Cjdnsencode

Parser and serializer for cjdns encoding schemes

Encoding schemes are the way that the engine explains to other nodes how it parses labels. Encoding schemes are represented as lists of encoding forms, an encoding form is a a packed array of bits comprising of a pair of 5 bit numbers followed by a number of bits which is defined by one of the numbers. Forms are packed together tightly in order to save bandwidth when transferring encoding schemes across the wire.

Cjdnsencode.parse(buffer)

Parse an encoding scheme representation into a js array.

> Cjdnsencode.parse(new Buffer('810c08', 'hex'))
[ { prefixLen: 1, bitCount: 4, prefix: '01' },
  { prefixLen: 1, bitCount: 8, prefix: '00' } ]

Cjdnsencode.serialize(scheme)

Serialize an encoding scheme representation back into a tightly packed Buffer.

> Cjdnsencode.serialize([ { prefixLen: 1, bitCount: 4, prefix: "01" }, { prefixLen: 1, bitCount: 8, prefix: "00" }, ])
<Buffer 81 0c 08>

Cjdnsencode.formSize(scheme[0])

As a scheme is represented as an array of forms, this function will tell you how many bits of label space is occupied by a representation of a given form.

> Cjdnsencode.formSize({ prefixLen: 1, bitCount: 8, prefix: "00" })
9

Cjdnsencode.isSane(scheme)

Returns an object containing sane: <true|false> and reason (a string telling why the scheme is not is valid if sane = false).

> Cjdnsencode.isSane([])
{ sane: false, reason: 'no forms' }

Node Version

Tested on 4.2.1, 4.5.0 and 6.6.0

License

GPLv3+