… | |
… | |
12 | $perl_value = decode_cbor $binary_cbor_data; |
12 | $perl_value = decode_cbor $binary_cbor_data; |
13 | |
13 | |
14 | # OO-interface |
14 | # OO-interface |
15 | |
15 | |
16 | $coder = CBOR::XS->new; |
16 | $coder = CBOR::XS->new; |
17 | #TODO |
17 | $binary_cbor_data = $coder->encode ($perl_value); |
|
|
18 | $perl_value = $coder->decode ($binary_cbor_data); |
|
|
19 | |
|
|
20 | # prefix decoding |
|
|
21 | |
|
|
22 | my $many_cbor_strings = ...; |
|
|
23 | while (length $many_cbor_strings) { |
|
|
24 | my ($data, $length) = $cbor->decode_prefix ($many_cbor_strings); |
|
|
25 | # data was decoded |
|
|
26 | substr $many_cbor_strings, 0, $length, ""; # remove decoded cbor string |
|
|
27 | } |
18 | |
28 | |
19 | =head1 DESCRIPTION |
29 | =head1 DESCRIPTION |
20 | |
30 | |
21 | WARNING! THIS IS A PRE-ALPHA RELEASE! IT WILL CRASH, CORRUPT YOUR DATA AND |
31 | This module converts Perl data structures to the Concise Binary Object |
22 | EAT YOUR CHILDREN! |
32 | Representation (CBOR) and vice versa. CBOR is a fast binary serialisation |
|
|
33 | format that aims to use an (almost) superset of the JSON data model, i.e. |
|
|
34 | when you can represent something useful in JSON, you should be able to |
|
|
35 | represent it in CBOR. |
23 | |
36 | |
24 | This module converts Perl data structures to CBOR and vice versa. Its |
37 | In short, CBOR is a faster and quite compact binary alternative to 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 |
|
|
40 | data later and speed is less important you might want to compare both |
|
|
41 | formats first). |
|
|
42 | |
|
|
43 | 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 |
|
|
45 | L<JSON::XS> and decodes about 15%-30% faster than those. The shorter the |
|
|
46 | data, the worse L<Storable> performs in comparison. |
|
|
47 | |
|
|
48 | Regarding compactness, C<CBOR::XS>-encoded data structures are usually |
|
|
49 | about 20% smaller than the same data encoded as (compact) JSON or |
|
|
50 | L<Storable>. |
|
|
51 | |
|
|
52 | In addition to the core CBOR data format, this module implements a |
|
|
53 | number of extensions, to support cyclic and shared data structures |
|
|
54 | (see C<allow_sharing> and C<allow_cycles>), string deduplication (see |
|
|
55 | C<pack_strings>) and scalar references (always enabled). |
|
|
56 | |
25 | primary goal is to be I<correct> and its secondary goal is to be |
57 | The primary goal of this module is to be I<correct> and the secondary goal |
26 | I<fast>. To reach the latter goal it was written in C. |
58 | is to be I<fast>. To reach the latter goal it was written in C. |
27 | |
59 | |
28 | 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 |
29 | vice versa. |
61 | vice versa. |
30 | |
62 | |
31 | =cut |
63 | =cut |
32 | |
64 | |
33 | package CBOR::XS; |
65 | package CBOR::XS; |
34 | |
66 | |
35 | use common::sense; |
67 | use common::sense; |
36 | |
68 | |
37 | our $VERSION = 0.02; |
69 | our $VERSION = 1.71; |
38 | our @ISA = qw(Exporter); |
70 | our @ISA = qw(Exporter); |
39 | |
71 | |
40 | our @EXPORT = qw(encode_cbor decode_cbor); |
72 | our @EXPORT = qw(encode_cbor decode_cbor); |
41 | |
73 | |
42 | use Exporter; |
74 | use Exporter; |
43 | use XSLoader; |
75 | use XSLoader; |
44 | |
76 | |
|
|
77 | use Types::Serialiser; |
|
|
78 | |
45 | our $MAGIC = "\xd9\xd9\xf7"; |
79 | our $MAGIC = "\xd9\xd9\xf7"; |
46 | |
80 | |
47 | =head1 FUNCTIONAL INTERFACE |
81 | =head1 FUNCTIONAL INTERFACE |
48 | |
82 | |
49 | The following convenience methods are provided by this module. They are |
83 | The following convenience methods are provided by this module. They are |
… | |
… | |
77 | strings. All boolean flags described below are by default I<disabled>. |
111 | strings. All boolean flags described below are by default I<disabled>. |
78 | |
112 | |
79 | 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 |
80 | be chained: |
114 | be chained: |
81 | |
115 | |
82 | #TODO |
|
|
83 | 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 | } |
84 | |
142 | |
85 | =item $cbor = $cbor->max_depth ([$maximum_nesting_depth]) |
143 | =item $cbor = $cbor->max_depth ([$maximum_nesting_depth]) |
86 | |
144 | |
87 | =item $max_depth = $cbor->get_max_depth |
145 | =item $max_depth = $cbor->get_max_depth |
88 | |
146 | |
… | |
… | |
104 | |
162 | |
105 | 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 |
106 | 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 |
107 | crashing. |
165 | crashing. |
108 | |
166 | |
109 | 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. |
110 | |
168 | |
111 | =item $cbor = $cbor->max_size ([$maximum_string_size]) |
169 | =item $cbor = $cbor->max_size ([$maximum_string_size]) |
112 | |
170 | |
113 | =item $max_size = $cbor->get_max_size |
171 | =item $max_size = $cbor->get_max_size |
114 | |
172 | |
… | |
… | |
119 | effect on C<encode> (yet). |
177 | effect on C<encode> (yet). |
120 | |
178 | |
121 | 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 |
122 | C<0> is specified). |
180 | C<0> is specified). |
123 | |
181 | |
124 | 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. |
|
|
183 | |
|
|
184 | =item $cbor = $cbor->allow_unknown ([$enable]) |
|
|
185 | |
|
|
186 | =item $enabled = $cbor->get_allow_unknown |
|
|
187 | |
|
|
188 | If C<$enable> is true (or missing), then C<encode> will I<not> throw an |
|
|
189 | exception when it encounters values it cannot represent in CBOR (for |
|
|
190 | example, filehandles) but instead will encode a CBOR C<error> value. |
|
|
191 | |
|
|
192 | If C<$enable> is false (the default), then C<encode> will throw an |
|
|
193 | exception when it encounters anything it cannot encode as CBOR. |
|
|
194 | |
|
|
195 | This option does not affect C<decode> in any way, and it is recommended to |
|
|
196 | leave it off unless you know your communications partner. |
|
|
197 | |
|
|
198 | =item $cbor = $cbor->allow_sharing ([$enable]) |
|
|
199 | |
|
|
200 | =item $enabled = $cbor->get_allow_sharing |
|
|
201 | |
|
|
202 | If C<$enable> is true (or missing), then C<encode> will not double-encode |
|
|
203 | values that have been referenced before (e.g. when the same object, such |
|
|
204 | as an array, is referenced multiple times), but instead will emit a |
|
|
205 | reference to the earlier value. |
|
|
206 | |
|
|
207 | This means that such values will only be encoded once, and will not result |
|
|
208 | in a deep cloning of the value on decode, in decoders supporting the value |
|
|
209 | sharing extension. This also makes it possible to encode cyclic data |
|
|
210 | structures (which need C<allow_cycles> to be enabled to be decoded by this |
|
|
211 | module). |
|
|
212 | |
|
|
213 | It is recommended to leave it off unless you know your |
|
|
214 | communication partner supports the value sharing extensions to CBOR |
|
|
215 | (L<http://cbor.schmorp.de/value-sharing>), as without decoder support, the |
|
|
216 | resulting data structure might be unusable. |
|
|
217 | |
|
|
218 | Detecting shared values incurs a runtime overhead when values are encoded |
|
|
219 | that have a reference counter large than one, and might unnecessarily |
|
|
220 | increase the encoded size, as potentially shared values are encode as |
|
|
221 | shareable whether or not they are actually shared. |
|
|
222 | |
|
|
223 | At the moment, only targets of references can be shared (e.g. scalars, |
|
|
224 | arrays or hashes pointed to by a reference). Weirder constructs, such as |
|
|
225 | an array with multiple "copies" of the I<same> string, which are hard but |
|
|
226 | not impossible to create in Perl, are not supported (this is the same as |
|
|
227 | with L<Storable>). |
|
|
228 | |
|
|
229 | If C<$enable> is false (the default), then C<encode> will encode shared |
|
|
230 | data structures repeatedly, unsharing them in the process. Cyclic data |
|
|
231 | structures cannot be encoded in this mode. |
|
|
232 | |
|
|
233 | This option does not affect C<decode> in any way - shared values and |
|
|
234 | references will always be decoded properly if present. |
|
|
