Function FindDriveLetter

src/butil/files/file_path.cc:47–58

If this FilePath contains a drive letter specification, returns the position of the last character of the drive letter specification, otherwise returns npos. This can only be true on Windows, when a pathname begins with a letter followed by a colon. On other platforms, this always returns npos.

// begins with a letter followed by a colon.  On other platforms, this always
// returns npos.
StringType::size_type FindDriveLetter(const StringType& path) {
#if defined(FILE_PATH_USES_DRIVE_LETTERS)
  // This is dependent on an ASCII-based character set, but that's a
  // reasonable assumption.  iswalpha can be too inclusive here.
  if (path.length() >= 2 && path[1] == L':' &&
      ((path[0] >= L'A' && path[0] <= L'Z') ||
       (path[0] >= L'a' && path[0] <= L'z'))) {
    return 1;
  }
#endif  // FILE_PATH_USES_DRIVE_LETTERS
  return StringType::npos;
}

#if defined(FILE_PATH_USES_DRIVE_LETTERS)
bool EqualDriveLetterCaseInsensitive(const StringType& a,