Converting between extprim::u128::u128 and primitive u128 in Rust?
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1
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I'm working with an old Rust module that uses the extprim crate to provide a u128 type.
I'm trying to use this with a newer crate that uses Rust's primitive u128 type (available since Rust 1.26).
What's an efficient way to convert back and forth between these two types?
rust
asked Nov 8 at 12:42
Dave Challis
1,4401336
add a comment |
up vote
1
down vote
favorite
I'm working with an old Rust module that uses the extprim crate to provide a u128 type.
I'm trying to use this with a newer crate that uses Rust's primitive u128 type (available since Rust 1.26).
What's an efficient way to convert back and forth between these two types?
rust
asked Nov 8 at 12:42
Dave Challis
1,4401336
2
I would suggest opening an issue or providing a pull request and remove that type in that crate completly ;)
– hellow
Nov 8 at 12:56
2
Maybeas_built_in? (docs.rs/extprim/1.6.0/src/extprim/u128.rs.html#178)
– phimuemue
Nov 8 at 13:02
@phimuemue that looks like a great option - I didn't find it in the public docs, I guess because it's only conditionally available?
– Dave Challis
Nov 8 at 13:31
1
@phimuemue look at my answer, it is even easier than that, thanks for the hint! ;)
– hellow
Nov 8 at 13:42
add a comment |
up vote
1
down vote
favorite
up vote
1
down vote
favorite
I'm working with an old Rust module that uses the extprim crate to provide a u128 type.
I'm trying to use this with a newer crate that uses Rust's primitive u128 type (available since Rust 1.26).
What's an efficient way to convert back and forth between these two types?
rust
asked Nov 8 at 12:42
Dave Challis
1,4401336
I'm working with an old Rust module that uses the extprim crate to provide a u128 type.
I'm trying to use this with a newer crate that uses Rust's primitive u128 type (available since Rust 1.26).
What's an efficient way to convert back and forth between these two types?
rust
rust
asked Nov 8 at 12:42
Dave Challis
1,4401336
asked Nov 8 at 12:42
Dave Challis
1,4401336
edited Nov 8 at 13:50
asked Nov 8 at 12:42
Dave Challis
1,4401336
asked Nov 8 at 12:42
Dave Challis
1,4401336
asked Nov 8 at 12:42
Dave Challis
1,4401336
1,4401336
2
I would suggest opening an issue or providing a pull request and remove that type in that crate completly ;)
– hellow
Nov 8 at 12:56
2
Maybeas_built_in? (docs.rs/extprim/1.6.0/src/extprim/u128.rs.html#178)
– phimuemue
Nov 8 at 13:02
@phimuemue that looks like a great option - I didn't find it in the public docs, I guess because it's only conditionally available?
– Dave Challis
Nov 8 at 13:31
1
@phimuemue look at my answer, it is even easier than that, thanks for the hint! ;)
– hellow
Nov 8 at 13:42
add a comment |
2
I would suggest opening an issue or providing a pull request and remove that type in that crate completly ;)
– hellow
Nov 8 at 12:56
2
Maybeas_built_in? (docs.rs/extprim/1.6.0/src/extprim/u128.rs.html#178)
– phimuemue
Nov 8 at 13:02
@phimuemue that looks like a great option - I didn't find it in the public docs, I guess because it's only conditionally available?
– Dave Challis
Nov 8 at 13:31
1
@phimuemue look at my answer, it is even easier than that, thanks for the hint! ;)
– hellow
Nov 8 at 13:42
2
2
I would suggest opening an issue or providing a pull request and remove that type in that crate completly ;)
– hellow
Nov 8 at 12:56
I would suggest opening an issue or providing a pull request and remove that type in that crate completly ;)
– hellow
Nov 8 at 12:56
2
2
Maybe
as_built_in? (docs.rs/extprim/1.6.0/src/extprim/u128.rs.html#178)– phimuemue
Nov 8 at 13:02
Maybe
as_built_in? (docs.rs/extprim/1.6.0/src/extprim/u128.rs.html#178)– phimuemue
Nov 8 at 13:02
@phimuemue that looks like a great option - I didn't find it in the public docs, I guess because it's only conditionally available?
– Dave Challis
Nov 8 at 13:31
@phimuemue that looks like a great option - I didn't find it in the public docs, I guess because it's only conditionally available?
– Dave Challis
Nov 8 at 13:31
1
1
@phimuemue look at my answer, it is even easier than that, thanks for the hint! ;)
– hellow
Nov 8 at 13:42
@phimuemue look at my answer, it is even easier than that, thanks for the hint! ;)
– hellow
Nov 8 at 13:42
add a comment |
1 Answer
1
active
oldest
votes
up vote
3
down vote
accepted
Update:
When your rustc version is greater than 1.26.0 the From trait is implemented and you can use into respectively from easily.
For a lower version than that see below.
As a note: "The most efficient way" is very subjective.
I would use the low64() and high64() methods to generate a rust u128.
extern crate extprim; // 1.6.0
use extprim::u128;
fn main() u128::from(number.low64());
println!(":?", number);
assert_eq!(number.to_string(), real_number.to_string());
// and back
let old_number = u128::u128::from_parts((real_number >> 64) as u64, (real_number) as u64);
assert_eq!(number, old_number);
(playground)
Since you can't compare both directly, I used the to_string() function to convert them to a string and compare those.
answered Nov 8 at 13:01
hellow
3,69812041
1
You could convert theextprim::u128to a string and then parse au128out of the string, that would be a way too, but not very efficient :D
– hellow
Nov 8 at 13:32
yup, that's the implementation I wanted to avoid :)
– Dave Challis
Nov 8 at 13:51
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
3
down vote
accepted
Update:
When your rustc version is greater than 1.26.0 the From trait is implemented and you can use into respectively from easily.
