Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1286 insertions, 0 deletions

diff --git a/third_party/rust/flagset/src/lib.rs b/third_party/rust/flagset/src/lib.rs
new file mode 100644
index 0000000000..220af6ba75
--- /dev/null
+++ b/third_party/rust/flagset/src/lib.rs
@@ -0,0 +1,1286 @@
+//
+// Copyright 2019 Red Hat, Inc.
+//
+// Author: Nathaniel McCallum <npmccallum@redhat.com>
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+//! # Welcome to FlagSet!
+//!
+//! FlagSet is a new, ergonomic approach to handling flags that combines the
+//! best of existing crates like `bitflags` and `enumflags` without their
+//! downsides.
+//!
+//! ## Existing Implementations
+//!
+//! The `bitflags` crate has long been part of the Rust ecosystem.
+//! Unfortunately, it doesn't feel like natural Rust. The `bitflags` crate
+//! uses a wierd struct format to define flags. Flags themselves are just
+//! integers constants, so there is little type-safety involved. But it doesn't
+//! have any dependencies. It also allows you to define implied flags (otherwise
+//! known as overlapping flags).
+//!
+//! The `enumflags` crate tried to improve on `bitflags` by using enumerations
+//! to define flags. This was a big improvement to the natural feel of the code.
+//! Unfortunately, there are some design flaws. To generate the flags,
+//! procedural macros were used. This implied two separate crates plus
+//! additional dependencies. Further, `enumflags` specifies the size of the
+//! flags using a `repr($size)` attribute. Unfortunately, this attribute
+//! cannot resolve type aliases, such as `c_int`. This makes `enumflags` a
+//! poor fit for FFI, which is the most important place for a flags library.
+//! The `enumflags` crate also disallows overlapping flags and is not
+//! maintained.
+//!
+//! FlagSet improves on both of these by adopting the `enumflags` natural feel
+//! and the `bitflags` mode of flag generation; as well as additional API usage
+//! niceties. FlagSet has no dependencies and is extensively documented and
+//! tested. It also tries very hard to prevent you from making mistakes by
+//! avoiding external usage of the integer types. FlagSet is also a zero-cost
+//! abstraction: all functions are inlineable and should reduce to the core
+//! integer operations. FlagSet also does not depend on stdlib, so it can be
+//! used in `no_std` libraries and applications.
+//!
+//! ## Defining Flags
+//!
+//! Flags are defined using the `flags!` macro:
+//!
+//! ```
+//! use flagset::{FlagSet, flags};
+//! use std::os::raw::c_int;
+//!
+//! flags! {
+//!     enum FlagsA: u8 {
+//!         Foo,
+//!         Bar,
+//!         Baz,
+//!     }
+//!
+//!     enum FlagsB: c_int {
+//!         Foo,
+//!         Bar,
+//!         Baz,
+//!     }
+//! }
+//! ```
+//!
+//! Notice that a flag definition looks just like a regular enumeration, with
+//! the addition of the field-size type. The field-size type is required and
+//! can be either a type or a type alias. Both examples are given above.
+//!
+//! Also note that the field-size type specifies the size of the corresponding
+//! `FlagSet` type, not size of the enumeration itself. To specify the size of
+//! the enumeration, use the `repr($size)` attribute as specified below.
+//!
+//! ## Flag Values
+//!
+//! Flags often need values assigned to them. This can be done implicitly,
+//! where the value depends on the order of the flags:
+//!
+//! ```
+//! use flagset::{FlagSet, flags};
+//!
+//! flags! {
+//!     enum Flags: u16 {
+//!         Foo, // Implicit Value: 0b0001
+//!         Bar, // Implicit Value: 0b0010
+//!         Baz, // Implicit Value: 0b0100
+//!     }
+//! }
+//! ```
+//!
+//! Alternatively, flag values can be defined explicitly, by specifying any
+//! `const` expression:
+//!
+//! ```
+//! use flagset::{FlagSet, flags};
+//!
+//! flags! {
+//!     enum Flags: u16 {
+//!         Foo = 0x01,   // Explicit Value: 0b0001
+//!         Bar = 2,      // Explicit Value: 0b0010
+//!         Baz = 0b0100, // Explicit Value: 0b0100
+//!     }
+//! }
+//! ```
+//!
+//! Flags can also overlap or "imply" other flags:
+//!
+//! ```
+//! use flagset::{FlagSet, flags};
+//!
+//! flags! {
+//!     enum Flags: u16 {
+//!         Foo = 0b0001,
+//!         Bar = 0b0010,
+//!         Baz = 0b0110, // Implies Bar
+//!         All = (Flags::Foo | Flags::Bar | Flags::Baz).bits(),
+//!     }
+//! }
+//! ```
+//!
+//! ## Specifying Attributes
+//!
+//! Attributes can be used on the enumeration itself or any of the values:
+//!
+//! ```
+//! use flagset::{FlagSet, flags};
+//!
+//! flags! {
+//!     #[derive(PartialOrd, Ord)]
+//!     enum Flags: u8 {
+//!         Foo,
+//!         #[deprecated]
+//!         Bar,
+//!         Baz,
+//!     }
+//! }
+//! ```
+//!
