Optimized lower_bound/binary_search algorithms.

include/stc/algo/quicksort.h

@@ -137,19 +137,21 @@ static inline void _c_MEMB(_quicksort_ij)(i_type* arr, intptr_t lo, intptr_t hi)
 
 static inline intptr_t // -1 = not found
 _c_MEMB(_lower_bound_range)(const i_type* arr, const _m_raw raw, intptr_t first, intptr_t last) {
-    intptr_t step, count = last - first;
+    intptr_t count = last - first, step = count/2;
 
     while (count > 0) {
         intptr_t it = first;
-        step = count / 2;
         it += step;
 
         const _m_raw rx = i_keyto(i_at(arr, it));
         if (i_less((&rx), (&raw))) {
             first = ++it;
             count -= step + 1;
-        } else
+            step = count*3/4;
+        } else {
             count = step;
+            step = count/4;
+        }
     }
     return first == last ? -1 : first;
 }

misc/benchmarks/plotbench/run_gcc.sh

@@ -1,12 +1,14 @@
-g++ -DNDEBUG -I../../../include -O3 -o deq_benchmark   deq_benchmark.cpp
-g++ -DNDEBUG -I../../../include -O3 -o list_benchmark  list_benchmark.cpp
-g++ -DNDEBUG -I../../../include -O3 -o hmap_benchmark  hmap_benchmark.cpp
-g++ -DNDEBUG -I../../../include -O3 -o smap_benchmark  smap_benchmark.cpp
-g++ -DNDEBUG -I../../../include -O3 -o vec_benchmark   vec_benchmark.cpp
+exe=''
+if [ "$OS" = "Windows_NT" ] ; then exe=".exe" ; fi
+g++ -DNDEBUG -I../../../include -O3 -o deq_benchmark$exe   deq_benchmark.cpp
+g++ -DNDEBUG -I../../../include -O3 -o list_benchmark$exe  list_benchmark.cpp
+g++ -DNDEBUG -I../../../include -O3 -o hmap_benchmark$exe   hmap_benchmark.cpp
+g++ -DNDEBUG -I../../../include -O3 -o smap_benchmark$exe  smap_benchmark.cpp
+g++ -DNDEBUG -I../../../include -O3 -o vec_benchmark$exe   vec_benchmark.cpp
 
 c='Mingw-g++-13.1.0'
-./deq_benchmark $c
-./list_benchmark $c
-./hmap_benchmark $c
-./smap_benchmark $c
-./vec_benchmark $c
+./deq_benchmark$exe $c
+./list_benchmark$exe $c
+./hmap_benchmark$exe $c
+./smap_benchmark$exe $c
+./vec_benchmark$exe $c

misc/benchmarks/various/binsearch_bench.c

@@ -13,7 +13,7 @@
 
 int main(int argc, char const *argv[])
 {
-    intptr_t N = 10000000;
+    intptr_t N = 5000000;
     unsigned mask = (1 << 23) - 1;
     ivec v = {0};
     c_forrange (i, N)