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 | |
|
|
275 | =item $cbor = $cbor->pack_strings ([$enable]) |
|
|
276 | |
|
|
277 | =item $enabled = $cbor->get_pack_strings |
|
|
278 | |
|
|
279 | If C<$enable> is true (or missing), then C<encode> will try not to encode |
|
|
280 | the same string twice, but will instead encode a reference to the string |
|
|
281 | instead. Depending on your data format, this can save a lot of space, but |
|
|
282 | also results in a very large runtime overhead (expect encoding times to be |
|
|
283 | 2-4 times as high as without). |
|
|
284 | |
|
|
285 | It is recommended to leave it off unless you know your |
|
|
286 | communications partner supports the stringref extension to CBOR |
|
|
287 | (L<http://cbor.schmorp.de/stringref>), as without decoder support, the |
|
|
288 | resulting data structure might not be usable. |
|
|
289 | |
|
|
290 | If C<$enable> is false (the default), then C<encode> will encode strings |
|
|
291 | the standard CBOR way. |
|
|
292 | |
|
|
293 | This option does not affect C<decode> in any way - string references will |
|
|
294 | always be decoded properly if present. |
|
|
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 encode byte |
|
|
336 | strings, which might break some C<FREEZE> and C<TO_CBOR> methods that rely |
|
|
337 | on this, such as bignum encoding, so this option is mainly useful for very |
|
|
338 | simple data. |
|
|
339 | |
|
|
340 | =item $cbor = $cbor->validate_utf8 ([$enable]) |
|
|
341 | |
|
|
342 | =item $enabled = $cbor->get_validate_utf8 |
|
|
343 | |
|
|
344 | If C<$enable> is true (or missing), then C<decode> will validate that |
|
|
345 | elements (text strings) containing UTF-8 data in fact contain valid UTF-8 |
|
|
346 | data (instead of blindly accepting it). This validation obviously takes |
|
|
347 | extra time during decoding. |
|
|
348 | |
|
|
349 | The concept of "valid UTF-8" used is perl's concept, which is a superset |
|
|
350 | of the official UTF-8. |
|
|
351 | |
|
|
352 | If C<$enable> is false (the default), then C<decode> will blindly accept |
|
|
353 | UTF-8 data, marking them as valid UTF-8 in the resulting data structure |
|
|
354 | regardless of whether that's true or not. |
|
|
355 | |
|
|
356 | Perl isn't too happy about corrupted UTF-8 in strings, but should |
|
|
357 | generally not crash or do similarly evil things. Extensions might be not |
|
|
358 | so forgiving, so it's recommended to turn on this setting if you receive |
|
|
359 | untrusted CBOR. |
|
|
360 | |
|
|
361 | This option does not affect C<encode> in any way - strings that are |
|
|
362 | supposedly valid UTF-8 will simply be dumped into the resulting CBOR |
|
|
363 | string without checking whether that is, in fact, true or not. |
|
|
364 | |
|
|
365 | =item $cbor = $cbor->filter ([$cb->($tag, $value)]) |
|
|
366 | |
|
|
367 | =item $cb_or_undef = $cbor->get_filter |
|
|
368 | |
|
|
369 | Sets or replaces the tagged value decoding filter (when C<$cb> is |
|
|
370 | specified) or clears the filter (if no argument or C<undef> is provided). |
|
|
371 | |
|
|
372 | The filter callback is called only during decoding, when a non-enforced |
|
|
373 | tagged value has been decoded (see L<TAG HANDLING AND EXTENSIONS> for a |
|
|
374 | list of enforced tags). For specific tags, it's often better to provide a |
|
|
375 | default converter using the C<%CBOR::XS::FILTER> hash (see below). |
|
|
376 | |
|
|
377 | The first argument is the numerical tag, the second is the (decoded) value |
|
|
378 | that has been tagged. |
|
|
379 | |
|
|
380 | The filter function should return either exactly one value, which will |
|
|
381 | replace the tagged value in the decoded data structure, or no values, |
|
|
382 | which will result in default handling, which currently means the decoder |
|
|
383 | creates a C<CBOR::XS::Tagged> object to hold the tag and the value. |
|
|
384 | |
|
|
385 | When the filter is cleared (the default state), the default filter |
|
|
386 | function, C<CBOR::XS::default_filter>, is used. This function simply |
|
|
387 | looks up the tag in the C<%CBOR::XS::FILTER> hash. If an entry exists |
|
|
388 | it must be a code reference that is called with tag and value, and is |
|
|
389 | responsible for decoding the value. If no entry exists, it returns no |
|
|
390 | values. C<CBOR::XS> provides a number of default filter functions already, |
|
|
391 | the the C<%CBOR::XS::FILTER> hash can be freely extended with more. |
|
|
392 | |
|
|
393 | C<CBOR::XS> additionally provides an alternative filter function that is |
|
|
394 | supposed to be safe to use with untrusted data (which the default filter |
|
|
395 | might not), called C<CBOR::XS::safe_filter>, which works the same as |
|
|
396 | the C<default_filter> but uses the C<%CBOR::XS::SAFE_FILTER> variable |
|
|
397 | instead. It is prepopulated with the tag decoding functions that are |
|
|
398 | deemed safe (basically the same as C<%CBOR::XS::FILTER> without all |
|
|
399 | the bignum tags), and can be extended by user code as wlel, although, |
|
|
400 | obviously, one should be very careful about adding decoding functions |
|
|
401 | here, since the expectation is that they are safe to use on untrusted |
|
|
402 | data, after all. |
|
|
403 | |
|
|
404 | Example: decode all tags not handled internally into C<CBOR::XS::Tagged> |
|
|
405 | objects, with no other special handling (useful when working with |
|
|
406 | potentially "unsafe" CBOR data). |
|
|
407 | |
|
|
408 | CBOR::XS->new->filter (sub { })->decode ($cbor_data); |
|
|
409 | |
|
|
410 | Example: provide a global filter for tag 1347375694, converting the value |
|
|
411 | into some string form. |
|
|
412 | |
|
|
413 | $CBOR::XS::FILTER{1347375694} = sub { |
|
|
414 | my ($tag, $value); |
|
|
415 | |
|
|
416 | "tag 1347375694 value $value" |
|
|
417 | }; |
|
|
418 | |
|
|
419 | Example: provide your own filter function that looks up tags in your own |
|
|
420 | hash: |
|
|
421 | |
|
|
422 | my %my_filter = ( |
|
|
423 | 998347484 => sub { |
|
|
424 | my ($tag, $value); |
|
|
425 | |
|
|
426 | "tag 998347484 value $value" |
|
|
427 | }; |
|
|
428 | ); |
|
|
429 | |
|
|
430 | my $coder = CBOR::XS->new->filter (sub { |
|
|
431 | &{ $my_filter{$_[0]} or return } |
|
|
432 | }); |
|
|
433 | |
|
|
434 | |
|
|
435 | Example: use the safe filter function (see L<SECURITY CONSIDERATIONS> for |
|
|
436 | more considerations on security). |
|
|
437 | |
|
|
438 | CBOR::XS->new->filter (\&CBOR::XS::safe_filter)->decode ($cbor_data); |
125 | |
439 | |
126 | =item $cbor_data = $cbor->encode ($perl_scalar) |
440 | =item $cbor_data = $cbor->encode ($perl_scalar) |
127 | |
441 | |
128 | Converts the given Perl data structure (a scalar value) to its CBOR |
442 | Converts the given Perl data structure (a scalar value) to its CBOR |
129 | representation. |
443 | representation. |
… | |
… | |
143 | and you need to know where the first CBOR string ends amd the next one |
457 | and you need to know where the first CBOR string ends amd the next one |
144 | starts. |
458 | starts. |
145 | |
459 | |
146 | CBOR::XS->new->decode_prefix ("......") |
460 | CBOR::XS->new->decode_prefix ("......") |
147 | => ("...", 3) |
461 | => ("...", 3) |
|
|
462 | |
|
|
463 | =back |
|
|
464 | |
|
|
465 | =head2 INCREMENTAL PARSING |
|
|
466 | |
|
|
467 | In some cases, there is the need for incremental parsing of JSON |
|
|
468 | texts. While this module always has to keep both CBOR text and resulting |
|
|
469 | Perl data structure in memory at one time, it does allow you to parse a |
|
|
470 | CBOR stream incrementally, using a similar to using "decode_prefix" to see |
|
|
471 | if a full CBOR object is available, but is much more efficient. |
|
|
472 | |
|
|
473 | It basically works by parsing as much of a CBOR string as possible - if |
|
|
474 | the CBOR data is not complete yet, the pasrer will remember where it was, |
|
|
475 | to be able to restart when more data has been accumulated. Once enough |
|
|
476 | data is available to either decode a complete CBOR value or raise an |
|
|
