Add API to SimpleBitstreamCursor to allow users to translate between
byte addresses and pointers.
- jumpToPointer: move the bit position to a particular pointer.
- getPointerToByte: get the pointer for a particular byte.
- getPointerToBit: get the pointer for the byte of the current bit.
- getCurrentByteNo: convenience function for assertions and tests.
Mainly adds unit tests (getPointerToBit/Byte already has a use), but
also preparation for eventually using jumpToPointer.
llvm-svn: 264546
This avoids an issue where AtEndOfStream mistakenly returns true at the /start/ of
a stream.
(In the rare case that the size is known and actually 0, the slow path will still
handle it correctly.)
llvm-svn: 221840
