3 ms·

This format seems to have a lot of parallels to Amazon’s Ion format, though I’m surprised to see a strongly typed binary encoding with 19 types! Definitely not

• kstenerud 6y ago
  Slightly more complex. The type code distribution is based on how often the type is likely to occur in your average document. The type field is almost always 1 byte long, except for typed arrays (which would generally in aggregate be long enough to offset the cost) and two uncommon types/variations. These have an effective 2-byte type field (0x94 selects a secondary type plane, and the next byte selects the specific type from there). The most common integer values (-100 to 100) are encoded directly into the types 0x9c to 0x64 (wraparound), such that interpreting them directly as signed 8-bit signed integers yields their actual value (type 0x00 = integer 0, type 0x64 = integer 100, type 0x9c = -100, etc). Strings are also optimized such that types 0x80 - 0x8f are used for the most common string lengths (0 to 15) so as not to require a separate length field. The rest have a 1-byte type field. There are also 3 reserved type codes left in the first plane in case something big comes up in the future. You can see the chart here: https://github.com/kstenerud/concise-encoding/blob/master/cbe-specification.md#encoding https://github.com/kstenerud/concise-encoding/blob/master/cb...