+//! ## Collections of Flags
+//!
+//! A collection of flags is a `FlagSet<T>`. If you are storing the flags in
+//! memory, the raw `FlagSet<T>` type should be used. However, if you want to
+//! receive flags as an input to a function, you should use
+//! `impl Into<FlagSet<T>>`. This allows for very ergonomic APIs:
+//!
+//! ```
+//! use flagset::{FlagSet, flags};
+//!
+//! flags! {
+//!     enum Flags: u8 {
+//!         Foo,
+//!         Bar,
+//!         Baz,
+//!     }
+//! }
+//!
+//! struct Container(FlagSet<Flags>);
+//!
+//! impl Container {
+//!     fn new(flags: impl Into<FlagSet<Flags>>) -> Container {
+//!         Container(flags.into())
+//!     }
+//! }
+//!
+//! assert_eq!(Container::new(Flags::Foo | Flags::Bar).0.bits(), 0b011);
+//! assert_eq!(Container::new(Flags::Foo).0.bits(), 0b001);
+//! assert_eq!(Container::new(None).0.bits(), 0b000);
+//! ```
+//!
+//! ## Operations
+//!
+//! Operations can be performed on a `FlagSet<F>` or on individual flags:
+//!
+//! | Operator | Assignment Operator | Meaning                |
+//! |----------|---------------------|------------------------|
+//! | \|       | \|=                 | Union                  |
+//! | &        | &=                  | Intersection           |
+//! | ^        | ^=                  | Toggle specified flags |
+//! | -        | -=                  | Difference             |
+//! | %        | %=                  | Symmetric difference   |
+//! | !        |                     | Toggle all flags       |
+//!
+#![cfg_attr(
+    feature = "serde",
+    doc = r#"
+
+## Optional Serde support
+
+[Serde] support can be enabled with the 'serde' feature flag. You can then serialize and
+deserialize `FlagSet<T>` to and from any of the [supported formats]:
+
+ ```
+ use flagset::{FlagSet, flags};
+
+ flags! {
+     enum Flags: u8 {
+         Foo,
+         Bar,
+     }
+ }
+
+ let flagset = Flags::Foo | Flags::Bar;
+ let json = serde_json::to_string(&flagset).unwrap();
+ let flagset: FlagSet<Flags> = serde_json::from_str(&json).unwrap();
+ assert_eq!(flagset.bits(), 0b011);
+ ```
+
+For serialization and deserialization of flags enum itself, you can use the [`serde_repr`] crate
+(or implement `serde::ser::Serialize` and `serde:de::Deserialize` manually), combined with the
+appropriate `repr` attribute:
+
+ ```
+ use flagset::{FlagSet, flags};
+ use serde_repr::{Serialize_repr, Deserialize_repr};
+
+ flags! {
+    #[repr(u8)]
+    #[derive(Deserialize_repr, Serialize_repr)]
+    enum Flags: u8 {
+         Foo,
+         Bar,
+    }
+ }
+
+ let json = serde_json::to_string(&Flags::Foo).unwrap();
+ let flag: Flags = serde_json::from_str(&json).unwrap();
+ assert_eq!(flag, Flags::Foo);
+ ```
+
+[Serde]: https://serde.rs/
+[supported formats]: https://serde.rs/#data-formats
+[`serde_repr`]: https://crates.io/crates/serde_repr
+"#
+)]
+#![allow(unknown_lints)]
+#![warn(clippy::all)]
+#![no_std]
+
+use core::fmt::{Debug, Formatter, Result};
+use core::ops::*;
+
+/// Error type returned when creating a new flagset from bits is invalid or undefined.
+/// ```
+/// use flagset::{FlagSet, flags};
+///
+/// flags! {
+///     pub enum Flag: u16 {
+///         Foo = 0b0001,
+///         Bar = 0b0010,
+///         Baz = 0b0100,
+///         Qux = 0b1010, // Implies Bar
+///     }
+/// }
+///
+/// assert_eq!(FlagSet::<Flag>::new(0b01101), Err(flagset::InvalidBits)); // Invalid
+/// assert_eq!(FlagSet::<Flag>::new(0b10101), Err(flagset::InvalidBits)); // Unknown
+/// ```
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub struct InvalidBits;
+
+impl core::fmt::Display for InvalidBits {
+    #[inline]
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        write!(f, "invalid bits")
+    }
+}
+
+#[doc(hidden)]
+pub trait Flags:
+    Copy
+    + Clone
+    + Debug
+    + PartialEq
+    + Eq
+    + BitAnd<Self, Output = FlagSet<Self>>
+    + BitOr<Self, Output = FlagSet<Self>>
+    + BitXor<Self, Output = FlagSet<Self>>
+    + Sub<Self, Output = FlagSet<Self>>
+    + Rem<Self, Output = FlagSet<Self>>
+    + Not<Output = FlagSet<Self>>
+    + Into<FlagSet<Self>>
+    + 'static
+{
+    type Type: Copy
+        + Clone
+        + Debug
+        + PartialEq
+        + Eq
+        + Default
+        + BitAnd<Self::Type, Output = Self::Type>
+        + BitAndAssign<Self::Type>
+        + BitOr<Self::Type, Output = Self::Type>
+        + BitOrAssign<Self::Type>
+        + BitXor<Self::Type, Output = Self::Type>
+        + BitXorAssign<Self::Type>
+        + Not<Output = Self::Type>;
+
+    /// A slice containing all the possible flag values.
