495 lines
15 KiB
Rust
495 lines
15 KiB
Rust
// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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#![no_std]
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#![deny(warnings)]
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//! A typesafe bitmask flag generator.
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#[cfg(test)]
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#[macro_use]
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extern crate std;
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/// The `bitflags!` macro generates a `struct` that holds a set of C-style
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/// bitmask flags. It is useful for creating typesafe wrappers for C APIs.
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///
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/// The flags should only be defined for integer types, otherwise unexpected
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/// type errors may occur at compile time.
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///
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/// # Examples
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///
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/// ```{.rust}
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/// #![feature(rustc_private)]
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/// #[macro_use] extern crate rustc_bitflags;
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///
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/// bitflags! {
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/// flags Flags: u32 {
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/// const FLAG_A = 0b00000001,
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/// const FLAG_B = 0b00000010,
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/// const FLAG_C = 0b00000100,
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/// const FLAG_ABC = Flags::FLAG_A.bits
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/// | Flags::FLAG_B.bits
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/// | Flags::FLAG_C.bits,
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/// }
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/// }
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///
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/// fn main() {
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/// let e1 = Flags::FLAG_A | Flags::FLAG_C;
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/// let e2 = Flags::FLAG_B | Flags::FLAG_C;
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/// assert!((e1 | e2) == Flags::FLAG_ABC); // union
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/// assert!((e1 & e2) == Flags::FLAG_C); // intersection
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/// assert!((e1 - e2) == Flags::FLAG_A); // set difference
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/// assert!(!e2 == Flags::FLAG_A); // set complement
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/// }
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/// ```
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///
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/// The generated `struct`s can also be extended with type and trait implementations:
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///
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/// ```{.rust}
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/// #![feature(rustc_private)]
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/// #[macro_use] extern crate rustc_bitflags;
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///
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/// use std::fmt;
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///
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/// bitflags! {
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/// flags Flags: u32 {
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/// const FLAG_A = 0b00000001,
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/// const FLAG_B = 0b00000010,
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/// }
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/// }
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///
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/// impl Flags {
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/// pub fn clear(&mut self) {
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/// self.bits = 0; // The `bits` field can be accessed from within the
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/// // same module where the `bitflags!` macro was invoked.
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/// }
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/// }
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///
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/// impl fmt::Debug for Flags {
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/// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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/// write!(f, "hi!")
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/// }
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/// }
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///
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/// fn main() {
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/// let mut flags = Flags::FLAG_A | Flags::FLAG_B;
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/// flags.clear();
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/// assert!(flags.is_empty());
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/// assert_eq!(format!("{:?}", flags), "hi!");
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/// }
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/// ```
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///
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/// # Attributes
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///
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/// Attributes can be attached to the generated `struct` by placing them
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/// before the `flags` keyword.
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///
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/// # Derived traits
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///
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/// The `PartialEq` and `Clone` traits are automatically derived for the `struct` using
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/// the `deriving` attribute. Additional traits can be derived by providing an
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/// explicit `deriving` attribute on `flags`.
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///
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/// # Operators
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///
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/// The following operator traits are implemented for the generated `struct`:
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///
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/// - `BitOr`: union
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/// - `BitAnd`: intersection
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/// - `BitXor`: toggle
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/// - `Sub`: set difference
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/// - `Not`: set complement
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///
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/// # Methods
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///
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/// The following methods are defined for the generated `struct`:
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///
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/// - `empty`: an empty set of flags
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/// - `all`: the set of all flags
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/// - `bits`: the raw value of the flags currently stored
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/// - `from_bits`: convert from underlying bit representation, unless that
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/// representation contains bits that do not correspond to a flag
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/// - `from_bits_truncate`: convert from underlying bit representation, dropping
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/// any bits that do not correspond to flags
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/// - `is_empty`: `true` if no flags are currently stored
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/// - `is_all`: `true` if all flags are currently set
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/// - `intersects`: `true` if there are flags common to both `self` and `other`
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/// - `contains`: `true` all of the flags in `other` are contained within `self`
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/// - `insert`: inserts the specified flags in-place
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/// - `remove`: removes the specified flags in-place
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/// - `toggle`: the specified flags will be inserted if not present, and removed
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/// if they are.
