34 lines
834 B
Rust
34 lines
834 B
Rust
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use std::collections::HashMap;
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use std::hash::Hash;
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use heapsize::HeapSizeOf;
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/// Should be used to squeeze collections to certain size in bytes
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trait Squeeze {
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fn squeeze(&mut self, size: usize);
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}
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impl<K, T> Squeeze for HashMap<K, T> where K: Eq + Hash + Clone + HeapSizeOf, T: HeapSizeOf {
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fn squeeze(&mut self, size: usize) {
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if self.len() == 0 {
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return
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}
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let size_of_entry = self.heap_size_of_children() / self.capacity();
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let mut shrinked_size = size_of_entry * self.len();
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while self.len() > 0 || shrinked_size > size {
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// could be optimized
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let key = self.keys().next().unwrap().clone();
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self.remove(&key);
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shrinked_size -= size_of_entry;
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}
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self.shrink_to_fit();
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// if we havent shrinked enough, squeeze again
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if self.heap_size_of_children() > size {
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self.squeeze(size);
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}
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}
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}
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