If you're interested in this kind of thing, Jon Bentley wrote a column called Programming Pearls which was later collected into books. One of the instalments w

If you're interested in this kind of thing, Jon Bentley wrote a column called Programming Pearls which was later collected into books. One of the instalments was called Squeezing Space, and talked about stuff like this. He also discussed the trade-offs involved, as sometimes the code introduced to compress the data more than offsets the savings.