+    const LIST: &'static [Self];
+
+    /// Creates an empty `FlagSet` of this type
+    #[inline]
+    fn none() -> FlagSet<Self> {
+        FlagSet::default()
+    }
+}
+
+#[derive(Copy, Clone, Eq)]
+pub struct FlagSet<F: Flags>(F::Type);
+
+#[doc(hidden)]
+#[derive(Copy, Clone)]
+pub struct Iter<F: Flags>(FlagSet<F>, usize);
+
+impl<F: Flags> Iterator for Iter<F> {
+    type Item = F;
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        while self.1 < F::LIST.len() {
+            let next = F::LIST[self.1];
+            self.1 += 1;
+
+            if self.0.contains(next) {
+                return Some(next);
+            }
+        }
+
+        None
+    }
+}
+
+impl<F: Flags> IntoIterator for FlagSet<F> {
+    type Item = F;
+    type IntoIter = Iter<F>;
+
+    /// Iterate over the flags in the set.
+    ///
+    /// **NOTE**: The order in which the flags are iterated is undefined.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     enum Flag: u8 {
+    ///         Foo = 0b001,
+    ///         Bar = 0b010,
+    ///         Baz = 0b100
+    ///     }
+    /// }
+    ///
+    /// let set = Flag::Foo | Flag::Bar;
+    /// let mut iter = set.into_iter();
+    /// assert_eq!(iter.next(), Some(Flag::Foo));
+    /// assert_eq!(iter.next(), Some(Flag::Bar));
+    /// assert_eq!(iter.next(), None);
+    /// ```
+    #[inline]
+    fn into_iter(self) -> Self::IntoIter {
+        Iter(self, 0)
+    }
+}
+
+impl<F: Flags> Debug for FlagSet<F> {
+    #[inline]
+    fn fmt(&self, f: &mut Formatter) -> Result {
+        write!(f, "FlagSet(")?;
+        for (i, flag) in self.into_iter().enumerate() {
+            write!(f, "{}{:?}", if i > 0 { " | " } else { "" }, flag)?;
+        }
+        write!(f, ")")
+    }
+}
+
+impl<F: Flags, R: Copy + Into<FlagSet<F>>> PartialEq<R> for FlagSet<F> {
+    #[inline]
+    fn eq(&self, rhs: &R) -> bool {
+        self.0 == (*rhs).into().0
+    }
+}
+
+impl<F: Flags> AsRef<F::Type> for FlagSet<F> {
+    #[inline]
+    fn as_ref(&self) -> &F::Type {
+        &self.0
+    }
+}
+
+impl<F: Flags> From<Option<FlagSet<F>>> for FlagSet<F> {
+    /// Converts from `Option<FlagSet<F>>` to `FlagSet<F>`.
+    ///
+    /// Most notably, this allows for the use of `None` in many places to
+    /// substitute for manually creating an empty `FlagSet<F>`. See below.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     enum Flag: u8 {
+    ///         Foo = 0b001,
+    ///         Bar = 0b010,
+    ///         Baz = 0b100
+    ///     }
+    /// }
+    ///
+    /// fn convert(v: impl Into<FlagSet<Flag>>) -> u8 {
+    ///     v.into().bits()
+    /// }
+    ///
+    /// assert_eq!(convert(Flag::Foo | Flag::Bar), 0b011);
+    /// assert_eq!(convert(Flag::Foo), 0b001);
+    /// assert_eq!(convert(None), 0b000);
+    /// ```
+    #[inline]
+    fn from(value: Option<FlagSet<F>>) -> FlagSet<F> {
+        value.unwrap_or_default()
+    }
+}
+
+impl<F: Flags> Default for FlagSet<F> {
+    /// Creates a new, empty FlagSet.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     enum Flag: u8 {
+    ///         Foo = 0b001,
+    ///         Bar = 0b010,
+    ///         Baz = 0b100
+    ///     }
+    /// }
+    ///
+    /// let set = FlagSet::<Flag>::default();
+    /// assert!(set.is_empty());
+    /// assert!(!set.is_full());
+    /// assert!(!set.contains(Flag::Foo));
+    /// assert!(!set.contains(Flag::Bar));
+    /// assert!(!set.contains(Flag::Baz));
+    /// ```
+    #[inline]
+    fn default() -> Self {
+        FlagSet(F::Type::default())
+    }
+}
+
+impl<F: Flags> Not for FlagSet<F> {
+    type Output = Self;
+
+    /// Calculates the complement of the current set.
