pub trait Ix: PartialOrd + Sized {
type Range: Iterator<Item = Self>;
// Required methods
fn range(min: Self, max: Self) -> Self::Range;
fn index_checked(self, min: Self, max: Self) -> Option<usize>;
fn in_range(self, min: Self, max: Self) -> bool;
fn range_size_checked(min: Self, max: Self) -> Option<usize>;
// Provided methods
fn index(self, min: Self, max: Self) -> usize { ... }
fn range_size(min: Self, max: Self) -> usize { ... }
}Expand description
A trait for values that permit contiguous subranges.
Implementations that override the provided functions must ensure their custom implementations are equivalent to the provided ones.
Implementations must uphold the following invariants:
ix.in_range(min, max)if and only ifIx::range(min, max).any(|x| x == ix)- If
ix.in_range(min, max), thenIx::range(min, max).nth(ix.index(min, max)) == Some(ix) Ix::range(min, max).map(|x| x.index(min, max))yields equal items to0..Ix::range_size(min, max)Ix::range(min, max).map(|x| x.index_checked(min, max))ever yieldsNoneif and only ifIx::range_size_checked(min, max).is_none()Ix::range_size(min, max) == Ix::range(min, max).count()Ix::range_size_checked(min, max).is_none()if and only ifIx::range(min, max).count()overflows or panics
Note that, for these properties, if one side of the equality panics or overflows the equality can be considered to hold.
§Examples
for (ix, i) in Ix::range(-45i128, 483).zip(0..) {
assert_eq!(ix.index(-45, 483), i);
}assert!(!(-30289i16).in_range(-746, 15564));assert_eq!(
2410117514u32.in_range(2073922791, 3401563124),
Ix::range(2073922791u32, 3401563124).any(|x| x == 2410117514)
); // Property 1assert!(20i32.in_range(17, 5432));
assert_eq!(Ix::range(17i32, 5432).nth(20i32.index(17, 5432)).unwrap(), 20);
// Property 2assert!(0.in_range(-31597i16, 16417));
assert_eq!(Ix::range(-31597i16, 16417).nth(0.index(-31597i16, 16417)).unwrap(), 0);
// Property 2assert!(
Ix::range(-633i32, 151)
.map(|x| x.index(-633, 151))
.eq(0..Ix::range_size(-633, 151))
) // Property 3assert_eq!(Ix::range(8079u32, 1836091).count(), Ix::range_size(8079u32, 1836091))
// Property 5Required Associated Types§
Required Methods§
Sourcefn range(min: Self, max: Self) -> Self::Range
fn range(min: Self, max: Self) -> Self::Range
Generate an iterator over a range starting from min and stopping at max.
The resulting iterator must produce min and max at some point, each.
§Panics
Should panic if min is greater than max.
Sourcefn index_checked(self, min: Self, max: Self) -> Option<usize>
fn index_checked(self, min: Self, max: Self) -> Option<usize>
Sourcefn range_size_checked(min: Self, max: Self) -> Option<usize>
fn range_size_checked(min: Self, max: Self) -> Option<usize>
Get the length of a range.
If this would overflow the range of usize, returns None.
Checked version of range_size.
§Panics
Should panic if min is greater than max.
Provided Methods§
Sourcefn index(self, min: Self, max: Self) -> usize
fn index(self, min: Self, max: Self) -> usize
Get the position of a value inside a range.
§Panics
Should panic if min is greater than max.
Should panic if the value is not in the range (as determined by in_range).
Panics if the resulting index is not representable as a usize value.
The default implementation does this by unwrapping the return value of index_checked.
Sourcefn range_size(min: Self, max: Self) -> usize
fn range_size(min: Self, max: Self) -> usize
Get the length of a range.
§Panics
Should panic if min is greater than max.
Panics if the resulting size is not representable as a usize value.
The default implementation does this by unwrapping the return value of range_size_checked.
Dyn Compatibility§
This trait is not dyn compatible.
In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.