quarantine 'em

Twitter has divided Unicode up into two sets for our purposes: "good" (0x0000 to 0x10FF, weight 1) and "bad" (0x1100 to 0x10FFFF, weight 2).

We need a new encoding which makes the maximum possible use of "safe" characters from the "good" range and uses none from the "bad" range.

If we can find 256 "good" characters (trivial), "Base256" would allow 280 bytes per 280-character Tweet, same as Base65536.

If we can find 512 "good" characters (easy?), "Base512" would express 9 bits per character, or 315 bytes per 280-character Tweet.

If we can find 1024 "good" characters (difficulty unclear), "Base1024" would express 10 bits per character = 350 bytes per Tweet

Base2048 -> 11 bits/character -> 385 bytes/Tweet (highly unlikely) Base4096 -> 12 bits/character -> 420 bytes/Tweet (definitely impossible)

Binary encodings using non-power-of-two Unicode character counts are possible but generally more inconvenient to implement.

With a power of two, you just dice the bits up and then put them back together in different groupings.