rust/src/libstd/bitflags.rs
Alex Crichton 1de4b65d2a Updates with core::fmt changes
1. Wherever the `buf` field of a `Formatter` was used, the `Formatter` is used
   instead.
2. The usage of `write_fmt` is minimized as much as possible, the `write!` macro
   is preferred wherever possible.
3. Usage of `fmt::write` is minimized, favoring the `write!` macro instead.
2014-05-15 23:22:06 -07:00

339 lines
10 KiB
Rust

// 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.
//! 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
//! bitflags!(
//! flags Flags: u32 {
//! static FlagA = 0x00000001,
//! static FlagB = 0x00000010,
//! static FlagC = 0x00000100,
//! static FlagABC = FlagA.bits
//! | FlagB.bits
//! | FlagC.bits
//! }
//! )
//!
//! fn main() {
//! let e1 = FlagA | FlagC;
//! let e2 = FlagB | FlagC;
//! assert!((e1 | e2) == FlagABC); // union
//! assert!((e1 & e2) == FlagC); // intersection
//! assert!((e1 - e2) == FlagA); // set difference
//! assert!(!e2 == FlagA); // set complement
//! }
//! ~~~
//!
//! The generated `struct`s can also be extended with type and trait implementations:
//!
//! ~~~rust
//! use std::fmt;
//!
//! bitflags!(
//! flags Flags: u32 {
//! static FlagA = 0x00000001,
//! static FlagB = 0x00000010
//! }
//! )
//!
//! 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::Show for Flags {
//! fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
//! write!(f, "hi!")
//! }
//! }
//!
//! fn main() {
//! let mut flags = FlagA | FlagB;
//! flags.clear();
//! assert!(flags.is_empty());
//! assert_eq!(format!("{}", flags).as_slice(), "hi!");
//! }
//! ~~~
//!
//! # Attributes
//!
//! Attributes can be attached to the generated `struct` by placing them
//! before the `flags` keyword.
//!
//! # Derived traits
//!
//! The `Eq` and `Clone` traits are automatically derived for the `struct` using
//! the `deriving` attribute. Additional traits can be derived by providing an
//! explicit `deriving` attribute on `flags`.
//!
//! # Operators
//!
//! The following operator traits are implemented for the generated `struct`:
//!
//! - `BitOr`: union
//! - `BitAnd`: intersection
//! - `Sub`: set difference
//! - `Not`: set complement
//!
//! # 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
//! - `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
#![macro_escape]
#[macro_export]
macro_rules! bitflags(
($(#[$attr:meta])* flags $BitFlags:ident: $T:ty {
$($(#[$Flag_attr:meta])* static $Flag:ident = $value:expr),+
}) => (
#[deriving(Eq, TotalEq, Clone)]
$(#[$attr])*
pub struct $BitFlags {
bits: $T,
}
$($(#[$Flag_attr])* pub static $Flag: $BitFlags = $BitFlags { bits: $value };)+
impl $BitFlags {
/// Returns an empty set of flags.
pub fn empty() -> $BitFlags {
$BitFlags { bits: 0 }
}
/// Returns the set containing all flags.
pub fn all() -> $BitFlags {
$BitFlags { bits: $($value)|+ }
}
/// Returns the raw value of the flags currently stored.
pub fn bits(&self) -> $T {
self.bits
}
/// Convert from underlying bit representation, unless that
/// representation contains bits that do not correspond to a flag.
pub fn from_bits(bits: $T) -> ::std::option::Option<$BitFlags> {
if (bits & !$BitFlags::all().bits()) != 0 {
::std::option::None
} else {
::std::option::Some($BitFlags { bits: bits })
}
}
/// Convert from underlying bit representation, dropping any bits
/// that do not correspond to flags.
pub fn from_bits_truncate(bits: $T) -> $BitFlags {
$BitFlags { bits: bits } & $BitFlags::all()
}
/// Returns `true` if no flags are currently stored.
pub fn is_empty(&self) -> bool {
*self == $BitFlags::empty()
}
/// Returns `true` if all flags are currently set.
pub fn is_all(&self) -> bool {
*self == $BitFlags::all()
}
/// Returns `true` if there are flags common to both `self` and `other`.
pub fn intersects(&self, other: $BitFlags) -> bool {
!(self & other).is_empty()
}
/// Returns `true` all of the flags in `other` are contained within `self`.
pub fn contains(&self, other: $BitFlags) -> bool {
(self & other) == other
}
/// Inserts the specified flags in-place.
pub fn insert(&mut self, other: $BitFlags) {
self.bits |= other.bits;
}
/// Removes the specified flags in-place.
pub fn remove(&mut self, other: $BitFlags) {
self.bits &= !other.bits;
}
}
impl BitOr<$BitFlags, $BitFlags> for $BitFlags {
/// Returns the union of the two sets of flags.
