R/utils.R

In glin/dcuolog: Combat Log Parser for DC Universe Online

#' Read text lines from a file.
#'
#' @param file Name of the file to read.
#' @return Character vector of text lines in UTF-8.
#' @importFrom stringi stri_read_lines
#' @export
read_lines <- function(file) {
  if (!is.character(file) || length(file) != 1) {
    stop("invalid 'file' argument", call. = FALSE)
  }

  if (!file.exists(file)) {
    stop(sprintf("file '%s' does not exist", file), call. = FALSE)
  }

  # Auto-detect encoding, but DCUO logs are usually in Latin-1
  stri_read_lines(file, fallback_encoding = "latin1")
}

#' Extract named capture groups from a string.
#' @keywords internal
str_match_named <- function(string, pattern) {
  match_info <- regexpr(pattern, string, perl = TRUE)
  capture_names <- attr(match_info, "capture.names")

  if (is.null(capture_names) || any(capture_names == "")) {
    stop("pattern must have named capture groups")
  }

  matched <- which(match_info > 0)
  start <- attr(match_info, "capture.start")
  end <- start + attr(match_info, "capture.length") - 1

  str_matches <- substring(string[matched], start[matched, ], end[matched, ])
  str_matches <- matrix(str_matches, length(matched), length(capture_names))
  colnames(str_matches) <- capture_names

  structure(str_matches, matched = matched)
}

#' Get names of numeric capture groups from a pattern.
#'
#' @importFrom stringi stri_match_all_regex
#' @keywords internal
get_numeric_groups <- function(pattern) {
  matches <- stri_match_all_regex(pattern, "\\(?<(?<num>[a-zA-Z]+)>\\[0-9\\]",
                                  omit_no_match = TRUE)
  matches[[1]][, 2]
}

#' Sort a `data.table` in place.
#'
#' @param dt A `data.table`.
#' @param sort_by Column to sort by.
#' @param sort_order Sort in "desc" or "asc" order (desc by default).
#' @keywords internal
sort_dt <- function(dt, by, order = c("desc", "asc")) {

  stopifnot(inherits(dt, "data.table"))

  by <- match.arg(by, choices = names(dt))
  order <- match.arg(order)
  setorderv(dt, by, order = ifelse(order == "asc", 1L, -1L))

  dt
}

#' Like `data.table::setcolorder`, but the column order can be a superset of
#' columns in the `data.table`.
#'
#' @keywords internal
set_dt_order <- function(dt, neworder) {
  neworder <- unique(neworder[neworder %in% names(dt)])
  setcolorder(dt, neworder)
}

# Backport of base::endsWith for R < 3.3.0
endsWith <- function(x, suffix) {
  strlen <- nchar(x)
  substr(x, strlen - nchar(suffix) + 1, strlen) == suffix
}