| … | |
… | |
| 200 | the standard CBOR way. |
200 | the standard CBOR way. |
| 201 | |
201 | |
| 202 | This option does not affect "decode" in any way - string references |
202 | This option does not affect "decode" in any way - string references |
| 203 | will always be decoded properly if present. |
203 | will always be decoded properly if present. |
| 204 | |
204 | |
|
|
205 | $cbor = $cbor->validate_utf8 ([$enable]) |
|
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206 | $enabled = $cbor->get_validate_utf8 |
|
|
207 | If $enable is true (or missing), then "decode" will validate that |
|
|
208 | elements (text strings) containing UTF-8 data in fact contain valid |
|
|
209 | UTF-8 data (instead of blindly accepting it). This validation |
|
|
210 | obviously takes extra time during decoding. |
|
|
211 | |
|
|
212 | The concept of "valid UTF-8" used is perl's concept, which is a |
|
|
213 | superset of the official UTF-8. |
|
|
214 | |
|
|
215 | If $enable is false (the default), then "decode" will blindly accept |
|
|
216 | UTF-8 data, marking them as valid UTF-8 in the resulting data |
|
|
217 | structure regardless of whether thats true or not. |
|
|
218 | |
|
|
219 | Perl isn't too happy about corrupted UTF-8 in strings, but should |
|
|
220 | generally not crash or do similarly evil things. Extensions might be |
|
|
221 | not so forgiving, so it's recommended to turn on this setting if you |
|
|
222 | receive untrusted CBOR. |
|
|
223 | |
|
|
224 | This option does not affect "encode" in any way - strings that are |
|
|
225 | supposedly valid UTF-8 will simply be dumped into the resulting CBOR |
|
|
226 | string without checking whether that is, in fact, true or not. |
|
|
227 | |
| 205 | $cbor = $cbor->filter ([$cb->($tag, $value)]) |
228 | $cbor = $cbor->filter ([$cb->($tag, $value)]) |
| 206 | $cb_or_undef = $cbor->get_filter |
229 | $cb_or_undef = $cbor->get_filter |
| 207 | Sets or replaces the tagged value decoding filter (when $cb is |
230 | Sets or replaces the tagged value decoding filter (when $cb is |
| 208 | specified) or clears the filter (if no argument or "undef" is |
231 | specified) or clears the filter (if no argument or "undef" is |
| 209 | provided). |
232 | provided). |
| … | |
… | |
| 263 | protocol and you need to know where the first CBOR string ends amd |
286 | protocol and you need to know where the first CBOR string ends amd |
| 264 | the next one starts. |
287 | the next one starts. |
| 265 | |
288 | |
| 266 | CBOR::XS->new->decode_prefix ("......") |
289 | CBOR::XS->new->decode_prefix ("......") |
| 267 | => ("...", 3) |
290 | => ("...", 3) |
|
|
291 | |
|
|
292 | INCREMENTAL PARSING |
|
|
293 | In some cases, there is the need for incremental parsing of JSON texts. |
|
|
294 | While this module always has to keep both CBOR text and resulting Perl |
|
|
295 | data structure in memory at one time, it does allow you to parse a CBOR |
|
|
296 | stream incrementally, using a similar to using "decode_prefix" to see if |
|
|
297 | a full CBOR object is available, but is much more efficient. |
|
|
298 | |
|
|
299 | It basically works by parsing as much of a CBOR string as possible - if |
|
|
300 | the CBOR data is not complete yet, the pasrer will remember where it |
|
|
301 | was, to be able to restart when more data has been accumulated. Once |
|
|
302 | enough data is available to either decode a complete CBOR value or raise |
|
|
303 | an error, a real decode will be attempted. |
|
|
304 | |
|
|
305 | A typical use case would be a network protocol that consists of sending |
|
|
306 | and receiving CBOR-encoded messages. The solution that works with CBOR |
|
|
307 | and about anything else is by prepending a length to every CBOR value, |
|
|
308 | so the receiver knows how many octets to read. More compact (and |
|
|
309 | slightly slower) would be to just send CBOR values back-to-back, as |
|
|
310 | "CBOR::XS" knows where a CBOR value ends, and doesn't need an explicit |
|
|
311 | length. |
|
|
312 | |
|
|
313 | The following methods help with this: |
|
|
314 | |
|
|
315 | @decoded = $cbor->incr_parse ($buffer) |
|
|
316 | This method attempts to decode exactly one CBOR value from the |
|
