This one verifies bitmasks where low bits are set to 1 (hence the name).
Any stray 0 among the lower ones or any stray 1 among the higher zeros
renders the mask invalid.
The edge cases of all zeros and all ones are considered valid masks.
It uses an efficient implementation. It's the counterpart of
https://graphics.stanford.edu/~seander/bithacks.html#DetermineIfPowerOf2
Using `EXPECT_EQ` with boolean literals can cause a warning in certain
versions of GCC. See https://github.com/google/googletest/issues/322
Fixes warnings:
```
../Source/UnitTests/Common/BitSetTest.cpp: In member function 'virtual void BitSet_Basics_Test::TestBody()':
../Source/UnitTests/Common/BitSetTest.cpp:15:165: error: converting 'false' to pointer type for argument 1 of 'char testing::internal::IsNullLiteralHelper(testing::internal::Secret*)' [-Werror=conversion-null]
../Source/UnitTests/Common/BitSetTest.cpp: In member function 'virtual void BitSet_BitGetSet_Test::TestBody()':
../Source/UnitTests/Common/BitSetTest.cpp:27:165: error: converting 'false' to pointer type for argument 1 of 'char testing::internal::IsNullLiteralHelper(testing::internal::Secret*)' [-Werror=conversion-null]
../Source/UnitTests/Common/StringUtilTest.cpp: In member function 'virtual void StringUtil_StringBeginsWith_Test::TestBody()':
../Source/UnitTests/Common/StringUtilTest.cpp:23:165: error: converting 'false' to pointer type for argument 1 of 'char testing::internal::IsNullLiteralHelper(testing::internal::Secret*)' [-Werror=conversion-null]
../Source/UnitTests/Common/StringUtilTest.cpp:25:165: error: converting 'false' to pointer type for argument 1 of 'char testing::internal::IsNullLiteralHelper(testing::internal::Secret*)' [-Werror=conversion-null]
../Source/UnitTests/Common/StringUtilTest.cpp:26:165: error: converting 'false' to pointer type for argument 1 of 'char testing::internal::IsNullLiteralHelper(testing::internal::Secret*)' [-Werror=conversion-null]
../Source/UnitTests/Common/StringUtilTest.cpp:27:165: error: converting 'false' to pointer type for argument 1 of 'char testing::internal::IsNullLiteralHelper(testing::internal::Secret*)' [-Werror=conversion-null]
../Source/UnitTests/Common/StringUtilTest.cpp: In member function 'virtual void StringUtil_StringEndsWith_Test::TestBody()':
../Source/UnitTests/Common/StringUtilTest.cpp:35:165: error: converting 'false' to pointer type for argument 1 of 'char testing::internal::IsNullLiteralHelper(testing::internal::Secret*)' [-Werror=conversion-null]
../Source/UnitTests/Common/StringUtilTest.cpp:37:165: error: converting 'false' to pointer type for argument 1 of 'char testing::internal::IsNullLiteralHelper(testing::internal::Secret*)' [-Werror=conversion-null]
../Source/UnitTests/Common/StringUtilTest.cpp:38:165: error: converting 'false' to pointer type for argument 1 of 'char testing::internal::IsNullLiteralHelper(testing::internal::Secret*)' [-Werror=conversion-null]
../Source/UnitTests/Common/StringUtilTest.cpp:39:165: error: converting 'false' to pointer type for argument 1 of 'char testing::internal::IsNullLiteralHelper(testing::internal::Secret*)' [-Werror=conversion-null]
c
```
Fixes warnings like:
```
dolphin/Source/UnitTests/Common/BitUtilsTest.cpp:5:
../Externals/gtest/googletest/include/gtest/gtest.h:1392:11: warning: comparison of integers of different signs: 'const unsigned long' and 'const int' [-Wsign-compare]
if (lhs == rhs) {
~~~ ^ ~~~
../Externals/gtest/googletest/include/gtest/gtest.h:1421:12: note: in instantiation of function template specialization 'testing::internal::CmpHelperEQ<unsigned long, int>' requested here
return CmpHelperEQ(lhs_expression, rhs_expression, lhs, rhs);
^
dolphin/Source/UnitTests/Common/BitUtilsTest.cpp:12:3: note: in instantiation of function template specialization 'testing::internal::EqHelper<false>::Compare<unsigned long, int>' requested here
EXPECT_EQ(Common::BitSize<s8>(), 8);
^
../Externals/gtest/googletest/include/gtest/gtest.h:1924:63: note: expanded from macro 'EXPECT_EQ'
EqHelper<GTEST_IS_NULL_LITERAL_(val1)>::Compare, \
```
This moves all the byte swapping utilities into a header named Swap.h.
A dedicated header is much more preferable here due to the size of the
code itself. In general usage throughout the codebase, CommonFuncs.h was
generally only included for these functions anyway. These being in their
own header avoids dumping the lesser used utilities into scope. As well
as providing a localized area for more utilities related to byte
swapping in the future (should they be needed). This also makes it nicer
to identify which files depend on the byte swapping utilities in
particular.
Since this is a completely new header, moving the code uncovered a few
indirect includes, as well as making some other inclusions unnecessary.
This attempts to make some bit arithmetic more self-documenting and also
make it easier during review to identify potential off-by-one errors by
making it possible to just specify which bits are being extracted.
Functions both support the case where bits being extracted can vary and
fixed bit extraction. In the case the bits are fixed, compile-time asserts
are present to prevent accidental API usage at compile-time.
e.g. Instead of shifting and masking to get bits 10 to 15,
Common::ExtractBits<10, 15>(value) can just be done instead.
MSVC's implementation of numeric_limits currently generates incorrect
signaling NaNs. The resulting values are actually quiet NaNs instead.
This commit is based off of a solution by shuffle2. The only
difference is a template specialization for floats is also added
to cover all bases
Niels Boehm