add API for greedly algorithm and make sure it passes tests

src/fuzzy_greedy.rs

@@ -4,7 +4,7 @@ use crate::Matcher;
 impl Matcher {
     /// greedy fallback algorithm, much faster (linear time) but reported scores/indicies
     /// might not be the best match
-    pub(crate) fn fuzzy_match_greedy<const INDICES: bool, H: Char + PartialEq<N>, N: Char>(
+    pub(crate) fn fuzzy_match_greedy_<const INDICES: bool, H: Char + PartialEq<N>, N: Char>(
         &mut self,
         haystack: &[H],
         needle: &[N],

src/fuzzy_optimal.rs

@@ -23,7 +23,7 @@ impl Matcher {
         // to avoid the slow O(mn) time complexity for large inputs. Furthermore, it allows
         // us to treat needle indices as u16
         let Some(mut matrix) = self.slab.alloc(&haystack[start..end], needle.len()) else {
-            return self.fuzzy_match_greedy::<INDICES, H, N>(
+            return self.fuzzy_match_greedy_::<INDICES, H, N>(
                 haystack,
                 needle,
                 start,

src/lib.rs

@@ -91,7 +91,7 @@ impl Matcher {
         );
         match (haystack, needle_) {
             (Utf32Str::Ascii(haystack), Utf32Str::Ascii(needle)) => {
-                let (start, greedy_end, end) = self.prefilter_ascii(haystack, needle)?;
+                let (start, greedy_end, end) = self.prefilter_ascii(haystack, needle, false)?;
                 self.fuzzy_match_optimal::<INDICES, AsciiChar, AsciiChar>(
                     AsciiChar::cast(haystack),
                     AsciiChar::cast(needle),
@@ -107,7 +107,7 @@ impl Matcher {
                 None
             }
             (Utf32Str::Unicode(haystack), Utf32Str::Ascii(needle)) => {
-                let (start, end) = self.prefilter_non_ascii(haystack, needle_)?;
+                let (start, end) = self.prefilter_non_ascii(haystack, needle_, false)?;
                 self.fuzzy_match_optimal::<INDICES, char, AsciiChar>(
                     haystack,
                     AsciiChar::cast(needle),
@@ -118,7 +118,7 @@ impl Matcher {
                 )
             }
             (Utf32Str::Unicode(haystack), Utf32Str::Unicode(needle)) => {
-                let (start, end) = self.prefilter_non_ascii(haystack, needle_)?;
+                let (start, end) = self.prefilter_non_ascii(haystack, needle_, false)?;
                 self.fuzzy_match_optimal::<INDICES, char, char>(
                     haystack,
                     needle,
@@ -130,30 +130,77 @@ impl Matcher {
             }
         }
     }
+    pub fn fuzzy_match_greedy(
+        &mut self,
+        haystack: Utf32Str<'_>,
+        needle: Utf32Str<'_>,
+    ) -> Option<u16> {
+        assert!(haystack.len() <= u32::MAX as usize);
+        self.fuzzy_match_greedy_impl::<false>(haystack, needle, &mut Vec::new())
+    }
 
