From cbe38b2f962443f5fefcbbb5f7552f50c0e841fc Mon Sep 17 00:00:00 2001
From: Maxime Coste <frrrwww@gmail.com>
Date: Mon, 29 Aug 2016 23:56:22 +0100
Subject: [PATCH] Use flags and bit operations instead of bools in RankedMatch

full match is now the most important flag for comparison.
---
 src/flags.hh        | 16 ++++++++++++++++
 src/ranked_match.cc | 35 +++++++++++++++++------------------
 src/ranked_match.hh | 17 ++++++++++++++---
 3 files changed, 47 insertions(+), 21 deletions(-)

diff --git a/src/flags.hh b/src/flags.hh
index 6b72ba05..824d37ca 100644
--- a/src/flags.hh
+++ b/src/flags.hh
@@ -37,6 +37,9 @@ struct TestableFlags
     Flags value;
     constexpr operator bool() const { return (UnderlyingType<Flags>)value; }
     constexpr operator Flags() const { return value; }
+
+    bool operator==(const TestableFlags<Flags>& other) const { return value == other.value; }
+    bool operator!=(const TestableFlags<Flags>& other) const { return value != other.value; }
 };
 
 template<typename Flags, typename = EnableIfWithBitOps<Flags>>
@@ -58,6 +61,19 @@ constexpr Flags operator~(Flags lhs)
     return (Flags)(~(UnderlyingType<Flags>)lhs);
 }
 
+template<typename Flags, typename = EnableIfWithBitOps<Flags>>
+constexpr Flags operator^(Flags lhs, Flags rhs)
+{
+    return (Flags)((UnderlyingType<Flags>) lhs ^ (UnderlyingType<Flags>) rhs);
+}
+
+template<typename Flags, typename = EnableIfWithBitOps<Flags>>
+Flags& operator^=(Flags& lhs, Flags rhs)
+{
+    (UnderlyingType<Flags>&) lhs ^= (UnderlyingType<Flags>) rhs;
+    return lhs;
+}
+
 }
 
 #endif // flags_hh_INCLUDED
diff --git a/src/ranked_match.cc b/src/ranked_match.cc
index 67be7038..d61d95f5 100644
--- a/src/ranked_match.cc
+++ b/src/ranked_match.cc
@@ -70,9 +70,9 @@ static bool smartcase_eq(Codepoint query, Codepoint candidate)
     return query == (islower(query) ? to_lower(candidate) : candidate);
 }
 
-static bool subsequence_match_smart_case(StringView str, StringView subseq, int& index_sum)
+static bool subsequence_match_smart_case(StringView str, StringView subseq, int& out_index_sum)
 {
-    index_sum = 0;
+    int index_sum = 0;
     auto it = str.begin();
     int index = 0;
     for (auto subseq_it = subseq.begin(); subseq_it != subseq.end();)
@@ -88,6 +88,7 @@ static bool subsequence_match_smart_case(StringView str, StringView subseq, int&
         }
         index_sum += index++;
     }
+    out_index_sum = index_sum;
     return true;
 }
 
@@ -103,10 +104,17 @@ RankedMatch::RankedMatch(StringView candidate, StringView query, TestFunc func)
     {
         m_candidate = candidate;
 
-        m_first_char_match = smartcase_eq(query[0], candidate[0]);
+        if (smartcase_eq(query[0], candidate[0]))
+            m_flags |= Flags::FirstCharMatch;
+        if (std::equal(query.begin(), query.end(), candidate.begin()))
+        {
+            m_flags |= Flags::Prefix;
+            if (query.length() == candidate.length())
+                m_flags |= Flags::FullMatch;
+        }
         m_word_boundary_match_count = count_word_boundaries_match(candidate, query);
-        m_only_word_boundary = m_word_boundary_match_count == query.length();
-        m_prefix = std::equal(query.begin(), query.end(), candidate.begin());
+        if (m_word_boundary_match_count == query.length())
+            m_flags |= Flags::OnlyWordBoundary;
     }
 }
 
@@ -127,19 +135,10 @@ bool RankedMatch::operator<(const RankedMatch& other) const
 {
     kak_assert((bool)*this and (bool)other);
 
-    if (m_prefix != other.m_prefix)
-        return m_prefix;
-
-    if (m_first_char_match != other.m_first_char_match)
-        return m_first_char_match;
-
-    if (m_only_word_boundary and other.m_only_word_boundary)
-    {
-        if (m_word_boundary_match_count != other.m_word_boundary_match_count)
-            return m_word_boundary_match_count > other.m_word_boundary_match_count;
-    }
-    else if (m_only_word_boundary or other.m_only_word_boundary)
-        return  m_only_word_boundary;
+    const auto diff = m_flags ^ other.m_flags;
+    // flags are different, use their ordering to return the first match
+    if (diff != Flags::None)
+        return (int)(m_flags & diff) > (int)(other.m_flags & diff);
 
     if (m_word_boundary_match_count != other.m_word_boundary_match_count)
         return m_word_boundary_match_count > other.m_word_boundary_match_count;
diff --git a/src/ranked_match.hh b/src/ranked_match.hh
index 0e0e49c4..35d76e15 100644
--- a/src/ranked_match.hh
+++ b/src/ranked_match.hh
@@ -2,6 +2,7 @@
 #define ranked_match_hh_INCLUDED
 
 #include "string.hh"
+#include "flags.hh"
 
 namespace Kakoune
 {
@@ -32,14 +33,24 @@ private:
     template<typename TestFunc>
     RankedMatch(StringView candidate, StringView query, TestFunc test);
 
+    enum class Flags : int
+    {
+        None = 0,
+        // Order is important, the highest bit has precedence for comparison
+        OnlyWordBoundary = 1 << 0,
+        FirstCharMatch = 1 << 1,
+        Prefix = 1 << 2,
+        FullMatch = 1 << 3,
+    };
+
     StringView m_candidate;
-    bool m_first_char_match = false;
-    bool m_prefix = false;
+    Flags m_flags = Flags::None;
     int m_word_boundary_match_count = 0;
     int m_match_index_sum = 0;
-    bool m_only_word_boundary = false;
 };
 
+template<> struct WithBitOps<RankedMatch::Flags> : std::true_type {};
+
 }
 
 #endif // ranked_match_hh_INCLUDED