477 | error, a real decode will be attempted. |
|
|
478 | |
|
|
479 | A typical use case would be a network protocol that consists of sending |
|
|
480 | and receiving CBOR-encoded messages. The solution that works with CBOR and |
|
|
481 | about anything else is by prepending a length to every CBOR value, so the |
|
|
482 | receiver knows how many octets to read. More compact (and slightly slower) |
|
|
483 | would be to just send CBOR values back-to-back, as C<CBOR::XS> knows where |
|
|
484 | a CBOR value ends, and doesn't need an explicit length. |
|
|
485 | |
|
|
486 | The following methods help with this: |
|
|
487 | |
|
|
488 | =over 4 |
|
|
489 | |
|
|
490 | =item @decoded = $cbor->incr_parse ($buffer) |
|
|
491 | |
|
|
492 | This method attempts to decode exactly one CBOR value from the beginning |
|
|
493 | of the given C<$buffer>. The value is removed from the C<$buffer> on |
|
|
494 | success. When C<$buffer> doesn't contain a complete value yet, it returns |
|
|
495 | nothing. Finally, when the C<$buffer> doesn't start with something |
|
|
496 | that could ever be a valid CBOR value, it raises an exception, just as |
|
|
497 | C<decode> would. In the latter case the decoder state is undefined and |
|
|
498 | must be reset before being able to parse further. |
|
|
499 | |
|
|
500 | This method modifies the C<$buffer> in place. When no CBOR value can be |
|
|
501 | decoded, the decoder stores the current string offset. On the next call, |
|
|
502 | continues decoding at the place where it stopped before. For this to make |
|
|
503 | sense, the C<$buffer> must begin with the same octets as on previous |
|
|
504 | unsuccessful calls. |
|
|
505 | |
|
|
506 | You can call this method in scalar context, in which case it either |
|
|
507 | returns a decoded value or C<undef>. This makes it impossible to |
|
|
508 | distinguish between CBOR null values (which decode to C<undef>) and an |
|
|
509 | unsuccessful decode, which is often acceptable. |
|
|
510 | |
|
|
511 | =item @decoded = $cbor->incr_parse_multiple ($buffer) |
|
|
512 | |
|
|
513 | Same as C<incr_parse>, but attempts to decode as many CBOR values as |
|
|
514 | possible in one go, instead of at most one. Calls to C<incr_parse> and |
|
|
515 | C<incr_parse_multiple> can be interleaved. |
|
|
516 | |
|
|
517 | =item $cbor->incr_reset |
|
|
518 | |
|
|
519 | Resets the incremental decoder. This throws away any saved state, so that |
|
|
520 | subsequent calls to C<incr_parse> or C<incr_parse_multiple> start to parse |
|
|
521 | a new CBOR value from the beginning of the C<$buffer> again. |
|
|
522 | |
|
|
523 | This method can be called at any time, but it I<must> be called if you want |
|
|
524 | to change your C<$buffer> or there was a decoding error and you want to |
|
|
525 | reuse the C<$cbor> object for future incremental parsings. |
148 | |
526 | |
149 | =back |
527 | =back |
150 | |
528 | |
151 | |
529 | |
152 | =head1 MAPPING |
530 | =head1 MAPPING |
… | |
… | |
170 | CBOR integers become (numeric) perl scalars. On perls without 64 bit |
548 | CBOR integers become (numeric) perl scalars. On perls without 64 bit |
171 | support, 64 bit integers will be truncated or otherwise corrupted. |
549 | support, 64 bit integers will be truncated or otherwise corrupted. |
172 | |
550 | |
173 | =item byte strings |
551 | =item byte strings |
174 | |
552 | |
175 | Byte strings will become octet strings in Perl (the byte values 0..255 |
553 | Byte strings will become octet strings in Perl (the Byte values 0..255 |
176 | will simply become characters of the same value in Perl). |
554 | will simply become characters of the same value in Perl). |
177 | |
555 | |
178 | =item UTF-8 strings |
556 | =item UTF-8 strings |
179 | |
557 | |
180 | UTF-8 strings in CBOR will be decoded, i.e. the UTF-8 octets will be |
558 | UTF-8 strings in CBOR will be decoded, i.e. the UTF-8 octets will be |
… | |
… | |
186 | |
564 | |
187 | CBOR arrays and CBOR maps will be converted into references to a Perl |
565 | CBOR arrays and CBOR maps will be converted into references to a Perl |
188 | array or hash, respectively. The keys of the map will be stringified |
566 | array or hash, respectively. The keys of the map will be stringified |
189 | during this process. |
567 | during this process. |
190 | |
568 | |
|
|
569 | =item null |
|
|
570 | |
|
|
571 | CBOR null becomes C<undef> in Perl. |
|
|
572 | |
191 | =item true, false |
573 | =item true, false, undefined |
192 | |
574 | |
193 | These CBOR values become C<CBOR::XS::true> and C<CBOR::XS::false>, |
575 | These CBOR values become C<Types:Serialiser::true>, |
|
|
576 | C<Types:Serialiser::false> and C<Types::Serialiser::error>, |
194 | respectively. They are overloaded to act almost exactly like the numbers |
577 | respectively. They are overloaded to act almost exactly like the numbers |
195 | C<1> and C<0>. You can check whether a scalar is a CBOR boolean by using |
578 | C<1> and C<0> (for true and false) or to throw an exception on access (for |
196 | the C<CBOR::XS::is_bool> function. |
579 | error). See the L<Types::Serialiser> manpage for details. |
197 | |
580 | |
198 | =item null, undefined |
581 | =item tagged values |
199 | |
582 | |
200 | CBOR null and undefined values becomes C<undef> in Perl (in the future, |
|
|
201 | Undefined may raise an exception or something else). |
|
|
202 | |
|
|
203 | =item tags |
|
|
204 | |
|
|
205 | Tagged items consists of a numeric tag and another CBOR value. The tag |
583 | Tagged items consists of a numeric tag and another CBOR value. |
206 | 55799 is ignored (this tag implements the magic header). |
|
|
207 | |
584 | |
208 | All other tags are currently converted into a L<CBOR::XS::Tagged> object, |
585 | See L<TAG HANDLING AND EXTENSIONS> and the description of C<< ->filter >> |
209 | which is simply a blessed array reference consistsing of the numeric tag |
586 | for details on which tags are handled how. |
210 | value followed by the (decoded) BOR value. |
|
|
211 | |
587 | |
212 | =item anything else |
588 | =item anything else |
213 | |
589 | |
214 | Anything else (e.g. unsupported simple values) will raise a decoding |
590 | Anything else (e.g. unsupported simple values) will raise a decoding |
215 | error. |
591 | error. |
… | |
… | |
218 | |
594 | |
219 | |
595 | |
220 | =head2 PERL -> CBOR |
596 | =head2 PERL -> CBOR |
221 | |
597 | |
222 | The mapping from Perl to CBOR is slightly more difficult, as Perl is a |
598 | The mapping from Perl to CBOR is slightly more difficult, as Perl is a |
223 | truly typeless language, so we can only guess which CBOR type is meant by |
599 | typeless language. That means this module can only guess which CBOR type |
224 | a Perl value. |
600 | is meant by a perl value. |
225 | |
601 | |
226 | =over 4 |
602 | =over 4 |
227 | |
603 | |
228 | =item hash references |
604 | =item hash references |
229 | |
605 | |
230 | Perl hash references become CBOR maps. As there is no inherent ordering in |
606 | Perl hash references become CBOR maps. As there is no inherent ordering in |
231 | hash keys (or CBOR maps), they will usually be encoded in a pseudo-random |
607 | hash keys (or CBOR maps), they will usually be encoded in a pseudo-random |
232 | order. |
608 | order. This order can be different each time a hash is encoded. |
233 | |
609 | |
234 | Currently, tied hashes will use the indefinite-length format, while normal |
610 | Currently, tied hashes will use the indefinite-length format, while normal |
235 | hashes will use the fixed-length format. |
611 | hashes will use the fixed-length format. |
236 | |
612 | |
237 | =item array references |
613 | =item array references |
238 | |
614 | |
239 | Perl array references become fixed-length CBOR arrays. |
615 | Perl array references become fixed-length CBOR arrays. |
240 | |
616 | |
241 | =item other references |
617 | =item other references |
242 | |
618 | |
243 | Other unblessed references are generally not allowed and will cause an |
619 | Other unblessed references will be represented using |
244 | exception to be thrown, except for references to the integers C<0> and |
