CBOR> or C<FREEZE>. See
520L<TAG HANDLING AND EXTENSIONS> for specific classes handled by this 657L<TAG HANDLING AND EXTENSIONS> for specific classes handled by this
544 my $x = 3.1; # some variable containing a number 681 my $x = 3.1; # some variable containing a number
545 "$x"; # stringified 682 "$x"; # stringified
546 $x .= ""; # another, more awkward way to stringify 683 $x .= ""; # another, more awkward way to stringify
547 print $x; # perl does it for you, too, quite often 684 print $x; # perl does it for you, too, quite often
548 685
549You can force whether a string ie encoded as byte or text string by using 686You can force whether a string is encoded as byte or text string by using
550C<utf8::upgrade> and C<utf8::downgrade>): 687C<utf8::upgrade> and C<utf8::downgrade> (if C<text_strings> is disabled).
551 688
552 utf8::upgrade $x; # encode $x as text string 689 utf8::upgrade $x; # encode $x as text string
553 utf8::downgrade $x; # encode $x as byte string 690 utf8::downgrade $x; # encode $x as byte string
554 691
692More options are available, see L<TYPE CASTS>, below, and the C<text_keys>
693and C<text_strings> options.
694
555Perl doesn't define what operations up- and downgrade strings, so if the 695Perl doesn't define what operations up- and downgrade strings, so if the
556difference between byte and text is important, you should up- or downgrade 696difference between byte and text is important, you should up- or downgrade
557your string as late as possible before encoding. 697your string as late as possible before encoding. You can also force the
698use of CBOR text strings by using C<text_keys> or C<text_strings>.
558 699
559You can force the type to be a CBOR number by numifying it: 700You can force the type to be a CBOR number by numifying it:
560 701
561 my $x = "3"; # some variable containing a string 702 my $x = "3"; # some variable containing a string
562 $x += 0; # numify it, ensuring it will be dumped as a number 703 $x += 0; # numify it, ensuring it will be dumped as a number
573represent numerical values are supported, but might suffer loss of 714represent numerical values are supported, but might suffer loss of
574precision. 715precision.
575 716
576=back 717=back
577 718
719=head2 TYPE CASTS
720
721B<EXPERIMENTAL>: As an experimental extension, C<CBOR::XS> allows you to
722force specific CBOR types to be used when encoding. That allows you to
723encode types not normally accessible (e.g. half floats) as well as force
724string types even when C<text_strings> is in effect.
725
726Type forcing is done by calling a special "cast" function which keeps a
727copy of the value and returns a new value that can be handed over to any
728CBOR encoder function.
729
730The following casts are currently available (all of which are unary
731operators, that is, have a prototype of C<$>):
732
733=over
734
735=item CBOR::XS::as_int $value
736
737Forces the value to be encoded as some form of (basic, not bignum) integer
738type.
739
740=item CBOR::XS::as_text $value
741
742Forces the value to be encoded as (UTF-8) text values.
743
744=item CBOR::XS::as_bytes $value
745
746Forces the value to be encoded as a (binary) string value.
747
748Example: encode a perl string as binary even though C<text_strings> is in
749effect.
750
751 CBOR::XS->new->text_strings->encode ([4, "text", CBOR::XS::bytes "bytevalue"]);
752
753=item CBOR::XS::as_bool $value
754
755Converts a Perl boolean (which can be any kind of scalar) into a CBOR
756boolean. Strictly the same, but shorter to write, than:
757
758 $value ? Types::Serialiser::true : Types::Serialiser::false
759
760=item CBOR::XS::as_float16 $value
761
762Forces half-float (IEEE 754 binary16) encoding of the given value.
763
764=item CBOR::XS::as_float32 $value
765
766Forces single-float (IEEE 754 binary32) encoding of the given value.
767
768=item CBOR::XS::as_float64 $value
769
770Forces double-float (IEEE 754 binary64) encoding of the given value.
771
772=item CBOR::XS::as_cbor $cbor_text
773
774Not a type cast per-se, this type cast forces the argument to be encoded
775as-is. This can be used to embed pre-encoded CBOR data.