+    ///
+    /// In common parlance, this returns the set of all possible flags that are
+    /// not in the current set.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     #[derive(PartialOrd, Ord)]
+    ///     enum Flag: u8 {
+    ///         Foo = 1 << 0,
+    ///         Bar = 1 << 1,
+    ///         Baz = 1 << 2
+    ///     }
+    /// }
+    ///
+    /// let set = !FlagSet::from(Flag::Foo);
+    /// assert!(!set.is_empty());
+    /// assert!(!set.is_full());
+    /// assert!(!set.contains(Flag::Foo));
+    /// assert!(set.contains(Flag::Bar));
+    /// assert!(set.contains(Flag::Baz));
+    /// ```
+    #[inline]
+    fn not(self) -> Self {
+        FlagSet(!self.0)
+    }
+}
+
+impl<F: Flags, R: Into<FlagSet<F>>> BitAnd<R> for FlagSet<F> {
+    type Output = Self;
+
+    /// Calculates the intersection of the current set and the specified flags.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     #[derive(PartialOrd, Ord)]
+    ///     pub enum Flag: u8 {
+    ///         Foo = 0b001,
+    ///         Bar = 0b010,
+    ///         Baz = 0b100
+    ///     }
+    /// }
+    ///
+    /// let set0 = Flag::Foo | Flag::Bar;
+    /// let set1 = Flag::Baz | Flag::Bar;
+    /// assert_eq!(set0 & set1, Flag::Bar);
+    /// assert_eq!(set0 & Flag::Foo, Flag::Foo);
+    /// assert_eq!(set1 & Flag::Baz, Flag::Baz);
+    /// ```
+    #[inline]
+    fn bitand(self, rhs: R) -> Self {
+        FlagSet(self.0 & rhs.into().0)
+    }
+}
+
+impl<F: Flags, R: Into<FlagSet<F>>> BitAndAssign<R> for FlagSet<F> {
+    /// Assigns the intersection of the current set and the specified flags.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     enum Flag: u64 {
+    ///         Foo = 0b001,
+    ///         Bar = 0b010,
+    ///         Baz = 0b100
+    ///     }
+    /// }
+    ///
+    /// let mut set0 = Flag::Foo | Flag::Bar;
+    /// let mut set1 = Flag::Baz | Flag::Bar;
+    ///
+    /// set0 &= set1;
+    /// assert_eq!(set0, Flag::Bar);
+    ///
+    /// set1 &= Flag::Baz;
+    /// assert_eq!(set0, Flag::Bar);
+    /// ```
+    #[inline]
+    fn bitand_assign(&mut self, rhs: R) {
+        self.0 &= rhs.into().0
+    }
+}
+
+impl<F: Flags, R: Into<FlagSet<F>>> BitOr<R> for FlagSet<F> {
+    type Output = Self;
+
+    /// Calculates the union of the current set with the specified flags.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     #[derive(PartialOrd, Ord)]
+    ///     pub enum Flag: u8 {
+    ///         Foo = 0b001,
+    ///         Bar = 0b010,
+    ///         Baz = 0b100
+    ///     }
+    /// }
+    ///
+    /// let set0 = Flag::Foo | Flag::Bar;
+    /// let set1 = Flag::Baz | Flag::Bar;
+    /// assert_eq!(set0 | set1, FlagSet::full());
+    /// ```
+    #[inline]
+    fn bitor(self, rhs: R) -> Self {
+        FlagSet(self.0 | rhs.into().0)
+    }
+}
+
+impl<F: Flags, R: Into<FlagSet<F>>> BitOrAssign<R> for FlagSet<F> {
+    /// Assigns the union of the current set with the specified flags.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     enum Flag: u64 {
+    ///         Foo = 0b001,
+    ///         Bar = 0b010,
+    ///         Baz = 0b100
+    ///     }
+    /// }
+    ///
+    /// let mut set0 = Flag::Foo | Flag::Bar;
+    /// let mut set1 = Flag::Bar | Flag::Baz;
+    ///
+    /// set0 |= set1;
+    /// assert_eq!(set0, FlagSet::full());
+    ///
+    /// set1 |= Flag::Baz;
+    /// assert_eq!(set1, Flag::Bar | Flag::Baz);
+    /// ```
+    #[inline]
+    fn bitor_assign(&mut self, rhs: R) {
+        self.0 |= rhs.into().0
+    }
+}
+
+impl<F: Flags, R: Into<FlagSet<F>>> BitXor<R> for FlagSet<F> {
+    type Output = Self;
+
+    /// Calculates the current set with the specified flags toggled.
