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use crate::*;
use wrapper::symbol::levels_symbol;
/// Iterator over name-value pairs in lists.
pub type NamedListIter = std::iter::Zip<StrIter, ListIter>;
/// Iterator over strings or string factors.
///
/// ```
/// use extendr_api::prelude::*;
/// test! {
/// let robj = r!(["a", "b", "c"]);
/// assert_eq!(robj.as_str_iter().unwrap().collect::<Vec<_>>(), vec!["a", "b", "c"]);
///
/// let factor = factor!(["abcd", "def", "fg", "fg"]);
/// assert_eq!(factor.levels().unwrap().collect::<Vec<_>>(), vec!["abcd", "def", "fg"]);
/// assert_eq!(factor.as_integer_vector().unwrap(), vec![1, 2, 3, 3]);
/// assert_eq!(factor.as_str_iter().unwrap().collect::<Vec<_>>(), vec!["abcd", "def", "fg", "fg"]);
/// assert_eq!(factor.as_str_iter().unwrap().collect::<Vec<_>>(), vec!["abcd", "def", "fg", "fg"]);
/// }
/// ```
#[derive(Clone)]
pub struct StrIter {
vector: Robj,
i: usize,
len: usize,
levels: SEXP,
}
impl Default for StrIter {
fn default() -> Self {
StrIter::new(0)
}
}
impl StrIter {
/// Make an empty str iterator.
pub fn new(len: usize) -> Self {
let vector = if len == 0 { nil_value() } else { na_string() };
unsafe {
Self {
vector,
i: 0,
len,
levels: R_NilValue,
}
}
}
pub fn na_iter(len: usize) -> StrIter {
Self {
len,
..Default::default()
}
}
}
// Get a string reference from a `CHARSXP`
pub(crate) fn str_from_strsxp<'a>(sexp: SEXP, index: usize) -> Option<&'a str> {
single_threaded(|| unsafe {
let charsxp = STRING_ELT(sexp, index as _);
rstr::charsxp_to_str(charsxp)
})
}
impl Iterator for StrIter {
type Item = &'static str;
fn size_hint(&self) -> (usize, Option<usize>) {
(self.len, Some(self.len))
}
fn next(&mut self) -> Option<Self::Item> {
unsafe {
let i = self.i;
self.i += 1;
let vector = self.vector.get();
if i >= self.len {
None
} else if TYPEOF(vector) == SEXPTYPE::NILSXP {
None
} else if TYPEOF(vector) == SEXPTYPE::STRSXP {
str_from_strsxp(vector, i)
} else if vector == R_NaString {
Some(<&str>::na())
} else if TYPEOF(vector) == SEXPTYPE::CHARSXP {
rstr::charsxp_to_str(vector)
} else if Rf_isFactor(vector).into() {
// factor support: factor is an integer, and we need
// the value of it, to retrieve the assigned label
let level_index = std::slice::from_raw_parts(INTEGER(vector), self.len as _);
let level_index = level_index.get(i)?;
let level_index = level_index
.checked_sub(1)
.expect("the factor integer has an invalid value in it");
str_from_strsxp(self.levels, level_index as _)
} else {
None
}
}
}
fn nth(&mut self, n: usize) -> Option<Self::Item> {
self.i += n;
self.next()
}
}
impl ExactSizeIterator for StrIter {
fn len(&self) -> usize {
self.len - self.i
}
}
macro_rules! impl_iter_debug {
($name: ty) => {
impl std::fmt::Debug for $name {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
write!(f, "[")?;
let mut comma = "";
for s in self.clone() {
write!(f, "{}{:?}", comma, s)?;
comma = ", ";
}
write!(f, "]")
}
}
};
}
impl_iter_debug!(ListIter);
impl_iter_debug!(PairlistIter);
impl_iter_debug!(StrIter);
impl_iter_debug!(EnvIter);
// Lets us create a StrIter from an Robj, e.g. Strings or a factor
impl TryFrom<&Robj> for StrIter {
type Error = Error;
fn try_from(value: &Robj) -> Result<Self> {
value
.as_str_iter()
.ok_or_else(|| Error::ExpectedString(value.clone()))
}
}
pub trait AsStrIter: GetSexp + Types + Length + Attributes + Rinternals {
/// Get an iterator over a string vector.
