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Comparing CBOR-XS/XS.pm (file contents):
Revision 1.35 by root, Sun Dec 1 16:40:25 2013 UTC vs.
Revision 1.42 by root, Sat Oct 25 06:36:34 2014 UTC

64 64
65package CBOR::XS; 65package CBOR::XS;
66 66
67use common::sense; 67use common::sense;
68 68
69our $VERSION = 1.11; 69our $VERSION = 1.26;
70our @ISA = qw(Exporter); 70our @ISA = qw(Exporter);
71 71
72our @EXPORT = qw(encode_cbor decode_cbor); 72our @EXPORT = qw(encode_cbor decode_cbor);
73 73
74use Exporter; 74use Exporter;
218isn't prepared for this will not leak memory. 218isn't prepared for this will not leak memory.
219 219
220If C<$enable> is false (the default), then C<decode> will throw an error 220If C<$enable> is false (the default), then C<decode> will throw an error
221when it encounters a self-referential/cyclic data structure. 221when it encounters a self-referential/cyclic data structure.
222 222
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
223This option does not affect C<encode> in any way - shared values and 228This option does not affect C<encode> in any way - shared values and
224references will always be decoded properly if present. 229references will always be encoded properly if present.
225 230
226=item $cbor = $cbor->pack_strings ([$enable]) 231=item $cbor = $cbor->pack_strings ([$enable])
227 232
228=item $enabled = $cbor->get_pack_strings 233=item $enabled = $cbor->get_pack_strings
229 234
330and you need to know where the first CBOR string ends amd the next one 335and you need to know where the first CBOR string ends amd the next one
331starts. 336starts.
332 337
333 CBOR::XS->new->decode_prefix ("......") 338 CBOR::XS->new->decode_prefix ("......")
334 => ("...", 3) 339 => ("...", 3)
340
341=back
342
343=head2 INCREMENTAL PARSING
344
345In some cases, there is the need for incremental parsing of JSON
346texts. While this module always has to keep both CBOR text and resulting
347Perl 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
349if a full CBOR object is available, but is much more efficient.
350
351It 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,
353to 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
355error, a real decode will be attempted.
356
357A typical use case would be a network protocol that consists of sending
358and receiving CBOR-encoded messages. The solution that works with CBOR and
359about anything else is by prepending a length to every CBOR value, so the
360receiver knows how many octets to read. More compact (and slightly slower)
361would be to just send CBOR values back-to-back, as C<CBOR::XS> knows where
362a CBOR value ends, and doesn't need an explicit length.
363
364The following methods help with this:
365
366=over 4
367
368=item @decoded = $cbor->incr_parse ($buffer)
369
370This method attempts to decode exactly one CBOR value from the beginning
371of the given C<$buffer>. The value is removed from the C<$buffer> on
372success. When C<$buffer> doesn't contain a complete value yet, it returns
373nothing. Finally, when the C<$buffer> doesn't start with something
374that could ever be a valid CBOR value, it raises an exception, just as
375C<decode> would. In the latter case the decoder state is undefined and
376must be reset before being able to parse further.
377
378This method modifies the C<$buffer> in place. When no CBOR value can be
379decoded, the decoder stores the current string offset. On the next call,
380continues decoding at the place where it stopped before. For this to make
381sense, the C<$buffer> must begin with the same octets as on previous
382unsuccessful calls.
383
384You can call this method in scalar context, in which case it either
385returns a decoded value or C<undef>. This makes it impossible to
386distinguish between CBOR null values (which decode to C<undef>) and an
387unsuccessful decode, which is often acceptable.
388
389=item @decoded = $cbor->incr_parse_multiple ($buffer)
390
391Same as C<incr_parse>, but attempts to decode as many CBOR values as
392possible in one go, instead of at most one. Calls to C<incr_parse> and
393C<incr_parse_multiple> can be interleaved.
394
395=item $cbor->incr_reset
396
397Resets the incremental decoder. This throws away any saved state, so that
398subsequent calls to C<incr_parse> or C<incr_parse_multiple> start to parse
399a new CBOR value from the beginning of the C<$buffer> again.
400
401This method can be caled at any time, but it I<must> be called if you want
402to change your C<$buffer> or there was a decoding error and you want to
403reuse the C<$cbor> object for future incremental parsings.
335 404
336=back 405=back
337 406
338 407
339=head1 MAPPING 408=head1 MAPPING
987 require Time::Piece; 1056 require Time::Piece;
988 # Time::Piece::Strptime uses the "incredibly flexible date parsing routine" 1057 # Time::Piece::Strptime uses the "incredibly flexible date parsing routine"
989 # from FreeBSD, which can't parse ISO 8601, RFC3339, RFC4287 or much of anything 1058 # from FreeBSD, which can't parse ISO 8601, RFC3339, RFC4287 or much of anything
990 # else either. Whats incredibe over standard strptime totally escapes me. 1059 # else either. Whats incredibe over standard strptime totally escapes me.
991 # doesn't do fractional times, either. sigh. 1060 # doesn't do fractional times, either. sigh.
1061 # In fact, it's all a lie, it uses whatever strptime it wants, and of course,
1062 # they are all incomptible. The openbsd one simply ignores %z (but according to the
1063 # docs, it would be much more incredibly flexible indeed. If it worked, that is.).
992 scalar eval { 1064 scalar eval {
993 my $s = $_[1]; 1065 my $s = $_[1];
994 1066
995 $s =~ s/Z$/+00:00/; 1067 $s =~ s/Z$/+00:00/;
996 $s =~ s/(\.[0-9]+)?([+-][0-9][0-9]):([0-9][0-9])/$2$3/ 1068 $s =~ s/(\.[0-9]+)?([+-][0-9][0-9]):([0-9][0-9])$//
997 or die; 1069 or die;
998 1070
999 my $f = $1; # fractional part. hopefully 1071 my $b = $1 - ($2 * 60 + $3) * 60; # fractional part + offset. hopefully
1000
1001 my $d = Time::Piece->strptime ($s, "%Y-%m-%dT%H:%M:%S%z"); 1072 my $d = Time::Piece->strptime ($s, "%Y-%m-%dT%H:%M:%S");
1002 1073
1003 Time::Piece::gmtime ($d->epoch + $f) 1074 Time::Piece::gmtime ($d->epoch + $b)
1004 } || die "corrupted CBOR date/time string ($_[0])"; 1075 } || die "corrupted CBOR date/time string ($_[0])";
1005 }, 1076 },
1006 1077
1007 1 => sub { # seconds since the epoch, possibly fractional 1078 1 => sub { # seconds since the epoch, possibly fractional
1008 require Time::Piece; 1079 require Time::Piece;
1070 my ($m, $e) = $_[0]->parts; 1141 my ($m, $e) = $_[0]->parts;
1071 tag 4, [$e->numify, $m] 1142 tag 4, [$e->numify, $m]
1072} 1143}
1073 1144
1074sub Time::Piece::TO_CBOR { 1145sub Time::Piece::TO_CBOR {
1075 tag 1, $_[0]->epoch 1146 tag 1, 0 + $_[0]->epoch
1076} 1147}
1077 1148
1078XSLoader::load "CBOR::XS", $VERSION; 1149XSLoader::load "CBOR::XS", $VERSION;
1079 1150
1080=head1 SEE ALSO 1151=head1 SEE ALSO

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