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Diffstat (limited to 'vendor/bitflags/src/iter.rs')
-rw-r--r-- | vendor/bitflags/src/iter.rs | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/vendor/bitflags/src/iter.rs b/vendor/bitflags/src/iter.rs new file mode 100644 index 0000000..7f7ce55 --- /dev/null +++ b/vendor/bitflags/src/iter.rs @@ -0,0 +1,145 @@ +/*! +Yield the bits of a source flags value in a set of contained flags values. +*/ + +use crate::{Flag, Flags}; + +/** +An iterator over flags values. + +This iterator will yield flags values for contained, defined flags first, with any remaining bits yielded +as a final flags value. +*/ +pub struct Iter<B: 'static> { + inner: IterNames<B>, + done: bool, +} + +impl<B: Flags> Iter<B> { + pub(crate) fn new(flags: &B) -> Self { + Iter { + inner: IterNames::new(flags), + done: false, + } + } +} + +impl<B: 'static> Iter<B> { + // Used by the `bitflags` macro + #[doc(hidden)] + pub const fn __private_const_new(flags: &'static [Flag<B>], source: B, remaining: B) -> Self { + Iter { + inner: IterNames::__private_const_new(flags, source, remaining), + done: false, + } + } +} + +impl<B: Flags> Iterator for Iter<B> { + type Item = B; + + fn next(&mut self) -> Option<Self::Item> { + match self.inner.next() { + Some((_, flag)) => Some(flag), + None if !self.done => { + self.done = true; + + // After iterating through valid names, if there are any bits left over + // then return one final value that includes them. This makes `into_iter` + // and `from_iter` roundtrip + if !self.inner.remaining().is_empty() { + Some(B::from_bits_retain(self.inner.remaining.bits())) + } else { + None + } + } + None => None, + } + } +} + +/** +An iterator over flags values. + +This iterator only yields flags values for contained, defined, named flags. Any remaining bits +won't be yielded, but can be found with the [`IterNames::remaining`] method. +*/ +pub struct IterNames<B: 'static> { + flags: &'static [Flag<B>], + idx: usize, + source: B, + remaining: B, +} + +impl<B: Flags> IterNames<B> { + pub(crate) fn new(flags: &B) -> Self { + IterNames { + flags: B::FLAGS, + idx: 0, + remaining: B::from_bits_retain(flags.bits()), + source: B::from_bits_retain(flags.bits()), + } + } +} + +impl<B: 'static> IterNames<B> { + // Used by the bitflags macro + #[doc(hidden)] + pub const fn __private_const_new(flags: &'static [Flag<B>], source: B, remaining: B) -> Self { + IterNames { + flags, + idx: 0, + remaining, + source, + } + } + + /// Get a flags value of any remaining bits that haven't been yielded yet. + /// + /// Once the iterator has finished, this method can be used to + /// check whether or not there are any bits that didn't correspond + /// to a contained, defined, named flag remaining. + pub fn remaining(&self) -> &B { + &self.remaining + } +} + +impl<B: Flags> Iterator for IterNames<B> { + type Item = (&'static str, B); + + fn next(&mut self) -> Option<Self::Item> { + while let Some(flag) = self.flags.get(self.idx) { + // Short-circuit if our state is empty + if self.remaining.is_empty() { + return None; + } + + self.idx += 1; + + // Skip unnamed flags + if flag.name().is_empty() { + continue; + } + + let bits = flag.value().bits(); + + // If the flag is set in the original source _and_ it has bits that haven't + // been covered by a previous flag yet then yield it. These conditions cover + // two cases for multi-bit flags: + // + // 1. When flags partially overlap, such as `0b00000001` and `0b00000101`, we'll + // yield both flags. + // 2. When flags fully overlap, such as in convenience flags that are a shorthand for others, + // we won't yield both flags. + if self.source.contains(B::from_bits_retain(bits)) + && self.remaining.intersects(B::from_bits_retain(bits)) + { + self.remaining.remove(B::from_bits_retain(bits)); + + return Some((flag.name(), B::from_bits_retain(bits))); + } + } + + None + } +} |