-    // pub fn fuzzy_indices(
-    //     &mut self,
-    //     query: &Query,
-    //     mut haystack: Utf32Str<'_>,
-    //     indices: &mut Vec<u32>,
-    // ) -> Option<u16> {
-    //     if haystack.len() > u32::MAX as usize {
-    //         haystack = &haystack[..u32::MAX as usize]
-    //     }
-    //     println!(
-    //         "start {haystack:?}, {:?} {} {}",
-    //         query.needle_chars, query.ignore_case, query.is_ascii
-    //     );
-    //     if self.config.use_v1 {
-    //         if query.is_ascii && !self.config.normalize {
-    //             self.fuzzy_matcher_v1::<true, true>(query, haystack, indices)
-    //         } else {
-    //             self.fuzzy_matcher_v1::<true, false>(query, haystack, indices)
-    //         }
-    //     } else if query.is_ascii && !self.config.normalize {
-    //         self.fuzzy_matcher_v2::<true, true>(query, haystack, indices)
-    //     } else {
-    //         self.fuzzy_matcher_v2::<true, false>(query, haystack, indices)
-    //     }
+    pub fn fuzzy_indices_greedy(
+        &mut self,
+        haystack: Utf32Str<'_>,
+        needle: Utf32Str<'_>,
+        indidies: &mut Vec<u32>,
+    ) -> Option<u16> {
+        assert!(haystack.len() <= u32::MAX as usize);
+        self.fuzzy_match_greedy_impl::<true>(haystack, needle, indidies)
+    }
+
+    fn fuzzy_match_greedy_impl<const INDICES: bool>(
+        &mut self,
+        haystack: Utf32Str<'_>,
+        needle_: Utf32Str<'_>,
+        indidies: &mut Vec<u32>,
+    ) -> Option<u16> {
+        if needle_.len() > haystack.len() {
+            return None;
+        }
+        // if needle_.len() == haystack.len() {
+        //     return self.exact_match();
         // }
+        assert!(
+            haystack.len() <= u32::MAX as usize,
+            "fuzzy matching is only support for up to 2^32-1 codepoints"
+        );
+        match (haystack, needle_) {
+            (Utf32Str::Ascii(haystack), Utf32Str::Ascii(needle)) => {
+                let (start, greedy_end, _) = self.prefilter_ascii(haystack, needle, true)?;
+                self.fuzzy_match_greedy_::<INDICES, AsciiChar, AsciiChar>(
+                    AsciiChar::cast(haystack),
+                    AsciiChar::cast(needle),
+                    start,
+                    greedy_end,
+                    indidies,
+                )
+            }
+            (Utf32Str::Ascii(_), Utf32Str::Unicode(_)) => {
+                // a purely ascii haystack can never be transformed to match
+                // a needle that contains non-ascii chars since we don't allow gaps
+                None
+            }
+            (Utf32Str::Unicode(haystack), Utf32Str::Ascii(needle)) => {
+                let (start, _) = self.prefilter_non_ascii(haystack, needle_, true)?;
+                self.fuzzy_match_greedy_::<INDICES, char, AsciiChar>(
+                    haystack,
+                    AsciiChar::cast(needle),
+                    start,
+                    start + 1,
+                    indidies,
+                )
+            }
+            (Utf32Str::Unicode(haystack), Utf32Str::Unicode(needle)) => {
+                let (start, _) = self.prefilter_non_ascii(haystack, needle_, true)?;
+                self.fuzzy_match_greedy_::<INDICES, char, char>(
+                    haystack,
+                    needle,
+                    start,
+                    start + 1,
+                    indidies,
+                )
+            }
+        }
+    }
 }

src/prefilter.rs

@@ -27,31 +27,41 @@ impl Matcher {
         &self,
         mut haystack: &[u8],
         needle: &[u8],
+        only_greedy: bool,
     ) -> Option<(usize, usize, usize)> {
         if self.config.ignore_case {
             let start = find_ascii_ignore_case(needle[0], haystack)?;
-            let mut eager_end = start + 1;
-            haystack = &haystack[eager_end..];
+            let mut greedy_end = start + 1;
+            haystack = &haystack[greedy_end..];
             for &c in &needle[1..] {
                 let idx = find_ascii_ignore_case(c, haystack)? + 1;
-                eager_end += idx;
+                greedy_end += idx;
                 haystack = &haystack[idx..];
             }
-            let end = eager_end
+            if only_greedy {
+                Some((start, greedy_end, greedy_end))
+            } else {
+                let end = greedy_end
                     + find_ascii_ignore_case_rev(*needle.last().unwrap(), haystack)
                         .map_or(0, |i| i + 1);
-            Some((start, eager_end, end))
+                Some((start, greedy_end, end))
+            }
         } else {
             let start = memchr(needle[0], haystack)?;
-            let mut eager_end = start + 1;
-            haystack = &haystack[eager_end..];
+            let mut greedy_end = start + 1;
+            haystack = &haystack[greedy_end..];
             for &c in &needle[1..] {
                 let idx = memchr(c, haystack)? + 1;
-                eager_end += idx;
+                greedy_end += idx;
                 haystack = &haystack[idx..];
             }
-            let end = eager_end + memrchr(*needle.last().unwrap(), haystack).map_or(0, |i| i + 1);
-            Some((start, eager_end, end))
+            if only_greedy {
+                Some((start, greedy_end, greedy_end))
+            } else {
+                let end =
+                    greedy_end + memrchr(*needle.last().unwrap(), haystack).map_or(0, |i| i + 1);
+                Some((start, greedy_end, end))
+            }
         }
     }
 
