Add additional restrictions to sparse bit set to avoid decoding values outside of unicode.

[garretrieger]

1. Add a maximum height to each branch factor, this is the largest height needed to encode any 32 bit unsigned integer value for each branch factor.
2. In the decoding algorithm specify that values beyond the unicode maximum 0x10FFFF should be ignored.

The height maximum (above which the encoding will be rejected) is placed at 32 bits to allow room for any future changes to the unicode maximum, while allowing fonts using codepoints above 0x10FFFF to not be rejected by clients implementing this version of the standard.

---

Preview | Diff