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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! A typesafe bitmask flag generator.
#![no_std]
#[cfg(test)]
#[macro_use]
extern crate std;
// Re-export libstd/libcore using an alias so that the macros can work in no_std
// crates while remaining compatible with normal crates.
#[allow(private_in_public)]
#[doc(hidden)]
pub use core as __core;
/// The `bitflags!` macro generates a `struct` that holds a set of C-style
/// bitmask flags. It is useful for creating typesafe wrappers for C APIs.
///
/// The flags should only be defined for integer types, otherwise unexpected
/// type errors may occur at compile time.
///
/// # Example
///
/// ```{.rust}
/// #[macro_use]
/// extern crate bitflags;
///
/// bitflags! {
/// flags Flags: u32 {
/// const FLAG_A = 0b00000001,
/// const FLAG_B = 0b00000010,
/// const FLAG_C = 0b00000100,
/// const FLAG_ABC = FLAG_A.bits
/// | FLAG_B.bits
/// | FLAG_C.bits,
/// }
/// }
///
/// fn main() {
/// let e1 = FLAG_A | FLAG_C;
/// let e2 = FLAG_B | FLAG_C;
/// assert_eq!((e1 | e2), FLAG_ABC); // union
/// assert_eq!((e1 & e2), FLAG_C); // intersection
/// assert_eq!((e1 - e2), FLAG_A); // set difference
/// assert_eq!(!e2, FLAG_A); // set complement
/// }
/// ```
///
/// The generated `struct`s can also be extended with type and trait
/// implementations:
///
/// ```{.rust}
/// #[macro_use]
/// extern crate bitflags;
///
/// use std::fmt;
///
/// bitflags! {
/// flags Flags: u32 {
/// const FLAG_A = 0b00000001,
/// const FLAG_B = 0b00000010,
/// }
/// }
///
/// impl Flags {
/// pub fn clear(&mut self) {
/// self.bits = 0; // The `bits` field can be accessed from within the
/// // same module where the `bitflags!` macro was invoked.
/// }
/// }
///
/// impl fmt::Display for Flags {
/// fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
/// write!(f, "hi!")
/// }
/// }
///
/// fn main() {
/// let mut flags = FLAG_A | FLAG_B;
/// flags.clear();
/// assert!(flags.is_empty());
/// assert_eq!(format!("{}", flags), "hi!");
/// assert_eq!(format!("{:?}", FLAG_A | FLAG_B), "FLAG_A | FLAG_B");
/// assert_eq!(format!("{:?}", FLAG_B), "FLAG_B");
/// }
/// ```
///
/// # Visibility
///
/// The generated struct and its associated flag constants are not exported
/// out of the current module by default. A definition can be exported out of
/// the current module by adding `pub` before `flags`:
///
/// ```{.rust},ignore
/// #[macro_use]
/// extern crate bitflags;
///
/// mod example {
/// bitflags! {
/// pub flags Flags1: u32 {
/// const FLAG_A = 0b00000001,
/// }
/// }
/// bitflags! {
/// flags Flags2: u32 {
/// const FLAG_B = 0b00000010,
/// }
/// }
/// }
///
/// fn main() {
/// let flag1 = example::FLAG_A;
/// let flag2 = example::FLAG_B; // error: const `FLAG_B` is private
/// }
/// ```
///
/// # Attributes
///
/// Attributes can be attached to the generated `struct` by placing them
/// before the `flags` keyword.
///
/// # Trait implementations
///
/// The `Copy`, `Clone`, `PartialEq`, `Eq`, `PartialOrd`, `Ord` and `Hash`
/// traits automatically derived for the `struct` using the `derive` attribute.
/// Additional traits can be derived by providing an explicit `derive`
/// attribute on `flags`.
///
/// The `Extend` and `FromIterator` traits are implemented for the `struct`,
/// too: `Extend` adds the union of the instances of the `struct` iterated over,
/// while `FromIterator` calculates the union.
