Trait rapidfuzz::HashableChar
source · pub trait HashableChar {
// Required method
fn hash_char(&self) -> Hash;
}Expand description
trait used to map between element types and unique hash values
RapidFuzz already implements this trait for most primitive types.
For custom types this trat can be used to support the internal hashmaps.
There are a couple of things to keep in mind when implementing this trait:
- hashes have to be a unique value in the range
i64::MIN-u64::MAX. If two distinct objects produce the same hash, they will be assumed to be similar by the hashmap. - the hash function should be very fast. For primitive types it can just be the identity function
- the hashmaps are optimized for extended ASCII, so values in the range 0-255 generally provide a better performance.
Example
use rapidfuzz::distance;
use rapidfuzz::{Hash, HashableChar};
#[derive(PartialEq)]
struct MyType {
val: u64,
}
impl HashableChar for &MyType {
fn hash_char(&self) -> Hash {
Hash::UNSIGNED(self.val)
}
}
assert_eq!(
1,
distance::levenshtein::distance(
&[MyType { val: 1 }, MyType { val: 1 }],
&[MyType { val: 2 }, MyType { val: 1 }],
)
);