haven.R

#' @useDynLib haven, .registration = TRUE
#' @importFrom Rcpp sourceCpp
#' @importFrom tibble tibble
#' @importFrom hms hms
NULL

#' Read and write SAS files.
#'
#' Reading supports both sas7bdat files and the accompanying sas7bdat files
#' that SAS uses to record value labels. Writing value labels is not currently
#' supported.
#'
#' @param data_file,catalog_file Path to data and catalog files. The files are
#'   processed with [readr::datasource()].
#' @param data Data frame to write.
#' @param path Path to file where the data will be written.
#' @param encoding,catalog_encoding The character encoding used for the
#'   `data_file` and `catalog_encoding` respectively. A value of `NULL`
#'   uses the encoding specified in the file; use this argument to override it
#'   if it is incorrect.
#' @param cols_only A character vector giving an experimental way to read in
#'   only specified columns.
#' @return A tibble, data frame variant with nice defaults.
#'
#'   Variable labels are stored in the "label" attribute of each variable.
#'   It is not printed on the console, but the RStudio viewer will show it.
#'
#'   `write_sas()` returns the input `data` invisibly.
#' @export
#' @examples
#' path <- system.file("examples", "iris.sas7bdat", package = "haven")
#' read_sas(path)
read_sas <- function(data_file, catalog_file = NULL,
                     encoding = NULL, catalog_encoding = encoding,
                     cols_only = NULL) {
  if (is.null(encoding)) {
    encoding <- ""
  }
  if (is.null(cols_only)) {
    cols_only <- character()
  }

  spec_data <- readr::datasource(data_file)
  if (is.null(catalog_file)) {
    spec_cat <- list()
  } else {
    spec_cat <- readr::datasource(catalog_file)
  }

  switch(class(spec_data)[1],
    source_file = df_parse_sas_file(spec_data, spec_cat, encoding = encoding, catalog_encoding = catalog_encoding, cols_only = cols_only),
    source_raw = df_parse_sas_raw(spec_data, spec_cat, encoding = encoding, catalog_encoding = catalog_encoding, cols_only = cols_only),
    stop("This kind of input is not handled", call. = FALSE)
  )
}

#' @export
#' @rdname read_sas
write_sas <- function(data, path) {
  validate_sas(data)
  write_sas_(data, normalizePath(path, mustWork = FALSE))
  invisible(data)
}

#' Read and write SAS transport files
#'
#' The SAS transport format is a open format, as is required for submission
#' of the data to the FDA.
#'
#' @inheritParams read_spss
#' @return A tibble, data frame variant with nice defaults.
#'
#'   Variable labels are stored in the "label" attribute of each variable.
#'   It is not printed on the console, but the RStudio viewer will show it.
#'
#'   `write_xpt()` returns the input `data` invisibly.
#' @export
#' @examples
#' tmp <- tempfile(fileext = ".xpt")
#' write_xpt(mtcars, tmp)
#' read_xpt(tmp)
read_xpt <- function(file) {
  spec <- readr::datasource(file)
  switch(class(spec)[1],
    source_file = df_parse_xpt_file(spec),
    source_raw = df_parse_xpt_raw(spec),
    stop("This kind of input is not handled", call. = FALSE)
  )
}

#' @export
#' @rdname read_xpt
#' @param version Version of transport file specification to use: either 5 or 8.
#' @param name Member name to record in file. Defaults to file name sans
#'   extension. Must be <= 8 characters for version 5, and <= 32 characters
#'   for version 8.
write_xpt <- function(data, path, version = 8, name = NULL) {
  stopifnot(version %in% c(5, 8))

  if (is.null(name)) {
    name <- tools::file_path_sans_ext(basename(path))
  }
  name <- validate_xpt_name(name, version)

  write_xpt_(
    data,
    normalizePath(path, mustWork = FALSE),
    version = version,
    name = name
  )
  invisible(data)
}

validate_xpt_name <- function(name, version) {
  if (version == 5) {
    if (nchar(name) > 8) {
      stop("`name` must be 8 characters or fewer", call. = FALSE)
    }

