Function digitToInt

libraries/lib-string-utils/FromChars.cpp:21–24

Converting c to unsigned here helps to eliminate one check

{
// Converting c to unsigned here helps to eliminate one check 
unsigned digitToInt(char c) noexcept
{
   return static_cast<unsigned>(c) - '0';
}

template <typename T>
bool safeMul10Add(T& result, T a, T b)