///
/// The `Debug` trait is also implemented by displaying the bits value of the
/// internal struct.
///
/// ## Operators
///
/// The following operator traits are implemented for the generated `struct`:
///
/// - `BitOr` and `BitOrAssign`: union
/// - `BitAnd` and `BitAndAssign`: intersection
/// - `BitXor` and `BitXorAssign`: toggle
/// - `Sub` and `SubAssign`: set difference
/// - `Not`: set complement
///
/// As long as the assignment operators are unstable rust feature they are only
/// available with the crate feature `assignment_ops` enabled.
///
/// # Methods
///
/// The following methods are defined for the generated `struct`:
///
/// - `empty`: an empty set of flags
/// - `all`: the set of all flags
/// - `bits`: the raw value of the flags currently stored
/// - `from_bits`: convert from underlying bit representation, unless that
/// representation contains bits that do not correspond to a flag
/// - `from_bits_truncate`: convert from underlying bit representation, dropping
/// any bits that do not correspond to flags
/// - `is_empty`: `true` if no flags are currently stored
/// - `is_all`: `true` if all flags are currently set
/// - `intersects`: `true` if there are flags common to both `self` and `other`
/// - `contains`: `true` all of the flags in `other` are contained within `self`
/// - `insert`: inserts the specified flags in-place
/// - `remove`: removes the specified flags in-place
/// - `toggle`: the specified flags will be inserted if not present, and removed
/// if they are.
#[macro_export]
macro_rules! bitflags {
($(#[$attr:meta])* pub flags $BitFlags:ident: $T:ty {
$($(#[$Flag_attr:meta])* const $Flag:ident = $value:expr),+
}) => {
#[derive(Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash)]
$(#[$attr])*
pub struct $BitFlags {
bits: $T,
}
$($(#[$Flag_attr])* pub const $Flag: $BitFlags = $BitFlags { bits: $value };)+
bitflags! {
@_impl flags $BitFlags: $T {
$($(#[$Flag_attr])* const $Flag = $value),+
}
}
};
($(#[$attr:meta])* flags $BitFlags:ident: $T:ty {
$($(#[$Flag_attr:meta])* const $Flag:ident = $value:expr),+
}) => {
#[derive(Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash)]
$(#[$attr])*
struct $BitFlags {
bits: $T,
}
$($(#[$Flag_attr])* const $Flag: $BitFlags = $BitFlags { bits: $value };)+
bitflags! {
@_impl flags $BitFlags: $T {
$($(#[$Flag_attr])* const $Flag = $value),+
}
}
};
(@_impl flags $BitFlags:ident: $T:ty {
$($(#[$Flag_attr:meta])* const $Flag:ident = $value:expr),+
}) => {
impl $crate::__core::fmt::Debug for $BitFlags {
fn fmt(&self, f: &mut $crate::__core::fmt::Formatter) -> $crate::__core::fmt::Result {
// This convoluted approach is to handle #[cfg]-based flag
// omission correctly. Some of the $Flag variants may not be
// defined in this module so we create an inner module which
// defines *all* flags to the value of 0. We then create a
// second inner module that defines all of the flags with #[cfg]
// to their real values. Afterwards the glob will import
// variants from the second inner module, shadowing all
// defined variants, leaving only the undefined ones with the
// bit value of 0.
#[allow(dead_code)]
#[allow(unused_assignments)]
mod dummy {
// We can't use the real $BitFlags struct because it may be
// private, which prevents us from using it to define
// public constants.
pub struct $BitFlags {
bits: u64,
}
mod real_flags {
use super::$BitFlags;
$($(#[$Flag_attr])* pub const $Flag: $BitFlags = $BitFlags {
bits: super::super::$Flag.bits as u64
};)+
}
// Now we define the "undefined" versions of the flags.
// This way, all the names exist, even if some are #[cfg]ed
// out.
