R/iris.R

In adokter/bioRad: Biological Analysis and Visualization of Weather Radar Data

#' Check the `task` type of an IRIS RAW file
#'
#' Checks what type of `task`(s), i.e. polar volume types, are contained in an
#' IRIS RAW file.
#'
#' @param file Character. Path to a polar volume file in IRIS RAW format.
#' @param header_size Integer. Number of header bytes to search.
#' @param task Character (vector). Task names to search for in the file header.
#'
#' @return Specified `task` names found in the header or `NA` if none of the
#'   task names were found.
#'
#' @export
get_iris_raw_task <- function(file, header_size=50, task=c("WIND","SURVEILLANCE","VOL_A","VOL_B")){
  assertthat::assert_that(file.exists(file))

  # read binary header
  types <- sapply(task, function(x) {
    suppressWarnings(
      any(grepl(pattern = x, readBin(file, n = header_size, "character")))
    )
  })

  if (!any(types)) {
    return(NA)
  }

  if (sum(types) > 1) {
    warning(paste(
      "Multiple file types found in binary header:",
      paste(task[types], collapse = ",")
    ))
  }

  task[types]
}