R/bi_open.R

In rbi: Interface to 'LibBi'

#' @rdname bi_open
#' @name bi_open
#' @title Bi Open
#' @description
#' This function opens an NetCDF file
#' The file can be specified as a string to the filepath, in which
#' case a NetCDF connection is opened, or directly as a NetCDF connection.
#'
#' @param x either a path to a NetCDF file, or a NetCDF connection created using
#'   \code{nc_open}, or a \code{\link{libbi}} object from which to read the
#'   output
#' @param file file to open (out of "input", "init", "obs", "output"), if
#'   \code{x} is given as a \code{libbi} object; by default, will read output
#'   file
#' @return an open NetCDF connection
#' @importFrom ncdf4 nc_open
#' @keywords internal
bi_open <- function(x, file = "output") {
  if (!missing(file) && !inherits(x, "libbi")) {
    warning(
      "'file' given to 'bi_open' although 'x' is not a 'libbi' object; ",
      "will be ignored"
    )
  }

  if (typeof(x) == "character") {
    nc <- nc_open(tools::file_path_as_absolute(x))
  } else if (inherits(x, "ncdf4")) {
    nc <- x
  } else if (inherits(x, "libbi")) {
    if (!(missing(file) || file == "output")) {
      opt_name <- paste(file, "file", sep = "-")
      if (!(opt_name %in% names(x$options))) {
        stop("libbi object does not contain an '", file, "' file")
      }
      filename <- x$options[[opt_name]]
    } else {
      assert_files(x)
      filename <- x$output_file_name
    }
    nc <- nc_open(filename)
  } else {
    stop("'x' must be a 'character', 'ncdf4' or 'libbi' object.")
  }

  return(nc)
}