62 lines
1.5 KiB
Rust
62 lines
1.5 KiB
Rust
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//! An example of implementing the `BitFlags` trait manually for a flags type.
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//!
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//! This example doesn't use any macros.
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use std::{fmt, str};
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use bitflags::{Flag, Flags};
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// First: Define your flags type. It just needs to be `Sized + 'static`.
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pub struct ManualFlags(u32);
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// Not required: Define some constants for valid flags
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impl ManualFlags {
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pub const A: ManualFlags = ManualFlags(0b00000001);
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pub const B: ManualFlags = ManualFlags(0b00000010);
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pub const C: ManualFlags = ManualFlags(0b00000100);
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pub const ABC: ManualFlags = ManualFlags(0b00000111);
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}
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// Next: Implement the `BitFlags` trait, specifying your set of valid flags
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// and iterators
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impl Flags for ManualFlags {
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const FLAGS: &'static [Flag<Self>] = &[
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Flag::new("A", Self::A),
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Flag::new("B", Self::B),
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Flag::new("C", Self::C),
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];
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type Bits = u32;
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fn bits(&self) -> u32 {
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self.0
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}
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fn from_bits_retain(bits: u32) -> Self {
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Self(bits)
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}
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}
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// Not required: Add parsing support
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impl str::FromStr for ManualFlags {
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type Err = bitflags::parser::ParseError;
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fn from_str(input: &str) -> Result<Self, Self::Err> {
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bitflags::parser::from_str(input)
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}
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}
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// Not required: Add formatting support
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impl fmt::Display for ManualFlags {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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bitflags::parser::to_writer(self, f)
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}
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}
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fn main() {
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println!(
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"{}",
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ManualFlags::A.union(ManualFlags::B).union(ManualFlags::C)
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);
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}
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