Extract WordDB::RankedWord as RankedMatch in its own file

1 files changed, 40 insertions, 0 deletions

diff --git a/src/ranked_match.cc b/src/ranked_match.cc
new file mode 100644
index 00000000..0063b8ae
--- /dev/null
+++ b/src/ranked_match.cc
@@ -0,0 +1,40 @@
+#include "ranked_match.hh"
+
+namespace Kakoune
+{
+
+int match_rank(StringView candidate, StringView query)
+{
+    int rank = 0;
+    auto it = candidate.begin();
+    char prev = 0;
+    for (auto c : query)
+    {
+        if (it == candidate.end())
+            return 0;
+
+        const bool islow = islower(c);
+        auto eq_c = [islow, c](char ch) { return islow ? tolower(ch) == c : ch == c; };
+
+        if (eq_c(*it)) // improve rank on contiguous
+            ++rank;
+
+        while (!eq_c(*it))
+        {
+            prev = *it;
+            if (++it == candidate.end())
+                return 0;
+        }
+        // Improve rank on word boundaries
+        if (prev == 0 or prev == '_' or
+            (islower(prev) and isupper(*it)))
+            rank += 5;
+
+        prev = c;
+        ++rank;
+        ++it;
+    }
+    return rank;
+}
+
+}