/// Returns None if the object is not a string vector
/// but works for factors.
///
/// ```
/// use extendr_api::prelude::*;
///
/// test! {
/// let obj = Robj::from(vec!["a", "b", "c"]);
/// assert_eq!(obj.as_str_iter().unwrap().collect::<Vec<_>>(), vec!["a", "b", "c"]);
///
/// let factor = factor!(vec!["abcd", "def", "fg", "fg"]);
/// assert_eq!(factor.levels().unwrap().collect::<Vec<_>>(), vec!["abcd", "def", "fg"]);
/// assert_eq!(factor.as_integer_vector().unwrap(), vec![1, 2, 3, 3]);
/// assert_eq!(factor.as_str_iter().unwrap().collect::<Vec<_>>(), vec!["abcd", "def", "fg", "fg"]);
/// assert_eq!(factor.as_str_iter().unwrap().collect::<Vec<_>>(), vec!["abcd", "def", "fg", "fg"]);
///
/// let obj = Robj::from(vec![Some("a"), Some("b"), None]);
/// assert_eq!(obj.as_str_iter().unwrap().map(|s| s.is_na()).collect::<Vec<_>>(), vec![false, false, true]);
///
/// let obj = Robj::from(vec!["a", "b", <&str>::na()]);
/// assert_eq!(obj.as_str_iter().unwrap().map(|s| s.is_na()).collect::<Vec<_>>(), vec![false, false, true]);
///
/// let obj = Robj::from(vec!["a", "b", "NA"]);
/// assert_eq!(obj.as_str_iter().unwrap().map(|s| s.is_na()).collect::<Vec<_>>(), vec![false, false, false]);
/// }
/// ```
fn as_str_iter(&self) -> Option<StrIter> {
let i = 0;
let len = self.len();
if self.sexptype() == SEXPTYPE::STRSXP {
unsafe {
Some(StrIter {
vector: self.as_robj().clone(),
i,
len,
levels: R_NilValue,
})
}
} else if self.sexptype() == SEXPTYPE::CHARSXP {
let len = 1;
unsafe {
Some(StrIter {
vector: self.as_robj().clone(),
i,
len,
levels: R_NilValue,
})
}
} else if self.is_factor() {
let levels = self.get_attrib(levels_symbol()).unwrap();
unsafe {
Some(StrIter {
vector: self.as_robj().clone(),
i,
len,
levels: levels.get(),
})
}
} else {
None
}
}
}
impl AsStrIter for Robj {}
#[cfg(test)]
mod tests {
use extendr_engine::with_r;
use super::*;
#[test]
fn single_charsxp_iterator() {
with_r(|| {
let single_charsxp = blank_string();
let s1: Vec<_> = single_charsxp.as_str_iter().unwrap().collect();
let single_charsxp = blank_scalar_string();
let s2: Vec<_> = single_charsxp.as_str_iter().unwrap().collect();
assert_eq!(s1, s2);
assert_eq!(s1.len(), 1);
assert_eq!(s2.len(), 1);
});
}
#[test]
fn test_new_constructor() {
with_r(|| {
let str_iter = StrIter::new(10);
assert_eq!(str_iter.collect::<Vec<_>>().len(), 10);
let str_iter = StrIter::new(0);
let str_iter_collect = str_iter.collect::<Vec<_>>();
assert_eq!(str_iter_collect.len(), 0);
assert!(str_iter_collect.is_empty());
let mut str_iter = StrIter::new(0);
assert!(str_iter.next().is_none());
});
}
}