Move inline classes into a separate file.
Make serialize() into a basic function, support numeric conversions with base option
Refactor numeric conversions and add some more helper functions for the
build flags.
- revert unintended change to include 2 bytes as part of empty value
fixes compatibility with old versions including Embedis and having empty values
- overwrite now empty space when moving
- re-shuffle internal logic to be more strict with cursor oob read / writes
- update comments
* wip based on early draft. todo benchmarking
* fixup eraser, assume keys are unique
* fix cursor copy, test removal at random
* small benchmark via permutations. todo lambdas and novirtual
* fix empty condition / reset
* overwrite optimizations, fix move offsets overflows
* ...erase using 0xff instead of 0
* test the theory with code, different length kv were bugged
* try to check for out-of-bounds writes / reads
* style
* trying to fix mover again
* clarify length, defend against reading len on edge
* fix uncommited rewind change
* prove space assumptions
* more concise traces, fix move condition (agrh!!!)
* slightly more internal knowledge (estimates API?)
* make sure cursor is only valid within the range
* ensure 0 does not blow things
* go back up
* cursor comments
* comments
* rewrite writes through cursor
* in del too
* estimate kv storage requirements, return available size
* move raw erase / move into a method, allow ::set to avoid scanning storage twice
* refactor naming, use in code
* amend storage slicing test
* fix crash handler offsets, cleanup configuration
* start -> begin
* eeprom readiness
* dependencies
* unused
* SPI_FLASH constants for older Core
* vtables -> templates
* less include dependencies
* gcov help, move estimate outside of the class
* writer position can never match, use begin + offset
* tweak save_crash to trigger only once in a serious crash
* doh, header function should be inline
* foreach api, tweak structs for public api
* use test helper class
* when not using foreach, move cursor reset closer to the loop using read_kv
* coverage comments, fix typo in tests decltype
* ensure set() does not break with offset
* make codacy happy again