For a lower version than that see below.
As a note: "The most efficient way" is very subjective.
I would use the low64() and high64() methods to generate a rust u128.
extern crate extprim; // 1.6.0
use extprim::u128;
fn main() u128::from(number.low64());
println!(":?", number);
assert_eq!(number.to_string(), real_number.to_string());
// and back
let old_number = u128::u128::from_parts((real_number >> 64) as u64, (real_number) as u64);
assert_eq!(number, old_number);
(playground)
Since you can't compare both directly, I used the to_string() function to convert them to a string and compare those.
answered Nov 8 at 13:01
hellow
3,69812041
1
You could convert theextprim::u128to a string and then parse au128out of the string, that would be a way too, but not very efficient :D
– hellow
Nov 8 at 13:32
yup, that's the implementation I wanted to avoid :)
– Dave Challis
Nov 8 at 13:51
add a comment |
up vote
3
down vote
accepted
Update:
When your rustc version is greater than 1.26.0 the From trait is implemented and you can use into respectively from easily.
For a lower version than that see below.
As a note: "The most efficient way" is very subjective.
I would use the low64() and high64() methods to generate a rust u128.
extern crate extprim; // 1.6.0
use extprim::u128;
fn main() u128::from(number.low64());
println!(":?", number);
assert_eq!(number.to_string(), real_number.to_string());
// and back
let old_number = u128::u128::from_parts((real_number >> 64) as u64, (real_number) as u64);
assert_eq!(number, old_number);
(playground)
Since you can't compare both directly, I used the to_string() function to convert them to a string and compare those.
answered Nov 8 at 13:01
hellow
3,69812041
1
You could convert theextprim::u128to a string and then parse au128out of the string, that would be a way too, but not very efficient :D
– hellow
Nov 8 at 13:32
yup, that's the implementation I wanted to avoid :)
– Dave Challis
Nov 8 at 13:51
add a comment |
up vote
3
down vote
accepted
up vote
3
down vote
accepted
Update:
When your rustc version is greater than 1.26.0 the From trait is implemented and you can use into respectively from easily.
For a lower version than that see below.
As a note: "The most efficient way" is very subjective.
I would use the low64() and high64() methods to generate a rust u128.
extern crate extprim; // 1.6.0
use extprim::u128;
fn main() u128::from(number.low64());
println!(":?", number);
assert_eq!(number.to_string(), real_number.to_string());
// and back
let old_number = u128::u128::from_parts((real_number >> 64) as u64, (real_number) as u64);
assert_eq!(number, old_number);
(playground)
Since you can't compare both directly, I used the to_string() function to convert them to a string and compare those.
answered Nov 8 at 13:01
hellow
3,69812041
Update:
When your rustc version is greater than 1.26.0 the From trait is implemented and you can use into respectively from easily.
For a lower version than that see below.
As a note: "The most efficient way" is very subjective.
I would use the low64() and high64() methods to generate a rust u128.
extern crate extprim; // 1.6.0
use extprim::u128;
fn main() u128::from(number.low64());
println!(":?", number);
assert_eq!(number.to_string(), real_number.to_string());
// and back
let old_number = u128::u128::from_parts((real_number >> 64) as u64, (real_number) as u64);
assert_eq!(number, old_number);
(playground)
Since you can't compare both directly, I used the to_string() function to convert them to a string and compare those.
answered Nov 8 at 13:01
hellow
3,69812041
edited Nov 8 at 13:48
answered Nov 8 at 13:01
hellow
3,69812041
answered Nov 8 at 13:01
hellow
3,69812041
answered Nov 8 at 13:01
hellow
3,69812041
3,69812041
1
You could convert theextprim::u128to a string and then parse au128out of the string, that would be a way too, but not very efficient :D
– hellow
Nov 8 at 13:32
yup, that's the implementation I wanted to avoid :)
– Dave Challis
Nov 8 at 13:51
add a comment |
1
You could convert theextprim::u128to a string and then parse au128out of the string, that would be a way too, but not very efficient :D
– hellow
Nov 8 at 13:32
yup, that's the implementation I wanted to avoid :)
– Dave Challis
Nov 8 at 13:51
1
1
You could convert the
extprim::u128 to a string and then parse a u128 out of the string, that would be a way too, but not very efficient :D– hellow
Nov 8 at 13:32
You could convert the
extprim::u128 to a string and then parse a u128 out of the string, that would be a way too, but not very efficient :D– hellow
Nov 8 at 13:32
yup, that's the implementation I wanted to avoid :)
– Dave Challis
Nov 8 at 13:51
yup, that's the implementation I wanted to avoid :)
– Dave Challis
Nov 8 at 13:51
add a comment |
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2
I would suggest opening an issue or providing a pull request and remove that type in that crate completly ;)
– hellow
Nov 8 at 12:56
2
Maybe
as_built_in? (docs.rs/extprim/1.6.0/src/extprim/u128.rs.html#178)– phimuemue
Nov 8 at 13:02
@phimuemue that looks like a great option - I didn't find it in the public docs, I guess because it's only conditionally available?
– Dave Challis
Nov 8 at 13:31
1
@phimuemue look at my answer, it is even easier than that, thanks for the hint! ;)
– hellow
Nov 8 at 13:42