+    ///
+    /// This is commonly known as toggling the presence
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     enum Flag: u32 {
+    ///         Foo = 0b001,
+    ///         Bar = 0b010,
+    ///         Baz = 0b100
+    ///     }
+    /// }
+    ///
+    /// let set0 = Flag::Foo | Flag::Bar;
+    /// let set1 = Flag::Baz | Flag::Bar;
+    /// assert_eq!(set0 ^ set1, Flag::Foo | Flag::Baz);
+    /// assert_eq!(set0 ^ Flag::Foo, Flag::Bar);
+    /// ```
+    #[inline]
+    fn bitxor(self, rhs: R) -> Self {
+        FlagSet(self.0 ^ rhs.into().0)
+    }
+}
+
+impl<F: Flags, R: Into<FlagSet<F>>> BitXorAssign<R> for FlagSet<F> {
+    /// Assigns the current set with the specified flags toggled.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     enum Flag: u16 {
+    ///         Foo = 0b001,
+    ///         Bar = 0b010,
+    ///         Baz = 0b100
+    ///     }
+    /// }
+    ///
+    /// let mut set0 = Flag::Foo | Flag::Bar;
+    /// let mut set1 = Flag::Baz | Flag::Bar;
+    ///
+    /// set0 ^= set1;
+    /// assert_eq!(set0, Flag::Foo | Flag::Baz);
+    ///
+    /// set1 ^= Flag::Baz;
+    /// assert_eq!(set1, Flag::Bar);
+    /// ```
+    #[inline]
+    fn bitxor_assign(&mut self, rhs: R) {
+        self.0 ^= rhs.into().0
+    }
+}
+
+impl<F: Flags, R: Into<FlagSet<F>>> Sub<R> for FlagSet<F> {
+    type Output = Self;
+
+    /// Calculates set difference (the current set without the specified flags).
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     pub enum Flag: u8 {
+    ///         Foo = 1,
+    ///         Bar = 2,
+    ///         Baz = 4
+    ///     }
+    /// }
+    ///
+    /// let set0 = Flag::Foo | Flag::Bar;
+    /// let set1 = Flag::Baz | Flag::Bar;
+    /// assert_eq!(set0 - set1, Flag::Foo);
+    /// ```
+    #[inline]
+    fn sub(self, rhs: R) -> Self {
+        self & !rhs.into()
+    }
+}
+
+impl<F: Flags, R: Into<FlagSet<F>>> SubAssign<R> for FlagSet<F> {
+    /// Assigns set difference (the current set without the specified flags).
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     pub enum Flag: u8 {
+    ///         Foo = 1,
+    ///         Bar = 2,
+    ///         Baz = 4
+    ///     }
+    /// }
+    ///
+    /// let mut set0 = Flag::Foo | Flag::Bar;
+    /// set0 -= Flag::Baz | Flag::Bar;
+    /// assert_eq!(set0, Flag::Foo);
+    /// ```
+    #[inline]
+    fn sub_assign(&mut self, rhs: R) {
+        *self &= !rhs.into();
+    }
+}
+
+impl<F: Flags, R: Into<FlagSet<F>>> Rem<R> for FlagSet<F> {
+    type Output = Self;
+
+    /// Calculates the symmetric difference between two sets.
+    ///
+    /// The symmetric difference between two sets is the set of all flags
+    /// that appear in one set or the other, but not both.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     pub enum Flag: u8 {
+    ///         Foo = 1,
+    ///         Bar = 2,
+    ///         Baz = 4
+    ///     }
+    /// }
+    ///
+    /// let set0 = Flag::Foo | Flag::Bar;
+    /// let set1 = Flag::Baz | Flag::Bar;
+    /// assert_eq!(set0 % set1, Flag::Foo | Flag::Baz);
+    /// ```
+    #[inline]
+    fn rem(self, rhs: R) -> Self {
+        let rhs = rhs.into();
+        (self - rhs) | (rhs - self)
+    }
+}
+
+impl<F: Flags, R: Into<FlagSet<F>>> RemAssign<R> for FlagSet<F> {
+    /// Assigns the symmetric difference between two sets.
+    ///
+    /// The symmetric difference between two sets is the set of all flags
+    /// that appear in one set or the other, but not both.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     pub enum Flag: u8 {
+    ///         Foo = 1,
+    ///         Bar = 2,
+    ///         Baz = 4
+    ///     }
+    /// }
+    ///
+    /// let mut set0 = Flag::Foo | Flag::Bar;
+    /// let set1 = Flag::Baz | Flag::Bar;
+    /// set0 %= set1;
+    /// assert_eq!(set0, Flag::Foo | Flag::Baz);
+    /// ```
+    #[inline]
+    fn rem_assign(&mut self, rhs: R) {
+        *self = *self % rhs
+    }
+}
+
+impl<F: Flags> FlagSet<F> {
+    /// Creates a new set from bits; returning `Err(InvalidBits)` on invalid/unknown bits.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     pub enum Flag: u16 {
+    ///         Foo = 0b0001,
+    ///         Bar = 0b0010,
+    ///         Baz = 0b0100,
+    ///         Qux = 0b1010, // Implies Bar
+    ///     }
+    /// }
+    ///
+    /// assert_eq!(FlagSet::<Flag>::new(0b00101), Ok(Flag::Foo | Flag::Baz));
+    /// assert_eq!(FlagSet::<Flag>::new(0b01101), Err(flagset::InvalidBits)); // Invalid
+    /// assert_eq!(FlagSet::<Flag>::new(0b10101), Err(flagset::InvalidBits)); // Unknown
+    /// ```
+    #[inline]
+    pub fn new(bits: F::Type) -> core::result::Result<Self, InvalidBits> {
+        if Self::new_truncated(bits).0 == bits {
+            return Ok(FlagSet(bits));
+        }
+
+        Err(InvalidBits)
+    }
+
+    /// Creates a new set from bits; truncating invalid/unknown bits.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     pub enum Flag: u16 {
+    ///         Foo = 0b0001,
+    ///         Bar = 0b0010,
+    ///         Baz = 0b0100,
+    ///         Qux = 0b1010, // Implies Bar
+    ///     }
+    /// }
+    ///
+    /// let set = FlagSet::new_truncated(0b11101);  // Has invalid and unknown.