776
777Note that no checking on the validity of the C<$cbor_text> is done - it's
778the callers responsibility to correctly encode values.
779
780=item CBOR::XS::as_map [key => value...]
781
782Treat the array reference as key value pairs and output a CBOR map. This
783allows you to generate CBOR maps with arbitrary key types (or, if you
784don't care about semantics, duplicate keys or pairs in a custom order),
785which is otherwise hard to do with Perl.
786
787The single argument must be an array reference with an even number of
788elements.
789
790Note that only the reference to the array is copied, the array itself is
791not. Modifications done to the array before calling an encoding function
792will be reflected in the encoded output.
793
794Example: encode a CBOR map with a string and an integer as keys.
795
796 encode_cbor CBOR::XS::as_map [string => "value", 5 => "value"]
797
798=back
799
800=cut
801
802sub CBOR::XS::as_cbor ($) { bless [$_[0], 0, undef], CBOR::XS::Tagged:: }
803sub CBOR::XS::as_int ($) { bless [$_[0], 1, undef], CBOR::XS::Tagged:: }
804sub CBOR::XS::as_bytes ($) { bless [$_[0], 2, undef], CBOR::XS::Tagged:: }
805sub CBOR::XS::as_text ($) { bless [$_[0], 3, undef], CBOR::XS::Tagged:: }
806sub CBOR::XS::as_float16 ($) { bless [$_[0], 4, undef], CBOR::XS::Tagged:: }
807sub CBOR::XS::as_float32 ($) { bless [$_[0], 5, undef], CBOR::XS::Tagged:: }
808sub CBOR::XS::as_float64 ($) { bless [$_[0], 6, undef], CBOR::XS::Tagged:: }
809
810sub CBOR::XS::as_bool ($) { $_[0] ? $Types::Serialiser::true : $Types::Serialiser::false }
811
812sub CBOR::XS::as_map ($) {
813 ARRAY:: eq ref $_[0]
814 and $#{ $_[0] } & 1
815 or do { require Carp; Carp::croak ("CBOR::XS::as_map only acepts array references with an even number of elements, caught") };
816
817 bless [$_[0], 7, undef], CBOR::XS::Tagged::
818}
819
578=head2 OBJECT SERIALISATION 820=head2 OBJECT SERIALISATION
579 821
580This module implements both a CBOR-specific and the generic 822This module implements both a CBOR-specific and the generic
581L<Types::Serialier> object serialisation protocol. The following 823L<Types::Serialier> object serialisation protocol. The following
582subsections explain both methods. 824subsections explain both methods.
663 "$self" # encode url string 905 "$self" # encode url string
664 } 906 }
665 907
666 sub URI::THAW { 908 sub URI::THAW {
667 my ($class, $serialiser, $uri) = @_; 909 my ($class, $serialiser, $uri) = @_;
668
669 $class->new ($uri) 910 $class->new ($uri)
670 } 911 }
671 912
672Unlike C<TO_CBOR>, multiple values can be returned by C<FREEZE>. For 913Unlike C<TO_CBOR>, multiple values can be returned by C<FREEZE>. For
673example, a C<FREEZE> method that returns "type", "id" and "variant" values 914example, a C<FREEZE> method that returns "type", "id" and "variant" values
804additional tags (such as base64url). 1045additional tags (such as base64url).
805 1046
806=head2 ENFORCED TAGS 1047=head2 ENFORCED TAGS
807 1048
808These tags are always handled when decoding, and their handling cannot be 1049These tags are always handled when decoding, and their handling cannot be
809overriden by the user. 1050overridden by the user.
810 1051
811=over 4 1052=over 4
812 1053
813=item 26 (perl-object, L<http://cbor.schmorp.de/perl-object>) 1054=item 26 (perl-object, L<http://cbor.schmorp.de/perl-object>)
814 1055
815These tags are automatically created (and decoded) for serialisable 1056These tags are automatically created (and decoded) for serialisable
816objects using the C<FREEZE/THAW> methods (the L<Types::Serialier> object 1057objects using the C<FREEZE/THAW> methods (the L<Types::Serialier> object
817serialisation protocol). See L<OBJECT SERIALISATION> for details. 1058serialisation protocol). See L<OBJECT SERIALISATION> for details.
