queue.c

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#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "queue.h"
#include "omx_comp_debug_levels.h"

int queue_init(queue_t* queue) {
  int i;
  qelem_t* newelem;
  qelem_t* current;
  i = pthread_mutex_init(&queue->mutex, NULL);
  if (i!=0) {
      return -1;
  }
  queue->first = malloc(sizeof(qelem_t));
  if (!(queue->first)) {
      return -1;
  }
  memset(queue->first, 0, sizeof(qelem_t));
  current = queue->last = queue->first;
  queue->nelem = 0;
  for (i = 0; i<MAX_QUEUE_ELEMENTS - 2; i++) {
    newelem = malloc(sizeof(qelem_t));
    if (!newelem) {
        // the memory is not enough. Free all
        while(queue->first!=NULL) {
            current = queue->first->q_forw;
            free(queue->first);
            queue->first = current;
        }
        return -1;
    }
    memset(newelem, 0, sizeof(qelem_t));
    current->q_forw = newelem;
    current = newelem;
  }
  current->q_forw = queue->first;
  return 0;
}

void queue_deinit(queue_t* queue) {
  int i;
  qelem_t* current;
  current = queue->first;
  for (i = 0; i<MAX_QUEUE_ELEMENTS - 2; i++) {
    if (current != NULL) {
      current = current->q_forw;
      free(queue->first);
      queue->first = current;
    }
  }
  if(queue->first) {
    free(queue->first);
    queue->first = NULL;
  }
  pthread_mutex_destroy(&queue->mutex);
}

int queue(queue_t* queue, void* data) {
  if (queue->last->data != NULL) {
    return -1;
  }
  pthread_mutex_lock(&queue->mutex);
  queue->last->data = data;
  queue->last = queue->last->q_forw;
  queue->nelem++;
  pthread_mutex_unlock(&queue->mutex);
  return 0;
}

void* dequeue(queue_t* queue) {
  void* data;
  if (queue->first->data == NULL) {
    return NULL;
  }
  pthread_mutex_lock(&queue->mutex);
  data = queue->first->data;
  queue->first->data = NULL;
  queue->first = queue->first->q_forw;
  queue->nelem--;
  pthread_mutex_unlock(&queue->mutex);

  return data;
}

int getquenelem(queue_t* queue) {
  int qelem;
  pthread_mutex_lock(&queue->mutex);
  qelem = queue->nelem;
  pthread_mutex_unlock(&queue->mutex);
  return qelem;
}