+    /// assert_eq!(set, Flag::Foo | Flag::Baz);
+    /// assert_eq!(set.bits(), 0b00101);            // Has neither.
+    /// ```
+    #[inline]
+    pub fn new_truncated(bits: F::Type) -> Self {
+        let mut set = Self::default();
+
+        for flag in FlagSet::<F>(bits) {
+            set |= flag;
+        }
+
+        set
+    }
+
+    /// Creates a new set from bits; use of invalid/unknown bits is undefined.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     pub enum Flag: u16 {
+    ///         Foo = 0b0001,
+    ///         Bar = 0b0010,
+    ///         Baz = 0b0100,
+    ///         Qux = 0b1010, // Implies Bar
+    ///     }
+    /// }
+    ///
+    /// // Unknown and invalid bits are retained. Behavior is undefined.
+    /// let set = unsafe { FlagSet::<Flag>::new_unchecked(0b11101) };
+    /// assert_eq!(set.bits(), 0b11101);
+    /// ```
+    ///
+    /// # Safety
+    ///
+    /// This constructor doesn't check that the bits are valid. If you pass
+    /// undefined flags, undefined behavior may result.
+    #[inline]
+    pub unsafe fn new_unchecked(bits: F::Type) -> Self {
+        FlagSet(bits)
+    }
+
+    /// Creates a new FlagSet containing all possible flags.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     pub enum Flag: u8 {
+    ///         Foo = 1,
+    ///         Bar = 2,
+    ///         Baz = 4
+    ///     }
+    /// }
+    ///
+    /// let set = FlagSet::full();
+    /// assert!(!set.is_empty());
+    /// assert!(set.is_full());
+    /// assert!(set.contains(Flag::Foo));
+    /// assert!(set.contains(Flag::Bar));
+    /// assert!(set.contains(Flag::Baz));
+    /// ```
+    #[inline]
+    pub fn full() -> Self {
+        let mut set = Self::default();
+        for f in F::LIST {
+            set |= *f
+        }
+        set
+    }
+
+    /// Returns the raw bits of the set.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     pub enum Flag: u16 {
+    ///         Foo = 0b0001,
+    ///         Bar = 0b0010,
+    ///         Baz = 0b0100,
+    ///     }
+    /// }
+    ///
+    /// let set = Flag::Foo | Flag::Baz;
+    /// assert_eq!(set.bits(), 0b0101u16);
+    /// ```
+    #[inline]
+    pub fn bits(self) -> F::Type {
+        self.0
+    }
+
+    /// Returns true if the FlagSet contains no flags.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     pub enum Flag: u8 {
+    ///         Foo = 1,
+    ///         Bar = 2,
+    ///         Baz = 4
+    ///     }
+    /// }
+    ///
+    /// let mut set = Flag::Foo | Flag::Bar;
+    /// assert!(!set.is_empty());
+    ///
+    /// set &= Flag::Baz;
+    /// assert!(set.is_empty());
+    /// ```
+    #[inline]
+    pub fn is_empty(self) -> bool {
+        self == Self::default()
+    }
+
+    /// Returns true if the FlagSet contains all possible flags.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     pub enum Flag: u8 {
+    ///         Foo = 1,
+    ///         Bar = 2,
+    ///         Baz = 4
+    ///     }
+    /// }
+    ///
+    /// let mut set = Flag::Foo | Flag::Bar;
+    /// assert!(!set.is_full());
+    ///
+    /// set |= Flag::Baz;
+    /// assert!(set.is_full());
+    /// ```
+    #[inline]
+    pub fn is_full(self) -> bool {
+        self == Self::full()
+    }
+
+    /// Returns true if the two `FlagSet`s do not share any flags.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     pub enum Flag: u8 {
+    ///         Foo = 1,
+    ///         Bar = 2,
+    ///         Baz = 4
+    ///     }
+    /// }
+    ///
+    /// let set = Flag::Foo | Flag::Bar;
+    /// assert!(!set.is_disjoint(Flag::Foo));
+    /// assert!(!set.is_disjoint(Flag::Foo | Flag::Baz));
+    /// assert!(set.is_disjoint(Flag::Baz));
