Felipe Gasper
and 1 contributors


CBOR::Free - Fast CBOR for everyone


    $cbor = CBOR::Free::encode( $scalar_or_ar_or_hr );

    $thing = CBOR::Free::decode( $cbor )

    my $tagged = CBOR::Free::tag( 1, '2019-01-02T00:01:02Z' );


This library implements CBOR via XS under a license that permits commercial usage with no “strings attached”.


This distribution is an experimental effort. Its interface is still subject to change. If you decide to use CBOR::Free in your project, please always check the changelog before upgrading.


$cbor = encode( $DATA, %OPTS )

Encodes a data structure or non-reference scalar to CBOR. The encoder recognizes and encodes integers, floats, binary and UTF-8 strings, array and hash references, CBOR::Free::Tagged instances, Types::Serialiser booleans, and undef (encoded as null).

The encoder currently does not handle any other blessed references.

%OPTS may be:

  • canonical - A boolean that makes the function output CBOR in canonical form.

Notes on mapping Perl to CBOR:

  • The internal state of a defined Perl scalar (e.g., whether it’s an integer, float, binary string, or UTF-8 string) determines its CBOR encoding.

  • Types::Serialiser booleans are encoded as CBOR booleans. Perl undef is encoded as CBOR null. (NB: No Perl value encodes as CBOR undefined.)

  • Instances of CBOR::Free::Tagged are encoded as tagged values.

An error is thrown on excess recursion or an unrecognized object.

$data = decode( $CBOR )

Decodes a data structure from CBOR. Errors are thrown to indicate invalid CBOR. A warning is thrown if $CBOR is longer than is needed for $data.

Notes on mapping CBOR to Perl:

  • CBOR UTF-8 strings become Perl UTF-8 strings. CBOR binary strings become Perl binary strings. (This may become configurable later.)

    Note that invalid UTF-8 in a CBOR UTF-8 string is considered invalid input and will thus prompt a thrown exception.

  • The only map keys that decode() accepts are integers and strings. An exception is thrown if the decoder finds anything else as a map key.

  • CBOR booleans become the corresponding Types::Serialiser values. Both CBOR null and undefined become Perl undef.

  • Tags are IGNORED for now. (This may become configurable later.)

$obj = tag( $NUMBER, $DATA )

Tags an item for encoding so that its CBOR encoding will preserve the tag number. (Include $obj, not $DATA, in the data structure that encode() receives.)


CBOR::Free::true(), CBOR::Free::false(), $CBOR::Free::true, and $CBOR::Free::false are defined as convenience aliases for the equivalent Types::Serialiser values.


Floating-point numbers are encoded in CBOR as IEEE 754 half-, single-, or double-precision. If your Perl is compiled to use “long double” floating-point numbers, you may see rounding errors when converting to/from CBOR. If that’s a problem for you, append an empty string to your floating-point numbers, which will cause CBOR::Free to encode them as strings.


CBOR handles up to 64-bit positive and negative integers. Most Perls nowadays can handle 64-bit integers, but if yours can’t then you’ll get an exception whenever trying to parse an integer that can’t be represented with 32 bits. This means:

  • Anything greater than 0xffff_ffff (4,294,967,295)

  • Anything less than -0x8000_0000 (2,147,483,648)

Note that even 64-bit Perls can’t parse negatives that are less than -0x8000_0000_0000_0000 (-9,223,372,036,854,775,808); these also prompt an exception since Perl can’t handle them. (It would be possible to load Math::BigInt to handle these; if that’s desirable for you, file a feature request.)


Most errors are represented via instances of subclasses of CBOR::Free::X, which subclasses X::Tiny::Base.


CBOR::Free is pretty snappy. I find that it keeps pace with or surpasses CBOR::XS, Cpanel::JSON::XS, JSON::XS, Sereal, and Data::MessagePack.


Gasper Software Consulting (FELIPE)


This code is licensed under the same license as Perl itself.


CBOR::XS is an older CBOR module on CPAN. It’s got more bells and whistles, so check it out if CBOR::Free lacks a feature you’d like. Note that its maintainer has abandoned support for Perl versions from 5.22 onward, though, and its GPL license limits its usefulness in commercial perlcc applications.