818 1059
819=item 28, 29 (shareable, sharedref, L <http://cbor.schmorp.de/value-sharing>) 1060=item 28, 29 (shareable, sharedref, L<http://cbor.schmorp.de/value-sharing>)
820 1061
821These tags are automatically decoded when encountered (and they do not 1062These tags are automatically decoded when encountered (and they do not
822result in a cyclic data structure, see C<allow_cycles>), resulting in 1063result in a cyclic data structure, see C<allow_cycles>), resulting in
823shared values in the decoded object. They are only encoded, however, when 1064shared values in the decoded object. They are only encoded, however, when
824C<allow_sharing> is enabled. 1065C<allow_sharing> is enabled.
834will be shared, others will not. While non-reference shared values can be 1075will be shared, others will not. While non-reference shared values can be
835generated in Perl with some effort, they were considered too unimportant 1076generated in Perl with some effort, they were considered too unimportant
836to be supported in the encoder. The decoder, however, will decode these 1077to be supported in the encoder. The decoder, however, will decode these
837values as shared values. 1078values as shared values.
838 1079
839=item 256, 25 (stringref-namespace, stringref, L <http://cbor.schmorp.de/stringref>) 1080=item 256, 25 (stringref-namespace, stringref, L<http://cbor.schmorp.de/stringref>)
840 1081
841These tags are automatically decoded when encountered. They are only 1082These tags are automatically decoded when encountered. They are only
842encoded, however, when C<pack_strings> is enabled. 1083encoded, however, when C<pack_strings> is enabled.
843 1084
844=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>) 1085=item 22098 (indirection, L<http://cbor.schmorp.de/indirection>)
845 1086
846This tag is automatically generated when a reference are encountered (with 1087This tag is automatically generated when a reference are encountered (with
847the exception of hash and array refernces). It is converted to a reference 1088the exception of hash and array references). It is converted to a reference
848when decoding. 1089when decoding.
849 1090
850=item 55799 (self-describe CBOR, RFC 7049) 1091=item 55799 (self-describe CBOR, RFC 7049)
851 1092
852This value is not generated on encoding (unless explicitly requested by 1093This value is not generated on encoding (unless explicitly requested by
855=back 1096=back
856 1097
857=head2 NON-ENFORCED TAGS 1098=head2 NON-ENFORCED TAGS
858 1099
859These tags have default filters provided when decoding. Their handling can 1100These tags have default filters provided when decoding. Their handling can
860be overriden by changing the C<%CBOR::XS::FILTER> entry for the tag, or by 1101be overridden by changing the C<%CBOR::XS::FILTER> entry for the tag, or by
861providing a custom C<filter> callback when decoding. 1102providing a custom C<filter> callback when decoding.
862 1103
863When they result in decoding into a specific Perl class, the module 1104When they result in decoding into a specific Perl class, the module
864usually provides a corresponding C<TO_CBOR> method as well. 1105usually provides a corresponding C<TO_CBOR> method as well.
865 1106
883 1124
884These tags are decoded into L<Math::BigInt> objects. The corresponding 1125These tags are decoded into L<Math::BigInt> objects. The corresponding
885C<Math::BigInt::TO_CBOR> method encodes "small" bigints into normal CBOR 1126C<Math::BigInt::TO_CBOR> method encodes "small" bigints into normal CBOR
886integers, and others into positive/negative CBOR bignums. 1127integers, and others into positive/negative CBOR bignums.
