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Diffstat (limited to 'vendor/bitflags/examples/macro_free.rs')
-rw-r--r-- | vendor/bitflags/examples/macro_free.rs | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/vendor/bitflags/examples/macro_free.rs b/vendor/bitflags/examples/macro_free.rs new file mode 100644 index 000000000..756337900 --- /dev/null +++ b/vendor/bitflags/examples/macro_free.rs @@ -0,0 +1,61 @@ +//! An example of implementing the `BitFlags` trait manually for a flags type. +//! +//! This example doesn't use any macros. + +use std::{fmt, str}; + +use bitflags::{Flag, Flags}; + +// First: Define your flags type. It just needs to be `Sized + 'static`. +pub struct ManualFlags(u32); + +// Not required: Define some constants for valid flags +impl ManualFlags { + pub const A: ManualFlags = ManualFlags(0b00000001); + pub const B: ManualFlags = ManualFlags(0b00000010); + pub const C: ManualFlags = ManualFlags(0b00000100); + pub const ABC: ManualFlags = ManualFlags(0b00000111); +} + +// Next: Implement the `BitFlags` trait, specifying your set of valid flags +// and iterators +impl Flags for ManualFlags { + const FLAGS: &'static [Flag<Self>] = &[ + Flag::new("A", Self::A), + Flag::new("B", Self::B), + Flag::new("C", Self::C), + ]; + + type Bits = u32; + + fn bits(&self) -> u32 { + self.0 + } + + fn from_bits_retain(bits: u32) -> Self { + Self(bits) + } +} + +// Not required: Add parsing support +impl str::FromStr for ManualFlags { + type Err = bitflags::parser::ParseError; + + fn from_str(input: &str) -> Result<Self, Self::Err> { + bitflags::parser::from_str(input) + } +} + +// Not required: Add formatting support +impl fmt::Display for ManualFlags { + fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { + bitflags::parser::to_writer(self, f) + } +} + +fn main() { + println!( + "{}", + ManualFlags::A.union(ManualFlags::B).union(ManualFlags::C) + ); +} |