ctype.R

double64 <-
function(length = 0L, ...)
{
  bytes <- 8L
  x <- raw(length = bytes * length)
  attr(x, "class") <- "ctype"
  attr(x, "rtype") <- "double"
  attr(x, "bytes") <- bytes
  attr(x, "signed") <- TRUE
  x
}

#`[.double64` <-
#function(x, i) {
#
#}

as.double64 <-
function(x, ...) {
  UseMethod("as.double64")
}

as.double64.double <-
function(x, ...)
{
  bytes <- 8L
  d <- writeBin(x, raw(), size = bytes)
  attr(d, "class") <- "ctype"
  attr(d, "rtype") <- "double"
  attr(d, "bytes") <- bytes
  attr(d, "signed") <- TRUE
  d
}

as.rtype <-
function(x)
{
  readBin(x,
          what = attr(x, "rtype"),
          n = length(x),
          size = attr(x, "bytes"))
}

as.double.ctype <-
function(x, ...)
{
  r <- as.rtype(x)
  as.double(r)
}

# methods
length.ctype <-
function(x, ...)
{
  .x <- unclass(x)
  length(.x) / attr(x, "bytes")
}

print.ctype <-
function(x, ...)
{
  r <- as.rtype(x)
  print(r, ...)
  return(x)
}

format.ctype <-
function(x, ...)
{
  r <- as.rtype(x)
  format(r, ...)
}

str.ctype <-
function(x, ...)
{
  # class and length
  klass <- class(x)
  len <- length(x)
  if (len > 1) {
    class_len <- paste0(" '", klass, "' [1:", len, "]")
  } else {
    class_len <- paste0(" '", klass, "'")
  }
  # storage information
  bytes <-
    paste0(paste0(if (!attr(x, "signed")) "un", "signed "),
           attr(x, "bytes") * 8, "-bit ",
           attr(x, "rtype"))
  # bits of data
  rdata <- format(as.rtype(x), digits = 10)
  # print
  cat(class_len, head(rdata, 3), "\n ", bytes, "\n")
}

as.data.frame.ctype <- as.data.frame.vector

# examples
str(x <- double64(10))
#   'ctype' [1:10] 0 0 0 
#   signed 64-bit double
str(as.rtype(x))
#   num [1:10] 0 0 0 0 0 0 0 0 0