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39 lines
886 B
39 lines
886 B
//! Extends the BufReader Lines to support summing based on newlines. |
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use std::io::BufRead; |
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use std::io::Lines; |
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pub struct Accumulator<B> { |
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lines: Lines<B>, |
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current: u32, |
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} |
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pub trait Elvish<B> { |
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fn elf(self) -> Accumulator<B>; |
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} |
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impl<B> Elvish<B> for Lines<B> { |
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fn elf(self) -> Accumulator<B> { |
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Accumulator { |
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lines: self, |
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current: 0, |
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} |
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} |
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} |
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impl<B: BufRead> Iterator for Accumulator<B> { |
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type Item = u32; |
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fn next(&mut self) -> Option<Self::Item> { |
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while let Some(Ok(line)) = self.lines.next() { |
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let line = line.trim(); |
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if line.is_empty() { |
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let result = self.current; |
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self.current = 0; |
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return Some(result); |
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} else { |
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self.current += line.parse::<u32>().unwrap(); |
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} |
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} |
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None |
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} |
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}
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