R/utils.R

In stringdist: Approximate String Matching, Fuzzy Text Search, and String Distance Functions

RECYCLEWARNING <- NULL

# calling message from .onLoad gives a NOTE on build, so we avoid it here.
mymsg <- message

.onLoad <- function(libname, pkgname){
  RECYCLEWARNING <<- gettext(tryCatch( (1:2)+(1:3),warning=function(w) w$message ))

  
  omp_num_threads <- as.numeric(Sys.getenv("OMP_NUM_THREADS"))
  if (!is.na(omp_num_threads) && omp_num_threads > 0){
    nthread <- omp_num_threads
  } else {
    nthread <- parallel::detectCores()
    if ( is.na(nthread) || !is.numeric(nthread) ){
      nthread <- 1L
      mymsg("Could not detect number of cores, defaulting to 1.")
    } else {
      # nthread=nr of detected cores. Leave one core free.
      if (nthread >= 4) nthread <- nthread - 1
    }
  }

  ## if OMP_THREAD_LIMIT is set, maximize on that limit.
  omp_thread_limit <- as.numeric(Sys.getenv("OMP_THREAD_LIMIT"))
  if ( is.na(omp_thread_limit) ) omp_thread_limit <- nthread
  nthread <- min(omp_thread_limit,nthread)
 
  options(sd_num_thread=as.integer(nthread))
}

# When necessary and possible, argument is coverted to integers.
ensure_int_list <- function(x){
  if (is.integer(x)|is.numeric(x)) return(list(as.integer(x)))
  if (!is.list(x)) stop("argument must be 'list', 'integer' or 'numeric'")
  if (!all_int(x)){
    lapply(x,as.integer)
  } else {
    x
  }
}

setNames <- function(object, nm){
  names(object) <- nm
  object
}

#' Detect the presence of non-printable or non-ascii characters
#' 
#' @param x a \code{character} vector
#'
#' @details
#' Printable ASCII characters consist of space, \code{A-Z}, \code{a-z}, \code{0-9} and the characters
#'
#' \code{! "" # $ \% & ' ( ) * + , . / : ; < = > ? @@ [ ] \\ ^ _ ` { | } ~ -} 
#'
#' Note that this excludes tab (as it is a control character).
#'
#' 
#' @example ../examples/printable_ascii.R
#'
#'
#' @return A \code{logical} indicating which elements consist solely of printable ASCII characters.
#' @export 
printable_ascii <- function(x){ 
  # To portably detect ASCII characters, we need to specify them literally. Hence this monster of a character class. See ?regexp.

  # notes:
  # - caret (^) at the beginning negates what comes after, the caret in the middle is the actual character.
  # - the closing square bracket ] needs to be specified first
  # - double quote " and backslash are escaped
  # - the dash "-" is specified at the end since it would indicate a range otherwise
  # - see ? regexp.
  charclass <- paste0("[^]"
    , "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
    , "0123456789"
    , " !\"#$%&'()*+,./:;<=>?@[\\^_`{|}~-"
    , "]"
  )  
  !grepl(charclass,x)
}

# check whether all elements of a list are of type 'integer'.
# x MUST be a list.
all_int <- function(x){
  .Call("R_all_int",x,PACKAGE="stringdist")
}