adaptivegrain/vapoursynth/src/map/iterators.rs
2019-05-30 11:06:53 +00:00

119 lines
3.3 KiB
Rust

use std::borrow::Cow;
use super::*;
/// An iterator over the keys of a map.
#[derive(Debug, Clone, Copy)]
pub struct Keys<'map, 'elem: 'map> {
map: &'map Map<'elem>,
count: usize,
index: usize,
}
impl<'map, 'elem> Keys<'map, 'elem> {
#[inline]
pub(crate) fn new(map: &'map Map<'elem>) -> Self {
Self {
map,
count: map.key_count(),
index: 0,
}
}
}
impl<'map, 'elem> Iterator for Keys<'map, 'elem> {
type Item = &'map str;
#[inline]
fn next(&mut self) -> Option<Self::Item> {
if self.index == self.count {
return None;
}
let key = self.map.key(self.index);
self.index += 1;
Some(key)
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
let len = self.count - self.index;
(len, Some(len))
}
}
impl<'map, 'elem> ExactSizeIterator for Keys<'map, 'elem> {}
/// An iterator over the values associated with a certain key of a map.
#[derive(Debug, Clone)]
pub struct ValueIter<'map, 'elem: 'map, T> {
map: &'map Map<'elem>,
key: CString,
count: i32,
index: i32,
_variance: PhantomData<fn() -> T>,
}
macro_rules! impl_value_iter {
($value_type:path, $type:ty, $func:ident) => {
impl<'map, 'elem> ValueIter<'map, 'elem, $type> {
/// Creates a `ValueIter` from the given `map` and `key`.
///
/// # Safety
/// The caller must ensure `key` is valid.
#[inline]
pub(crate) unsafe fn new(map: &'map Map<'elem>, key: CString) -> Result<Self> {
// Check if the value type is correct.
match map.value_type_raw_unchecked(&key)? {
$value_type => {}
_ => return Err(Error::WrongValueType),
};
let count = map.value_count_raw_unchecked(&key)? as i32;
Ok(Self {
map,
key,
count,
index: 0,
_variance: PhantomData,
})
}
}
impl<'map, 'elem> Iterator for ValueIter<'map, 'elem, $type> {
type Item = $type;
#[inline]
fn next(&mut self) -> Option<Self::Item> {
if self.index == self.count {
return None;
}
let value = unsafe { self.map.$func(&self.key, self.index).unwrap() };
self.index += 1;
Some(value)
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
let len = (self.count - self.index) as usize;
(len, Some(len))
}
}
impl<'map, 'elem> ExactSizeIterator for ValueIter<'map, 'elem, $type> {}
};
}
impl_value_iter!(ValueType::Int, i64, get_int_raw_unchecked);
impl_value_iter!(ValueType::Float, f64, get_float_raw_unchecked);
impl_value_iter!(ValueType::Data, &'map [u8], get_data_raw_unchecked);
impl_value_iter!(ValueType::Node, Node<'elem>, get_node_raw_unchecked);
impl_value_iter!(ValueType::Frame, FrameRef<'elem>, get_frame_raw_unchecked);
impl_value_iter!(
ValueType::Function,
Function<'elem>,
get_function_raw_unchecked
);