887 1128
888=item 4, 5 (decimal fraction/bigfloat) 1129=item 4, 5, 264, 265 (decimal fraction/bigfloat)
889 1130
890Both decimal fractions and bigfloats are decoded into L<Math::BigFloat> 1131Both decimal fractions and bigfloats are decoded into L<Math::BigFloat>
891objects. The corresponding C<Math::BigFloat::TO_CBOR> method I<always> 1132objects. The corresponding C<Math::BigFloat::TO_CBOR> method I<always>
892encodes into a decimal fraction. 1133encodes into a decimal fraction (either tag 4 or 264).
893 1134
894CBOR cannot represent bigfloats with I<very> large exponents - conversion 1135NaN and infinities are not encoded properly, as they cannot be represented
895of such big float objects is undefined. 1136in CBOR.
896 1137
897Also, NaN and infinities are not encoded properly. 1138See L<BIGNUM SECURITY CONSIDERATIONS> for more info.
1139
1140=item 30 (rational numbers)
1141
1142These tags are decoded into L<Math::BigRat> objects. The corresponding
1143C<Math::BigRat::TO_CBOR> method encodes rational numbers with denominator
1144C<1> via their numerator only, i.e., they become normal integers or
1145C<bignums>.
1146
1147See L<BIGNUM SECURITY CONSIDERATIONS> for more info.
898 1148
899=item 21, 22, 23 (expected later JSON conversion) 1149=item 21, 22, 23 (expected later JSON conversion)
900 1150
901CBOR::XS is not a CBOR-to-JSON converter, and will simply ignore these 1151CBOR::XS is not a CBOR-to-JSON converter, and will simply ignore these
902tags. 1152tags.
907C<URI::TO_CBOR> method again results in a CBOR URI value. 1157C<URI::TO_CBOR> method again results in a CBOR URI value.
908 1158
909=back 1159=back
910 1160
911=cut 1161=cut
912
913our %FILTER = (
914 # 0 # rfc4287 datetime, utf-8
915 # 1 # unix timestamp, any
916
917 2 => sub { # pos bigint
918 require Math::BigInt;
919 Math::BigInt->new ("0x" . unpack "H*", pop)
920 },
921
922 3 => sub { # neg bigint
923 require Math::BigInt;
924 -Math::BigInt->new ("0x" . unpack "H*", pop)
925 },
926
927 4 => sub { # decimal fraction, array
928 require Math::BigFloat;
929 Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
930 },
931
932 5 => sub { # bigfloat, array
933 require Math::BigFloat;
934 scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2)
935 },
936
937 21 => sub { pop }, # expected conversion to base64url encoding
938 22 => sub { pop }, # expected conversion to base64 encoding
939 23 => sub { pop }, # expected conversion to base16 encoding
940
941 # 24 # embedded cbor, byte string
942
943 32 => sub {
944 require URI;
945 URI->new (pop)
946 },
947
948 # 33 # base64url rfc4648, utf-8
949 # 34 # base64 rfc46484, utf-8
950 # 35 # regex pcre/ecma262, utf-8
951 # 36 # mime message rfc2045, utf-8
952);
953
954 1162
955=head1 CBOR and JSON 1163=head1 CBOR and JSON
956 1164
957CBOR is supposed to implement a superset of the JSON data model, and is, 1165CBOR is supposed to implement a superset of the JSON data model, and is,
958with some coercion, able to represent all JSON texts (something that other 1166with some coercion, able to represent all JSON texts (something that other
967CBOR intact. 1175CBOR intact.
968 1176
969 1177
970=head1 SECURITY CONSIDERATIONS 1178=head1 SECURITY CONSIDERATIONS
971 1179
972When you are using CBOR in a protocol, talking to untrusted potentially 1180Tl;dr... if you want to decode or encode CBOR from untrusted sources, you
973hostile creatures requires relatively few measures. 1181should start with a coder object created via C<new_safe> (which implements
1182the mitigations explained below):
974 1183
1184 my $coder = CBOR::XS->new_safe;
1185
1186 my $data = $coder->decode ($cbor_text);
1187 my $cbor = $coder->encode ($data);
1188
1189Longer version: When you are using CBOR in a protocol, talking to
1190untrusted potentially hostile creatures requires some thought:
1191
1192=over 4
1193
1194=item Security of the CBOR decoder itself
1195
975First of all, your CBOR decoder should be secure, that is, should not have 1196First and foremost, your CBOR decoder should be secure, that is, should
1197not have any buffer overflows or similar bugs that could potentially be
976any buffer overflows. Obviously, this module should ensure that and I am 1198exploited. Obviously, this module should ensure that and I am trying hard
977trying hard on making that true, but you never know. 1199on making that true, but you never know.