  } else {
    if (nchar(name) > 32) {
      stop("`name` must be 32 characters or fewer", call. = FALSE)
    }
  }
  name
}

#' Read SPSS (`.sav`, `.zsav`, `.por`) files. Write `.sav` and `.zsav` files.
#'
#' `read_sav()` reads both `.sav` and `.zsav` files; `write_sav()` creates
#' `.zsav` files when `compress = TRUE`. `read_por()` reads `.por` files.
#' `read_spss()` uses either `read_por()` or `read_sav()` based on the
#' file extension.
#'
#' Currently haven can read and write logical, integer, numeric, character
#' and factors. See [labelled_spss()] for how labelled variables in
#' SPSS are handled in R.
#'
#' @inheritParams readr::datasource
#' @param path Path to a file where the data will be written.
#' @param data Data frame to write.
#' @param encoding The character encoding used for the file. The default,
#'   `NULL`, use the encoding specified in the file, but sometimes this
#'   value is incorrect and it is useful to be able to override it.
#' @return A tibble, data frame variant with nice defaults.
#'
#'   Variable labels are stored in the "label" attribute of each variable.
#'   It is not printed on the console, but the RStudio viewer will show it.
#'
#'   `write_sav()` returns the input `data` invisibly.
#' @name read_spss
#' @examples
#' path <- system.file("examples", "iris.sav", package = "haven")
#' read_sav(path)
#'
#' tmp <- tempfile(fileext = ".sav")
#' write_sav(mtcars, tmp)
#' read_sav(tmp)
NULL

#' @export
#' @rdname read_spss
read_sav <- function(file, encoding = NULL, user_na = FALSE) {
  spec <- readr::datasource(file)
  if (is.null(encoding)) {
    encoding <- ""
  }
  switch(class(spec)[1],
    source_file = df_parse_sav_file(spec, encoding, user_na),
    source_raw = df_parse_sav_raw(spec, encoding, user_na),
    stop("This kind of input is not handled", call. = FALSE)
  )
}

#' @export
#' @rdname read_spss
read_por <- function(file, user_na = FALSE) {
  spec <- readr::datasource(file)

  switch(class(spec)[1],
    source_file = df_parse_por_file(spec, encoding = "", user_na = user_na),
    source_raw = df_parse_por_raw(spec, encoding = "", user_na = user_na),
    stop("This kind of input is not handled", call. = FALSE)
  )
}

#' @export
#' @rdname read_spss
#' @param compress If `TRUE`, will compress the file, resulting in a `.zsav`
#'   file.
write_sav <- function(data, path, compress = FALSE) {
  validate_sav(data)
  write_sav_(data, normalizePath(path, mustWork = FALSE), compress = compress)
  invisible(data)
}


#' @export
#' @rdname read_spss
#' @param user_na If `TRUE` variables with user defined missing will
#'   be read into [labelled_spss()] objects. If `FALSE`, the
#'   default, user-defined missings will be converted to `NA`.
read_spss <- function(file, user_na = FALSE) {
  ext <- tolower(tools::file_ext(file))

  switch(ext,
    sav = read_sav(file, user_na = user_na),
    zsav = read_sav(file, user_na = user_na),
    por = read_por(file, user_na = user_na),
    stop("Unknown extension '.", ext, "'", call. = FALSE)
  )
}

