Awesome
varint
encode whole numbers to an array of protobuf-style varint bytes and also decode them.
var varint = require('varint')
var bytes = varint.encode(300) // === [0xAC, 0x02]
varint.decode(bytes) // 300
varint.decode.bytes // 2 (the last decode() call required 2 bytes)
api
varint = require('varint')
varint.encode(num[, buffer=[], offset=0]) -> buffer
Encodes num
into buffer
starting at offset
. returns buffer
, with the encoded varint written into it. If buffer
is not provided, it will default to a new array.
varint.encode.bytes
will now be set to the number of bytes
modified.
varint.decode(data[, offset=0]) -> number
decodes data
, which can be either a buffer or array of integers, from position offset
or default 0 and returns the decoded original integer.
Throws a RangeError
when data
does not represent a valid encoding.
varint.decode.bytes
if you also require the length (number of bytes) that were required to decode the integer you can access it via varint.decode.bytes
. this is an integer property that will tell you the number of bytes that the last .decode() call had to use to decode.
varint.encode.bytes
similar to decode.bytes
when encoding a number it can be useful to know how many bytes where written (especially if you pass an output array). you can access this via varint.encode.bytes
which holds the number of bytes written in the last encode.
varint.encodingLength(num)
returns the number of bytes this number will be encoded as, up to a maximum of 8.
usage notes
If varint is passed a buffer that does not contain a valid end
byte, then decode
will throw RangeError
, and decode.bytes
will be set to 0. If you are reading from a streaming source,
it's okay to pass an incomplete buffer into decode
, detect this
case, and then concatenate the next buffer.
License
MIT