stream_budget.h File Reference

Optional constant-work snapshot and checked cold sizing. More...

#include "nexus/core/time.h"
#include "nexus/io/stream.h"

Go to the source code of this file.

Data Structures
struct	nx_stream_observation_t
	O(1) aggregate facts; free total does not imply cursor is free. More...
struct	nx_stream_budget_t
	Explicit engineering assumptions, no inferred hardware rate. More...
struct	nx_stream_budget_result_t
	Conservative declared-assumption budget; never physical evidence. More...

Functions
nx_result_t	nx_stream_observe (const nx_stream_t *stream, nx_stream_observation_t *out)
	Snapshot maintained metadata under one short IRQ guard.
nx_result_t	nx_stream_budget_calculate (const nx_stream_budget_t *budget, nx_stream_budget_result_t *out)
	Checked cold calculation, no stream mutation or allocation.

Detailed Description

Optional constant-work snapshot and checked cold sizing.

Author

Nexus Team

Definition in file stream_budget.h.

Function Documentation

nx_stream_budget_calculate()

nx_result_t nx_stream_budget_calculate	(	const nx_stream_budget_t *	budget,
		nx_stream_budget_result_t *	out )

Checked cold calculation, no stream mutation or allocation.

Parameters

[in]	budget	Explicit rate, longest release delay and pipeline.
[out]	out	Distinct output, unchanged on error or overflow.

Returns

SUCCESS, INVALID or EXHAUSTED for arithmetic overflow.

Note

required = targets + spares + ceil(rate*release_delay / (block_units*1000000)); payload is required*block*unit_bytes. Finite math is conservative under the declared FIFO frontier release bound; out-of-order release may still block the next cursor. Latency requires target_delay < floor(block/rate). This creates no backpressure or hardware qualification.

nx_stream_observe()

nx_result_t nx_stream_observe	(	const nx_stream_t *	stream,
		nx_stream_observation_t *	out )

Snapshot maintained metadata under one short IRQ guard.

Parameters

[in]	stream	Live initialized storage, no concurrent destruction.
[out]	out	Distinct output, unchanged on rejected metadata/alias.

Returns

SUCCESS, INVALID or STATE for inconsistent control facts.

Note

Task/IRQ fixed work, no slot scan or payload access. Caller keeps all storage alive; no observer reference is retained. next_free is the ordinary stream cursor, not the private preposted cursor. Output is distinct from every payload.