Struct multififo

Struct Documentation

struct multififo

A FIFO which itself contains multiple child shadow FIFOs.

Useful when you want to put large packets of data into a FIFO, but have consumers pull them out in much smaller chunks, such as when you have a process which produces large packets of data which you want to send over UART without disrupting/preempting the main process. This can be easily done with this data structure and a say 1ms “tick” ISR which pulls data out of a child FIFO as it becomes available.

All data lives in the “root” FIFO; no copies are made to child FIFOs.

NOT thread safe.

Synchronization safe, as in non-concurrent asynchronous accesses are OK: FIFO provides a simple internal boolean “lock” which is taken and release during:

All other functions must be called synchronously or bad things will probably happen.

Public Members

struct fifo root

Root FIFO. All actual data is stored here.

uint8_t front_refmask

Bitmask indicating which child FIFOs have finished processing the current front element in multififo::root, and which haven’t. Child FIFO i sets bit

1 << i
.

bool locked

Super simple, non-threadsafe synchronization mechanism indicating if the multififo is currently busy doing stuff. Callers consuming data through child FIFOs should check this flag before attempting to remove any data; if it is set, then an operation is in progress and any sort of dequeueing will probably cause errors.

struct multififo_children_mgmt children

Management of all root and child datablocks and metadata for the multi-FIFO.

uint32_t flags

Run-time configuration parameters. Valid flags are:

All other flags are ignored.