1915_开源C语言实现的通用队列

经常在工作中遇到一些队列处理的场景，以前要么是借用FreeRTOS这样的系统中的相关功能，要么是通过数组做一个简单的队列模型。但是，这两种方案都具有一定的局限性能，前者要求的FreeRTOS不见得相应的软件中有，而后者只能够是设计专用的功能。为此，尝试找了一个开源的通用方案。

参考链接： GitHub - SMFSW/cQueue: Queue handling library (written in plain c)

● Initialize a Queue using q_init(Queue_t * pQ, size_t size_rec, uint16_t nb_recs, QueueType type, bool overwrite):pQ - pointer to the queue struct

○ size_rec - size of a record in the queue

○ nb_recs - number of records in the queue

○ type - queue implementation type: FIFO, LIFO

○ overwrite - overwrite previous records when queue is full if set to true

● OR a statically allocated Queue using q_init_static(Queue_t * pQ, size_t size_rec, uint16_t nb_recs, QueueType type, bool overwrite, void * pQDat, size_t lenQDat):pQ - pointer to the queue struct

○ size_rec - size of a record in the queue

○ nb_recs - number of records in the queue

○ type - queue implementation type: FIFO, LIFO

○ overwrite - overwrite previous records when queue is full if set to true

○ pQDat - pointer to static data queue

○ lenQDat - length of static data queue (in bytes)

● Push stuff to the queue using q_push(Queue_t * pQ, void * rec)returns true if successfully pushed into queue

○ returns false is queue is full

● Pop stuff from the queue using q_pop(Queue_t * pQ, void * rec) or q_pull(Queue_t * pQ, void * rec)returns true if successfully popped from queue

○ returns false if queue is empty

● Peek stuff from the queue using q_peek(Queue_t * pQ, void * rec)returns true if successfully peeked from queue

○ returns false if queue is empty

● Drop stuff from the queue using q_drop(Queue_t * pQ)returns true if successfully dropped from queue

○ returns false if queue is empty

● Peek stuff at index from the queue using q_peekIdx(Queue_t * pQ, void * rec, uint16_t idx)returns true if successfully peeked from queue

○ returns false if index is out of range

○ warning: no associated drop function, not to use with q_drop

● Peek latest stored from the queue using q_peekPrevious(Queue_t * pQ, void * rec)returns true if successfully peeked from queue

○ returns false if queue is empty

○ warning: no associated drop function, not to use with q_drop

○ note: only useful with FIFO implementation, use q_peek instead with a LIFO

● Other methods:q_isInitialized(Queue_t * pQ): true if initialized properly, false otherwise

○ q_isEmpty(Queue_t * pQ): true if empty, false otherwise

○ q_isFull(Queue_t * pQ): true if full, false otherwise

○ q_sizeof(Queue_t * pQ): queue size in bytes (returns 0 in case queue allocation failed)

○ q_getCount(Queue_t * pQ) or q_nbRecs(Queue_t * pQ): number of records stored in the queue

○ q_getRemainingCount(Queue_t * pQ): number of records left in the queue

○ q_clean(Queue_t * pQ) or q_flush(Queue_t * pQ): remove all items in the queue

就这个模块库提供的基本功能来说还是很全面了，尤其是针对小型的嵌入式系统，提供的这种静态创建的方式非常不错。

接下来，针对常用的接口做个简单的测试：

#include <stdio.h>
#include <stdint.h>
#include "cQueue.h"
 
Queue_t queue_hanlde;
uint8_t * queue_data[5];
uint8_t a = 1U;
uint8_t b = 2U;
uint8_t c = 3U;
uint8_t d = 4U;
 
void queue_lld_init(void)
{
    (void)q_init_static(&queue_hanlde, sizeof(uint8_t *), 5U, FIFO, false, queue_data, sizeof(uint8_t *) * 5);
}
 
int main(void)
{
    uint8_t *rec;
 
    printf("test for queue.\n");
    printf("initialize the queue.\n");
    queue_lld_init();
 
    printf("size of queue: %d\n", q_sizeof(&queue_hanlde));
    printf("count of queue: %d\n", q_getCount(&queue_hanlde));
 
    printf("push data...\n");
    printf("count of queue: %d\n", q_getCount(&queue_hanlde));
    printf("remaining count: %d\n", q_getRemainingCount(&queue_hanlde));
    rec = &a;
    q_push(&queue_hanlde, &rec);
    printf("count of queue: %d\n", q_getCount(&queue_hanlde));
    printf("remaining count: %d\n", q_getRemainingCount(&queue_hanlde));
    rec = &b;
    q_push(&queue_hanlde, &rec);
    printf("count of queue: %d\n", q_getCount(&queue_hanlde));
    printf("remaining count: %d\n", q_getRemainingCount(&queue_hanlde));
    rec = &c;
    q_push(&queue_hanlde, &rec);
    printf("count of queue: %d\n", q_getCount(&queue_hanlde));
    printf("remaining count: %d\n", q_getRemainingCount(&queue_hanlde));
    rec = &d;
    q_push(&queue_hanlde, &rec);
    printf("count of queue: %d\n", q_getCount(&queue_hanlde));
    printf("remaining count: %d\n", q_getRemainingCount(&queue_hanlde));
    printf("push data done...\n");
 
    printf("pop data...\n");
    q_pop(&queue_hanlde, &rec);
    printf("count of queue: %d\n", q_getCount(&queue_hanlde));
    printf("remaining count: %d\n", q_getRemainingCount(&queue_hanlde));
    printf("data 1: %d\n", *rec);
    q_pop(&queue_hanlde, &rec);
    printf("count of queue: %d\n", q_getCount(&queue_hanlde));
    printf("remaining count: %d\n", q_getRemainingCount(&queue_hanlde));
    printf("data 2: %d\n", *rec);
    q_pop(&queue_hanlde, &rec);
    printf("count of queue: %d\n", q_getCount(&queue_hanlde));
    printf("remaining count: %d\n", q_getRemainingCount(&queue_hanlde));
    printf("data 3: %d\n", *rec);
    q_pop(&queue_hanlde, &rec);
    printf("count of queue: %d\n", q_getCount(&queue_hanlde));
    printf("remaining count: %d\n", q_getRemainingCount(&queue_hanlde));
    printf("data 4: %d\n", *rec);
 
    return 0;
}

测试运行效果：

这里只是做了一个简单的功能性的尝试，这个模块的优点还在于具备了类似FreeRTOS的复用性。有这样的功能之后，一些嵌入式中的处理功能写起来就更加得心应手了。