R/dec2base.R

In neuroconductor-devel/oro.dicom: Rigorous - DICOM Input / Output

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#' Convert Decimal to Base N Number in String
#' 
#' This function converts the nonnegative integer to the specified base.
#' 
#' This function converts the nonnegative integer \code{n} to the specified
#' base, where \code{n} must be a nonnegative integer smaller than \eqn{2^52},
#' \code{base} must be an integer between 2 and 36 and \code{len} suggests the
#' length of the character string.
#' 
#' @aliases dec2base dec2hex
#' @param n Non-negative integer.
#' @param base Number between 2 and 36.
#' @param len Length of the character string.
#' @return The returned argument is a string.
#' @author Brandon Whitcher \email{bwhitcher@@gmail.com}
#' @keywords misc
#' @examples
#' 
#' x <- dec2base(23, 2)
#' 
#' @export
dec2base <- function(n, base, len=0) {
  symbols <- c(as.character(0:9), LETTERS)
  max.len <- max(trunc(log(max(n, 1)) / log(base)) + 1, len)
  ## determine digits for each number
  power <- rep(1, length(n)) * base^((max.len-1):0)
  n <- n * rep(1, max.len)
  digits <- floor((n %% (base * power)) / power)
  ## convert digits to symbols
  paste(symbols[digits + 1], collapse="")
}
#' @rdname dec2base
#' @export
dec2hex <- function(n, len=0) {
  dec2base(n, 16, len)
}