620 | the indirection tag extension (tag value C<22098>, |
245 | C<1>, which get turned into false and true in CBOR. |
621 | L<http://cbor.schmorp.de/indirection>). CBOR decoders are guaranteed |
|
|
622 | to be able to decode these values somehow, by either "doing the right |
|
|
623 | thing", decoding into a generic tagged object, simply ignoring the tag, or |
|
|
624 | something else. |
246 | |
625 | |
247 | =item CBOR::XS::Tagged objects |
626 | =item CBOR::XS::Tagged objects |
248 | |
627 | |
249 | Objects of this type must be arrays consisting of a single C<[tag, value]> |
628 | Objects of this type must be arrays consisting of a single C<[tag, value]> |
250 | pair. The (numerical) tag will be encoded as a CBOR tag, the value will be |
629 | pair. The (numerical) tag will be encoded as a CBOR tag, the value will |
251 | encoded as appropriate for the value. |
630 | be encoded as appropriate for the value. You must use C<CBOR::XS::tag> to |
|
|
631 | create such objects. |
252 | |
632 | |
253 | =item CBOR::XS::true, CBOR::XS::false |
633 | =item Types::Serialiser::true, Types::Serialiser::false, Types::Serialiser::error |
254 | |
634 | |
255 | These special values become CBOR true and CBOR false values, |
635 | These special values become CBOR true, CBOR false and CBOR undefined |
256 | respectively. You can also use C<\1> and C<\0> directly if you want. |
636 | values, respectively. You can also use C<\1>, C<\0> and C<\undef> directly |
|
|
637 | if you want. |
257 | |
638 | |
258 | =item blessed objects |
639 | =item other blessed objects |
259 | |
640 | |
260 | Other blessed objects currently need to have a C<TO_CBOR> method. It |
641 | Other blessed objects are serialised via C<TO_CBOR> or C<FREEZE>. See |
261 | will be called on every object that is being serialised, and must return |
642 | L<TAG HANDLING AND EXTENSIONS> for specific classes handled by this |
262 | something that can be encoded in CBOR. |
643 | module, and L<OBJECT SERIALISATION> for generic object serialisation. |
263 | |
644 | |
264 | =item simple scalars |
645 | =item simple scalars |
265 | |
646 | |
266 | TODO |
|
|
267 | Simple Perl scalars (any scalar that is not a reference) are the most |
647 | Simple Perl scalars (any scalar that is not a reference) are the most |
268 | difficult objects to encode: CBOR::XS will encode undefined scalars as |
648 | difficult objects to encode: CBOR::XS will encode undefined scalars as |
269 | CBOR null values, scalars that have last been used in a string context |
649 | CBOR null values, scalars that have last been used in a string context |
270 | before encoding as CBOR strings, and anything else as number value: |
650 | before encoding as CBOR strings, and anything else as number value: |
271 | |
651 | |
272 | # dump as number |
652 | # dump as number |
273 | encode_cbor [2] # yields [2] |
653 | encode_cbor [2] # yields [2] |
274 | encode_cbor [-3.0e17] # yields [-3e+17] |
654 | encode_cbor [-3.0e17] # yields [-3e+17] |
275 | my $value = 5; encode_cbor [$value] # yields [5] |
655 | my $value = 5; encode_cbor [$value] # yields [5] |
276 | |
656 | |
277 | # used as string, so dump as string |
657 | # used as string, so dump as string (either byte or text) |
278 | print $value; |
658 | print $value; |
279 | encode_cbor [$value] # yields ["5"] |
659 | encode_cbor [$value] # yields ["5"] |
280 | |
660 | |
281 | # undef becomes null |
661 | # undef becomes null |
282 | encode_cbor [undef] # yields [null] |
662 | encode_cbor [undef] # yields [null] |
… | |
… | |
285 | |
665 | |
286 | my $x = 3.1; # some variable containing a number |
666 | my $x = 3.1; # some variable containing a number |
287 | "$x"; # stringified |
667 | "$x"; # stringified |
288 | $x .= ""; # another, more awkward way to stringify |
668 | $x .= ""; # another, more awkward way to stringify |
289 | print $x; # perl does it for you, too, quite often |
669 | print $x; # perl does it for you, too, quite often |
|
|
670 | |
|
|
671 | You can force whether a string is encoded as byte or text string by using |
|
|
672 | C<utf8::upgrade> and C<utf8::downgrade> (if C<text_strings> is disabled): |
|
|
673 | |
|
|
674 | utf8::upgrade $x; # encode $x as text string |
|
|
675 | utf8::downgrade $x; # encode $x as byte string |
|
|
676 | |
|
|
677 | Perl doesn't define what operations up- and downgrade strings, so if the |
|
|
678 | difference between byte and text is important, you should up- or downgrade |
|
|
679 | your string as late as possible before encoding. You can also force the |
|
|
680 | use of CBOR text strings by using C<text_keys> or C<text_strings>. |
290 | |
681 | |
291 | You can force the type to be a CBOR number by numifying it: |
682 | You can force the type to be a CBOR number by numifying it: |
292 | |
683 | |
293 | my $x = "3"; # some variable containing a string |
684 | my $x = "3"; # some variable containing a string |
294 | $x += 0; # numify it, ensuring it will be dumped as a number |
685 | $x += 0; # numify it, ensuring it will be dumped as a number |
… | |
… | |
305 | represent numerical values are supported, but might suffer loss of |
696 | represent numerical values are supported, but might suffer loss of |
306 | precision. |
697 | precision. |
307 | |
698 | |
308 | =back |
699 | =back |
309 | |
700 | |
|
|
701 | =head2 OBJECT SERIALISATION |
310 | |
702 | |
|
|
703 | This module implements both a CBOR-specific and the generic |
|
|
704 | L<Types::Serialier> object serialisation protocol. The following |
|
|
705 | subsections explain both methods. |
|
|
706 | |
|
|
707 | =head3 ENCODING |
|
|
708 | |
|
|
709 | This module knows two way to serialise a Perl object: The CBOR-specific |
|
|
710 | way, and the generic way. |
|
|
711 | |
|
|
712 | Whenever the encoder encounters a Perl object that it cannot serialise |
|
|
713 | directly (most of them), it will first look up the C<TO_CBOR> method on |
|
|
714 | it. |
|
|
715 | |
|
|
716 | If it has a C<TO_CBOR> method, it will call it with the object as only |
|
|
717 | argument, and expects exactly one return value, which it will then |
|
|
718 | substitute and encode it in the place of the object. |
|
|
719 | |
|
|
720 | Otherwise, it will look up the C<FREEZE> method. If it exists, it will |
|
|
721 | call it with the object as first argument, and the constant string C<CBOR> |
|
|
722 | as the second argument, to distinguish it from other serialisers. |
|
|
723 | |
|
|
724 | The C<FREEZE> method can return any number of values (i.e. zero or |
|
|
725 | more). These will be encoded as CBOR perl object, together with the |
|
|
726 | classname. |
|
|
727 | |
|
|
728 | These methods I<MUST NOT> change the data structure that is being |
|
|
729 | serialised. Failure to comply to this can result in memory corruption - |
|
|
730 | and worse. |
|
|
731 | |
|
|
732 | If an object supports neither C<TO_CBOR> nor C<FREEZE>, encoding will fail |
|
|
733 | with an error. |
|
|
734 | |
|
|
735 | =head3 DECODING |
|
|
736 | |
|
|
737 | Objects encoded via C<TO_CBOR> cannot (normally) be automatically decoded, |
|
|
738 | but objects encoded via C<FREEZE> can be decoded using the following |
|
|
739 | protocol: |
|
|
740 | |
|
|
741 | When an encoded CBOR perl object is encountered by the decoder, it will |
|
|
742 | look up the C<THAW> method, by using the stored classname, and will fail |
|
|
743 | if the method cannot be found. |
|
|
744 | |
|
|
745 | After the lookup it will call the C<THAW> method with the stored classname |
|
|
746 | as first argument, the constant string C<CBOR> as second argument, and all |
|
|
747 | values returned by C<FREEZE> as remaining arguments. |
|
|
748 | |
|
|
749 | =head3 EXAMPLES |
|
|
750 | |
|
|
751 | Here is an example C<TO_CBOR> method: |
|
|
752 | |
|
|
753 | sub My::Object::TO_CBOR { |
|
|
754 | my ($obj) = @_; |
|
|
755 | |
|
|
756 | ["this is a serialised My::Object object", $obj->{id}] |
|
|
757 | } |
|
|
758 | |
|
|
759 | When a C<My::Object> is encoded to CBOR, it will instead encode a simple |
|
|
