1. "unsigned" -> "uint32_t" to gaurantee its bit width on all platforms.

   Size matters in this case.
2. Remove the unused whichByte private function, which was also broken.
3. Remove the non-const overload of the getWord function, getWord() is
   never used as an lvalue.
4. Rename some local variables for clarity (e.g. API -> Result).

llvm-svn: 34390