$(const $Flag: $BitFlags = $BitFlags { bits: 0 };)+
#[inline]
pub fn fmt(self_: u64,
f: &mut $crate::__core::fmt::Formatter)
-> $crate::__core::fmt::Result {
// Now we import the real values for the flags.
// Only ones that are #[cfg]ed out will be 0.
use self::real_flags::*;
let mut first = true;
$(
// $Flag.bits == 0 means that $Flag doesn't exist
if $Flag.bits != 0 && self_ & $Flag.bits as u64 == $Flag.bits as u64 {
if !first {
try!(f.write_str(" | "));
}
first = false;
try!(f.write_str(stringify!($Flag)));
}
)+
Ok(())
}
}
dummy::fmt(self.bits as u64, f)
}
}
#[allow(dead_code)]
impl $BitFlags {
/// Returns an empty set of flags.
#[inline]
pub fn empty() -> $BitFlags {
$BitFlags { bits: 0 }
}
/// Returns the set containing all flags.
#[inline]
pub fn all() -> $BitFlags {
// See above `dummy` module for why this approach is taken.
#[allow(dead_code)]
mod dummy {
pub struct $BitFlags {
bits: u64,
}
mod real_flags {
use super::$BitFlags;
$($(#[$Flag_attr])* pub const $Flag: $BitFlags = $BitFlags {
bits: super::super::$Flag.bits as u64
};)+
}
$(const $Flag: $BitFlags = $BitFlags { bits: 0 };)+
#[inline]
pub fn all() -> u64 {
use self::real_flags::*;
$($Flag.bits)|+
}
}
$BitFlags { bits: dummy::all() as $T }
}
/// Returns the raw value of the flags currently stored.
#[inline]
pub fn bits(&self) -> $T {
self.bits
}
/// Convert from underlying bit representation, unless that
/// representation contains bits that do not correspond to a flag.
#[inline]
pub fn from_bits(bits: $T) -> $crate::__core::option::Option<$BitFlags> {
if (bits & !$BitFlags::all().bits()) == 0 {
$crate::__core::option::Option::Some($BitFlags { bits: bits })
} else {
$crate::__core::option::Option::None
}
}
/// Convert from underlying bit representation, dropping any bits
/// that do not correspond to flags.
#[inline]
pub fn from_bits_truncate(bits: $T) -> $BitFlags {
$BitFlags { bits: bits } & $BitFlags::all()
}
/// Returns `true` if no flags are currently stored.
#[inline]
pub fn is_empty(&self) -> bool {
*self == $BitFlags::empty()
}
/// Returns `true` if all flags are currently set.
#[inline]
pub fn is_all(&self) -> bool {
*self == $BitFlags::all()
}
/// Returns `true` if there are flags common to both `self` and `other`.
#[inline]
pub fn intersects(&self, other: $BitFlags) -> bool {
!(*self & other).is_empty()
}
/// Returns `true` all of the flags in `other` are contained within `self`.
#[inline]
pub fn contains(&self, other: $BitFlags) -> bool {
(*self & other) == other
}
/// Inserts the specified flags in-place.
#[inline]
pub fn insert(&mut self, other: $BitFlags) {
self.bits |= other.bits;
}
/// Removes the specified flags in-place.
#[inline]
pub fn remove(&mut self, other: $BitFlags) {
self.bits &= !other.bits;
}
/// Toggles the specified flags in-place.
#[inline]
pub fn toggle(&mut self, other: $BitFlags) {
self.bits ^= other.bits;
}
}
impl $crate::__core::ops::BitOr for $BitFlags {
type Output = $BitFlags;
/// Returns the union of the two sets of flags.
#[inline]
fn bitor(self, other: $BitFlags) -> $BitFlags {
$BitFlags { bits: self.bits | other.bits }
}
}
impl $crate::__core::ops::BitOrAssign for $BitFlags {
/// Adds the set of flags.
#[inline]
fn bitor_assign(&mut self, other: $BitFlags) {
self.bits |= other.bits;
}
}
impl $crate::__core::ops::BitXor for $BitFlags {
type Output = $BitFlags;
/// Returns the left flags, but with all the right flags toggled.