760 | array with two members: a string, and the "object id". Decoding this CBOR |
|
|
761 | string will yield a normal perl array reference in place of the object. |
|
|
762 | |
|
|
763 | A more useful and practical example would be a serialisation method for |
|
|
764 | the URI module. CBOR has a custom tag value for URIs, namely 32: |
|
|
765 | |
|
|
766 | sub URI::TO_CBOR { |
|
|
767 | my ($self) = @_; |
|
|
768 | my $uri = "$self"; # stringify uri |
|
|
769 | utf8::upgrade $uri; # make sure it will be encoded as UTF-8 string |
|
|
770 | CBOR::XS::tag 32, "$_[0]" |
|
|
771 | } |
|
|
772 | |
|
|
773 | This will encode URIs as a UTF-8 string with tag 32, which indicates an |
|
|
774 | URI. |
|
|
775 | |
|
|
776 | Decoding such an URI will not (currently) give you an URI object, but |
|
|
777 | instead a CBOR::XS::Tagged object with tag number 32 and the string - |
|
|
778 | exactly what was returned by C<TO_CBOR>. |
|
|
779 | |
|
|
780 | To serialise an object so it can automatically be deserialised, you need |
|
|
781 | to use C<FREEZE> and C<THAW>. To take the URI module as example, this |
|
|
782 | would be a possible implementation: |
|
|
783 | |
|
|
784 | sub URI::FREEZE { |
|
|
785 | my ($self, $serialiser) = @_; |
|
|
786 | "$self" # encode url string |
|
|
787 | } |
|
|
788 | |
|
|
789 | sub URI::THAW { |
|
|
790 | my ($class, $serialiser, $uri) = @_; |
|
|
791 | $class->new ($uri) |
|
|
792 | } |
|
|
793 | |
|
|
794 | Unlike C<TO_CBOR>, multiple values can be returned by C<FREEZE>. For |
|
|
795 | example, a C<FREEZE> method that returns "type", "id" and "variant" values |
|
|
796 | would cause an invocation of C<THAW> with 5 arguments: |
|
|
797 | |
|
|
798 | sub My::Object::FREEZE { |
|
|
799 | my ($self, $serialiser) = @_; |
|
|
800 | |
|
|
801 | ($self->{type}, $self->{id}, $self->{variant}) |
|
|
802 | } |
|
|
803 | |
|
|
804 | sub My::Object::THAW { |
|
|
805 | my ($class, $serialiser, $type, $id, $variant) = @_; |
|
|
806 | |
|
|
807 | $class-<new (type => $type, id => $id, variant => $variant) |
|
|
808 | } |
|
|
809 | |
|
|
810 | |
311 | =head2 MAGIC HEADER |
811 | =head1 MAGIC HEADER |
312 | |
812 | |
313 | There is no way to distinguish CBOR from other formats |
813 | There is no way to distinguish CBOR from other formats |
314 | programmatically. To make it easier to distinguish CBOR from other |
814 | programmatically. To make it easier to distinguish CBOR from other |
315 | formats, the CBOR specification has a special "magic string" that can be |
815 | formats, the CBOR specification has a special "magic string" that can be |
316 | prepended to any CBOR string without changing it's meaning. |
816 | prepended to any CBOR string without changing its meaning. |
317 | |
817 | |
318 | This string is available as C<$CBOR::XS::MAGIC>. This module does not |
818 | This string is available as C<$CBOR::XS::MAGIC>. This module does not |
319 | prepend this string tot he CBOR data it generates, but it will ignroe it |
819 | prepend this string to the CBOR data it generates, but it will ignore it |
320 | if present, so users can prepend this string as a "file type" indicator as |
820 | if present, so users can prepend this string as a "file type" indicator as |
321 | required. |
821 | required. |
322 | |
822 | |
323 | |
823 | |
|
|
824 | =head1 THE CBOR::XS::Tagged CLASS |
|
|
825 | |
|
|
826 | CBOR has the concept of tagged values - any CBOR value can be tagged with |
|
|
827 | a numeric 64 bit number, which are centrally administered. |
|
|
828 | |
|
|
829 | C<CBOR::XS> handles a few tags internally when en- or decoding. You can |
|
|
830 | also create tags yourself by encoding C<CBOR::XS::Tagged> objects, and the |
|
|
831 | decoder will create C<CBOR::XS::Tagged> objects itself when it hits an |
|
|
832 | unknown tag. |
|
|
833 | |
|
|
834 | These objects are simply blessed array references - the first member of |
|
|
835 | the array being the numerical tag, the second being the value. |
|
|
836 | |
|
|
837 | You can interact with C<CBOR::XS::Tagged> objects in the following ways: |
|
|
838 | |
|
|
839 | =over 4 |
|
|
840 | |
|
|
841 | =item $tagged = CBOR::XS::tag $tag, $value |
|
|
842 | |
|
|
843 | This function(!) creates a new C<CBOR::XS::Tagged> object using the given |
|
|
844 | C<$tag> (0..2**64-1) to tag the given C<$value> (which can be any Perl |
|
|
845 | value that can be encoded in CBOR, including serialisable Perl objects and |
|
|
846 | C<CBOR::XS::Tagged> objects). |
|
|
847 | |
|
|
848 | =item $tagged->[0] |
|
|
849 | |
|
|
850 | =item $tagged->[0] = $new_tag |
|
|
851 | |
|
|
852 | =item $tag = $tagged->tag |
|
|
853 | |
|
|
854 | =item $new_tag = $tagged->tag ($new_tag) |
|
|
855 | |
|
|
856 | Access/mutate the tag. |
|
|
857 | |
|
|
858 | =item $tagged->[1] |
|
|
859 | |
|
|
860 | =item $tagged->[1] = $new_value |
|
|
861 | |
|
|
862 | =item $value = $tagged->value |
|
|
863 | |
|
|
864 | =item $new_value = $tagged->value ($new_value) |
|
|
865 | |
|
|
866 | Access/mutate the tagged value. |
|
|
867 | |
|
|
868 | =back |
|
|
869 | |
|
|
870 | =cut |
|
|
871 | |
|
|
872 | sub tag($$) { |
|
|
873 | bless [@_], CBOR::XS::Tagged::; |
|
|
874 | } |
|
|
875 | |
|
|
876 | sub CBOR::XS::Tagged::tag { |
|
|
877 | $_[0][0] = $_[1] if $#_; |
|
|
878 | $_[0][0] |
|
|
879 | } |
|
|
880 | |
|
|
881 | sub CBOR::XS::Tagged::value { |
|
|
882 | $_[0][1] = $_[1] if $#_; |
|
|
883 | $_[0][1] |
|
|
884 | } |
|
|
885 | |
|
|
886 | =head2 EXAMPLES |
|
|
887 | |
|
|
888 | Here are some examples of C<CBOR::XS::Tagged> uses to tag objects. |
|
|
889 | |
|
|
890 | You can look up CBOR tag value and emanings in the IANA registry at |
|
|
891 | L<http://www.iana.org/assignments/cbor-tags/cbor-tags.xhtml>. |
|
|
892 | |
|
|
893 | Prepend a magic header (C<$CBOR::XS::MAGIC>): |
|
|
894 | |
|
|
895 | my $cbor = encode_cbor CBOR::XS::tag 55799, $value; |
|
|
896 | # same as: |
|
|
897 | my $cbor = $CBOR::XS::MAGIC . encode_cbor $value; |
|
|
898 | |
|
|
899 | Serialise some URIs and a regex in an array: |
|
|
900 | |
|
|
901 | my $cbor = encode_cbor [ |
|
|
902 | (CBOR::XS::tag 32, "http://www.nethype.de/"), |
|
|
903 | (CBOR::XS::tag 32, "http://software.schmorp.de/"), |
|
|
904 | (CBOR::XS::tag 35, "^[Pp][Ee][Rr][lL]\$"), |
|
|
905 | ]; |
|
|
906 | |
|
|
907 | Wrap CBOR data in CBOR: |
|
|
908 | |
|
|
909 | my $cbor_cbor = encode_cbor |
|
|
910 | CBOR::XS::tag 24, |
|
|
911 | encode_cbor [1, 2, 3]; |
|
|
912 | |
|
|
913 | =head1 TAG HANDLING AND EXTENSIONS |
|
|
914 | |
|
|
915 | This section describes how this module handles specific tagged values |
|
|
916 | and extensions. If a tag is not mentioned here and no additional filters |
|
|
917 | are provided for it, then the default handling applies (creating a |
|
|
918 | CBOR::XS::Tagged object on decoding, and only encoding the tag when |
|
|
919 | explicitly requested). |
|
|
920 | |
|
|
921 | Tags not handled specifically are currently converted into a |
|
|
922 | L<CBOR::XS::Tagged> object, which is simply a blessed array reference |
|
|
923 | consisting of the numeric tag value followed by the (decoded) CBOR value. |
|
|
924 | |
|
|
925 | Future versions of this module reserve the right to special case |
|
|
926 | additional tags (such as base64url). |
|
|
927 | |
|
|
928 | =head2 ENFORCED TAGS |
|
|
929 | |
|
|
930 | These tags are always handled when decoding, and their handling cannot be |
|
|
931 | overridden by the user. |
|
|
932 | |
|
|
933 | =over 4 |
|
|
934 | |
|
|
935 | =item 26 (perl-object, L<http://cbor.schmorp.de/perl-object>) |
|
|
936 | |
|
|
937 | These tags are automatically created (and decoded) for serialisable |
|
|
938 | objects using the C<FREEZE/THAW> methods (the L<Types::Serialier> object |
|
|
939 | serialisation protocol). See L<OBJECT SERIALISATION> for details. |
|
|
940 | |
|
|
941 | =item 28, 29 (shareable, sharedref, L<http://cbor.schmorp.de/value-sharing>) |
|
|
942 | |
|
|
943 | These tags are automatically decoded when encountered (and they do not |
|
|
944 | result in a cyclic data structure, see C<allow_cycles>), resulting in |
|
|
945 | shared values in the decoded object. They are only encoded, however, when |
