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42 lines
622 B
42 lines
622 B
//! Utils
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pub trait NewCapacity: Sized
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{
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fn new() -> Self;
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fn with_capacity(cap: usize) -> Self;
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}
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impl NewCapacity for String
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{
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fn new() -> Self
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{
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Self::new()
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}
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fn with_capacity(cap: usize) -> Self
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{
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Self::with_capacity(cap)
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}
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}
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impl<T> NewCapacity for Vec<T>
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{
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fn new() -> Self
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{
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Self::new()
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}
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fn with_capacity(cap: usize) -> Self
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{
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Self::with_capacity(cap)
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}
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}
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pub fn hint_cap<T: NewCapacity, I: Iterator>(iter: &I) -> T
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{
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match iter.size_hint() {
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(0, Some(0)) | (0, None) => T::new(),
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(_, Some(x)) | (x, _) => T::with_capacity(x)
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}
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}
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