Merge pull request #326 from elbeno/empty-bitset-issue

🐛 Fix bitset construction

Author: elbeno

include/stdx/bitset.hpp

@@ -175,7 +175,9 @@ class bitset {
         for (auto &elem : storage) {
             elem = allbits;
         }
-        storage.back() &= lastmask;
+        if constexpr (N > 0) {
+            storage.back() &= lastmask;
+        }
     }
 
     constexpr explicit bitset(std::string_view str, std::size_t pos = 0,

test/bitset.cpp

@@ -516,4 +516,6 @@ TEST_CASE("zero size bitset", "[bitset]") {
     CHECK(bs3.to<std::uint8_t>() == 0);
     bs3 >>= 1;
     CHECK(bs3.to<std::uint8_t>() == 0);
+    bs3 = stdx::bitset<0>{stdx::all_bits};
+    CHECK(bs3.to<std::uint8_t>() == 0);
 }

test/type_bitset.cpp

@@ -10,6 +10,7 @@
 #include <type_traits>
 
 TEST_CASE("bitset size", "[type_bitset]") {
+    STATIC_CHECK(stdx::type_bitset<>{}.size() == 0u);
     STATIC_CHECK(stdx::type_bitset<int>{}.size() == 1u);
     STATIC_CHECK(stdx::type_bitset<int, float>{}.size() == 2u);
 }