@@ -59,12 +69,16 @@ impl Matcher {
         &self,
         haystack: &[char],
         needle: Utf32Str<'_>,
+        only_greedy: bool,
     ) -> Option<(usize, usize)> {
         let needle_char = needle.get(0);
         let start = haystack
             .iter()
             .position(|c| c.normalize(&self.config) == needle_char)?;
         let needle_char = needle.last();
+        if only_greedy {
+            Some((start, start + 1))
+        } else {
             let end = start + haystack.len()
                 - haystack[start..]
                     .iter()
@@ -73,4 +87,5 @@ impl Matcher {
 
             Some((start, end))
         }
+    }
 }

src/score.rs

@@ -78,6 +78,7 @@ impl Matcher {
         indices: &mut Vec<u32>,
     ) -> u16 {
         if INDICES {
+            indices.clear();
             indices.reserve(needle.len());
         }
 
@@ -95,15 +96,18 @@ impl Matcher {
         if INDICES {
             indices.push(start as u32)
         }
-        let mut first_bonus = self.bonus_for(prev_class, haystack[0].char_class(&self.config));
+        let class = haystack[start].char_class(&self.config);
+        let mut first_bonus = self.bonus_for(prev_class, class);
         let mut score = SCORE_MATCH + first_bonus * BONUS_FIRST_CHAR_MULTIPLIER;
+        prev_class = class;
+        needle_char = *needle_iter.next().unwrap_or(&needle_char);
 
         for (i, c) in haystack[start + 1..end].iter().enumerate() {
             let class = c.char_class(&self.config);
             let c = c.normalize(&self.config);
             if c == needle_char {
                 if INDICES {
-                    indices.push(i as u32 + start as u32)
+                    indices.push(i as u32 + start as u32 + 1)
                 }
                 let mut bonus = self.bonus_for(prev_class, class);
                 if consecutive == 0 {

src/tests.rs

@@ -35,7 +35,11 @@ pub fn assert_matches(
         let haystack = Utf32Str::new(haystack, &mut haystack_buf);
         score += needle.len() as u16 * SCORE_MATCH;
 
-        let res = matcher.fuzzy_indices(haystack, needle, &mut indices);
+        let res = if use_v1 {
+            matcher.fuzzy_indices_greedy(haystack, needle, &mut indices)
+        } else {
+            matcher.fuzzy_indices(haystack, needle, &mut indices)
+        };
         let match_chars: Vec<_> = indices
             .iter()
             .map(|&i| haystack.get(i).normalize(&matcher.config))

src/utf32_str.rs

@@ -1,5 +1,5 @@
 use std::ops::{Bound, RangeBounds};
-use std::slice;
+use std::{fmt, slice};
 
 /// A UTF32 encoded (char array) String that can be used as an input to fuzzy matching.
 ///
@@ -27,7 +27,7 @@ use std::slice;
 /// produce char indices (instead of utf8 offsets) annyway. With a
 /// codepoint basec representation like this the indices can be used
 /// directly
-#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Hash, Debug)]
+#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Hash)]
 pub enum Utf32Str<'a> {
     /// A string represented as ASCII encoded bytes.
     /// Correctness invariant: must only contain valid ASCII (<=127)
@@ -116,6 +116,27 @@ impl<'a> Utf32Str<'a> {
         }
     }
 }
+impl fmt::Debug for Utf32Str<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "\"")?;
+        for c in self.chars() {
+            for c in c.escape_debug() {
+                write!(f, "{c}")?
+            }
+        }
+        write!(f, "\"")
+    }
+}
+
+impl fmt::Display for Utf32Str<'_> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, "\"")?;
+        for c in self.chars() {
+            write!(f, "{c}")?
+        }
+        write!(f, "\"")
+    }
+}
 
 pub enum Chars<'a> {
     Ascii(slice::Iter<'a, u8>),