R/C.R

In yihui/rmini: A Minimal R Package as an Example of Writing R Packages

## Examples of C code

#' Reverse elements
#'
#' This function takes a numeric vector and returns a reversed version of this
#' vector. The internal computation is via C.
#' @param x a numeric vector
#' @return a numeric vector (reversed \code{x})
#' @author Yihui Xie <\url{http://yihui.name}>
#' @examples reverse(c(1, 9.3, 8.2, 4.33)); reverse(1:10)
#' @export
#' @useDynLib rmini, .registration = TRUE
reverse = function(x) {
  n = length(x)
  res = .C('rmini_reverse', as.numeric(x), n, numeric(n), package = 'rmini')
  res[[3L]]
}

#' Reverse an integer vector
#'
#' This function takes an integer vector and reverses it (in C).
#' @param x An integer vector
#' @return An integer vector (reversed \code{x})
#' @author Michael Chirico
#' @export
reverse_int = function(x) {
  .Call('rmini_reverse_int', x, PACKAGE = 'rmini')
}