There are a few examples in the "Numeric Encoding" section of the Wiki page titled "SQLite4: Key Encoding"¹ that I don't understand. I think the table entries may be erroneous. By working through the examples here, I hope to either correct my misunderstading or to get the Wiki page corrected.
Value Exponent E Significand M (in hex) ===== ========== ====================== 99.0 1 b4 99.01 1 b5 02 99.0001 1 b5 01 02 Here, in all three cases, the first centimal digit shold be 99. In the first example, that's the only digit, so it should be encoded as 2 * 99 = 198 = 0xC6 which is not the same as 0xB4, as shown in the current table. Likewise, the second example should have the digits 99 and 01, which would be multiplied as follows: 2 * 99 + 1 = 199 = 0xC7 2 * 01 = 2 = 0x02 Finally, the third example should have the digits 99, 00, and 01, yielding: 2 * 99 + 1 = 199 = 0xC7 2 * 00 + 1 = 1 = 0x01 2 * 01 = 2 = 0x02 Another one I can't figure out: Value Exponent E Significand M (in hex) ===== ========== ====================== 100.1 2 03 02 I expect that this should have the digits 01, 00, and 10, yielding: 2 * 01 + 1 = 3 = 0x03 2 * 00 + 1 = 1 = 0x01 2 * 10 = 20 = 0x14 The table's current values 0x03 and 0x02 with exponent 2 yield 101 instead: (3 - 1) / 2 = 01 2 / 1 = 01 . 01 01 * (100 ^ 2) = .0101 * 10000 = 101 Are these examples wrong on the Wiki page, or am I misunderstanding the encoding approach? Footnotes: ¹ http://www.sqlite.org/src4/doc/trunk/www/key_encoding.wiki -- Steven E. Harris _______________________________________________ sqlite-users mailing list [email protected] http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
