Queue API

Data Structures
struct	JUNO_DS_QUEUE_API_TAG
	Queue API vtable. More...

Functions
struct JUNO_DS_QUEUE_ROOT_TAG	JUNO_MODULE_ROOT (JUNO_DS_QUEUE_API_T, JUNO_DS_ARRAY_ROOT_T *ptQueueArray;size_t iStartIndex;size_t zLength;)
	The queue root module instance.

Detailed Description

A lightweight, fixed-capacity FIFO queue that stores elements in a circular buffer backed by a Juno Array instance. The queue uses JUNO_POINTER_T to copy elements into the backing array and to return them.

Characteristics:

• Deterministic O(1) enqueue/dequeue/peek.
• Capacity defined by the backing array; no dynamic allocation.
• Non-thread-safe by default; guard externally if needed.

Invariants:

• 0 <= zLength <= ptQueueArray->zCapacity
• iStartIndex < ptQueueArray->zCapacity (when capacity > 0)
• Backing array API must be valid (see JunoDs_ArrayVerify).

Error behavior (per implementation):

• Enqueue on full queue: returns JUNO_STATUS_INVALID_SIZE_ERROR.
• Dequeue on empty queue: returns JUNO_STATUS_ERR.
• Peek on empty queue: returns JUNO_STATUS_INVALID_SIZE_ERROR.

Element ownership:

• Elements are copied into/out of the array via the pointer API (Copy), so tItem/tReturn must describe a valid storage location and size.

Function Documentation

JUNO_MODULE_ROOT()

struct JUNO_DS_QUEUE_ROOT_TAG JUNO_MODULE_ROOT	(	JUNO_DS_QUEUE_API_T	,
		JUNO_DS_ARRAY_ROOT_T *ptQueueArray;size_t iStartIndex;size_t zLength;
	)

The queue root module instance.

Queue root instance and state.