Class ValidFileNameCharChecker

libcppcryptfs/filename/cryptfilename.cpp:227–275

}

class ValidFileNameCharChecker
{
private:
	bool invalid_lut[128];
public:
	ValidFileNameCharChecker()
	{
		memset(invalid_lut, 0, sizeof(invalid_lut));

		invalid_lut['<'] = true; // (less than)
		invalid_lut['>'] = true; // (greater than)
		invalid_lut[':'] = true; // (colon)
		invalid_lut['"'] = true; // (double quote)
		invalid_lut['/'] = true; // (forward slash)
		invalid_lut['\\'] = true; // (backslash)
		invalid_lut['|'] = true; // (vertical bar or pipe)
		invalid_lut['?'] = true; // (question mark)
		invalid_lut['*'] = true; // (asterisk)		
	}

	virtual ~ValidFileNameCharChecker() = default;

	// disallow copying
	ValidFileNameCharChecker(ValidFileNameCharChecker const&) = delete;
	void operator=(ValidFileNameCharChecker const&) = delete;

	bool is_valid(const WCHAR* s, bool bStream) const
	{
		if (!s)
			return false;

		// from https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file

		for (; *s; s++) {
			static_assert(sizeof(WCHAR) <= sizeof(size_t), "cannot fit a WCHAR in a size_t");
			size_t c = static_cast<size_t>(*s);
			// control chars are allowed only in stream names
			if (!bStream && c >= 1 && c <= 31)
				return false;
			// chars outside 7-bit ascii are all allowed
			if (c > 127)
				continue;
			if (invalid_lut[c])
				return false;
		}
		return true;
	}
	
};


const WCHAR * // returns UNICODE plaintext filename