1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336
use core::{
fmt,
ops::{BitAnd, BitOr, BitXor, Not},
};
use crate::{
iter,
parser::{ParseError, ParseHex, WriteHex},
};
/// Metadata for an individual flag.
pub struct Flag<B> {
name: &'static str,
value: B,
}
impl<B> Flag<B> {
/// Create a new flag with the given name and value.
pub const fn new(name: &'static str, value: B) -> Self {
Flag { name, value }
}
/// Get the name of this flag.
pub const fn name(&self) -> &'static str {
self.name
}
/// Get the value of this flag.
pub const fn value(&self) -> &B {
&self.value
}
}
/// A set of flags.
///
/// This trait is automatically implemented for flags types defined using the `bitflags!` macro.
/// It can also be implemented manually for custom flags types.
pub trait Flags: Sized + 'static {
/// The set of available flags and their names.
const FLAGS: &'static [Flag<Self>];
/// The underlying storage type.
type Bits: Bits;
/// Returns an empty set of flags.
fn empty() -> Self {
Self::from_bits_retain(Self::Bits::EMPTY)
}
/// Returns the set containing all flags.
fn all() -> Self {
Self::from_bits_truncate(Self::Bits::ALL)
}
/// Returns the raw value of the flags currently stored.
fn bits(&self) -> Self::Bits;
/// Convert from underlying bit representation, unless that
/// representation contains bits that do not correspond to a flag.
///
/// Note that each [multi-bit flag] is treated as a unit for this comparison.
///
/// [multi-bit flag]: index.html#multi-bit-flags
fn from_bits(bits: Self::Bits) -> Option<Self> {
let truncated = Self::from_bits_truncate(bits);
if truncated.bits() == bits {
Some(truncated)
} else {
None
}
}
/// Convert from underlying bit representation, dropping any bits
/// that do not correspond to flags.
///
/// Note that each [multi-bit flag] is treated as a unit for this comparison.
///
/// [multi-bit flag]: index.html#multi-bit-flags
fn from_bits_truncate(bits: Self::Bits) -> Self {
if bits == Self::Bits::EMPTY {
return Self::empty();
}
let mut truncated = Self::Bits::EMPTY;
for flag in Self::FLAGS.iter() {
let flag = flag.value();
if bits & flag.bits() == flag.bits() {
truncated = truncated | flag.bits();
}
}
Self::from_bits_retain(truncated)
}
/// Convert from underlying bit representation, preserving all
/// bits (even those not corresponding to a defined flag).
fn from_bits_retain(bits: Self::Bits) -> Self;
/// Get the flag for a particular name.
fn from_name(name: &str) -> Option<Self> {
for flag in Self::FLAGS {
if flag.name() == name {
return Some(Self::from_bits_retain(flag.value().bits()));
}
}
None
}
/// Iterate over enabled flag values.
fn iter(&self) -> iter::Iter<Self> {
iter::Iter::new(self)
}
/// Iterate over the raw names and bits for enabled flag values.
fn iter_names(&self) -> iter::IterNames<Self> {
iter::IterNames::new(self)
}
/// Returns `true` if no flags are currently stored.
fn is_empty(&self) -> bool {
self.bits() == Self::Bits::EMPTY
}
/// Returns `true` if all flags are currently set.
fn is_all(&self) -> bool {
// NOTE: We check against `Self::all` here, not `Self::Bits::ALL`
// because the set of all flags may not use all bits
Self::all().bits() | self.bits() == self.bits()
}
/// Returns `true` if there are flags common to both `self` and `other`.
fn intersects(&self, other: Self) -> bool
where
Self: Sized,
{
self.bits() & other.bits() != Self::Bits::EMPTY
}
/// Returns `true` if all of the flags in `other` are contained within `self`.
fn contains(&self, other: Self) -> bool
where
Self: Sized,
{
self.bits() & other.bits() == other.bits()
}
/// Inserts the specified flags in-place.
///
/// This method is equivalent to `union`.
fn insert(&mut self, other: Self)
where
Self: Sized,
{
*self = Self::from_bits_retain(self.bits() | other.bits());
}
/// Removes the specified flags in-place.
///
/// This method is equivalent to `difference`.
fn remove(&mut self, other: Self)
where
Self: Sized,
{
*self = Self::from_bits_retain(self.bits() & !other.bits());
}
/// Toggles the specified flags in-place.