|
317 | beginning of the given $buffer. The value is removed from the |
|
|
318 | $buffer on success. When $buffer doesn't contain a complete value |
|
|
319 | yet, it returns nothing. Finally, when the $buffer doesn't start |
|
|
320 | with something that could ever be a valid CBOR value, it raises an |
|
|
321 | exception, just as "decode" would. In the latter case the decoder |
|
|
322 | state is undefined and must be reset before being able to parse |
|
|
323 | further. |
|
|
324 | |
|
|
325 | This method modifies the $buffer in place. When no CBOR value can be |
|
|
326 | decoded, the decoder stores the current string offset. On the next |
|
|
327 | call, continues decoding at the place where it stopped before. For |
|
|
328 | this to make sense, the $buffer must begin with the same octets as |
|
|
329 | on previous unsuccessful calls. |
|
|
330 | |
|
|
331 | You can call this method in scalar context, in which case it either |
|
|
332 | returns a decoded value or "undef". This makes it impossible to |
|
|
333 | distinguish between CBOR null values (which decode to "undef") and |
|
|
334 | an unsuccessful decode, which is often acceptable. |
|
|
335 | |
|
|
336 | @decoded = $cbor->incr_parse_multiple ($buffer) |
|
|
337 | Same as "incr_parse", but attempts to decode as many CBOR values as |
|
|
338 | possible in one go, instead of at most one. Calls to "incr_parse" |
|
|
339 | and "incr_parse_multiple" can be interleaved. |
|
|
340 | |
|
|
341 | $cbor->incr_reset |
|
|
342 | Resets the incremental decoder. This throws away any saved state, so |
|
|
343 | that subsequent calls to "incr_parse" or "incr_parse_multiple" start |
|
|
344 | to parse a new CBOR value from the beginning of the $buffer again. |
|
|
345 | |
|
|
346 | This method can be caled at any time, but it *must* be called if you |
|
|
347 | want to change your $buffer or there was a decoding error and you |
|
|
348 | want to reuse the $cbor object for future incremental parsings. |
| 268 | |
349 | |
| 269 | MAPPING |
350 | MAPPING |
| 270 | This section describes how CBOR::XS maps Perl values to CBOR values and |
351 | This section describes how CBOR::XS maps Perl values to CBOR values and |
| 271 | vice versa. These mappings are designed to "do the right thing" in most |
352 | vice versa. These mappings are designed to "do the right thing" in most |
| 272 | circumstances automatically, preserving round-tripping characteristics |
353 | circumstances automatically, preserving round-tripping characteristics |
| … | |
… | |
| 653 | |
734 | |
| 654 | When any of these need to load additional modules that are not part of |
735 | When any of these need to load additional modules that are not part of |
| 655 | the perl core distribution (e.g. URI), it is (currently) up to the user |
736 | the perl core distribution (e.g. URI), it is (currently) up to the user |
| 656 | to provide these modules. The decoding usually fails with an exception |
737 | to provide these modules. The decoding usually fails with an exception |
| 657 | if the required module cannot be loaded. |
738 | if the required module cannot be loaded. |
|
|
739 | |
|
|
740 | 0, 1 (date/time string, seconds since the epoch) |
|
|
741 | These tags are decoded into Time::Piece objects. The corresponding |
|
|
742 | "Time::Piece::TO_CBOR" method always encodes into tag 1 values |
|
|
743 | currently. |
|
|
744 | |
|
|
745 | The Time::Piece API is generally surprisingly bad, and fractional |
|
|
746 | seconds are only accidentally kept intact, so watch out. On the plus |
|
|
747 | side, the module comes with perl since 5.10, which has to count for |
|
|
748 | something. |
| 658 | |
749 | |
| 659 | 2, 3 (positive/negative bignum) |
750 | 2, 3 (positive/negative bignum) |
| 660 | These tags are decoded into Math::BigInt objects. The corresponding |
751 | These tags are decoded into Math::BigInt objects. The corresponding |
| 661 | "Math::BigInt::TO_CBOR" method encodes "small" bigints into normal |
752 | "Math::BigInt::TO_CBOR" method encodes "small" bigints into normal |
| 662 | CBOR integers, and others into positive/negative CBOR bignums. |
753 | CBOR integers, and others into positive/negative CBOR bignums. |
