The previous approach was too easily fooled (a rotate() sufficed).
* Use it->counter to determine when iteration is complete. The
previous approach was too complex.
* Strengthen an assertion and add a comment here or there.
* Change the centering by one to make it possible to test the module
with BLOCKLEN's as low as two. Testing small blocks makes end-point
errors surface more readily.
decoding incomplete input (when the input stream is temporarily exhausted).
codecs.StreamReader now implements buffering, which enables proper
readline support for the UTF-16 decoders. codecs.StreamReader.read()
has a new argument chars which specifies the number of characters to
return. codecs.StreamReader.readline() and codecs.StreamReader.readlines()
have a new argument keepends. Trailing "\n"s will be stripped from the lines
if keepends is false. Added C APIs PyUnicode_DecodeUTF8Stateful and
PyUnicode_DecodeUTF16Stateful.
Several functions adopted the strategy of altering a full lengthed
string copy and resizing afterwards. That would fail if the initial
string was short enough (0 or 1) to be interned. Interning precluded
the subsequent resizing operation.
The solution was to make sure the initial string was at least two
characters long.
Added tests to verify that all binascii functions do not crater when
given an empty string argument.