978 1200
1201=item CBOR::XS can invoke almost arbitrary callbacks during decoding
1202
1203CBOR::XS supports object serialisation - decoding CBOR can cause calls
1204to I<any> C<THAW> method in I<any> package that exists in your process
1205(that is, CBOR::XS will not try to load modules, but any existing C<THAW>
1206method or function can be called, so they all have to be secure).
1207
1208Less obviously, it will also invoke C<TO_CBOR> and C<FREEZE> methods -
1209even if all your C<THAW> methods are secure, encoding data structures from
1210untrusted sources can invoke those and trigger bugs in those.
1211
1212So, if you are not sure about the security of all the modules you
1213have loaded (you shouldn't), you should disable this part using
1214C<forbid_objects> or using C<new_safe>.
1215
1216=item CBOR can be extended with tags that call library code
1217
1218CBOR can be extended with tags, and C<CBOR::XS> has a registry of
1219conversion functions for many existing tags that can be extended via
1220third-party modules (see the C<filter> method).
1221
1222If you don't trust these, you should configure the "safe" filter function,
1223C<CBOR::XS::safe_filter> (C<new_safe> does this), which by default only
1224includes conversion functions that are considered "safe" by the author
1225(but again, they can be extended by third party modules).
1226
1227Depending on your level of paranoia, you can use the "safe" filter:
1228
1229 $cbor->filter (\&CBOR::XS::safe_filter);
1230
1231... your own filter...
1232
1233 $cbor->filter (sub { ... do your stuffs here ... });
1234
1235... or even no filter at all, disabling all tag decoding:
1236
1237 $cbor->filter (sub { });
1238
1239This is never a problem for encoding, as the tag mechanism only exists in
1240CBOR texts.
1241
1242=item Resource-starving attacks: object memory usage
1243
979Second, you need to avoid resource-starving attacks. That means you should 1244You need to avoid resource-starving attacks. That means you should limit
980limit the size of CBOR data you accept, or make sure then when your 1245the size of CBOR data you accept, or make sure then when your resources
981resources run out, that's just fine (e.g. by using a separate process that 1246run out, that's just fine (e.g. by using a separate process that can
982can crash safely). The size of a CBOR string in octets is usually a good 1247crash safely). The size of a CBOR string in octets is usually a good
983indication of the size of the resources required to decode it into a Perl 1248indication of the size of the resources required to decode it into a Perl
984structure. While CBOR::XS can check the size of the CBOR text, it might be 1249structure. While CBOR::XS can check the size of the CBOR text (using
985too late when you already have it in memory, so you might want to check 1250C<max_size> - done by C<new_safe>), it might be too late when you already
986the size before you accept the string. 1251have it in memory, so you might want to check the size before you accept
1252the string.
987 1253
1254As for encoding, it is possible to construct data structures that are
1255relatively small but result in large CBOR texts (for example by having an
1256array full of references to the same big data structure, which will all be
1257deep-cloned during encoding by default). This is rarely an actual issue
1258(and the worst case is still just running out of memory), but you can
1259reduce this risk by using C<allow_sharing>.
