--- CBOR-XS/XS.pm 2013/11/20 16:29:02 1.21 +++ CBOR-XS/XS.pm 2013/11/22 16:00:30 1.23 @@ -120,7 +120,6 @@ The mutators for flags all return the CBOR object again and thus calls can be chained: -#TODO my $cbor = CBOR::XS->new->encode ({a => [1,2]}); =item $cbor = $cbor->max_depth ([$maximum_nesting_depth]) @@ -232,6 +231,12 @@ This option does not affect C in any way - string references will always be decoded properly if present. +=item $cbor = $cbor->filter ([$cb->($tag, $value)]) + +=item $cb_or_undef = $cbor->get_filter + +TODO + =item $cbor_data = $cbor->encode ($perl_scalar) Converts the given Perl data structure (a scalar value) to its CBOR @@ -309,24 +314,12 @@ C<1> and C<0> (for true and false) or to throw an exception on access (for error). See the L manpage for details. -=item CBOR tag 256 (perl object) - -The tag value C<256> (TODO: pending iana registration) will be used -to deserialise a Perl object serialised with C. See L, below, for details. +=item tagged values -=item CBOR tag 55799 (magic header) +Tagged items consists of a numeric tag and another CBOR value. -The tag 55799 is ignored (this tag implements the magic header). - -=item other CBOR tags - -Tagged items consists of a numeric tag and another CBOR value. Tags not -handled internally are currently converted into a L -object, which is simply a blessed array reference consisting of the -numeric tag value followed by the (decoded) CBOR value. - -In the future, support for user-supplied conversions might get added. +See L and the description of C<< ->filter >> +for details. =item anything else @@ -379,11 +372,11 @@ =item other blessed objects Other blessed objects are serialised via C or C. See -L, below, for details. +L for specific classes handled by this +module, and L for generic object serialisation. =item simple scalars -TODO Simple Perl scalars (any scalar that is not a reference) are the most difficult objects to encode: CBOR::XS will encode undefined scalars as CBOR null values, scalars that have last been used in a string context @@ -629,21 +622,31 @@ =head1 TAG HANDLING AND EXTENSIONS -This section describes how this module handles specific tagged values and -extensions. If a tag is not mentioned here, then the default handling -applies (creating a CBOR::XS::Tagged object on decoding, and only encoding -the tag when explicitly requested). +This section describes how this module handles specific tagged values +and extensions. If a tag is not mentioned here and no additional filters +are provided for it, then the default handling applies (creating a +CBOR::XS::Tagged object on decoding, and only encoding the tag when +explicitly requested). + +Tags not handled specifically are currently converted into a +L object, which is simply a blessed array reference +consisting of the numeric tag value followed by the (decoded) CBOR value. Future versions of this module reserve the right to special case -additional tags (such as bigfloat or base64url). +additional tags (such as base64url). + +=head2 ENFORCED TAGS + +These tags are always handled when decoding, and their handling cannot be +overriden by the user. =over 4 =item (perl-object, L) -These tags are automatically created for serialisable objects using the -C methods (the L object serialisation -protocol). +These tags are automatically created (and decoded) for serialisable +objects using the C methods (the L object +serialisation protocol). See L for details. =item , (sharable, sharedref, L ) @@ -669,6 +672,94 @@ =back +=head2 OPTIONAL TAGS + +These tags have default filters provided when decoding. Their handling can +be overriden by changing the C<%CBOR::XS::FILTER> entry for the tag, or by +providing a custom C function when decoding. + +When they