Created
March 21, 2019 10:08
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#![feature(test)] | |
extern crate test; | |
use std::iter::FromIterator; | |
#[cfg(test)] | |
use test::Bencher; | |
fn from_iter_with_scan_with_freevar<C, T, E, I>(iter: I) -> Result<C, E> | |
where I: Iterator<Item = Result<T, E>>, | |
C: FromIterator<T>, | |
{ | |
let mut err = None; | |
let v = { | |
let adapter = iter.scan((), |_, item| { | |
match item { | |
Ok(x) => Some(x), | |
Err(x) => { | |
err = Some(x); | |
None | |
}, | |
} | |
}); | |
FromIterator::from_iter(adapter) | |
}; | |
match err { | |
Some(err) => Err(err), | |
None => Ok(v), | |
} | |
} | |
fn from_iter_with_scan_passing_state<C, T, E, I>(iter: I) -> Result<C, E> | |
where I: Iterator<Item = Result<T, E>>, | |
C: FromIterator<T>, | |
{ | |
let mut err = None; | |
let v = { | |
let adapter = iter.scan(&mut err, |err, item| { | |
match item { | |
Ok(x) => Some(x), | |
Err(x) => { | |
**err = Some(x); | |
None | |
}, | |
} | |
}); | |
FromIterator::from_iter(adapter) | |
}; | |
match err { | |
Some(err) => Err(err), | |
None => Ok(v), | |
} | |
} | |
fn from_iter_with_filter_map<C, T, E, I>(iter: I) -> Result<C, E> | |
where I: Iterator<Item = Result<T, E>>, | |
C: FromIterator<T>, | |
{ | |
let mut err = None; | |
let v = { | |
let adapter = iter.filter_map(|item| { | |
match item { | |
Ok(x) => Some(x), | |
Err(x) => { | |
err = Some(x); | |
None | |
}, | |
} | |
}); | |
FromIterator::from_iter(adapter) | |
}; | |
match err { | |
Some(err) => Err(err), | |
None => Ok(v), | |
} | |
} | |
fn main() { | |
let one: Result<Vec<u8>, _> = FromIterator::from_iter("1,2,3".split(",").map(|x| x.parse())); | |
let two_a: Result<Vec<u8>, _> = from_iter_with_scan_passing_state("1,2,3".split(",").map(|x| x.parse())); | |
let two_b: Result<Vec<u8>, _> = from_iter_with_scan_with_freevar("1,2,3".split(",").map(|x| x.parse())); | |
let three: Result<Vec<u8>, _> = from_iter_with_filter_map("1,2,3".split(",").map(|x| x.parse())); | |
println!("{:?}", one); | |
println!("{:?}", two_a); | |
println!("{:?}", two_b); | |
println!("{:?}", three); | |
let one: Result<Vec<u8>, _> = FromIterator::from_iter("1,a,3".split(",").map(|x| x.parse())); | |
let two_a: Result<Vec<u8>, _> = from_iter_with_scan_passing_state("1,a,3".split(",").map(|x| x.parse())); | |
let two_b: Result<Vec<u8>, _> = from_iter_with_scan_with_freevar("1,a,3".split(",").map(|x| x.parse())); | |
let three: Result<Vec<u8>, _> = from_iter_with_filter_map("1,a,3".split(",").map(|x| x.parse())); | |
println!("{:?}", one); | |
println!("{:?}", two_a); | |
println!("{:?}", two_b); | |
println!("{:?}", three); | |
} | |
#[bench] | |
fn bench_from_iter(b: &mut Bencher) { | |
let expected = vec![1; 1000]; | |
let v: Vec<Result<isize, String>> = vec![Ok(1); 1000]; | |
b.iter(|| { | |
let result: Result<Vec<isize>, String> = FromIterator::from_iter(v.iter().cloned()); | |
assert_eq!(result.unwrap(), expected); | |
}); | |
} | |
#[bench] | |
fn bench_from_iter_with_scan_passing_state(b: &mut Bencher) { | |
let expected = vec![1; 1000]; | |
let v: Vec<Result<isize, String>> = vec![Ok(1); 1000]; | |
b.iter(|| { | |
let result: Result<Vec<isize>, String> = from_iter_with_scan_passing_state(v.iter().cloned()); | |
assert_eq!(result.unwrap(), expected); | |
}); | |
} | |
#[bench] | |
fn bench_from_iter_with_scan_with_freevar(b: &mut Bencher) { | |
let expected = vec![1; 1000]; | |
let v: Vec<Result<isize, String>> = vec![Ok(1); 1000]; | |
b.iter(|| { | |
let result: Result<Vec<isize>, String> = from_iter_with_scan_with_freevar(v.iter().cloned()); | |
assert_eq!(result.unwrap(), expected); | |
}); | |
} | |
#[bench] | |
fn bench_from_iter_with_filter_map(b: &mut Bencher) { | |
let expected = vec![1; 1000]; | |
let v: Vec<Result<isize, String>> = vec![Ok(1); 1000]; | |
b.iter(|| { | |
let result: Result<Vec<isize>, String> = from_iter_with_filter_map(v.iter().cloned()); | |
assert_eq!(result.unwrap(), expected); | |
}); | |
} |
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