Use writeBin() for large objects?

[wlandau]

cc @nettoyoussef, re ropensci/drake#907 and #103.

storr/R/hash.R

Lines 61 to 63 in 2750823

	## For current R (3.3.2 or thereabouts) writeBin does not work with
	## long vectors. We can work around this for now, but in future
	## versions this will just use native R support.

Is it time to allow writeBin() for versions of R where it works for large vectors? I.e. change

storr/R/hash.R

Line 94 in 2750823

if (len < long) {

to something like

if (r_version > min_r_version || len < long) {

I would be happy to check the R versions and platforms where writeBin() would work. From #103 (comment), I think this is one of the best things we can do to improve speed.

[wlandau]

Turns out even R 3.6.0 lacks support for long vectors in writeBin().

> print(R.version$version.string)                                                            
[1] "R version 3.6.0 (2019-04-26)"                                                           
> data <- data.frame(x = runif(1e9))                                                         
> obj <- serialize(data, NULL, ascii = FALSE, xdr = TRUE)                                    
> con <- file(tempfile(), "wb")                                                              
> writeBin(obj, con)                                                                         
Error in writeBin(obj, con) :                                                                
  long vectors not supported yet: connections.c:4418                                         
Execution halted