packMsg: Convert R objects to msgpack format.

In msgpack: A Compact, High Speed Data Format

Description

Convert R objects to msgpack format.

packOpts() interprets the ... argument of packMsg and packMsgs. it is not exported.

Usage

packMsg(x, ...)

packMsgs(xs, ...)

packOpts(compatible = FALSE, as_is = FALSE, use_dict = TRUE,
  max_size = NA, buf_size = 512)

prepack(x)

## Default S3 method:
prepack(x)

## S3 method for class 'data.frame'
prepack(x)

Arguments

x	An R object, which can be null, a vector, list, environment, raw, or any combinations thereof.
...	Options passed to packOpts()
xs	a list of objects to pack.
compatible	If TRUE, emitted bytes conform to version 1.0 of msgpack encoding. This means that msgpack strings are used for raw objects.
as_is	If TRUE, singletons (R primitive vectors of length 1 having no names attribute) are encoded as msgpack arrays of length 1. Otherwise singletons are simplified to msgpack scalars.
use_dict	If TRUE, vectors having a "names" attribute are encoded as dicts. If false, they are encoded as arrays and the names are discarded.
max_size	The largest buffer that will be allocated.
buf_size	The initial amount of memory, in bytes, to allocate for packing each message. This will be dynamically grown if a larger message is passed, so there is little reason to change this.

Details

Strings are re-encoded to UTF-8 if necessary. Real numbers taking integral values may be emitted as integers to save space.

Normally an R vector of length 1 will be unboxed, e.g. packMsg(1) will make a msgpack integer, but packMsg(c(1,2)) will make a msgpack list. To prevent this and produce a list of length 1 in the first case, specify as_is = TRUE. Objects of class AsIs or data.frame will always be encoded as-is.

A hook for pre-processing R objects before packing is supported, by giving the object an S3 class and implementing a method prepack. For instance, prepack.data.frame(x) simply adds the "AsIs" class to x.

Environment objects are written out with the keys in sorted order, but named vectors are written in the order which the entries appear.

Object attributes other than names and class are ignored.

Value

An object of class "raw".

Examples

packMsg( list(compact=TRUE, schema=0) )
x <- packMsgs(list("one", "two", "three"))
unpackMsgs(x, 2)

msgpack documentation built on Feb. 22, 2018, 5:01 p.m.