queue.h

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/*
 * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */
 
#ifndef _PICO_UTIL_QUEUE_H
#define _PICO_UTIL_QUEUE_H
 
#include "pico.h"
#include "hardware/sync.h"
 
// PICO_CONFIG: PICO_QUEUE_MAX_LEVEL, Maintain a field for the highest level that has been reached by a queue, type=bool, default=0, advanced=true, group=queue
#ifndef PICO_QUEUE_MAX_LEVEL
#define PICO_QUEUE_MAX_LEVEL 0
#endif

 
#ifdef __cplusplus
extern "C" {
#endif
 
#include "pico/lock_core.h"

typedef struct {
    lock_core_t core; 
    uint8_t *data; 
    uint16_t wptr; 
    uint16_t rptr; 
    uint16_t element_size; 
    uint16_t element_count; 
#if PICO_QUEUE_MAX_LEVEL
    uint16_t max_level; 
#endif
} queue_t;

bool queue_init_with_spinlock(queue_t *q, uint element_size, uint element_count, uint spinlock_num);

static inline bool queue_init(queue_t *q, uint element_size, uint element_count) {
    return queue_init_with_spinlock(q, element_size, element_count, next_striped_spin_lock_num());
}

void queue_free(queue_t *q);

static inline uint queue_get_level_unsafe(queue_t *q) {
    int32_t rc = (int32_t)q->wptr - (int32_t)q->rptr;
    if (rc < 0) {
        rc += q->element_count + 1;
    }
    return (uint)rc;
}

static inline uint queue_get_level(queue_t *q) {
    uint32_t save = spin_lock_blocking(q->core.spin_lock);
    uint level = queue_get_level_unsafe(q);
    spin_unlock(q->core.spin_lock, save);
    return level;
}
 
#if PICO_QUEUE_MAX_LEVEL
static inline uint queue_get_max_level(queue_t *q) {
    return q->max_level;
}
#endif
 
#if PICO_QUEUE_MAX_LEVEL
static inline void queue_reset_max_level(queue_t *q) {
    uint32_t save = spin_lock_blocking(q->core.spin_lock);
    q->max_level = queue_get_level_unsafe(q);
    spin_unlock(q->core.spin_lock, save);
}
#endif

static inline bool queue_is_empty(queue_t *q) {
    return queue_get_level(q) == 0;
}

static inline bool queue_is_full(queue_t *q) {
    return queue_get_level(q) == q->element_count;
}
 
// nonblocking queue access functions:

bool queue_try_add(queue_t *q, const void *data);

bool queue_try_remove(queue_t *q, void *data);

bool queue_try_peek(queue_t *q, void *data);
 
// blocking queue access functions:

void queue_add_blocking(queue_t *q, const void *data);

void queue_remove_blocking(queue_t *q, void *data);

void queue_peek_blocking(queue_t *q, void *data);
 
#ifdef __cplusplus
}
#endif
#endif