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/// Macro for consistent implementation of font resource iterators.
macro_rules! impl_iter {
($name:ident, $item:ident) => {
impl<'a> Iterator for $name<'a> {
type Item = $item<'a>;
fn size_hint(&self) -> (usize, Option<usize>) {
let remaining = self.len - self.pos;
(remaining, Some(remaining))
}
fn nth(&mut self, n: usize) -> Option<Self::Item> {
let pos = self.pos.checked_add(n)?;
if pos >= self.len {
self.pos = self.len;
None
} else {
self.pos = pos + 1;
self.get(pos)
}
}
fn next(&mut self) -> Option<Self::Item> {
if self.pos >= self.len {
None
} else {
let pos = self.pos;
self.pos += 1;
self.get(pos)
}
}
}
impl<'a> ExactSizeIterator for $name<'a> {
fn len(&self) -> usize {
self.len - self.pos
}
}
};
}