NandPaths: Resolve Android tautological comparison warning

[Dentomologist]

Android interprets char as unsigned char, so comparing the char parameter in IsIllegalCharacter with 0 triggers a tautological-unsigned-char-zero-compare warning.

Casting the parameter to an unsigned char and removing the comparison with 0 resolves the warning while needing one less comparison on all platforms.

[AdmiralCurtiss]

...There's no way this is faster than just having a constexpr std::array or similar.

[Dentomologist]

Do you mean replacing the unordered_set with an array, or getting rid of the find entirely and having a bool array for all 256 chars? I'm sure the latter would be faster, though less legible.

[AdmiralCurtiss]

I mean:

static bool IsIllegalCharacter(char c)
{
  static constexpr auto illegal_chars = {'\"', '*', '/', ':', '<', '>', '?', '\\', '|', '\x7f'};
  return static_cast<unsigned char>(c) <= 0x1F ||
         std::find(illegal_chars.begin(), illegal_chars.end(), c) != illegal_chars.end();
}