result in decoding into a specific Perl class, the module +usually provides a corresponding C method as well. + +When any of these need to load additional modules that are not part of the +perl core distribution (e.g. L), it is (currently) up to the user to +provide these modules. The decoding usually fails with an exception if the +required module cannot be loaded. + +=over 4 + +=item 2, 3 (positive/negative bignum) + +These tags are decoded into L objects. The corresponding +C method encodes "small" bigints into normal CBOR +integers, and others into positive/negative CBOR bignums. + +=item 4, 5 (decimal fraction/bigfloat) + +Both decimal fractions and bigfloats are decoded into L +objects. The corresponding C method I +encodes into a decimal fraction. + +CBOR cannot represent bigfloats with I large exponents - conversion +of such big float objects is undefined. + +Also, NaN and infinities are not encoded properly. + +=item 21, 22, 23 (expected later JSON conversion) + +CBOR::XS is not a CBOR-to-JSON converter, and will simply ignore these +tags. + +=item 32 (URI) + +These objects decode into L objects. The corresponding +C method again results in a CBOR URI value. + +=back + +=cut + +our %FILTER = ( + # 0 # rfc4287 datetime, utf-8 + # 1 # unix timestamp, any + + 2 => sub { # pos bigint + require Math::BigInt; + Math::BigInt->new ("0x" . unpack "H*", pop) + }, + + 3 => sub { # neg bigint + require Math::BigInt; + -Math::BigInt->new ("0x" . unpack "H*", pop) + }, + + 4 => sub { # decimal fraction, array + require Math::BigFloat; + Math::BigFloat->new ($_[1][1] . "E" . $_[1][0]) + }, + + 5 => sub { # bigfloat, array + require Math::BigFloat; + scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2) + }, + + 21 => sub { pop }, # expected conversion to base64url encoding + 22 => sub { pop }, # expected conversion to base64 encoding + 23 => sub { pop }, # expected conversion to base16 encoding + + # 24 # embedded cbor, byte string + + 32 => sub { + require URI; + URI->new (pop) + }, + + # 33 # base64url rfc4648, utf-8 + # 34 # base64 rfc46484, utf-8 + # 35 # regex pcre/ecma262, utf-8 + # 36 # mime message rfc2045, utf-8 +); + =head1 CBOR and JSON @@ -760,6 +851,72 @@ =cut +our %FILTER = ( + # 0 # rfc4287 datetime, utf-8 + # 1 # unix timestamp, any + + 2 => sub { # pos bigint + require Math::BigInt; + Math::BigInt->new ("0x" . unpack "H*", pop) + }, + + 3 => sub { # neg bigint + require Math::BigInt; + -Math::BigInt->new ("0x" . unpack "H*", pop) + }, + + 4 => sub { # decimal fraction, array + require Math::BigFloat; + Math::BigFloat->new ($_[1][1] . "E" . $_[1][0]) + }, + + 5 => sub { # bigfloat, array + require Math::BigFloat; + scalar Math::BigFloat->new ($_[1][1])->blsft ($_[1][0], 2) + }, + + 21 => sub { pop }, # expected conversion to base64url encoding + 22 => sub { pop }, # expected conversion to base64 encoding + 23 => sub { pop }, # expected conversion to base16 encoding + + # 24 # embedded cbor, byte string + + 32 => sub { + require URI; + URI->new (pop) + }, + + # 33 # base64url rfc4648, utf-8 + # 34 # base64 rfc46484, utf-8 + # 35 # regex pcre/ecma262, utf-8 + # 36 # mime message rfc2045, utf-8 +); + +sub CBOR::XS::default_filter { + &{ $FILTER{$_[0]} or return } +} + +sub URI::TO_CBOR { + my $uri = $_[0]->as_string; + utf8::upgrade $uri; + CBOR::XS::tag 32, $uri +} + +sub Math::BigInt::TO_CBOR { + if ($_[0] >= -2147483648 && $_[0] <= 2147483647) { + $_[0]->numify + } else { + my $hex = substr $_[0]->as_hex, 2; + $hex = "0$hex" if 1 & length $hex; # sigh + CBOR::XS::tag $_[0] >= 0 ? 2 : 3, pack "H*", $hex + } +} + +sub Math::BigFloat::TO_CBOR { + my ($m, $e) = $_[0]->parts; + CBOR::XS::tag 4, [$e->numify, $m] +} + XSLoader::load "CBOR::XS", $VERSION; =head1 SEE ALSO