+    /// ```
+    #[inline]
+    pub fn is_disjoint(self, rhs: impl Into<FlagSet<F>>) -> bool {
+        self & rhs == Self::default()
+    }
+
+    /// Returns true if this FlagSet is a superset of the specified flags.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     pub enum Flag: u8 {
+    ///         Foo = 1,
+    ///         Bar = 2,
+    ///         Baz = 4
+    ///     }
+    /// }
+    ///
+    /// let set = Flag::Foo | Flag::Bar;
+    /// assert!(set.contains(Flag::Foo));
+    /// assert!(set.contains(Flag::Foo | Flag::Bar));
+    /// assert!(!set.contains(Flag::Foo | Flag::Bar | Flag::Baz));
+    /// ```
+    #[inline]
+    pub fn contains(self, rhs: impl Into<FlagSet<F>>) -> bool {
+        let rhs = rhs.into();
+        self & rhs == rhs
+    }
+
+    /// Removes all flags from the FlagSet.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     pub enum Flag: u8 {
+    ///         Foo = 1,
+    ///         Bar = 2,
+    ///         Baz = 4
+    ///     }
+    /// }
+    ///
+    /// let mut set = Flag::Foo | Flag::Bar;
+    /// assert!(!set.is_empty());
+    ///
+    /// set.clear();
+    /// assert!(set.is_empty());
+    /// ```
+    #[inline]
+    pub fn clear(&mut self) {
+        *self = Self::default();
+    }
+
+    /// Clears the current set and returns an iterator of all removed flags.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     pub enum Flag: u8 {
+    ///         Foo = 1,
+    ///         Bar = 2,
+    ///         Baz = 4
+    ///     }
+    /// }
+    ///
+    /// let mut set = Flag::Foo | Flag::Bar;
+    /// let mut iter = set.drain();
+    /// assert!(set.is_empty());
+    /// assert_eq!(iter.next(), Some(Flag::Foo));
+    /// assert_eq!(iter.next(), Some(Flag::Bar));
+    /// assert_eq!(iter.next(), None);
+    /// ```
+    #[inline]
+    pub fn drain(&mut self) -> Iter<F> {
+        let iter = self.into_iter();
+        *self = Self::default();
+        iter
+    }
+
+    /// Retain only the flags flags specified by the predicate.
+    ///
+    /// ```
+    /// use flagset::{FlagSet, flags};
+    ///
+    /// flags! {
+    ///     pub enum Flag: u8 {
+    ///         Foo = 1,
+    ///         Bar = 2,
+    ///         Baz = 4
+    ///     }
+    /// }
+    ///
+    /// let mut set0 = Flag::Foo | Flag::Bar;
+    /// set0.retain(|f| f != Flag::Foo);
+    /// assert_eq!(set0, Flag::Bar);
+    /// ```
+    #[inline]
+    pub fn retain(&mut self, func: impl Fn(F) -> bool) {
+        for f in self.into_iter() {
+            if !func(f) {
+                *self -= f
+            }
+        }
+    }
+}
+
+#[cfg(feature = "serde")]
+impl<F: Flags> serde::Serialize for FlagSet<F>
+where
+    F::Type: serde::ser::Serialize,
+{
+    #[inline]
+    fn serialize<S>(&self, serializer: S) -> core::result::Result<S::Ok, S::Error>
+    where
+        S: serde::ser::Serializer,
+    {
+        self.0.serialize(serializer)
+    }
+}
+
+#[cfg(feature = "serde")]
+impl<'de, F: Flags> serde::Deserialize<'de> for FlagSet<F>
+where
+    F::Type: serde::de::Deserialize<'de>,
+{
+    #[inline]
+    fn deserialize<D>(deserializer: D) -> core::result::Result<Self, D::Error>
+    where
+        D: serde::de::Deserializer<'de>,
+    {
+        Ok(FlagSet(F::Type::deserialize(deserializer)?))
+    }
+}
+
+/// Define flag value using the `enum` syntax. See below for details.
+///
+/// Each enumeration value **MUST** have a specified value.
+///
+/// The width of the bitfield **MUST** also be specified by its integer type.
+///
+/// It is important to note that the size of the flag enumeration itself is
+/// unrelated to the size of the corresponding `FlagSet` instance.
