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Use expect/match instead of unwrap

This commit is contained in:
Wei Tang 2018-04-09 20:27:53 +08:00
parent 6ad1ef5d9e
commit eb548831ab
1 changed files with 34 additions and 33 deletions
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67
script/src/num.rs
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@ -87,40 +87,41 @@ impl From<Num> for usize {
impl Num {
// Reduce the data size to its minimal, and then try to convert it to a num.
pub fn minimally_encode(data: &[u8], max_size: usize) -> Result<Self, Error> {
if data.is_empty() {
return Num::from_slice(data, true, max_size);
match data.last() {
None => Num::from_slice(data, true, max_size),
Some(last) => {
if *last != 0x00 && *last != 0x80 {
return Num::from_slice(data, true, max_size);
}
if data.len() == 1 {
return Num::from_slice(&[], true, max_size);
}
if data[data.len() - 2] & 0x80 == 0x80 {
return Num::from_slice(data, true, max_size);
}
// We are not minimally encoded. Create a vector so that we can trim the result. The last byte is not included,
// as we first trim all zeros. And then a conditional to decide what to do with the last byte.
let mut data: Vec<u8> = data[0..(data.len()-1)].iter().map(|x| *x).rev().skip_while(|x| *x == 0x00).collect();
data.reverse();
if data.len() == 0 {
// At this point, last is either equal to 0x00 or 0x80. The result is empty.
return Num::from_slice(&[], true, max_size);
}
let second_last = *data.last().expect("vec emptiness is checked above; qed");
if second_last & 0x80 == 0x80 {
data.push(*last);
} else {
*data.last_mut().expect("vec emptiness is checked above; qed") |= *last
}
Num::from_slice(&data, true, max_size)
}
}
let last = *data.last().unwrap();
if last != 0x00 && last != 0x80 {
return Num::from_slice(data, true, max_size);
}
if data.len() == 1 {
return Num::from_slice(&[], true, max_size);
}
if data[data.len() - 2] & 0x80 == 0x80 {
return Num::from_slice(data, true, max_size);
}
// We are not minimally encoded. Create a vector so that we can trim the result. The last byte is not included,
// as we first trim all zeros. And then a conditional to decide what to do with the last byte.
let mut data: Vec<u8> = data[0..(data.len()-1)].iter().map(|x| *x).rev().skip_while(|x| *x == 0x00).collect();
data.reverse();
if data.len() == 0 {
// At this point, last is either equal to 0x00 or 0x80. The result is empty.
return Num::from_slice(&[], true, max_size);
}
if data.last().unwrap() & 0x80 == 0x80 {
data.push(last);
} else {
*data.last_mut().unwrap() |= last;
}
Num::from_slice(&data, true, max_size)
}
pub fn from_slice(data: &[u8], require_minimal: bool, max_size: usize) -> Result<Self, Error> {