49 lines
1.5 KiB
Rust
49 lines
1.5 KiB
Rust
use levenshtein_automata::{LevenshteinAutomatonBuilder as LevBuilder, DFA};
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use once_cell::sync::OnceCell;
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static LEVDIST0: OnceCell<LevBuilder> = OnceCell::new();
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static LEVDIST1: OnceCell<LevBuilder> = OnceCell::new();
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static LEVDIST2: OnceCell<LevBuilder> = OnceCell::new();
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#[derive(Copy, Clone)]
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enum PrefixSetting {
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Prefix,
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NoPrefix,
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}
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fn build_dfa_with_setting(query: &str, setting: PrefixSetting) -> DFA {
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use PrefixSetting::{NoPrefix, Prefix};
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match query.len() {
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0..=4 => {
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let builder = LEVDIST0.get_or_init(|| LevBuilder::new(0, true));
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match setting {
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Prefix => builder.build_prefix_dfa(query),
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NoPrefix => builder.build_dfa(query),
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}
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}
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5..=8 => {
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let builder = LEVDIST1.get_or_init(|| LevBuilder::new(1, true));
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match setting {
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Prefix => builder.build_prefix_dfa(query),
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NoPrefix => builder.build_dfa(query),
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}
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}
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_ => {
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let builder = LEVDIST2.get_or_init(|| LevBuilder::new(2, true));
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match setting {
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Prefix => builder.build_prefix_dfa(query),
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NoPrefix => builder.build_dfa(query),
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}
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}
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}
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}
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pub fn build_prefix_dfa(query: &str) -> DFA {
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build_dfa_with_setting(query, PrefixSetting::Prefix)
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}
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pub fn build_dfa(query: &str) -> DFA {
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build_dfa_with_setting(query, PrefixSetting::NoPrefix)
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}
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