Function countl_zero

modules/core/base/include/SkrBase/misc/bit.hpp:96–104

// 得到 bit 中左（高位起）和右（低位起）的 0 个数
template <typename T>
SKR_INLINE constexpr T countl_zero(T v)
{
    static_assert(std::is_integral_v<T> && !std::is_signed_v<T>);
#if SKR_CXX_VERSION >= 20
    return std::countl_zero(v);
#else
    return detail::countl_zero_fallback(v);
#endif
}
template <typename T>
SKR_INLINE constexpr T countr_zero(T v)
{