Math: add branch-less BitVector::set() and reset().

Not sure why these weren't there since ever -- I was pretty sure I added
them.

doc/changelog.dox

@@ -523,6 +523,8 @@ See also:
 
 @subsubsection changelog-latest-changes-math Math library
 
+-   Added @ref Math::BitVector::set(std::size_t) and
+    @ref Math::BitVector::reset(std::size_t) for branchless bit setting
 -   Added @ref Math::castInto() overloads for casting between @ref UnsignedByte
     and @ref UnsignedShort or @ref Byte and @ref Short, from and to
     @ref UnsignedLong / @ref Long, between integral types and @ref Double and

src/Magnum/Math/BitVector.h

@@ -153,7 +153,30 @@ template<std::size_t size> class BitVector {
             return (_data[i/8] >> i%8) & 0x01;
         }
 
-        /** @brief Set a bit at given position */
+        /**
+         * @brief Set a bit at given position
+         * @m_since_latest
+         */
+        BitVector<size>& set(std::size_t i) {
+            _data[i/8] |= 1 << i%8;
+            return *this;
+        }
+
+        /**
+         * @brief Reset a bit at given position
+         * @m_since_latest
+         */
+        BitVector<size>& reset(std::size_t i) {
+            _data[i/8] &= ~(1 << i%8);
+            return *this;
+        }
+
+        /**
+         * @brief Set or reset a bit at given position
+         *
+         * Prefer to use @ref set(std::size_t) and @ref reset(std::size_t)
+         * where possible as that's a simpler operation.
+         */
         BitVector<size>& set(std::size_t i, bool value) {
             value ? _data[i/8] |=  (1 << i%8) :
                     _data[i/8] &= ~(1 << i%8);

src/Magnum/Math/Test/BitVectorTest.cpp

@@ -220,23 +220,30 @@ void BitVectorTest::data() {
     constexpr bool b = ca[9];
     CORRADE_COMPARE(b, true);
 
-    BitVector19 a(0x08, 0x03, 0x04);
-    a.set(15, true);
-    CORRADE_VERIFY(a[15]);
-    CORRADE_COMPARE(a, BitVector19(0x08, 0x83, 0x04));
-    a.set(15, false);
-    CORRADE_VERIFY(!a[15]);
-    CORRADE_COMPARE(a, BitVector19(0x08, 0x03, 0x04));
+    BitVector19 a1(0x08, 0x03, 0x04);
+    BitVector19 a2(0x08, 0x03, 0x04);
+    a1.set(15);
+    a2.set(15, true);
+    CORRADE_VERIFY(a1[15]);
+    CORRADE_VERIFY(a2[15]);
+    CORRADE_COMPARE(a1, BitVector19(0x08, 0x83, 0x04));
+    CORRADE_COMPARE(a2, BitVector19(0x08, 0x83, 0x04));
+    a1.reset(15);
+    a2.set(15, false);
+    CORRADE_VERIFY(!a1[15]);
+    CORRADE_VERIFY(!a2[15]);
+    CORRADE_COMPARE(a1, BitVector19(0x08, 0x03, 0x04));
+    CORRADE_COMPARE(a2, BitVector19(0x08, 0x03, 0x04));
 
     #ifndef CORRADE_MSVC2015_COMPATIBILITY /* Apparently dereferencing pointer is verboten */
     constexpr
     #endif
     UnsignedByte c = *ca.data();
-    CORRADE_COMPARE(a.data()[1], 0x03);
+    CORRADE_COMPARE(a1.data()[1], 0x03);
     CORRADE_COMPARE(c, 0x08);
 
     /* It actually returns an array */
-    CORRADE_COMPARE(Corrade::Containers::arraySize(a.data()), 3);
+    CORRADE_COMPARE(Corrade::Containers::arraySize(a1.data()), 3);
     CORRADE_COMPARE(Corrade::Containers::arraySize(ca.data()), 3);
 }
 
@@ -336,12 +343,12 @@ void BitVectorTest::booleanOperationEquivalents() {
 void BitVectorTest::strictWeakOrdering() {
     BitVector<11> a, b, c;
 
-    a.set(0, true);
-    a.set(1, true);
+    a.set(0);
+    a.set(1);
 
-    c.set(7, true);
+    c.set(7);
 
-    b.set(8, true);
+    b.set(8);
 
     StrictWeakOrdering o;
     CORRADE_VERIFY( o(b, a));
@@ -353,8 +360,8 @@ void BitVectorTest::strictWeakOrdering() {
     CORRADE_VERIFY(!o(a, a));
 
     /* Check uninitialized padding reads */
-    a.set(8, true);
-    a.set(10, true);
+    a.set(8);
+    a.set(10);
     b = a;
     a.data()[1] |= 0x08;
     b.data()[1] |= 0x20;