tree 112d48212b90f70fd8016c1aeaff92bb9b358e58
parent 6fb715eddc0469cd72a7877f505c9f206e031e61
author Jonathan Amsterdam <jba@google.com> 1404530409 -0400
committer Jonathan Amsterdam <jba@google.com> 1406810418 -0400

Changed main diff machinery to use []rune instead of string.

The main benefit is avoiding invalid UTF-8 strings due indexing by byte instead of rune.
Some code was rune-aware, but some wasn't. And some code, like the HalfMatch code, indexed
directly into the middle of a string, so it would have been difficult to make it rune-aware.

As an additional benefit, large diffs are sped up significantly: compare the DiffMainLarge
and DiffMainLargeLines benchmarks, which sped up by a factor of 2 or more.

Did not change match or patch code.  Did not change functions that manipulate diffs.
Did not change the line-mode diff cleanup routines.