1260
1261=item Resource-starving attacks: stack overflows
1262
988Third, CBOR::XS recurses using the C stack when decoding objects and 1263CBOR::XS recurses using the C stack when decoding objects and arrays. The
989arrays. The C stack is a limited resource: for instance, on my amd64 1264C stack is a limited resource: for instance, on my amd64 machine with 8MB
990machine with 8MB of stack size I can decode around 180k nested arrays but 1265of stack size I can decode around 180k nested arrays but only 14k nested
991only 14k nested CBOR objects (due to perl itself recursing deeply on croak 1266CBOR objects (due to perl itself recursing deeply on croak to free the
992to free the temporary). If that is exceeded, the program crashes. To be 1267temporary). If that is exceeded, the program crashes. To be conservative,
993conservative, the default nesting limit is set to 512. If your process 1268the default nesting limit is set to 512. If your process has a smaller
994has a smaller stack, you should adjust this setting accordingly with the 1269stack, you should adjust this setting accordingly with the C<max_depth>
995C<max_depth> method. 1270method.
1271
1272=item Resource-starving attacks: CPU en-/decoding complexity
1273
1274CBOR::XS will use the L<Math::BigInt>, L<Math::BigFloat> and
1275L<Math::BigRat> libraries to represent encode/decode bignums. These can be
1276very slow (as in, centuries of CPU time) and can even crash your program
1277(and are generally not very trustworthy). See the next section on bignum
1278security for details.
1279
1280=item Data breaches: leaking information in error messages
1281
1282CBOR::XS might leak contents of your Perl data structures in its error
1283messages, so when you serialise sensitive information you might want to
1284make sure that exceptions thrown by CBOR::XS will not end up in front of
1285untrusted eyes.
1286
1287=item Something else...
996 1288
997Something else could bomb you, too, that I forgot to think of. In that 1289Something else could bomb you, too, that I forgot to think of. In that
998case, you get to keep the pieces. I am always open for hints, though... 1290case, you get to keep the pieces. I am always open for hints, though...
999 1291
1000Also keep in mind that CBOR::XS might leak contents of your Perl data 1292=back
1001structures in its error messages, so when you serialise sensitive 1293
1002information you might want to make sure that exceptions thrown by CBOR::XS 1294
1003will not end up in front of untrusted eyes. 1295=head1 BIGNUM SECURITY CONSIDERATIONS
1296
1297CBOR::XS provides a C<TO_CBOR> method for both L<Math::BigInt> and
1298L<Math::BigFloat> that tries to encode the number in the simplest possible
1299way, that is, either a CBOR integer, a CBOR bigint/decimal fraction (tag
13004) or an arbitrary-exponent decimal fraction (tag 264). Rational numbers
1301(L<Math::BigRat>, tag 30) can also contain bignums as members.
1302
1303CBOR::XS will also understand base-2 bigfloat or arbitrary-exponent
1304bigfloats (tags 5 and 265), but it will never generate these on its own.
1305
1306Using the built-in L<Math::BigInt::Calc> support, encoding and decoding
1307decimal fractions is generally fast. Decoding bigints can be slow for very
1308big numbers (tens of thousands of digits, something that could potentially
1309be caught by limiting the size of CBOR texts), and decoding bigfloats or
1310arbitrary-exponent bigfloats can be I<extremely> slow (minutes, decades)
1311for large exponents (roughly 40 bit and longer).
1312
1313Additionally, L<Math::BigInt> can take advantage of other bignum
1314libraries, such as L<Math::GMP>, which cannot handle big floats with large
1315exponents, and might simply abort or crash your program, due to their code
1316quality.
1317
1318This can be a concern if you want to parse untrusted CBOR. If it is, you
1319might want to disable decoding of tag 2 (bigint) and 3 (negative bigint)
1320types. You should also disable types 5 and 265, as these can be slow even
1321without bigints.
1322
1323Disabling bigints will also partially or fully disable types that rely on
1324them, e.g. rational numbers that use bignums.