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#[macro_export]
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macro_rules! bitflags {
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($(#[$attr:meta])* flags $BitFlags:ident: $T:ty {
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$($(#[$Flag_attr:meta])* const $Flag:ident = $value:expr),+
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}) => {
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#[derive(Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash)]
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$(#[$attr])*
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pub struct $BitFlags {
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bits: $T,
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}
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impl $BitFlags {
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$($(#[$Flag_attr])* pub const $Flag: $BitFlags = $BitFlags { bits: $value };)+
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/// Returns an empty set of flags.
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#[inline]
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pub fn empty() -> $BitFlags {
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$BitFlags { bits: 0 }
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}
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/// Returns the set containing all flags.
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#[inline]
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pub fn all() -> $BitFlags {
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$BitFlags { bits: $($value)|+ }
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}
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/// Returns the raw value of the flags currently stored.
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#[inline]
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pub fn bits(&self) -> $T {
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self.bits
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}
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/// Convert from underlying bit representation, unless that
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/// representation contains bits that do not correspond to a flag.
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#[inline]
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pub fn from_bits(bits: $T) -> ::std::option::Option<$BitFlags> {
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if (bits & !$BitFlags::all().bits()) != 0 {
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::std::option::Option::None
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} else {
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::std::option::Option::Some($BitFlags { bits: bits })
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}
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}
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/// Convert from underlying bit representation, dropping any bits
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/// that do not correspond to flags.
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#[inline]
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pub fn from_bits_truncate(bits: $T) -> $BitFlags {
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$BitFlags { bits: bits } & $BitFlags::all()
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}
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/// Returns `true` if no flags are currently stored.
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#[inline]
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pub fn is_empty(&self) -> bool {
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*self == $BitFlags::empty()
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}
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/// Returns `true` if all flags are currently set.
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#[inline]
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pub fn is_all(&self) -> bool {
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*self == $BitFlags::all()
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}
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/// Returns `true` if there are flags common to both `self` and `other`.
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#[inline]
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pub fn intersects(&self, other: $BitFlags) -> bool {
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!(*self & other).is_empty()
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}
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/// Returns `true` if all of the flags in `other` are contained within `self`.
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#[inline]
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pub fn contains(&self, other: $BitFlags) -> bool {
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(*self & other) == other
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}
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/// Inserts the specified flags in-place.
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#[inline]
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pub fn insert(&mut self, other: $BitFlags) {
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self.bits |= other.bits;
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}
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/// Removes the specified flags in-place.
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#[inline]
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pub fn remove(&mut self, other: $BitFlags) {
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self.bits &= !other.bits;
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}
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/// Toggles the specified flags in-place.
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#[inline]
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pub fn toggle(&mut self, other: $BitFlags) {
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self.bits ^= other.bits;
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}
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}
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impl ::std::ops::BitOr for $BitFlags {
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type Output = $BitFlags;
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/// Returns the union of the two sets of flags.
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#[inline]
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fn bitor(self, other: $BitFlags) -> $BitFlags {
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$BitFlags { bits: self.bits | other.bits }
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}
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}
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impl ::std::ops::BitXor for $BitFlags {
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type Output = $BitFlags;
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/// Returns the left flags, but with all the right flags toggled.
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#[inline]
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fn bitxor(self, other: $BitFlags) -> $BitFlags {
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$BitFlags { bits: self.bits ^ other.bits }
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}
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}
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impl ::std::ops::BitAnd for $BitFlags {
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type Output = $BitFlags;
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/// Returns the intersection between the two sets of flags.
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#[inline]
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fn bitand(self, other: $BitFlags) -> $BitFlags {
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$BitFlags { bits: self.bits & other.bits }
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}
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}
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impl ::std::ops::Sub for $BitFlags {
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type Output = $BitFlags;
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/// Returns the set difference of the two sets of flags.
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#[inline]
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fn sub(self, other: $BitFlags) -> $BitFlags {
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$BitFlags { bits: self.bits & !other.bits }
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}
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}
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impl ::std::ops::Not for $BitFlags {
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type Output = $BitFlags;
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/// Returns the complement of this set of flags.
