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

> 
> pathname <- tempfile()
> 
> # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> # Writing
> # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> # Open the temporary file for writing
> out <- file(pathname, open="wb")
> b <- -128:127
> Java$writeByte(out, b)
> s <- -32768:32767
> Java$writeShort(out, s)
> i <- c(-2147483648, -2147483647, -1, 0, +1, 2147483646, 2147483647)
> Java$writeInt(out, i)
> str <- c("This R string was written (using the UTF-8 format) using",
+          "the static methods of the Java class in the R.utils package.")
> str <- paste(str, collapse="\n")
> Java$writeUTF(out, str)
> close(out)
> 
> 
> # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> # Reading
> # - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> for (as.character in c(TRUE, FALSE)) {
+   # Open the temporary file for reading
+   inn <- file(pathname, open="rb")
+ 
+   bfr <- Java$readByte(inn, n=length(b))
+   cat("Read ", length(bfr), " bytes.\n", sep="")
+   if (!identical(bfr, b))
+     throw("Failed to read the same data that was written.")
+ 
+   bfr <- Java$readShort(inn, n=length(s))
+   cat("Read ", length(bfr), " shorts.\n", sep="")
+   if (!identical(bfr, s))
+     throw("Failed to read the same data that was written.")
+ 
+   bfr <- Java$readInt(inn, n=length(i))
+   cat("Read ", length(bfr), " ints.\n", sep="")
+   if (!identical(bfr, i))
+     throw("Failed to read the same data that was written.")
+ 
+   bfr <- Java$readUTF(inn, as.character=TRUE)
+   if (is.character(bfr)) {
+     cat("Read ", nchar(bfr), " UTF characters:\n", "'", bfr, "'\n", sep="")
+   } else {
+     cat("Read ", length(bfr), " UTF character bytes:\n", "'", hpaste(bfr), "'\n", sep="")
+   }
+ 
+   # Trying to read more when there isn't anything else available
+   bfr <- Java$readUTF(inn, as.character=FALSE)
+   cat("Read ", length(bfr), " UTF character bytes:\n", "'", hpaste(bfr), "'\n", sep="")
+ 
+   close(inn)
+ } # for (as.character ...)
Read 256 bytes.
Read 65536 shorts.
Read 7 ints.
Read 117 UTF characters:
'This R string was written (using the UTF-8 format) using
the static methods of the Java class in the R.utils package.'
Read 0 UTF character bytes:
''
Read 256 bytes.
Read 65536 shorts.
Read 7 ints.
Read 117 UTF characters:
'This R string was written (using the UTF-8 format) using
the static methods of the Java class in the R.utils package.'
Read 0 UTF character bytes:
''
> 
> 
> file.remove(pathname)
[1] TRUE
> 
> proc.time()
   user  system elapsed 
   0.40    0.06    0.45