#[inline]
fn bitxor(self, other: $BitFlags) -> $BitFlags {
$BitFlags { bits: self.bits ^ other.bits }
}
}
impl $crate::__core::ops::BitXorAssign for $BitFlags {
/// Toggles the set of flags.
#[inline]
fn bitxor_assign(&mut self, other: $BitFlags) {
self.bits ^= other.bits;
}
}
impl $crate::__core::ops::BitAnd for $BitFlags {
type Output = $BitFlags;
/// Returns the intersection between the two sets of flags.
#[inline]
fn bitand(self, other: $BitFlags) -> $BitFlags {
$BitFlags { bits: self.bits & other.bits }
}
}
impl $crate::__core::ops::BitAndAssign for $BitFlags {
/// Disables all flags disabled in the set.
#[inline]
fn bitand_assign(&mut self, other: $BitFlags) {
self.bits &= other.bits;
}
}
impl $crate::__core::ops::Sub for $BitFlags {
type Output = $BitFlags;
/// Returns the set difference of the two sets of flags.
#[inline]
fn sub(self, other: $BitFlags) -> $BitFlags {
$BitFlags { bits: self.bits & !other.bits }
}
}
impl $crate::__core::ops::SubAssign for $BitFlags {
/// Disables all flags enabled in the set.
#[inline]
fn sub_assign(&mut self, other: $BitFlags) {
self.bits &= !other.bits;
}
}
impl $crate::__core::ops::Not for $BitFlags {
type Output = $BitFlags;
/// Returns the complement of this set of flags.
#[inline]
fn not(self) -> $BitFlags {
$BitFlags { bits: !self.bits } & $BitFlags::all()
}
}
impl $crate::__core::iter::Extend<$BitFlags> for $BitFlags {
fn extend<T: $crate::__core::iter::IntoIterator<Item=$BitFlags>>(&mut self, iterator: T) {
for item in iterator {
self.insert(item)
}
}
}
impl $crate::__core::iter::FromIterator<$BitFlags> for $BitFlags {
fn from_iter<T: $crate::__core::iter::IntoIterator<Item=$BitFlags>>(iterator: T) -> $BitFlags {
let mut result = Self::empty();
result.extend(iterator);
result
}
}
};
($(#[$attr:meta])* pub flags $BitFlags:ident: $T:ty {
$($(#[$Flag_attr:meta])* const $Flag:ident = $value:expr),+,
}) => {
bitflags! {
$(#[$attr])*
pub flags $BitFlags: $T {
$($(#[$Flag_attr])* const $Flag = $value),+
}
}
};
($(#[$attr:meta])* flags $BitFlags:ident: $T:ty {
$($(#[$Flag_attr:meta])* const $Flag:ident = $value:expr),+,
}) => {
bitflags! {
$(#[$attr])*
flags $BitFlags: $T {
$($(#[$Flag_attr])* const $Flag = $value),+
}
}
};
}
#[cfg(test)]
#[allow(non_upper_case_globals, dead_code)]
mod tests {
use std::hash::{SipHasher, Hash, Hasher};
bitflags! {
#[doc = "> The first principle is that you must not fool yourself — and"]
#[doc = "> you are the easiest person to fool."]
#[doc = "> "]
#[doc = "> - Richard Feynman"]
flags Flags: u32 {
const FlagA = 0b00000001,
#[doc = "<pcwalton> macros are way better at generating code than trans is"]
const FlagB = 0b00000010,
const FlagC = 0b00000100,
#[doc = "* cmr bed"]
#[doc = "* strcat table"]
#[doc = "<strcat> wait what?"]
