I have to parse date from raw bytes I get from the database for my application on C++. I've found out that date in MySQL is 4 bytes and the last two are month and day respectively. But the first two bytes strangely encode the year, so if the date is 2002-08-30, the content will be 210, 15, 8, 31. If the date is 1996-12-22, the date will be stored as 204, 15, 12, 22. Obviously, the first byte can't be bigger than 255, so I've checked year 2047 -- it's 255, 15, and 2048 -- it's 128, 16.
At first I thought that the key is binary operations, but I did not quite understand the logic:
2047: 0111 1111 1111
255: 0000 1111 1111
15: 0000 0000 1111
2048: 1000 0000 0000
128: 0000 1000 0000
16: 0000 0001 0000
Any idea?
Based on what you provide, it seems to be N1 - 128 + N2 * 128.