R Under development (unstable) (2023-11-16 r85542 ucrt) -- "Unsuffered Consequences"
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> library("R.utils")
Loading required package: R.oo
Loading required package: R.methodsS3
R.methodsS3 v1.8.2 (2022-06-13 22:00:14 UTC) successfully loaded. See ?R.methodsS3 for help.
R.oo v1.25.0 (2022-06-12 02:20:02 UTC) successfully loaded. See ?R.oo for help.

Attaching package: 'R.oo'

The following object is masked from 'package:R.methodsS3':

    throw

The following objects are masked from 'package:methods':

    getClasses, getMethods

The following objects are masked from 'package:base':

    attach, detach, load, save

R.utils v2.12.3 successfully loaded. See ?R.utils for help.

Attaching package: 'R.utils'

The following object is masked from 'package:utils':

    timestamp

The following objects are masked from 'package:base':

    cat, commandArgs, getOption, isOpen, nullfile, parse, warnings

> 
> if ("covr" %in% loadedNamespaces())
+   options("R.utils::onNonSeekable"="warning")
> 
> # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> # Create a data file
> # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> data <- 1:255
> size <- 2
> pathname <- tempfile("exampleReadBinFragments")
> writeBin(con=pathname, data, size=size)
> 
> 
> # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> # Read and write using index vectors
> # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> cat("Read file...\n")
Read file...
> # Read every 16:th byte in the file
> idxs <- seq(from=1, to=255, by=16)
> x <- readBinFragments(pathname, what="integer", size=size, signed=FALSE, idxs=idxs)
> stopifnot(identical(x, data[idxs]))
> print(x)
 [1]   1  17  33  49  65  81  97 113 129 145 161 177 193 209 225 241
> # Read every 16:th byte in a connection starting with the 6th.
> idxs <- idxs + 5L
> x <- readBinFragments(pathname, what="integer", size=size, signed=FALSE, idxs=idxs)
> stopifnot(identical(x, data[idxs]))
> print(x)
 [1]   6  22  38  54  70  86 102 118 134 150 166 182 198 214 230 246
> cat("Read file...done\n")
Read file...done
> 
> cat("Write file...\n")
Write file...
> # Update every 16:th byte in the file
> idxs <- seq(from=1, to=255, by=16)
> x0 <- data[idxs]
> writeBinFragments(pathname, idxs=idxs, rev(x0), size=size)
> x <- readBinFragments(pathname, what="integer", size=size, signed=FALSE, idxs=idxs)
> print(x)
 [1] 241 225 209 193 177 161 145 129 113  97  81  65  49  33  17   1
> stopifnot(identical(rev(x0), x))
> 
> # Update every 16:th byte in the file
> idxs <- seq(from=1, to=255, by=16)
> writeBinFragments(pathname, idxs=idxs, rev(x), size=size)
> x <- readBinFragments(pathname, what="integer", size=size, signed=FALSE, idxs=idxs)
> print(x)
 [1]   1  17  33  49  65  81  97 113 129 145 161 177 193 209 225 241
> stopifnot(identical(x0, x))
> 
> # Assert everything is as expected
> # Read the complete file
> x <- readBin(pathname, what="integer", size=size, signed=FALSE, n=length(data))
> stopifnot(identical(x, data))
> cat("Write file...done\n")
Write file...done
> 
> 
> # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> # Ditto but via a connection
> # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> cat("Read connection...\n")
Read connection...
> # Read every 16:th byte in a connection
> con <- file(pathname, open="rb")
> idxs <- seq(from=1, to=255, by=16)
> x <- readBinFragments(con, what="integer", size=size, signed=FALSE, idxs=idxs)
> stopifnot(identical(x, data[idxs]))
> print(x)
 [1]   1  17  33  49  65  81  97 113 129 145 161 177 193 209 225 241
> 
> # Read every 16:th byte in a connection starting with the 6th.
> idxs <- idxs + 5L
> x <- readBinFragments(con, what="integer", size=size, signed=FALSE, idxs=idxs, origin="start")
> stopifnot(identical(x, data[idxs]))
> print(x)
 [1]   6  22  38  54  70  86 102 118 134 150 166 182 198 214 230 246
> close(con)
> cat("Read connection...done\n")
Read connection...done
> 
> 
> # Update every 16:th byte in a connection
> cat("Write connection...\n")
Write connection...
> con <- file(pathname, open="r+b")
> idxs <- seq(from=1, to=255, by=16)
> x0 <- data[idxs]
> writeBinFragments(pathname, idxs=idxs, rev(x0), size=size)
> x <- readBinFragments(pathname, what="integer", size=size, signed=FALSE, idxs=idxs)
> print(x)
 [1] 241 225 209 193 177 161 145 129 113  97  81  65  49  33  17   1
> stopifnot(identical(rev(x0), x))
> 
> # Update every 16:th byte in the file
> idxs <- seq(from=1, to=255, by=16)
> writeBinFragments(pathname, idxs=idxs, rev(x), size=size)
> x <- readBinFragments(pathname, what="integer", size=size, signed=FALSE, idxs=idxs, origin="start")
> print(x)
 [1]   1  17  33  49  65  81  97 113 129 145 161 177 193 209 225 241
> stopifnot(identical(x0, x))
> 
> close(con)
> 
> # Assert everything is as expected
> # Read the complete file
> x <- readBin(pathname, what=integer(), size=size, signed=FALSE, n=length(data))
> stopifnot(identical(x, data))
> cat("Write connection...done\n")
Write connection...done
> 
> # Read bytes 1-4, 11-14, 21-24, ...
> idxs <- seq(from=1, to=255, by=10)
> idxs <- cbind(idxs, idxs+3)
> x <- readBinFragments(pathname, what="integer", size=size, signed=FALSE, idxs=idxs, verbose=TRUE)
Number of elements skipped: 0
Remaining indices (relative to current position):
 num [1:104] 1 2 3 4 11 12 13 14 21 22 ...
Data read:
 int [1:255] 1 2 3 4 5 6 7 8 9 10 ...
> idxsX <- intervalsToSeq(idxs)
> stopifnot(identical(x, data[idxsX]))
> print(x)
  [1]   1   2   3   4  11  12  13  14  21  22  23  24  31  32  33  34  41  42
 [19]  43  44  51  52  53  54  61  62  63  64  71  72  73  74  81  82  83  84
 [37]  91  92  93  94 101 102 103 104 111 112 113 114 121 122 123 124 131 132
 [55] 133 134 141 142 143 144 151 152 153 154 161 162 163 164 171 172 173 174
 [73] 181 182 183 184 191 192 193 194 201 202 203 204 211 212 213 214 221 222
 [91] 223 224 231 232 233 234 241 242 243 244 251 252 253 254
> 
> # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> # Clean up
> # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> file.remove(pathname)
[1] TRUE
> 
> proc.time()
   user  system elapsed 
   0.43    0.04    0.48