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#[inline]
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fn not(self) -> $BitFlags {
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$BitFlags { bits: !self.bits } & $BitFlags::all()
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}
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}
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};
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($(#[$attr:meta])* flags $BitFlags:ident: $T:ty {
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$($(#[$Flag_attr:meta])* const $Flag:ident = $value:expr),+,
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}) => {
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bitflags! {
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$(#[$attr])*
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flags $BitFlags: $T {
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$($(#[$Flag_attr])* const $Flag = $value),+
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}
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}
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};
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}
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#[cfg(test)]
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#[allow(non_upper_case_globals)]
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mod tests {
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use std::hash::{Hash, Hasher};
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use std::collections::hash_map::DefaultHasher;
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use std::option::Option::{None, Some};
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bitflags! {
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#[doc = "> The first principle is that you must not fool yourself — and"]
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#[doc = "> you are the easiest person to fool."]
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#[doc = "> "]
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#[doc = "> - Richard Feynman"]
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flags Flags: u32 {
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const FlagA = 0b00000001,
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#[doc = "<pcwalton> macros are way better at generating code than trans is"]
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const FlagB = 0b00000010,
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const FlagC = 0b00000100,
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#[doc = "* cmr bed"]
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#[doc = "* strcat table"]
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#[doc = "<strcat> wait what?"]
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const FlagABC = Flags::FlagA.bits
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| Flags::FlagB.bits
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| Flags::FlagC.bits,
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}
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}
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bitflags! {
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flags AnotherSetOfFlags: i8 {
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const AnotherFlag = -1,
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}
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}
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#[test]
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fn test_bits() {
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assert_eq!(Flags::empty().bits(), 0b00000000);
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assert_eq!(Flags::FlagA.bits(), 0b00000001);
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assert_eq!(Flags::FlagABC.bits(), 0b00000111);
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assert_eq!(AnotherSetOfFlags::empty().bits(), 0b00);
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assert_eq!(AnotherSetOfFlags::AnotherFlag.bits(), !0);
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}
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#[test]
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fn test_from_bits() {
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assert!(Flags::from_bits(0) == Some(Flags::empty()));
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assert!(Flags::from_bits(0b1) == Some(Flags::FlagA));
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assert!(Flags::from_bits(0b10) == Some(Flags::FlagB));
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assert!(Flags::from_bits(0b11) == Some(Flags::FlagA | Flags::FlagB));
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assert!(Flags::from_bits(0b1000) == None);
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assert!(AnotherSetOfFlags::from_bits(!0) == Some(AnotherSetOfFlags::AnotherFlag));
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}
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#[test]
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fn test_from_bits_truncate() {
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assert!(Flags::from_bits_truncate(0) == Flags::empty());
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assert!(Flags::from_bits_truncate(0b1) == Flags::FlagA);
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assert!(Flags::from_bits_truncate(0b10) == Flags::FlagB);
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assert!(Flags::from_bits_truncate(0b11) == (Flags::FlagA | Flags::FlagB));
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assert!(Flags::from_bits_truncate(0b1000) == Flags::empty());
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assert!(Flags::from_bits_truncate(0b1001) == Flags::FlagA);
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assert!(AnotherSetOfFlags::from_bits_truncate(0) == AnotherSetOfFlags::empty());
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}
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#[test]
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fn test_is_empty() {
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assert!(Flags::empty().is_empty());
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assert!(!Flags::FlagA.is_empty());
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assert!(!Flags::FlagABC.is_empty());
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assert!(!AnotherSetOfFlags::AnotherFlag.is_empty());
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}
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#[test]
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fn test_is_all() {
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assert!(Flags::all().is_all());
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assert!(!Flags::FlagA.is_all());
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assert!(Flags::FlagABC.is_all());
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assert!(AnotherSetOfFlags::AnotherFlag.is_all());
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}
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#[test]
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fn test_two_empties_do_not_intersect() {
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let e1 = Flags::empty();
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let e2 = Flags::empty();
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assert!(!e1.intersects(e2));
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assert!(AnotherSetOfFlags::AnotherFlag.intersects(AnotherSetOfFlags::AnotherFlag));
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}
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#[test]
