Do not template TimSort class on Compare and Projection

Several functions in the class do not depend on those template parameters, which leads to more function template instantiations than needed. This commit templates individual functions needing it on the Compare and Projection types instead of templating the whole classe, leading to small gains in binary size.
timsort · Jan 23, 2024 · 7ee9139 · 7ee9139
1 parent 0f1c9d3
commit 7ee9139
Showing 1 changed file with 15 additions and 5 deletions.
diff --git a/include/gfx/timsort.hpp b/include/gfx/timsort.hpp
@@ -89,7 +89,7 @@ struct run {
     }
 };
 
-template <typename RandomAccessIterator, typename Compare, typename Projection>
+template <typename RandomAccessIterator>
 class TimSort {
     using iter_t = RandomAccessIterator;
     using value_t = typename std::iterator_traits<iter_t>::value_type;
@@ -105,6 +105,7 @@ class TimSort {
 
     std::vector<run<RandomAccessIterator> > pending_;
 
+    template <typename Compare, typename Projection>
     static void binarySort(iter_t const lo, iter_t const hi, iter_t start,
                            Compare comp, Projection proj) {
         GFX_TIMSORT_ASSERT(lo <= start);
@@ -124,6 +125,7 @@ class TimSort {
         }
     }
 
+    template <typename Compare, typename Projection>
     static diff_t countRunAndMakeAscending(iter_t const lo, iter_t const hi,
                                            Compare comp, Projection proj) {
         GFX_TIMSORT_ASSERT(lo < hi);
@@ -172,6 +174,7 @@ class TimSort {
         pending_.push_back(run<iter_t>(runBase, runLen));
     }
 
+    template <typename Compare, typename Projection>
     void mergeCollapse(Compare comp, Projection proj) {
         while (pending_.size() > 1) {
             diff_t n = pending_.size() - 2;
@@ -190,6 +193,7 @@ class TimSort {
         }
     }
 
+    template <typename Compare, typename Projection>
     void mergeForceCollapse(Compare comp, Projection proj) {
         while (pending_.size() > 1) {
             diff_t n = pending_.size() - 2;
@@ -201,6 +205,7 @@ class TimSort {
         }
     }
 
+    template <typename Compare, typename Projection>
     void mergeAt(diff_t const i, Compare comp, Projection proj) {
         diff_t const stackSize = pending_.size();
         GFX_TIMSORT_ASSERT(stackSize >= 2);
@@ -223,6 +228,7 @@ class TimSort {
         mergeConsecutiveRuns(base1, len1, base2, len2, std::move(comp), std::move(proj));
     }
 
+    template <typename Compare, typename Projection>
     void mergeConsecutiveRuns(iter_t base1, diff_t len1, iter_t base2, diff_t len2,
                               Compare comp, Projection proj) {
         GFX_TIMSORT_ASSERT(len1 > 0);
@@ -252,7 +258,7 @@ class TimSort {
         }
     }
 
-    template <typename T, typename Iter>
+    template <typename T, typename Iter, typename Compare, typename Projection>
     static diff_t gallopLeft(T const& key, Iter const base, diff_t const len, diff_t const hint,
                              Compare comp, Projection proj) {
         GFX_TIMSORT_ASSERT(len > 0);
@@ -303,7 +309,7 @@ class TimSort {
         return std::ranges::lower_bound(base + (lastOfs + 1), base + ofs, key, comp, proj) - base;
     }
 
-    template <typename T, typename Iter>
+    template <typename T, typename Iter, typename Compare, typename Projection>
     static diff_t gallopRight(T const& key, Iter const base, diff_t const len, diff_t const hint,
                               Compare comp, Projection proj) {
         GFX_TIMSORT_ASSERT(len > 0);
@@ -367,6 +373,7 @@ class TimSort {
         *first = std::move(tmp);
     }
 
+    template <typename Compare, typename Projection>
     void mergeLo(iter_t const base1, diff_t len1, iter_t const base2, diff_t len2,
                  Compare comp, Projection proj) {
         GFX_TIMSORT_ASSERT(len1 > 0);
@@ -487,6 +494,7 @@ class TimSort {
         }
     }
 
+    template <typename Compare, typename Projection>
     void mergeHi(iter_t const base1, diff_t len1, iter_t const base2, diff_t len2,
                  Compare comp, Projection proj) {
         GFX_TIMSORT_ASSERT(len1 > 0);
@@ -625,6 +633,7 @@ class TimSort {
 
 public:
 
+    template <typename Compare, typename Projection>
     static void merge(iter_t const lo, iter_t const mid, iter_t const hi,
                       Compare comp, Projection proj) {
         GFX_TIMSORT_ASSERT(lo <= mid);
@@ -641,6 +650,7 @@ class TimSort {
                                      << "; tmp_.size(): " << ts.tmp_.size());
     }
 
+    template <typename Compare, typename Projection>
     static void sort(iter_t const lo, iter_t const hi, Compare comp, Projection proj) {
         GFX_TIMSORT_ASSERT(lo <= hi);
 
@@ -709,7 +719,7 @@ auto timmerge(Iterator first, Iterator middle, Sentinel last,
     auto last_it = std::ranges::next(first, last);
     GFX_TIMSORT_AUDIT(std::ranges::is_sorted(first, middle, comp, proj) && "Precondition");
     GFX_TIMSORT_AUDIT(std::ranges::is_sorted(middle, last_it, comp, proj) && "Precondition");
-    detail::TimSort<Iterator, Compare, Projection>::merge(first, middle, last_it, comp, proj);
+    detail::TimSort<Iterator>::merge(first, middle, last_it, comp, proj);
     GFX_TIMSORT_AUDIT(std::ranges::is_sorted(first, last_it, comp, proj) && "Postcondition");
     return last_it;
 }
@@ -746,7 +756,7 @@ auto timsort(Iterator first, Sentinel last,
     -> Iterator
 {
     auto last_it = std::ranges::next(first, last);
-    detail::TimSort<Iterator, Compare, Projection>::sort(first, last_it, comp, proj);
+    detail::TimSort<Iterator>::sort(first, last_it, comp, proj);
     GFX_TIMSORT_AUDIT(std::ranges::is_sorted(first, last_it, comp, proj) && "Postcondition");
     return last_it;
 }