javascript diff_cleanupSemantic uses negative indexes in the equalities array

```
javascript diff_cleanupSemantic uses negative indexes in the equalities array.

This is because it equalitiesLength is allowed to go into a negative range.

Normally this doesn't cause any problems, because it will just be stored as a
property on the array, but Safari 1.5.x seems to have some issues and doesn't
always get the value that's stored in equalities[-1] back out. (Or perhaps it
didn't properly go in in some cases.)
```

Original issue reported on code.google.com by `d...@twkie.net` on 21 Jun 2013 at 10:48

Attachments:
- [diff_match_patch.js.patch](https://storage.googleapis.com/google-code-attachments/google-diff-match-patch/issue-89/comment-0/diff_match_patch.js.patch)