1325
1004 1326
1005=head1 CBOR IMPLEMENTATION NOTES 1327=head1 CBOR IMPLEMENTATION NOTES
1006 1328
1007This section contains some random implementation notes. They do not 1329This section contains some random implementation notes. They do not
1008describe guaranteed behaviour, but merely behaviour as-is implemented 1330describe guaranteed behaviour, but merely behaviour as-is implemented
1024=head1 LIMITATIONS ON PERLS WITHOUT 64-BIT INTEGER SUPPORT 1346=head1 LIMITATIONS ON PERLS WITHOUT 64-BIT INTEGER SUPPORT
1025 1347
1026On perls that were built without 64 bit integer support (these are rare 1348On perls that were built without 64 bit integer support (these are rare
1027nowadays, even on 32 bit architectures, as all major Perl distributions 1349nowadays, even on 32 bit architectures, as all major Perl distributions
1028are built with 64 bit integer support), support for any kind of 64 bit 1350are built with 64 bit integer support), support for any kind of 64 bit
1029integer in CBOR is very limited - most likely, these 64 bit values will 1351value in CBOR is very limited - most likely, these 64 bit values will
1030be truncated, corrupted, or otherwise not decoded correctly. This also 1352be truncated, corrupted, or otherwise not decoded correctly. This also
1031includes string, array and map sizes that are stored as 64 bit integers. 1353includes string, float, array and map sizes that are stored as 64 bit
1354integers.
1032 1355
1033 1356
1034=head1 THREADS 1357=head1 THREADS
1035 1358
1036This module is I<not> guaranteed to be thread safe and there are no 1359This module is I<not> guaranteed to be thread safe and there are no
1049 1372
1050Please refrain from using rt.cpan.org or any other bug reporting 1373Please refrain from using rt.cpan.org or any other bug reporting
1051service. I put the contact address into my modules for a reason. 1374service. I put the contact address into my modules for a reason.
1052 1375
1053=cut 1376=cut
1377
1378# clumsy and slow hv_store-in-hash helper function
1379sub _hv_store {
1380 $_[0]{$_[1]} = $_[2];
1381}
1054 1382
1055our %FILTER = ( 1383our %FILTER = (
1056 0 => sub { # rfc4287 datetime, utf-8 1384 0 => sub { # rfc4287 datetime, utf-8
1057 require Time::Piece; 1385 require Time::Piece;
1058 # Time::Piece::Strptime uses the "incredibly flexible date parsing routine" 1386 # Time::Piece::Strptime uses the "incredibly flexible date parsing routine"
1059 # from FreeBSD, which can't parse ISO 8601, RFC3339, RFC4287 or much of anything 1387 # from FreeBSD, which can't parse ISO 8601, RFC3339, RFC4287 or much of anything
1060 # else either. Whats incredibe over standard strptime totally escapes me. 1388 # else either. Whats incredibe over standard strptime totally escapes me.
1061 # doesn't do fractional times, either. sigh. 1389 # doesn't do fractional times, either. sigh.
1062 # In fact, it's all a lie, it uses whatever strptime it wants, and of course, 1390 # In fact, it's all a lie, it uses whatever strptime it wants, and of course,
1063 # they are all incomptible. The openbsd one simply ignores %z (but according to the 1391 # they are all incompatible. The openbsd one simply ignores %z (but according to the
1064 # docs, it would be much more incredibly flexible indeed. If it worked, that is.). 1392 # docs, it would be much more incredibly flexible indeed. If it worked, that is.).