+///
+/// It is also worth noting that this macro automatically implements a variety
+/// of standard traits including:
+///   * Copy
+///   * Clone
+///   * Debug
+///   * PartialEq
+///   * Eq
+///   * From<$enum> for $integer
+///   * Not
+///   * BitAnd
+///   * BitOr
+///   * BitXor
+///   * Sub
+///   * Rem
+///
+/// ```
+/// use std::mem::{align_of, size_of};
+/// use flagset::{FlagSet, flags};
+///
+/// flags! {
+///     enum FlagEmpty: u32 {}
+///
+///     enum Flag8: u8 {
+///         Foo = 0b001,
+///         Bar = 0b010,
+///         Baz = 0b100
+///     }
+///
+///     pub enum Flag16: u16 {
+///         Foo,
+///         Bar,
+///         #[deprecated]
+///         Baz,
+///     }
+///
+///     #[derive(PartialOrd, Ord)]
+///     enum Flag32: u32 {
+///         Foo = 0b001,
+///         #[deprecated]
+///         Bar = 0b010,
+///         Baz = 0b100
+///     }
+///
+///     #[repr(u64)]
+///     enum Flag64: u64 {
+///         Foo = 0b001,
+///         Bar = 0b010,
+///         Baz = 0b100
+///     }
+///
+///     #[repr(u32)]
+///     enum Flag128: u128 {
+///         Foo = 0b001,
+///         Bar = 0b010,
+///         Baz = 0b100
+///     }
+/// }
+///
+/// assert_eq!(size_of::<Flag8>(), 1);
+/// assert_eq!(size_of::<Flag16>(), 1);
+/// assert_eq!(size_of::<Flag32>(), 1);
+/// assert_eq!(size_of::<Flag64>(), 8);
+/// assert_eq!(size_of::<Flag128>(), 4);
+///
+/// assert_eq!(align_of::<Flag8>(), 1);
+/// assert_eq!(align_of::<Flag16>(), 1);
+/// assert_eq!(align_of::<Flag32>(), 1);
+/// assert_eq!(align_of::<Flag64>(), align_of::<u64>());
+/// assert_eq!(align_of::<Flag128>(), align_of::<u32>());
+///
+/// assert_eq!(size_of::<FlagSet<Flag8>>(), size_of::<u8>());
+/// assert_eq!(size_of::<FlagSet<Flag16>>(), size_of::<u16>());
+/// assert_eq!(size_of::<FlagSet<Flag32>>(), size_of::<u32>());
+/// assert_eq!(size_of::<FlagSet<Flag64>>(), size_of::<u64>());
+/// assert_eq!(size_of::<FlagSet<Flag128>>(), size_of::<u128>());
+///
+/// assert_eq!(align_of::<FlagSet<Flag8>>(), align_of::<u8>());
+/// assert_eq!(align_of::<FlagSet<Flag16>>(), align_of::<u16>());
+/// assert_eq!(align_of::<FlagSet<Flag32>>(), align_of::<u32>());
+/// assert_eq!(align_of::<FlagSet<Flag64>>(), align_of::<u64>());
+/// assert_eq!(align_of::<FlagSet<Flag128>>(), align_of::<u128>());
+/// ```
+#[macro_export]
+macro_rules! flags {
+    () => {};
+
+    // Entry point for enumerations without values.
+    ($(#[$m:meta])* $p:vis enum $n:ident: $t:ty { $($(#[$a:meta])* $k:ident),+ $(,)* } $($next:tt)*) => {
+        $crate::flags! { $(#[$m])* $p enum $n: $t { $($(#[$a])* $k = (1 << $n::$k as $t)),+ } $($next)* }
+    };
+
+    // Entrypoint for enumerations with values.
+    ($(#[$m:meta])* $p:vis enum $n:ident: $t:ty { $($(#[$a:meta])*$k:ident = $v:expr),* $(,)* } $($next:tt)*) => {
+        $(#[$m])*
+        #[derive(Copy, Clone, Debug, PartialEq, Eq)]
+        $p enum $n { $($(#[$a])* $k),* }
+
+        impl $crate::Flags for $n {
+            type Type = $t;
+
+            const LIST: &'static [Self] = &[$($n::$k),*];
+        }
+
+        impl core::convert::From<$n> for $crate::FlagSet<$n> {
+            #[inline]
+            fn from(value: $n) -> Self {
+                unsafe {
+                    match value {
+                        $($n::$k => Self::new_unchecked($v)),*
+                    }
+                }
+            }
+        }
+
+        impl core::ops::Not for $n {
+            type Output = $crate::FlagSet<$n>;
+
+            #[inline]
+            fn not(self) -> Self::Output {
+                !$crate::FlagSet::from(self)
+            }
+        }
+
+        impl<R: core::convert::Into<$crate::FlagSet<$n>>> core::ops::BitAnd<R> for $n {
+            type Output = $crate::FlagSet<$n>;
+
+            #[inline]
+            fn bitand(self, rhs: R) -> Self::Output {
+                $crate::FlagSet::from(self) & rhs
+            }
+        }
+
+        impl<R: core::convert::Into<$crate::FlagSet<$n>>> core::ops::BitOr<R> for $n {
+            type Output = $crate::FlagSet<$n>;
+
+            #[inline]
+            fn bitor(self, rhs: R) -> Self::Output {
+                $crate::FlagSet::from(self) | rhs
+            }
+        }
+
+        impl<R: core::convert::Into<$crate::FlagSet<$n>>> core::ops::BitXor<R> for $n {
+            type Output = $crate::FlagSet<$n>;
+
+            #[inline]
+            fn bitxor(self, rhs: R) -> Self::Output {
+                $crate::FlagSet::from(self) ^ rhs
+            }
+        }
+
+        impl<R: core::convert::Into<$crate::FlagSet<$n>>> core::ops::Sub<R> for $n {
+            type Output = $crate::FlagSet<$n>;
+
+            #[inline]
+            fn sub(self, rhs: R) -> Self::Output {
+                $crate::FlagSet::from(self) - rhs
+            }
+        }
+
+        impl<R: core::convert::Into<$crate::FlagSet<$n>>> core::ops::Rem<R> for $n {
+            type Output = $crate::FlagSet<$n>;
+
+            #[inline]
+            fn rem(self, rhs: R) -> Self::Output {
+                $crate::FlagSet::from(self) % rhs
+            }
+        }
+
+        $crate::flags! { $($next)* }
+    };
+}