///
/// This method is equivalent to `symmetric_difference`.
fn toggle(&mut self, other: Self)
where
Self: Sized,
{
*self = Self::from_bits_retain(self.bits() ^ other.bits());
}
/// Inserts or removes the specified flags depending on the passed value.
fn set(&mut self, other: Self, value: bool)
where
Self: Sized,
{
if value {
self.insert(other);
} else {
self.remove(other);
}
}
/// Returns the intersection between the flags in `self` and `other`.
#[must_use]
fn intersection(self, other: Self) -> Self {
Self::from_bits_retain(self.bits() & other.bits())
}
/// Returns the union of between the flags in `self` and `other`.
#[must_use]
fn union(self, other: Self) -> Self {
Self::from_bits_retain(self.bits() | other.bits())
}
/// Returns the difference between the flags in `self` and `other`.
#[must_use]
fn difference(self, other: Self) -> Self {
Self::from_bits_retain(self.bits() & !other.bits())
}
/// Returns the symmetric difference between the flags
/// in `self` and `other`.
#[must_use]
fn symmetric_difference(self, other: Self) -> Self {
Self::from_bits_retain(self.bits() ^ other.bits())
}
/// Returns the complement of this set of flags.
#[must_use]
fn complement(self) -> Self {
Self::from_bits_truncate(!self.bits())
}
}
/// Underlying storage for a flags type.
pub trait Bits:
Clone
+ Copy
+ PartialEq
+ BitAnd<Output = Self>
+ BitOr<Output = Self>
+ BitXor<Output = Self>
+ Not<Output = Self>
+ Sized
+ 'static
{
/// The value of `Self` where no bits are set.
const EMPTY: Self;
/// The value of `Self` where all bits are set.
const ALL: Self;
}
// Not re-exported: prevent custom `Bits` impls being used in the `bitflags!` macro,
// or they may fail to compile based on crate features
pub trait Primitive {}
macro_rules! impl_bits {
($($u:ty, $i:ty,)*) => {
$(
impl Bits for $u {
const EMPTY: $u = 0;
const ALL: $u = <$u>::MAX;
}
impl Bits for $i {
const EMPTY: $i = 0;
const ALL: $i = <$u>::MAX as $i;
}
impl ParseHex for $u {
fn parse_hex(input: &str) -> Result<Self, ParseError> {
<$u>::from_str_radix(input, 16).map_err(|_| ParseError::invalid_hex_flag(input))
}
}
impl ParseHex for $i {
fn parse_hex(input: &str) -> Result<Self, ParseError> {
<$i>::from_str_radix(input, 16).map_err(|_| ParseError::invalid_hex_flag(input))
}
}
impl WriteHex for $u {
fn write_hex<W: fmt::Write>(&self, mut writer: W) -> fmt::Result {
write!(writer, "{:x}", self)
}
}
impl WriteHex for $i {
fn write_hex<W: fmt::Write>(&self, mut writer: W) -> fmt::Result {
write!(writer, "{:x}", self)
}
}
impl Primitive for $i {}
impl Primitive for $u {}
)*
}
}
impl_bits! {
u8, i8,
u16, i16,
u32, i32,
u64, i64,
u128, i128,
usize, isize,
}
/// A trait for referencing the `bitflags`-owned internal type
/// without exposing it publicly.
pub trait PublicFlags {
/// The type of the underlying storage.
type Primitive: Primitive;
/// The type of the internal field on the generated flags type.
type Internal;
}
#[deprecated(note = "use the `Flags` trait instead")]
pub trait BitFlags: ImplementedByBitFlagsMacro + Flags {
/// An iterator over enabled flags in an instance of the type.
type Iter: Iterator<Item = Self>;
/// An iterator over the raw names and bits for enabled flags in an instance of the type.
type IterNames: Iterator<Item = (&'static str, Self)>;
}
#[allow(deprecated)]
impl<B: Flags> BitFlags for B {
type Iter = iter::Iter<Self>;
type IterNames = iter::IterNames<Self>;
}
impl<B: Flags> ImplementedByBitFlagsMacro for B {}
/// A marker trait that signals that an implementation of `BitFlags` came from the `bitflags!` macro.
///
/// There's nothing stopping an end-user from implementing this trait, but we don't guarantee their
/// manual implementations won't break between non-breaking releases.
#[doc(hidden)]
pub trait ImplementedByBitFlagsMacro {}
pub(crate) mod __private {
pub use super::{ImplementedByBitFlagsMacro, PublicFlags};
}