R/execute_file.R

In JohannesFriedrich/HypeRIMU: Analysing Sensor Data from Smartphones

#' Performs data acquisition from local file
#'
#' @param file [character] (**required**): Path or file to be imported.
#' @param timestamp [logical] (**optional**): Is a timestamp available in the data?
#' @examples
#' ##=====================================
#' ## Example 1: read data from local file
#' ##=====================================
#'
#' file <- system.file("extdata", "short_y_impulse.csv", package="HypeRIMU")
#'
#' data <- execute_file(file, timestamp = TRUE)
#'
#' @md
#' @export

execute_file <- function(file, timestamp = FALSE) {

  ##============================================================================##
  ##ERROR HANDLING
  ##============================================================================##

  if(missing(file))
    stop("[execute_file()] Argument 'file' is missing", call. = FALSE)

  if(class(file) != "character")
    stop("[execute_file()] Argument 'file' has to be of type character", call. = FALSE)

  if(class(timestamp) != "logical")
    stop("[execute_file()] Argument 'timestamp' has to be of type logical",  call. = FALSE)

  ## Read data
  sensor_data_all <- read.csv(file = file,
                              skip = 3)

  ##check if timestamp = FALSE, but data suggest to have one:
  if(!timestamp && (ncol(sensor_data_all) %% 3 == 1)){
    cat("\n[execute_file()]: ")
    cat("Timestamp detected. Used first coloumn as timestamp.\n")
    timestamp <- TRUE

  }

  if(timestamp && ncol(sensor_data_all) %% 3 != 1){
    cat("\n[execute_file()]: ")
    cat("No timestamp detected, but argument 'timestamp = TRUE`. Set to 'FALSE'.\n")
    timestamp <- FALSE
  }

  if(!timestamp){

    ## Extract sampling time from file (is in the second line)
    samplingTime <- readLines(con = file, n = 2)[2] %>%
      strsplit(" ") %>%
      unlist() %>%
      dplyr::last()

    samplingTime <- gsub("[^0-9]", "", samplingTime) %>%
      as.numeric()

    sensor_data_all$timestamp <- seq(0, (nrow(sensor_data_all) - 1)*samplingTime, samplingTime)
  } else { # convert from UNIX time
    sensor_data_all[,1] <- as.POSIXct(sensor_data_all$timestamp/1000, origin = "1970-01-01")
  }

  return(sensor_data_all)
}