const FlagABC = FlagA.bits
| FlagB.bits
| FlagC.bits,
}
}
bitflags! {
flags _CfgFlags: u32 {
#[cfg(windows)]
const _CfgA = 0b01,
#[cfg(unix)]
const _CfgB = 0b01,
#[cfg(windows)]
const _CfgC = _CfgA.bits | 0b10,
}
}
bitflags! {
flags AnotherSetOfFlags: i8 {
const AnotherFlag = -1_i8,
}
}
#[test]
fn test_bits(){
assert_eq!(Flags::empty().bits(), 0b00000000);
assert_eq!(FlagA.bits(), 0b00000001);
assert_eq!(FlagABC.bits(), 0b00000111);
assert_eq!(AnotherSetOfFlags::empty().bits(), 0b00);
assert_eq!(AnotherFlag.bits(), !0_i8);
}
#[test]
fn test_from_bits() {
assert_eq!(Flags::from_bits(0), Some(Flags::empty()));
assert_eq!(Flags::from_bits(0b1), Some(FlagA));
assert_eq!(Flags::from_bits(0b10), Some(FlagB));
assert_eq!(Flags::from_bits(0b11), Some(FlagA | FlagB));
assert_eq!(Flags::from_bits(0b1000), None);
assert_eq!(AnotherSetOfFlags::from_bits(!0_i8), Some(AnotherFlag));
}
#[test]
fn test_from_bits_truncate() {
assert_eq!(Flags::from_bits_truncate(0), Flags::empty());
assert_eq!(Flags::from_bits_truncate(0b1), FlagA);
assert_eq!(Flags::from_bits_truncate(0b10), FlagB);
assert_eq!(Flags::from_bits_truncate(0b11), (FlagA | FlagB));
assert_eq!(Flags::from_bits_truncate(0b1000), Flags::empty());
assert_eq!(Flags::from_bits_truncate(0b1001), FlagA);
assert_eq!(AnotherSetOfFlags::from_bits_truncate(0_i8), AnotherSetOfFlags::empty());
}
#[test]
fn test_is_empty(){
assert!(Flags::empty().is_empty());
assert!(!FlagA.is_empty());
assert!(!FlagABC.is_empty());
assert!(!AnotherFlag.is_empty());
}
#[test]
fn test_is_all() {
assert!(Flags::all().is_all());
assert!(!FlagA.is_all());
assert!(FlagABC.is_all());
assert!(AnotherFlag.is_all());
}
#[test]
fn test_two_empties_do_not_intersect() {
let e1 = Flags::empty();
let e2 = Flags::empty();
assert!(!e1.intersects(e2));
assert!(AnotherFlag.intersects(AnotherFlag));
}
#[test]
fn test_empty_does_not_intersect_with_full() {
let e1 = Flags::empty();
let e2 = FlagABC;
assert!(!e1.intersects(e2));
}
#[test]
fn test_disjoint_intersects() {
let e1 = FlagA;
let e2 = FlagB;
assert!(!e1.intersects(e2));
}
#[test]
fn test_overlapping_intersects() {
let e1 = FlagA;
let e2 = FlagA | FlagB;
assert!(e1.intersects(e2));
}
#[test]
fn test_contains() {
let e1 = FlagA;
let e2 = FlagA | FlagB;
assert!(!e1.contains(e2));
assert!(e2.contains(e1));
assert!(FlagABC.contains(e2));
assert!(AnotherFlag.contains(AnotherFlag));
}
#[test]
fn test_insert(){
let mut e1 = FlagA;
let e2 = FlagA | FlagB;
e1.insert(e2);
assert_eq!(e1, e2);
let mut e3 = AnotherSetOfFlags::empty();
e3.insert(AnotherFlag);
assert_eq!(e3, AnotherFlag);
}
#[test]
fn test_remove(){
let mut e1 = FlagA | FlagB;
let e2 = FlagA | FlagC;
e1.remove(e2);
assert_eq!(e1, FlagB);
let mut e3 = AnotherFlag;
e3.remove(AnotherFlag);
assert_eq!(e3, AnotherSetOfFlags::empty());