#[inline]
fn bitor(&self, other: &$BitFlags) -> $BitFlags {
$BitFlags { bits: self.bits | other.bits }
}
}
impl BitAnd<$BitFlags, $BitFlags> for $BitFlags {
/// Returns the intersection between the two sets of flags.
#[inline]
fn bitand(&self, other: &$BitFlags) -> $BitFlags {
$BitFlags { bits: self.bits & other.bits }
}
}
impl Sub<$BitFlags, $BitFlags> for $BitFlags {
/// Returns the set difference of the two sets of flags.
#[inline]
fn sub(&self, other: &$BitFlags) -> $BitFlags {
$BitFlags { bits: self.bits & !other.bits }
}
}
impl Not<$BitFlags> for $BitFlags {
/// Returns the complement of this set of flags.
#[inline]
fn not(&self) -> $BitFlags {
$BitFlags { bits: !self.bits } & $BitFlags::all()
}
}
)
)
#[cfg(test)]
mod tests {
use option::{Some, None};
use ops::{BitOr, BitAnd, Sub, Not};
bitflags!(
flags Flags: u32 {
static FlagA = 0x00000001,
static FlagB = 0x00000010,
static FlagC = 0x00000100,
static FlagABC = FlagA.bits
| FlagB.bits
| FlagC.bits
}
)
#[test]
fn test_bits(){
assert_eq!(Flags::empty().bits(), 0x00000000);
assert_eq!(FlagA.bits(), 0x00000001);
assert_eq!(FlagABC.bits(), 0x00000111);
}
#[test]
fn test_from_bits() {
assert!(Flags::from_bits(0) == Some(Flags::empty()));
assert!(Flags::from_bits(0x1) == Some(FlagA));
assert!(Flags::from_bits(0x10) == Some(FlagB));
assert!(Flags::from_bits(0x11) == Some(FlagA | FlagB));
assert!(Flags::from_bits(0x1000) == None);
}
#[test]
fn test_from_bits_truncate() {
assert!(Flags::from_bits_truncate(0) == Flags::empty());
assert!(Flags::from_bits_truncate(0x1) == FlagA);
assert!(Flags::from_bits_truncate(0x10) == FlagB);
assert!(Flags::from_bits_truncate(0x11) == (FlagA | FlagB));
assert!(Flags::from_bits_truncate(0x1000) == Flags::empty());
assert!(Flags::from_bits_truncate(0x1001) == FlagA);
}
#[test]
fn test_is_empty(){
assert!(Flags::empty().is_empty());
assert!(!FlagA.is_empty());
assert!(!FlagABC.is_empty());
}
#[test]
fn test_is_all() {
assert!(Flags::all().is_all());
assert!(!FlagA.is_all());
assert!(FlagABC.is_all());
}
#[test]
fn test_two_empties_do_not_intersect() {
let e1 = Flags::empty();
let e2 = Flags::empty();
assert!(!e1.intersects(e2));
}
#[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));
}
#[test]
fn test_insert(){
let mut e1 = FlagA;
let e2 = FlagA | FlagB;
e1.insert(e2);
assert!(e1 == e2);
}
#[test]
fn test_remove(){
let mut e1 = FlagA | FlagB;
let e2 = FlagA | FlagC;
e1.remove(e2);
assert!(e1 == FlagB);
}
#[test]
fn test_operators() {
let e1 = FlagA | FlagC;
let e2 = FlagB | FlagC;
assert!((e1 | e2) == FlagABC); // union
assert!((e1 & e2) == FlagC); // intersection
assert!((e1 - e2) == FlagA); // set difference
assert!(!e2 == FlagA); // set complement
}
}