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fn test_empty_does_not_intersect_with_full() {
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let e1 = Flags::empty();
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let e2 = Flags::FlagABC;
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assert!(!e1.intersects(e2));
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}
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#[test]
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fn test_disjoint_intersects() {
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let e1 = Flags::FlagA;
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let e2 = Flags::FlagB;
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assert!(!e1.intersects(e2));
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}
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#[test]
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fn test_overlapping_intersects() {
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let e1 = Flags::FlagA;
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let e2 = Flags::FlagA | Flags::FlagB;
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assert!(e1.intersects(e2));
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}
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#[test]
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fn test_contains() {
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let e1 = Flags::FlagA;
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let e2 = Flags::FlagA | Flags::FlagB;
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assert!(!e1.contains(e2));
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assert!(e2.contains(e1));
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assert!(Flags::FlagABC.contains(e2));
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assert!(AnotherSetOfFlags::AnotherFlag.contains(AnotherSetOfFlags::AnotherFlag));
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}
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#[test]
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fn test_insert() {
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let mut e1 = Flags::FlagA;
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let e2 = Flags::FlagA | Flags::FlagB;
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e1.insert(e2);
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assert!(e1 == e2);
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let mut e3 = AnotherSetOfFlags::empty();
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e3.insert(AnotherSetOfFlags::AnotherFlag);
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assert!(e3 == AnotherSetOfFlags::AnotherFlag);
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}
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#[test]
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fn test_remove() {
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let mut e1 = Flags::FlagA | Flags::FlagB;
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let e2 = Flags::FlagA | Flags::FlagC;
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e1.remove(e2);
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assert!(e1 == Flags::FlagB);
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let mut e3 = AnotherSetOfFlags::AnotherFlag;
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e3.remove(AnotherSetOfFlags::AnotherFlag);
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assert!(e3 == AnotherSetOfFlags::empty());
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}
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#[test]
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fn test_operators() {
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let e1 = Flags::FlagA | Flags::FlagC;
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let e2 = Flags::FlagB | Flags::FlagC;
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assert!((e1 | e2) == Flags::FlagABC); // union
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assert!((e1 & e2) == Flags::FlagC); // intersection
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assert!((e1 - e2) == Flags::FlagA); // set difference
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assert!(!e2 == Flags::FlagA); // set complement
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assert!(e1 ^ e2 == Flags::FlagA | Flags::FlagB); // toggle
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let mut e3 = e1;
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e3.toggle(e2);
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assert!(e3 == Flags::FlagA | Flags::FlagB);
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let mut m4 = AnotherSetOfFlags::empty();
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m4.toggle(AnotherSetOfFlags::empty());
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assert!(m4 == AnotherSetOfFlags::empty());
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}
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#[test]
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fn test_lt() {
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let mut a = Flags::empty();
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let mut b = Flags::empty();
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assert!(!(a < b) && !(b < a));
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b = Flags::FlagB;
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assert!(a < b);
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a = Flags::FlagC;
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assert!(!(a < b) && b < a);
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b = Flags::FlagC | Flags::FlagB;
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assert!(a < b);
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}
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#[test]
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fn test_ord() {
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let mut a = Flags::empty();
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let mut b = Flags::empty();
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assert!(a <= b && a >= b);
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a = Flags::FlagA;
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assert!(a > b && a >= b);
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assert!(b < a && b <= a);
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b = Flags::FlagB;
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assert!(b > a && b >= a);
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assert!(a < b && a <= b);
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}
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#[test]
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fn test_hash() {
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let mut x = Flags::empty();
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let mut y = Flags::empty();
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assert!(hash(&x) == hash(&y));
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x = Flags::all();
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y = Flags::FlagABC;
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assert!(hash(&x) == hash(&y));
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}
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fn hash<T: Hash>(t: &T) -> u64 {
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let mut s = DefaultHasher::new();
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t.hash(&mut s);
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s.finish()
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}
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}
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