I found as Duncan, but then I saw
https://stackoverflow.com/questions/54144239/how-to-use-saverds-refhook-parameter
and found more info as follows. (It will take me a while to go through the
output, but basically I am seeing code from the "oce" package, which makes me
think I ought to get rid of the "Imports:" listing in my DESCRIPTION and
instead use "Suggests:" and then grab things at runtime, as needed. Maybe that
will trim down the rds file, e.g. I see in the output from below about 1000
lines that correspond to a particular oce function (or set of specialized
versions of a generic, actually), which yields size 38649 in a references$`env`
entry.
unser <- function(s){
i <- as.numeric(s)
return(rdx$variables[[i]])
}
readRDB <- function(filename, offset, size, type = 'gzip') {
f <- file(filename, 'rb')
on.exit(close(f))
seek(f, offset + 4)
unserialize(memDecompress(readBin(f, 'raw', size - 4), type),
refhook=unser)
}
Dan E. Kelley [he/him/his 314ppm]
Professor and Senator
Department of Oceanography
Dalhousie University
PO BOX 15000
Halifax, NS, Canada B3H 4R2
(902)494-1694 dan.kel...@dal.ca<mailto:dan.kel...@dal.ca>
On Jun 15, 2020, at 4:12 PM, Duncan Murdoch
<murdoch.dun...@gmail.com<mailto:murdoch.dun...@gmail.com>> wrote:
CAUTION: The Sender of this email is not from within Dalhousie.
On 15/06/2020 1:24 p.m., Ivan Krylov wrote:
On Mon, 15 Jun 2020 12:52:20 -0400
Duncan Murdoch <murdoch.dun...@gmail.com<mailto:murdoch.dun...@gmail.com>>
wrote:
maybe someone else can suggest how to read an object from
the .rdb file using R code. Internally R uses C code for this.
This function seems to work for me:
# filename: the .rdb file
# offset, size: the pair of values from the .rdx
# type: 'gzip' if $compressed is TRUE, 'bzip2' for 2, 'xz' for 3
readRDB <- function(filename, offset, size, type = 'gzip') {
f <- file(filename, 'rb')
on.exit(close(f))
seek(f, offset + 4)
unserialize(memDecompress(readBin(f, 'raw', size - 4), type))
}
Thanks, though it didn't work for me. I get
Error in unserialize(memDecompress(readBin(f, "raw", size - 4), type)) :
no restore method available
on every object I tried. However, maybe Dan will have better luck.
Duncan Murdoch
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