|
|
946 | C<allow_sharing> is enabled. |
|
|
947 | |
|
|
948 | Not all shared values can be successfully decoded: values that reference |
|
|
949 | themselves will I<currently> decode as C<undef> (this is not the same |
|
|
950 | as a reference pointing to itself, which will be represented as a value |
|
|
951 | that contains an indirect reference to itself - these will be decoded |
|
|
952 | properly). |
|
|
953 | |
|
|
954 | Note that considerably more shared value data structures can be decoded |
|
|
955 | than will be encoded - currently, only values pointed to by references |
|
|
956 | will be shared, others will not. While non-reference shared values can be |
|
|
957 | generated in Perl with some effort, they were considered too unimportant |
|
|
958 | to be supported in the encoder. The decoder, however, will decode these |
|
|
959 | values as shared values. |
|
|
960 | |
|
|
961 | =item 256, 25 (stringref-namespace, stringref, L<http://cbor.schmorp.de/stringref>) |
|
|
962 | |
|
|
963 | These tags are automatically decoded when encountered. They are only |
|
|
964 | encoded, however, when C<pack_strings> is enabled. |
|
|
965 | |
|
|
966 | =item 22098 (indirection, L<http://cbor.schmorp.de/indirection>) |
|
|
967 | |
|
|
968 | This tag is automatically generated when a reference are encountered (with |
|
|
969 | the exception of hash and array references). It is converted to a reference |
|
|
970 | when decoding. |
|
|
971 | |
|
|
972 | =item 55799 (self-describe CBOR, RFC 7049) |
|
|
973 | |
|
|
974 | This value is not generated on encoding (unless explicitly requested by |
|
|
975 | the user), and is simply ignored when decoding. |
|
|
976 | |
|
|
977 | =back |
|
|
978 | |
|
|
979 | =head2 NON-ENFORCED TAGS |
|
|
980 | |
|
|
981 | These tags have default filters provided when decoding. Their handling can |
|
|
982 | be overridden by changing the C<%CBOR::XS::FILTER> entry for the tag, or by |
|
|
983 | providing a custom C<filter> callback when decoding. |
|
|
984 | |
|
|
985 | When they result in decoding into a specific Perl class, the module |
|
|
986 | usually provides a corresponding C<TO_CBOR> method as well. |
|
|
987 | |
|
|
988 | When any of these need to load additional modules that are not part of the |
|
|
989 | perl core distribution (e.g. L<URI>), it is (currently) up to the user to |
|
|
990 | provide these modules. The decoding usually fails with an exception if the |
|
|
991 | required module cannot be loaded. |
|
|
992 | |
|
|
993 | =over 4 |
|
|
994 | |
|
|
995 | =item 0, 1 (date/time string, seconds since the epoch) |
|
|
996 | |
|
|
997 | These tags are decoded into L<Time::Piece> objects. The corresponding |
|
|
998 | C<Time::Piece::TO_CBOR> method always encodes into tag 1 values currently. |
|
|
999 | |
|
|
1000 | The L<Time::Piece> API is generally surprisingly bad, and fractional |
|
|
1001 | seconds are only accidentally kept intact, so watch out. On the plus side, |
|
|
1002 | the module comes with perl since 5.10, which has to count for something. |
|
|
1003 | |
|
|
1004 | =item 2, 3 (positive/negative bignum) |
|
|
1005 | |
|
|
1006 | These tags are decoded into L<Math::BigInt> objects. The corresponding |
|
|
1007 | C<Math::BigInt::TO_CBOR> method encodes "small" bigints into normal CBOR |
|
|
1008 | integers, and others into positive/negative CBOR bignums. |
|
|
1009 | |
|
|
1010 | =item 4, 5, 264, 265 (decimal fraction/bigfloat) |
|
|
1011 | |
|
|
1012 | Both decimal fractions and bigfloats are decoded into L<Math::BigFloat> |
|
|
1013 | objects. The corresponding C<Math::BigFloat::TO_CBOR> method I<always> |
|
|
1014 | encodes into a decimal fraction (either tag 4 or 264). |
|
|
1015 | |
|
|
1016 | NaN and infinities are not encoded properly, as they cannot be represented |
|
|
1017 | in CBOR. |
|
|
1018 | |
|
|
1019 | See L<BIGNUM SECURITY CONSIDERATIONS> for more info. |
|
|
1020 | |
|
|
1021 | =item 30 (rational numbers) |
|
|
1022 | |
|
|
1023 | These tags are decoded into L<Math::BigRat> objects. The corresponding |
|
|
1024 | C<Math::BigRat::TO_CBOR> method encodes rational numbers with denominator |
|
|
1025 | C<1> via their numerator only, i.e., they become normal integers or |
|
|
1026 | C<bignums>. |
|
|
1027 | |
|
|
1028 | See L<BIGNUM SECURITY CONSIDERATIONS> for more info. |
|
|
1029 | |
|
|
1030 | =item 21, 22, 23 (expected later JSON conversion) |
|
|
1031 | |
|
|
1032 | CBOR::XS is not a CBOR-to-JSON converter, and will simply ignore these |
|
|
1033 | tags. |
|
|
1034 | |
|
|
1035 | =item 32 (URI) |
|
|
1036 | |
|
|
1037 | These objects decode into L<URI> objects. The corresponding |
|
|
1038 | C<URI::TO_CBOR> method again results in a CBOR URI value. |
|
|
1039 | |
|
|
1040 | =back |
|
|
1041 | |
|
|
1042 | =cut |
|
|
1043 | |
324 | =head2 CBOR and JSON |
1044 | =head1 CBOR and JSON |
325 | |
1045 | |
326 | CBOR is supposed to implement a superset of the JSON data model, and is, |
1046 | CBOR is supposed to implement a superset of the JSON data model, and is, |
327 | with some coercion, able to represent all JSON texts (something that other |
1047 | with some coercion, able to represent all JSON texts (something that other |
328 | "binary JSON" formats such as BSON generally do not support). |
1048 | "binary JSON" formats such as BSON generally do not support). |
329 | |
1049 | |
… | |
… | |
336 | CBOR intact. |
1056 | CBOR intact. |
337 | |
1057 | |
338 | |
1058 | |
339 | =head1 SECURITY CONSIDERATIONS |
1059 | =head1 SECURITY CONSIDERATIONS |
340 | |
1060 | |
341 | When you are using CBOR in a protocol, talking to untrusted potentially |
1061 | Tl;dr... if you want to decode or encode CBOR from untrusted sources, you |
342 | hostile creatures requires relatively few measures. |
1062 | should start with a coder object created via C<new_safe>: |
343 | |
1063 | |
|
|
1064 | my $coder = CBOR::XS->new_safe; |
|
|
1065 | |
|
|
1066 | my $data = $coder->decode ($cbor_text); |
|
|
1067 | my $cbor = $coder->encode ($data); |
|
|
1068 | |
|
|
1069 | Longer version: When you are using CBOR in a protocol, talking to |
|
|
1070 | untrusted potentially hostile creatures requires some thought: |
|
|
1071 | |
|
|
1072 | =over 4 |
|
|
1073 | |
|
|
1074 | =item Security of the CBOR decoder itself |
|
|
1075 | |
344 | First of all, your CBOR decoder should be secure, that is, should not have |
1076 | First and foremost, your CBOR decoder should be secure, that is, should |
|
|
1077 | not have any buffer overflows or similar bugs that could potentially be |
345 | any buffer overflows. Obviously, this module should ensure that and I am |
1078 | exploited. Obviously, this module should ensure that and I am trying hard |
346 | trying hard on making that true, but you never know. |
1079 | on making that true, but you never know. |
347 | |
1080 | |
|
|
1081 | =item CBOR::XS can invoke almost arbitrary callbacks during decoding |
|
|
1082 | |
|
|
1083 | CBOR::XS supports object serialisation - decoding CBOR can cause calls |
|
|
1084 | to I<any> C<THAW> method in I<any> package that exists in your process |
|
|
1085 | (that is, CBOR::XS will not try to load modules, but any existing C<THAW> |
|
|
1086 | method or function can be called, so they all have to be secure). |
|
|
1087 | |
|
|
1088 | Less obviously, it will also invoke C<TO_CBOR> and C<FREEZE> methods - |
|
|
1089 | even if all your C<THAW> methods are secure, encoding data structures from |
|
|
1090 | untrusted sources can invoke those and trigger bugs in those. |
|
|
1091 | |
|
|
1092 | So, if you are not sure about the security of all the modules you |
|
|
1093 | have loaded (you shouldn't), you should disable this part using |
|
|
1094 | C<forbid_objects>. |
|
|
1095 | |
|
|
1096 | =item CBOR can be extended with tags that call library code |
|
|
1097 | |
|
|
1098 | CBOR can be extended with tags, and C<CBOR::XS> has a registry of |
|
|
1099 | conversion functions for many existing tags that can be extended via |
|
|
1100 | third-party modules (see the C<filter> method). |
|
|
1101 | |
|
|
