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Optimize builtins/range #2460

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Merged
coolreader18 merged 1 commit into from
Feb 15, 2021
Merged

Optimize builtins/range #2460

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44 changes: 29 additions & 15 deletions vm/src/builtins/range.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -78,28 +78,36 @@ impl PyRange {
pub fn get(&self, index: &BigInt) -> Option<BigInt> {
let start = self.start.borrow_value();
let step = self.step.borrow_value();
let index = index.clone();
let stop = self.stop.borrow_value();
if self.is_empty() {
return None;
}

let length = self.length();

let index = if index.is_negative() {
let new_index: BigInt = &length + &index;
if new_index.is_negative() {
if index.is_negative() {
let length = self.length();
let index: BigInt = &length + index;
if index.is_negative() {
return None;
}
length + index

Some(if step.is_one() {
start + index
} else {
start + step * index
})
} else {
if length <= index {
return None;
}
index
};
let index = if step.is_one() {
start + index
} else {
start + step * index
};

let result = start + step * index;
Some(result)
if (step.is_positive() && stop > &index) || (step.is_negative() && stop < &index) {
Some(index)
} else {
None
}
}
}

#[inline]
Expand All @@ -109,7 +117,13 @@ impl PyRange {
let step = self.step.borrow_value();

match step.sign() {
Sign::Plus if start < stop => (stop - start - 1usize) / step + 1,
Sign::Plus if start < stop => {
if step.is_one() {
stop - start
} else {
(stop - start - 1usize) / step + 1
}
}
Sign::Minus if start > stop => (start - stop - 1usize) / (-step) + 1,
Sign::Plus | Sign::Minus => BigInt::zero(),
Sign::NoSign => unreachable!(),
Expand Down