#' Read and write Stata DTA files.
#'
#' Currently haven can read and write logical, integer, numeric, character
#' and factors. See [labelled()] for how labelled variables in
#' Stata are handled in R.
#'
#' @section Character encoding:
#' Prior to Stata 14, files did not declare a text encoding, and the
#' default encoding differed across platforms. If `encoding = NULL`,
#' haven assumes the encoding is windows-1252, the text encoding used by
#' Stata on Windows. Unfortunately Stata on Mac and Linux use a different
#' default encoding, "latin1". If you encounter an error such as
#' "Unable to convert string to the requested encoding", try
#' `encoding = "latin1"`
#'
#' For Stata 14 and later, you should not need to manually specify `encoding`
#' value unless the value was incorrectly recorded in the source file.
#'
#' @inheritParams readr::datasource
#' @inheritParams read_spss
#' @param encoding The character encoding used for the file. Generally,
#'   only needed for Stata 13 files and earlier. See Encoding section
#'   for details.
#' @return A tibble, data frame variant with nice defaults.
#'
#'   Variable labels are stored in the "label" attribute of each variable.
#'   It is not printed on the console, but the RStudio viewer will show it.
#'
#'   `write_dta()` returns the input `data` invisibly.
#' @export
#' @examples
#' path <- system.file("examples", "iris.dta", package = "haven")
#' read_dta(path)
#'
#' tmp <- tempfile(fileext = ".dta")
#' write_dta(mtcars, tmp)
#' read_dta(tmp)
#' read_stata(tmp)
read_dta <- function(file, encoding = NULL) {
  if (is.null(encoding)) {
    encoding <- ""
  }

  spec <- readr::datasource(file)
  switch(class(spec)[1],
    source_file = df_parse_dta_file(spec, encoding),
    source_raw = df_parse_dta_raw(spec, encoding),
    stop("This kind of input is not handled", call. = FALSE)
  )
}

#' @export
#' @rdname read_dta
read_stata <- function(file, encoding = NULL) {
  read_dta(file, encoding)
}

#' @export
#' @rdname read_dta
#' @param version File version to use. Supports versions 8-15.
write_dta <- function(data, path, version = 14) {
  validate_dta(data, version = version)
  write_dta_(data,
    normalizePath(path, mustWork = FALSE),
    version = stata_file_format(version)
  )
  invisible(data)
}

stata_file_format <- function(version) {
  stopifnot(is.numeric(version), length(version) == 1)
  version <- as.integer(version)

  if (version == 15L) {
    119
  } else if (version == 14L) {
    118
  } else if (version == 13L) {
    117
  } else if (version == 12L) {
    115
  } else if (version %in% c(10L, 11L)) {
    114
  } else if (version %in% c(8L, 9L)) {
    113
  } else {
    stop("Version ", version, " not currently supported", call. = FALSE)
  }
}

validate_dta <- function(data, version) {
  stopifnot(is.data.frame(data))

  # Check variable names
  bad_names <- !grepl("^[A-Za-z_]{1}[A-Za-z0-9_]{0,31}$", names(data))
  if (version < 14 && any(bad_names)) {
    stop(
      "The following variable names are not valid Stata variables: ",
      var_names(data, bad_names),
      call. = FALSE
    )
  }

  # Check for labelled double vectors
  is_labelled <- vapply(data, is.labelled, logical(1))
  is_integer <- vapply(data, is_integerish, logical(1))
  bad_labels <- is_labelled & !is_integer
  if (any(bad_labels)) {
    stop(
      "Stata only supports labelled integers.\nProblems: ",
      var_names(data, bad_labels),
      call. = FALSE
    )
  }
}

validate_sav <- function(data) {
  stopifnot(is.data.frame(data))

  # Check factor lengths
  level_lengths <- vapply(data, max_level_length, integer(1))

  bad_lengths <- level_lengths > 120
  if (any(bad_lengths)) {
    stop(
      "SPSS only supports levels with <= 120 characters\n",
      "Problems: ", var_names(data, bad_lengths),
      call. = FALSE
    )
  }
}

validate_sas <- function(data) {
  stopifnot(is.data.frame(data))

}

var_names <- function(data, i) {
  x <- names(data)[i]
  paste(encodeString(x, quote = "`"), collapse = ", ")
}