1102 | If you don't trust these, you should configure the "safe" filter function, |
|
|
1103 | C<CBOR::XS::safe_filter>, which by default only includes conversion |
|
|
1104 | functions that are considered "safe" by the author (but again, they can be |
|
|
1105 | extended by third party modules). |
|
|
1106 | |
|
|
1107 | Depending on your level of paranoia, you can use the "safe" filter: |
|
|
1108 | |
|
|
1109 | $cbor->filter (\&CBOR::XS::safe_filter); |
|
|
1110 | |
|
|
1111 | ... your own filter... |
|
|
1112 | |
|
|
1113 | $cbor->filter (sub { ... do your stuffs here ... }); |
|
|
1114 | |
|
|
1115 | ... or even no filter at all, disabling all tag decoding: |
|
|
1116 | |
|
|
1117 | $cbor->filter (sub { }); |
|
|
1118 | |
|
|
1119 | This is never a problem for encoding, as the tag mechanism only exists in |
|
|
1120 | CBOR texts. |
|
|
1121 | |
|
|
1122 | =item Resource-starving attacks: object memory usage |
|
|
1123 | |
348 | Second, you need to avoid resource-starving attacks. That means you should |
1124 | You need to avoid resource-starving attacks. That means you should limit |
349 | limit the size of CBOR data you accept, or make sure then when your |
1125 | the size of CBOR data you accept, or make sure then when your resources |
350 | resources run out, that's just fine (e.g. by using a separate process that |
1126 | run out, that's just fine (e.g. by using a separate process that can |
351 | can crash safely). The size of a CBOR string in octets is usually a good |
1127 | crash safely). The size of a CBOR string in octets is usually a good |
352 | indication of the size of the resources required to decode it into a Perl |
1128 | indication of the size of the resources required to decode it into a Perl |
353 | structure. While CBOR::XS can check the size of the CBOR text, it might be |
1129 | structure. While CBOR::XS can check the size of the CBOR text (using |
354 | too late when you already have it in memory, so you might want to check |
1130 | C<max_size>), it might be too late when you already have it in memory, so |
355 | the size before you accept the string. |
1131 | you might want to check the size before you accept the string. |
356 | |
1132 | |
|
|
1133 | As for encoding, it is possible to construct data structures that are |
|
|
1134 | relatively small but result in large CBOR texts (for example by having an |
|
|
1135 | array full of references to the same big data structure, which will all be |
|
|
1136 | deep-cloned during encoding by default). This is rarely an actual issue |
|
|
1137 | (and the worst case is still just running out of memory), but you can |
|
|
1138 | reduce this risk by using C<allow_sharing>. |
|
|
1139 | |
|
|
1140 | =item Resource-starving attacks: stack overflows |
|
|
1141 | |
357 | Third, CBOR::XS recurses using the C stack when decoding objects and |
1142 | CBOR::XS recurses using the C stack when decoding objects and arrays. The |
358 | arrays. The C stack is a limited resource: for instance, on my amd64 |
1143 | C stack is a limited resource: for instance, on my amd64 machine with 8MB |
359 | machine with 8MB of stack size I can decode around 180k nested arrays but |
1144 | of stack size I can decode around 180k nested arrays but only 14k nested |
360 | only 14k nested CBOR objects (due to perl itself recursing deeply on croak |
1145 | CBOR objects (due to perl itself recursing deeply on croak to free the |
361 | to free the temporary). If that is exceeded, the program crashes. To be |
1146 | temporary). If that is exceeded, the program crashes. To be conservative, |
362 | conservative, the default nesting limit is set to 512. If your process |
1147 | the default nesting limit is set to 512. If your process has a smaller |
363 | has a smaller stack, you should adjust this setting accordingly with the |
1148 | stack, you should adjust this setting accordingly with the C<max_depth> |
364 | C<max_depth> method. |
1149 | method. |
|
|
1150 | |
|
|
1151 | =item Resource-starving attacks: CPU en-/decoding complexity |
|
|
1152 | |
|
|
1153 | CBOR::XS will use the L<Math::BigInt>, L<Math::BigFloat> and |
|
|
1154 | L<Math::BigRat> libraries to represent encode/decode bignums. These can |
|
|
1155 | be very slow (as in, centuries of CPU time) and can even crash your |
|
|
1156 | program (and are generally not very trustworthy). See the next section for |
|
|
1157 | details. |
|
|
1158 | |
|
|
1159 | =item Data breaches: leaking information in error messages |
|
|
1160 | |
|
|
1161 | CBOR::XS might leak contents of your Perl data structures in its error |
|
|
1162 | messages, so when you serialise sensitive information you might want to |
|
|
1163 | make sure that exceptions thrown by CBOR::XS will not end up in front of |
|
|
1164 | untrusted eyes. |
|
|
1165 | |
|
|
1166 | =item Something else... |
365 | |
1167 | |
366 | Something else could bomb you, too, that I forgot to think of. In that |
1168 | Something else could bomb you, too, that I forgot to think of. In that |
367 | case, you get to keep the pieces. I am always open for hints, though... |
1169 | case, you get to keep the pieces. I am always open for hints, though... |
368 | |
1170 | |
369 | Also keep in mind that CBOR::XS might leak contents of your Perl data |
1171 | =back |
370 | structures in its error messages, so when you serialise sensitive |
1172 | |
371 | information you might want to make sure that exceptions thrown by CBOR::XS |
1173 | |
372 | will not end up in front of untrusted eyes. |
1174 | =head1 BIGNUM SECURITY CONSIDERATIONS |
|
|
1175 | |
|
|
1176 | CBOR::XS provides a C<TO_CBOR> method for both L<Math::BigInt> and |
|
|
1177 | L<Math::BigFloat> that tries to encode the number in the simplest possible |
|
|
1178 | way, that is, either a CBOR integer, a CBOR bigint/decimal fraction (tag |
|
|
1179 | 4) or an arbitrary-exponent decimal fraction (tag 264). Rational numbers |
|
|
1180 | (L<Math::BigRat>, tag 30) can also contain bignums as members. |
|
|
1181 | |
|
|
1182 | CBOR::XS will also understand base-2 bigfloat or arbitrary-exponent |
|
|
1183 | bigfloats (tags 5 and 265), but it will never generate these on its own. |
|
|
1184 | |
|
|
1185 | Using the built-in L<Math::BigInt::Calc> support, encoding and decoding |
|
|
1186 | decimal fractions is generally fast. Decoding bigints can be slow for very |
|
|
1187 | big numbers (tens of thousands of digits, something that could potentially |
|
|
1188 | be caught by limiting the size of CBOR texts), and decoding bigfloats or |
|
|
1189 | arbitrary-exponent bigfloats can be I<extremely> slow (minutes, decades) |
|
|
1190 | for large exponents (roughly 40 bit and longer). |
|
|
1191 | |
|
|
1192 | Additionally, L<Math::BigInt> can take advantage of other bignum |
|
|
1193 | libraries, such as L<Math::GMP>, which cannot handle big floats with large |
|
|
1194 | exponents, and might simply abort or crash your program, due to their code |
|
|
1195 | quality. |
|
|
1196 | |
|
|
1197 | This can be a concern if you want to parse untrusted CBOR. If it is, you |
|
|
1198 | might want to disable decoding of tag 2 (bigint) and 3 (negative bigint) |
|
|
1199 | types. You should also disable types 5 and 265, as these can be slow even |
|
|
1200 | without bigints. |
|
|
1201 | |
|
|
1202 | Disabling bigints will also partially or fully disable types that rely on |
|
|
1203 | them, e.g. rational numbers that use bignums. |
|
|
1204 | |
373 | |
1205 | |
374 | =head1 CBOR IMPLEMENTATION NOTES |
1206 | =head1 CBOR IMPLEMENTATION NOTES |
375 | |
1207 | |
376 | This section contains some random implementation notes. They do not |
1208 | This section contains some random implementation notes. They do not |
377 | describe guaranteed behaviour, but merely behaviour as-is implemented |
1209 | describe guaranteed behaviour, but merely behaviour as-is implemented |
… | |
… | |
386 | Only the double data type is supported for NV data types - when Perl uses |
1218 | Only the double data type is supported for NV data types - when Perl uses |
387 | long double to represent floating point values, they might not be encoded |