}
#[test]
fn test_operators() {
let e1 = FlagA | FlagC;
let e2 = FlagB | FlagC;
assert_eq!((e1 | e2), FlagABC); // union
assert_eq!((e1 & e2), FlagC); // intersection
assert_eq!((e1 - e2), FlagA); // set difference
assert_eq!(!e2, FlagA); // set complement
assert_eq!(e1 ^ e2, FlagA | FlagB); // toggle
let mut e3 = e1;
e3.toggle(e2);
assert_eq!(e3, FlagA | FlagB);
let mut m4 = AnotherSetOfFlags::empty();
m4.toggle(AnotherSetOfFlags::empty());
assert_eq!(m4, AnotherSetOfFlags::empty());
}
#[test]
fn test_assignment_operators() {
let mut m1 = Flags::empty();
let e1 = FlagA | FlagC;
// union
m1 |= FlagA;
assert_eq!(m1, FlagA);
// intersection
m1 &= e1;
assert_eq!(m1, FlagA);
// set difference
m1 -= m1;
assert_eq!(m1, Flags::empty());
// toggle
m1 ^= e1;
assert_eq!(m1, e1);
}
#[test]
fn test_extend() {
let mut flags;
flags = Flags::empty();
flags.extend([].iter().cloned());
assert_eq!(flags, Flags::empty());
flags = Flags::empty();
flags.extend([FlagA, FlagB].iter().cloned());
assert_eq!(flags, FlagA | FlagB);
flags = FlagA;
flags.extend([FlagA, FlagB].iter().cloned());
assert_eq!(flags, FlagA | FlagB);
flags = FlagB;
flags.extend([FlagA, FlagABC].iter().cloned());
assert_eq!(flags, FlagABC);
}
#[test]
fn test_from_iterator() {
assert_eq!([].iter().cloned().collect::<Flags>(), Flags::empty());
assert_eq!([FlagA, FlagB].iter().cloned().collect::<Flags>(), FlagA | FlagB);
assert_eq!([FlagA, FlagABC].iter().cloned().collect::<Flags>(), FlagABC);
}
#[test]
fn test_lt() {
let mut a = Flags::empty();
let mut b = Flags::empty();
assert!(!(a < b) && !(b < a));
b = FlagB;
assert!(a < b);
a = FlagC;
assert!(!(a < b) && b < a);
b = FlagC | FlagB;
assert!(a < b);
}
#[test]
fn test_ord() {
let mut a = Flags::empty();
let mut b = Flags::empty();
assert!(a <= b && a >= b);
a = FlagA;
assert!(a > b && a >= b);
assert!(b < a && b <= a);
b = FlagB;
assert!(b > a && b >= a);
assert!(a < b && a <= b);
}
fn hash<T: Hash>(t: &T) -> u64 {
let mut s = SipHasher::new_with_keys(0, 0);
t.hash(&mut s);
s.finish()
}
#[test]
fn test_hash() {
let mut x = Flags::empty();
let mut y = Flags::empty();
assert_eq!(hash(&x), hash(&y));
x = Flags::all();
y = FlagABC;
assert_eq!(hash(&x), hash(&y));
}
#[test]
fn test_debug() {
assert_eq!(format!("{:?}", FlagA | FlagB), "FlagA | FlagB");
assert_eq!(format!("{:?}", FlagABC), "FlagA | FlagB | FlagC | FlagABC");
}
mod submodule {
bitflags! {
pub flags PublicFlags: i8 {
const FlagX = 0,
}
}
bitflags! {
flags PrivateFlags: i8 {
const FlagY = 0,
}
}
#[test]
fn test_private() {
let _ = FlagY;
}
}
#[test]
fn test_public() {
let _ = submodule::FlagX;
}
mod t1 {
mod foo {
pub type Bar = i32;
}
bitflags! {
/// baz
flags Flags: foo::Bar {
const A = 0b00000001,
#[cfg(foo)]
const B = 0b00000010,
#[cfg(foo)]
const C = 0b00000010,
}
}
}
}