You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
26 lines
1.5 KiB
Markdown
26 lines
1.5 KiB
Markdown
# coders
|
|
|
|
Every coder has two different encoding modes, though they may share the same implementation:
|
|
|
|
1. Index key mode, which produces a binary-sortable representation for usage in index building
|
|
2. Value mode, which produces a reversible representation for actual data storage
|
|
|
|
Both modes should result in a Buffer and optionally an auxiliary blob (for out-of-band blob storage).
|
|
|
|
## Index key mode
|
|
|
|
Technical priorities and requirements:
|
|
|
|
- Must be binary-sortable; that is, upon sorting a list of encoded representations, its order *must* match that of the original corresponding inputs if those were to be lexicographically sorted (according to the sorting rules for their data type).
|
|
- Must be deterministic; the same input value must result in the same encoded representation every time. If there is a controllable form of non-determinism (eg. a versioned set of sorting rules such as DUCET), it must be possible to regenerate the index keys for all existing values with the new version of the encoding.
|
|
- Must be space-efficient.
|
|
- Prioritize encoding speed over other (non-required) characteristics such as reversibility.
|
|
|
|
## Value mode
|
|
|
|
Technical priorities and requirements:
|
|
|
|
- Must be reversible; ie. it must be possible to *losslessly* decode the encoded representation back into its original value.
|
|
- Must be space-efficient.
|
|
- Prioritize *decoding* speed over encoding speed (within reasonable bounds) as well as other (non-required) characteristics such as binary-sortability.
|