After this patch, the codebase no longer overrides system printf
functions. Instead it explicitly calls either the curl printf functions
`curl_m*printf()` or the system ones using their original names.
Also:
- drop unused `curl_printf.h` includes.
- checksrc: ban system printf functions, allow where necessary.
Follow-up to db98daab05#18844
Follow-up to 4deea9396b#18814Closes#18866
- markup some functions UNITTEST, so that they are static unless in a
unit test build
- make some functions #ifdef UNITTESTS as they are only used from unit
tests
- adjusted unit tests accordingly to use local prototypes for functions
not global in the library
Closes#17734
* calculate capacity growth on multi's xfer table and bitsets to
work correctly when approaching UINT_MAX
* uint-bset: track the first 64bit slot used. This avoids slot scans
on empty sets.
* uint-tbl: remove restriction to grow ot UINT_MAX, it is multi's
job to enforce limits suitable for its use
* test751: use curl_mfprintf() for error messages
Closes#17731
Change multi's book keeping of transfers to no longer use lists, but a
special table and bitsets for unsigned int values.
`multi-xfers` is the `uint_tbl` where `multi_add_handle()` inserts a new
transfer which assigns it a unique identifier `mid`. Use bitsets to keep
track of transfers that are in state "process" or "pending" or
"msgsent".
Use sparse bitsets to replace `conn->easyq` and event handlings tracking
of transfers per socket. Instead of pointers, keep the mids involved.
Provide base data structures and document them in docs/internal:
* `uint_tbl`: a table of transfers with `mid` as lookup key,
handing out a mid for adds between 0 - capacity.
* `uint_bset`: a bitset keeping unsigned ints from 0 - capacity.
* `uint_spbset`: a sparse bitset for keeping a small number of
unsigned int values
* `uint_hash`: for associating `mid`s with a pointer.
This makes the `mid` the recommended way to refer to transfers inside
the same multi without risk of running into a UAF.
Modifying table and bitsets is safe while iterating over them. Overall
memory requirements are lower as with the double linked list apprach.
Closes#16761
