R/information_storage.R

In nevrome/txtstorage: A very simple string and number storage system

#' store
#'
#' Store a named value in a storage file. The storage file is created if it does not exist.
#'
#' @param name Character or number. Name of value.
#' @param value Character or number. Value
#' @param path Character. Path to storage file.
#'
#' @export
store <- function(name, value, path) {
  check_if_equal_length(name, value)
  create_storage_if_not_exists(path)
  storage <- read_storage(path)
  for (i in seq_along(name)) {
    storage <- store_single_value_df(storage, name[i], value[i])
  }
  utils::write.csv(storage, file = path, row.names = F)
}

#' read
#' 
#' Read info from the storage file.
#'
#' @param name Character or number. Name of value.
#' @param path Character. Path to storage file.
#'
#' @return Character.
#' 
#' @export
read <- function(name, path) {
  storage <- read_storage(path)
  return(storage$value[storage$name == name])
}



##### helper functions ####

create_storage <- function(path) {
  utils::write.csv(
    data.frame(name = character(), value = character(), stringsAsFactors = F), 
    file = path,
    row.names = F
  )
  message(paste0("Created a new storage file at: ", path))
}

check_if_storage_exists <- function(path) file.exists(path)

create_storage_if_not_exists <- function(path) if (!check_if_storage_exists(path)) create_storage(path)

read_storage <- function(path) utils::read.csv(path, stringsAsFactors = F)

store_single_value_df <- function(storage, name, value) {
  if (any(storage$name == name)) { 
    storage$value[storage$name == name] <- value 
  } else {
    storage <- rbind(storage, data.frame(name, value))
  }
  return(storage)
}

check_if_equal_length <- function(a, b) {
  if (length(a) != length(b)) stop("Input Vectors don't have an equal length.")
}