Rename MeiliDB into MeiliSearch

meilisearch-core/src/automaton/dfa.rs

@@ -0,0 +1,48 @@
+use levenshtein_automata::{LevenshteinAutomatonBuilder as LevBuilder, DFA};
+use once_cell::sync::OnceCell;
+
+static LEVDIST0: OnceCell<LevBuilder> = OnceCell::new();
+static LEVDIST1: OnceCell<LevBuilder> = OnceCell::new();
+static LEVDIST2: OnceCell<LevBuilder> = OnceCell::new();
+
+#[derive(Copy, Clone)]
+enum PrefixSetting {
+    Prefix,
+    NoPrefix,
+}
+
+fn build_dfa_with_setting(query: &str, setting: PrefixSetting) -> DFA {
+    use PrefixSetting::{NoPrefix, Prefix};
+
+    match query.len() {
+        0..=4 => {
+            let builder = LEVDIST0.get_or_init(|| LevBuilder::new(0, true));
+            match setting {
+                Prefix => builder.build_prefix_dfa(query),
+                NoPrefix => builder.build_dfa(query),
+            }
+        }
+        5..=8 => {
+            let builder = LEVDIST1.get_or_init(|| LevBuilder::new(1, true));
+            match setting {
+                Prefix => builder.build_prefix_dfa(query),
+                NoPrefix => builder.build_dfa(query),
+            }
+        }
+        _ => {
+            let builder = LEVDIST2.get_or_init(|| LevBuilder::new(2, true));
+            match setting {
+                Prefix => builder.build_prefix_dfa(query),
+                NoPrefix => builder.build_dfa(query),
+            }
+        }
+    }
+}
+
+pub fn build_prefix_dfa(query: &str) -> DFA {
+    build_dfa_with_setting(query, PrefixSetting::Prefix)
+}
+
+pub fn build_dfa(query: &str) -> DFA {
+    build_dfa_with_setting(query, PrefixSetting::NoPrefix)
+}