1065 scalar eval { 1393 scalar eval {
1066 my $s = $_[1]; 1394 my $s = $_[1];
1067 1395
1068 $s =~ s/Z$/+00:00/; 1396 $s =~ s/Z$/+00:00/;
1094 4 => sub { # decimal fraction, array 1422 4 => sub { # decimal fraction, array
1095 require Math::BigFloat; 1423 require Math::BigFloat;
1096 Math::BigFloat->new ($_[1][1] . "E" . $_[1][0]) 1424 Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
1097 }, 1425 },
1098 1426
1427 264 => sub { # decimal fraction with arbitrary exponent
1428 require Math::BigFloat;
1429 Math::BigFloat->new ($_[1][1] . "E" . $_[1][0])
1430 },
1431
1099 5 => sub { # bigfloat, array 1432 5 => sub { # bigfloat, array
1100 require Math::BigFloat; 1433 require Math::BigFloat;
1101 scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2) 1434 scalar Math::BigFloat->new ($_[1][1]) * Math::BigFloat->new (2)->bpow ($_[1][0])
1435 },
1436
1437 265 => sub { # bigfloat with arbitrary exponent
1438 require Math::BigFloat;
1439 scalar Math::BigFloat->new ($_[1][1]) * Math::BigFloat->new (2)->bpow ($_[1][0])
1440 },
1441
1442 30 => sub { # rational number
1443 require Math::BigRat;
1444 Math::BigRat->new ("$_[1][0]/$_[1][1]") # separate parameters only work in recent versons
1102 }, 1445 },
1103 1446
1104 21 => sub { pop }, # expected conversion to base64url encoding 1447 21 => sub { pop }, # expected conversion to base64url encoding
1105 22 => sub { pop }, # expected conversion to base64 encoding 1448 22 => sub { pop }, # expected conversion to base64 encoding
1106 23 => sub { pop }, # expected conversion to base16 encoding 1449 23 => sub { pop }, # expected conversion to base16 encoding
1116 # 34 # base64 rfc46484, utf-8 1459 # 34 # base64 rfc46484, utf-8
1117 # 35 # regex pcre/ecma262, utf-8 1460 # 35 # regex pcre/ecma262, utf-8
1118 # 36 # mime message rfc2045, utf-8 1461 # 36 # mime message rfc2045, utf-8
1119); 1462);
1120 1463
1121sub CBOR::XS::default_filter { 1464sub default_filter {
1122 &{ $FILTER{$_[0]} or return } 1465 &{ $FILTER{$_[0]} or return }
1466}
1467
1468our %SAFE_FILTER = map { $_ => $FILTER{$_} } 0, 1, 21, 22, 23, 32;
1469
1470sub safe_filter {
1471 &{ $SAFE_FILTER{$_[0]} or return }
1123} 1472}
1124 1473
1125sub URI::TO_CBOR { 1474sub URI::TO_CBOR {
1126 my $uri = $_[0]->as_string; 1475 my $uri = $_[0]->as_string;
1127 utf8::upgrade $uri; 1476 utf8::upgrade $uri;
1128 tag 32, $uri 1477 tag 32, $uri
1129} 1478}
1130 1479
1131sub Math::BigInt::TO_CBOR { 1480sub Math::BigInt::TO_CBOR {
1132 if ($_[0] >= -2147483648 && $_[0] <= 2147483647) { 1481 if (-2147483648 <= $_[0] && $_[0] <= 2147483647) {
1133 $_[0]->numify 1482 $_[0]->numify
1134 } else { 1483 } else {
1135 my $hex = substr $_[0]->as_hex, 2; 1484 my $hex = substr $_[0]->as_hex, 2;
1136 $hex = "0$hex" if 1 & length $hex; # sigh 1485 $hex = "0$hex" if 1 & length $hex; # sigh
1137 tag $_[0] >= 0 ? 2 : 3, pack "H*", $hex 1486 tag $_[0] >= 0 ? 2 : 3, pack "H*", $hex
1138 } 1487 }
1139} 1488}
1140 1489
1141sub Math::BigFloat::TO_CBOR { 1490sub Math::BigFloat::TO_CBOR {
1142 my ($m, $e) = $_[0]->parts; 1491 my ($m, $e) = $_[0]->parts;
1492
1493 -9223372036854775808 <= $e && $e <= 18446744073709551615
1143 tag 4, [$e->numify, $m] 1494 ? tag 4, [$e->numify, $m]
1495 : tag 264, [$e, $m]
1496}
1497
1498sub Math::BigRat::TO_CBOR {
1499 my ($n, $d) = $_[0]->parts;
1500
1501 # older versions of BigRat need *1, as they not always return numbers
1502
1503 $d*1 == 1
1504 ? $n*1
1505 : tag 30, [$n*1, $d*1]
1144} 1506}
1145 1507
1146sub Time::Piece::TO_CBOR { 1508sub Time::Piece::TO_CBOR {
1147 tag 1, 0 + $_[0]->epoch 1509 tag 1, 0 + $_[0]->epoch
1148} 1510}

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