rawConversion
Convert to or from Raw Vectors
Conversion and manipulation of objects of type "raw".
- Keywords
- classes
Usage
charToRaw(x)
rawToChar(x, multiple = FALSE)rawShift(x, n)
rawToBits(x)
intToBits(x)
packBits(x, type = c("raw", "integer"))
Arguments
- x
object to be converted or shifted.
- multiple
logical: should the conversion be to a single character string or multiple individual characters?
- n
the number of bits to shift. Positive numbers shift right and negative numbers shift left: allowed values are
-8 ... 8.- type
the result type, partially matched.
Details
packBits accepts raw, integer or logical inputs, the last two
without any NAs.
Note that ‘bytes’ are not necessarily the same as characters, e.g.in UTF-8 locales.
Value
charToRaw converts a length-one character string to raw bytes.
It does so without taking into account any declared encoding (see
Encoding).
rawToChar converts raw bytes either to a single character
string or a character vector of single bytes (with "" for
0). (Note that a single character string could contain
embedded nuls; only trailing nulls are allowed and will be removed.)
In either case it is possible to create a result which is invalid in a
multibyte locale, e.g.one using UTF-8. Long vectors are
allowed if multiple is true.
rawShift(x, n) shift the bits in x by n positions
to the right, see the argument n, above.
rawToBits returns a raw vector of 8 times the length of a raw
vector with entries 0 or 1. intToBits returns a raw vector
of 32 times the length of an integer vector with entries 0 or 1.
(Non-integral numeric values are truncated to integers.) In
both cases the unpacking is least-significant bit first.
packBits packs its input (using only the lowest bit for raw or
integer vectors) least-significant bit first to a raw or integer vector.
Examples
library(base)
# NOT RUN {
x <- "A test string"
(y <- charToRaw(x))
is.vector(y) # TRUE
rawToChar(y)
rawToChar(y, multiple = TRUE)
(xx <- c(y, charToRaw("&"), charToRaw("more")))
rawToChar(xx)
rawShift(y, 1)
rawShift(y, -2)
rawToBits(y)
showBits <- function(r) stats::symnum(as.logical(rawToBits(r)))
z <- as.raw(5)
z ; showBits(z)
showBits(rawShift(z, 1)) # shift to right
showBits(rawShift(z, 2))
showBits(z)
showBits(rawShift(z, -1)) # shift to left
showBits(rawShift(z, -2)) # ..
showBits(rawShift(z, -3)) # shifted off entirely
# }