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1 use std::{ |
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2 iter, |
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3 mem::replace, |
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4 ops::{Index, IndexMut}, |
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5 }; |
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6 |
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7 pub struct IndexSlab<T> { |
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8 data: Vec<Option<T>>, |
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9 } |
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10 |
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11 impl<T> IndexSlab<T> { |
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12 pub fn new() -> Self { |
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13 Self { data: Vec::new() } |
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14 } |
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15 |
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16 pub fn with_capacity(capacity: usize) -> Self { |
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17 Self { |
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18 data: Vec::with_capacity(capacity), |
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19 } |
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20 } |
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21 |
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22 pub fn insert(&mut self, index: usize, value: T) { |
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23 if index >= self.data.len() { |
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24 self.data.reserve(index - self.data.len() + 1); |
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25 self.data.extend((self.data.len()..index).map(|_| None)); |
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26 self.data.push(Some(value)) |
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27 } else { |
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28 self.data[index] = Some(value); |
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29 } |
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30 } |
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31 |
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32 pub fn contains(&self, index: usize) -> bool { |
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33 self.data.get(index).and_then(|x| x.as_ref()).is_some() |
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34 } |
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35 |
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36 pub fn remove(&mut self, index: usize) -> Option<T> { |
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37 if let Some(x) = self.data.get_mut(index) { |
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38 replace(x, None) |
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39 } else { |
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40 None |
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41 } |
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42 } |
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43 |
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44 pub fn iter(&self) -> impl Iterator<Item = (usize, &T)> { |
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45 self.data |
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46 .iter() |
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47 .enumerate() |
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48 .filter_map(|(index, opt)| opt.as_ref().and_then(|x| Some((index, x)))) |
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49 } |
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50 |
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51 pub fn iter_mut(&mut self) -> impl Iterator<Item = (usize, &mut T)> { |
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52 self.data |
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53 .iter_mut() |
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54 .enumerate() |
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55 .filter_map(|(index, opt)| opt.as_mut().and_then(|x| Some((index, x)))) |
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56 } |
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57 } |
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58 |
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59 impl<T> Index<usize> for IndexSlab<T> { |
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60 type Output = T; |
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61 |
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62 fn index(&self, index: usize) -> &Self::Output { |
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63 self.data[index].as_ref().unwrap() |
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64 } |
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65 } |
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66 |
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67 impl<T> IndexMut<usize> for IndexSlab<T> { |
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68 fn index_mut(&mut self, index: usize) -> &mut Self::Output { |
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69 self.data[index].as_mut().unwrap() |
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70 } |
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71 } |