1219 | long double to represent floating point values, they might not be encoded |
388 | properly. Half precision types are accepted, but not encoded. |
1220 | properly. Half precision types are accepted, but not encoded. |
389 | |
1221 | |
390 | Strict mode and canonical mode are not implemented. |
1222 | Strict mode and canonical mode are not implemented. |
|
|
1223 | |
|
|
1224 | |
|
|
1225 | =head1 LIMITATIONS ON PERLS WITHOUT 64-BIT INTEGER SUPPORT |
|
|
1226 | |
|
|
1227 | On perls that were built without 64 bit integer support (these are rare |
|
|
1228 | nowadays, even on 32 bit architectures, as all major Perl distributions |
|
|
1229 | are built with 64 bit integer support), support for any kind of 64 bit |
|
|
1230 | integer in CBOR is very limited - most likely, these 64 bit values will |
|
|
1231 | be truncated, corrupted, or otherwise not decoded correctly. This also |
|
|
1232 | includes string, array and map sizes that are stored as 64 bit integers. |
391 | |
1233 | |
392 | |
1234 | |
393 | =head1 THREADS |
1235 | =head1 THREADS |
394 | |
1236 | |
395 | This module is I<not> guaranteed to be thread safe and there are no |
1237 | This module is I<not> guaranteed to be thread safe and there are no |
… | |
… | |
409 | Please refrain from using rt.cpan.org or any other bug reporting |
1251 | Please refrain from using rt.cpan.org or any other bug reporting |
410 | service. I put the contact address into my modules for a reason. |
1252 | service. I put the contact address into my modules for a reason. |
411 | |
1253 | |
412 | =cut |
1254 | =cut |
413 | |
1255 | |
414 | our $true = do { bless \(my $dummy = 1), "CBOR::XS::Boolean" }; |
1256 | # clumsy and slow hv_store-in-hash helper function |
415 | our $false = do { bless \(my $dummy = 0), "CBOR::XS::Boolean" }; |
1257 | sub _hv_store { |
416 | |
1258 | $_[0]{$_[1]} = $_[2]; |
417 | sub true() { $true } |
|
|
418 | sub false() { $false } |
|
|
419 | |
|
|
420 | sub is_bool($) { |
|
|
421 | UNIVERSAL::isa $_[0], "CBOR::XS::Boolean" |
|
|
422 | # or UNIVERSAL::isa $_[0], "CBOR::Literal" |
|
|
423 | } |
1259 | } |
424 | |
1260 | |
|
|
1261 | our %FILTER = ( |
|
|
1262 | 0 => sub { # rfc4287 datetime, utf-8 |
|
|
1263 | require Time::Piece; |
|
|
1264 | # Time::Piece::Strptime uses the "incredibly flexible date parsing routine" |
|
|
1265 | # from FreeBSD, which can't parse ISO 8601, RFC3339, RFC4287 or much of anything |
|
|
1266 | # else either. Whats incredibe over standard strptime totally escapes me. |
|
|
1267 | # doesn't do fractional times, either. sigh. |
|
|
1268 | # In fact, it's all a lie, it uses whatever strptime it wants, and of course, |
|
|
1269 | # they are all incompatible. The openbsd one simply ignores %z (but according to the |
|
|
1270 | # docs, it would be much more incredibly flexible indeed. If it worked, that is.). |
|
|
1271 | scalar eval { |
|
|
1272 | my $s = $_[1]; |
|
|
1273 | |
|
|
1274 | $s =~ s/Z$/+00:00/; |
|
|
1275 | $s =~ s/(\.[0-9]+)?([+-][0-9][0-9]):([0-9][0-9])$// |
|
|
1276 | or die; |
|
|
1277 | |
|
|
1278 | my $b = $1 - ($2 * 60 + $3) * 60; # fractional part + offset. hopefully |
|
|
1279 | my $d = Time::Piece->strptime ($s, "%Y-%m-%dT%H:%M:%S"); |
|
|
1280 | |
|
|
1281 | Time::Piece::gmtime ($d->epoch + $b) |
|
|
1282 | } || die "corrupted CBOR date/time string ($_[0])"; |
|
|
1283 | }, |
|
|
1284 | |
|
|
1285 | 1 => sub { # seconds since the epoch, possibly fractional |
|
|
1286 | require Time::Piece; |
|
|
1287 | scalar Time::Piece::gmtime (pop) |
|
|
1288 | }, |
|
|
1289 | |
|
|
1290 | 2 => sub { # pos bigint |
|
|
1291 | require Math::BigInt; |
|
|
1292 | Math::BigInt->new ("0x" . unpack "H*", pop) |
|
|
1293 | }, |
|
|
1294 | |
|
|
1295 | 3 => sub { # neg bigint |
|
|
1296 | require Math::BigInt; |
|
|
1297 | -Math::BigInt->new ("0x" . unpack "H*", pop) |
|
|
1298 | }, |
|
|
1299 | |
|
|
1300 | 4 => sub { # decimal fraction, array |
|
|
1301 | require Math::BigFloat; |
|
|
1302 | Math::BigFloat->new ($_[1][1] . "E" . $_[1][0]) |
|
|
1303 | }, |
|
|
1304 | |
|
|
1305 | 264 => sub { # decimal fraction with arbitrary exponent |
|
|
1306 | require Math::BigFloat; |
|
|
1307 | Math::BigFloat->new ($_[1][1] . "E" . $_[1][0]) |
|
|
1308 | }, |
|
|
1309 | |
|
|
1310 | 5 => sub { # bigfloat, array |
|
|
1311 | require Math::BigFloat; |
|
|
1312 | scalar Math::BigFloat->new ($_[1][1]) * Math::BigFloat->new (2)->bpow ($_[1][0]) |
|
|
1313 | }, |
|
|
1314 | |
|
|
1315 | 265 => sub { # bigfloat with arbitrary exponent |
|
|
1316 | require Math::BigFloat; |
|
|
1317 | scalar Math::BigFloat->new ($_[1][1]) * Math::BigFloat->new (2)->bpow ($_[1][0]) |
|
|
1318 | }, |
|
|
1319 | |
|
|
1320 | 30 => sub { # rational number |
|
|
1321 | require Math::BigRat; |
|
|
1322 | Math::BigRat->new ("$_[1][0]/$_[1][1]") # separate parameters only work in recent versons |
|
|
1323 | }, |
|
|
1324 | |
|
|
1325 | 21 => sub { pop }, # expected conversion to base64url encoding |
|
|
1326 | 22 => sub { pop }, # expected conversion to base64 encoding |
|
|
1327 | 23 => sub { pop }, # expected conversion to base16 encoding |
|
|
1328 | |
|
|
1329 | # 24 # embedded cbor, byte string |
|
|
1330 | |
|
|
1331 | 32 => sub { |
|
|
1332 | require URI; |
|
|
1333 | URI->new (pop) |
|
|
1334 | }, |
|
|
1335 | |
|
|
1336 | # 33 # base64url rfc4648, utf-8 |
|
|
1337 | # 34 # base64 rfc46484, utf-8 |
|
|
1338 | # 35 # regex pcre/ecma262, utf-8 |
|
|
1339 | # 36 # mime message rfc2045, utf-8 |
|
|
1340 | ); |
|
|
1341 | |
|
|
1342 | sub default_filter { |
|
|
1343 | &{ $FILTER{$_[0]} or return } |
|
|
1344 | } |
|
|
1345 | |
|
|
1346 | our %SAFE_FILTER = map { $_ => $FILTER{$_} } 0, 1, 21, 22, 23, 32; |
|
|
1347 | |
|
|
1348 | sub safe_filter { |
|
|
1349 | &{ $SAFE_FILTER{$_[0]} or return } |
|
|
1350 | } |
|
|
1351 | |
|
|
1352 | sub URI::TO_CBOR { |
|
|
1353 | my $uri = $_[0]->as_string; |
|
|
1354 | utf8::upgrade $uri; |
|
|
1355 | tag 32, $uri |
|
|
1356 | } |
|
|
1357 | |
|
|
1358 | sub Math::BigInt::TO_CBOR { |
|
|
1359 | if (-2147483648 <= $_[0] && $_[0] <= 2147483647) { |
|
|
1360 | $_[0]->numify |
|
|
1361 | } else { |
|
|
1362 | my $hex = substr $_[0]->as_hex, 2; |
|
|
1363 | $hex = "0$hex" if 1 & length $hex; # sigh |
|
|
1364 | tag $_[0] >= 0 ? 2 : 3, pack "H*", $hex |
|
|
1365 | } |
|
|
1366 | } |
|
|
1367 | |
|
|
1368 | sub Math::BigFloat::TO_CBOR { |
|
|
1369 | my ($m, $e) = $_[0]->parts; |
|
|
1370 | |
|
|
1371 | -9223372036854775808 <= $e && $e <= 18446744073709551615 |
|
|
1372 | ? tag 4, [$e->numify, $m] |
|
|
1373 | : tag 264, [$e, $m] |
|
|
1374 | } |
|
|
1375 | |
|
|
1376 | sub Math::BigRat::TO_CBOR { |
|
|
1377 | my ($n, $d) = $_[0]->parts; |
|
|
1378 | |
|
|
1379 | # older versions of BigRat need *1, as they not always return numbers |
|
|
1380 | |
|
|
1381 | $d*1 == 1 |
|
|
1382 | ? $n*1 |
|
|
1383 | : tag 30, [$n*1, $d*1] |
|
|
1384 | } |
|
|
1385 | |
|
|
1386 | sub Time::Piece::TO_CBOR { |
|
|
1387 | tag 1, 0 + $_[0]->epoch |
|
|
1388 | } |
|
|
1389 | |
425 | XSLoader::load "CBOR::XS", $VERSION; |
1390 | XSLoader::load "CBOR::XS", $VERSION; |
426 | |
|
|
427 | package CBOR::XS::Boolean; |
|
|
428 | |
|
|
429 | use overload |
|
|
430 | "0+" => sub { ${$_[0]} }, |
|
|
431 | "++" => sub { $_[0] = ${$_[0]} + 1 }, |
|
|
432 | "--" => sub { $_[0] = ${$_[0]} - 1 }, |
|
|
433 | fallback => 1; |
|
|
434 | |
|
|
435 | 1; |
|
|
436 | |
1391 | |
437 | =head1 SEE ALSO |
1392 | =head1 SEE ALSO |
438 | |
1393 | |
439 | The L<JSON> and L<JSON::XS> modules that do similar, but human-readable, |
1394 | The L<JSON> and L<JSON::XS> modules that do similar, but human-readable, |
440 | serialisation. |
1395 | serialisation. |
441 | |
1396 | |
|
|
1397 | The L<Types::Serialiser> module provides the data model for true, false |
|
|
1398 | and error values. |
|
|
1399 | |
442 | =head1 AUTHOR |
1400 | =head1 AUTHOR |
443 | |
1401 | |
444 | Marc Lehmann <schmorp@schmorp.de> |
1402 | Marc Lehmann <schmorp@schmorp.de> |
445 | http://home.schmorp.de/ |
1403 | http://home.schmorp.de/ |
446 | |
1404 | |
447 | =cut |
1405 | =cut |
448 | |
1406 | |
|
|
1407 | 1 |
|
|
1408 | |