90 lines
1.7 KiB
C
90 lines
1.7 KiB
C
#include "myqueue.h"
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#include <stdlib.h>
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#include <string.h>
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mcl_queue *mcl_queue_init(size_t queue_size, size_t elem_size) {
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mcl_queue *queue = malloc(sizeof(mcl_queue));
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if (queue == NULL) {
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return NULL;
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}
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queue->buffer = malloc(queue_size * elem_size);
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if (queue->buffer == NULL) {
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free(queue);
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return NULL;
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}
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queue->front = 0;
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queue->rear = 0;
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queue->size = 0;
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queue->capacity = queue_size;
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queue->elem_size = elem_size;
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return queue;
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}
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int mcl_queue_push(mcl_queue *queue, const void *elem) {
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if (queue->size == queue->capacity) {
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/* Queue full */
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return -1;
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}
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/* Copy the elem in the buffer */
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void *dest = (void *)queue->buffer + (queue->rear * queue->elem_size);
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memcpy(dest, elem, queue->elem_size);
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queue->size++;
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queue->rear = (queue->rear + 1) % queue->capacity;
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return 0;
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}
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int mcl_queue_pop(mcl_queue *queue, void *out_elem) {
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if (queue->size == 0) {
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/* Queue empty */
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return -1;
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}
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void *src = (void *)queue->buffer + (queue->front * queue->elem_size);
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memcpy(out_elem, src, queue->elem_size);
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queue->front = (queue->front + 1) % queue->capacity;
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queue->size--;
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return 0;
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}
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void *mcl_queue_get_front(mcl_queue *queue) {
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if (queue->size == 0) {
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return NULL;
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}
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return (void *)queue->buffer + (queue->front * queue->elem_size);
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}
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void *mcl_queue_get_rear(mcl_queue *queue) {
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if (queue->size == 0) {
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return NULL;
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}
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size_t rear_index;
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if (queue->rear == 0) {
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rear_index = queue->capacity - 1;
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} else {
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rear_index = queue->rear - 1;
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}
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return (void *)queue->buffer + (rear_index * queue->elem_size);
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}
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void mcl_queue_free(mcl_queue *queue) {
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if (queue == NULL) {
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return;
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}
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free(queue->buffer);
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free(queue);
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}
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