c/pthread_extra/pthread_msgqueue.c

   1 #include <pthread.h>
   2 #include <pthread_extra.h>
   3 #include <time.h>
   4 #include <string.h>
   5 #include <stdio.h>
   6 #include <stdbool.h>
   7 #include <stdlib.h>
   8 #include <assert.h>
   9
  10 bool pthread_mq_readable(pthread_mq_t *mq) { return (mq->msg_count > 0); }
  11 bool pthread_mq_writable(pthread_mq_t *mq) { return (mq->msg_count < mq->msg_count_max); }
  12
  13 bool pthread_mq_init(pthread_mq_t *mq, size_t msg_size, size_t msg_count_max) {
  14         pthread_mutex_init(&mq->lock, NULL);
  15         pthread_cond_init(&mq->cond_readable, NULL);
  16         pthread_cond_init(&mq->cond_writable, NULL);
  17         //pthread_mutexattr_setclock(&mq->lock, CLOCK_MONOTONIC);
  18         mq->data = malloc(msg_size*msg_count_max);
  19         mq->msg_size = msg_size;
  20         mq->msg_count_max = msg_count_max;
  21         mq->msg_count = 0;
  22         mq->head_idx = 0;
  23         mq->name = NULL;
  24
  25         if(((msg_size*msg_count_max) > 0) && mq->data == NULL) return false;
  26         return true;
  27 }
  28
  29 void pthread_mq_free(pthread_mq_t *mq) {
  30         free(mq->data);
  31 }
  32
  33 void pthread_mq_cond(pthread_mq_t *mq) {
  34         if(pthread_mq_readable(mq)) pthread_cond_broadcast(&mq->cond_readable);
  35         if(pthread_mq_writable(mq)) pthread_cond_broadcast(&mq->cond_writable);
  36 }
  37
  38 size_t pthread_mq_waiting(pthread_mq_t *mq) {
  39         return mq->msg_count;
  40 }
  41
  42 bool pthread_mq_reset(pthread_mq_t *mq) {
  43         if(pthread_mutex_lock(&mq->lock)) return false;
  44         mq->msg_count = 0;
  45         mq->head_idx = 0;
  46         pthread_mq_cond(mq);
  47         pthread_mutex_unlock(&mq->lock);
  48         return true;
  49 }
  50
  51 bool pthread_mq_send_generic(pthread_mq_t *mq, void * data, bool to_front, const struct timespec *restrict abs_timeout) {
  52         int ret;
  53
  54         //Lock queue
  55         if(pthread_mutex_timedlock(&mq->lock, abs_timeout)) return false;
  56
  57         //Wait for queue to be in writable condition
  58         while(!pthread_mq_writable(mq)) {
  59                 if(abs_timeout == NULL) {
  60                         ret = pthread_cond_wait(&mq->cond_writable, &mq->lock);
  61                 } else {
  62                         ret = pthread_cond_timedwait(&mq->cond_writable, &mq->lock, abs_timeout);
  63                 }
  64                 if(ret) {
  65                         pthread_mutex_unlock(&mq->lock);
  66                         return false;
  67                 }
  68         }
  69
  70         //Write data to queue
  71         size_t idx = ( ( mq->msg_count_max + mq->head_idx + (to_front?-1:mq->msg_count) ) % mq->msg_count_max );
  72         void *ptr = mq->data + (idx * mq->msg_size);
  73         mq->msg_count++;
  74         if(to_front) mq->head_idx = (mq->msg_count_max + mq->head_idx - 1) % mq->msg_count_max;
  75         memcpy(ptr, data, mq->msg_size);
  76
  77         //Signal conditions and unlock
  78         pthread_mq_cond(mq);
  79         pthread_mutex_unlock(&mq->lock);
  80         return true;
  81 }
  82
  83 bool pthread_mq_receive_generic(pthread_mq_t *mq, void * data, bool peek, const struct timespec *restrict abs_timeout) {
  84         int ret;
  85
  86         //Lock queue
  87         if(pthread_mutex_timedlock(&mq->lock, abs_timeout)) return false;
  88
  89         //Wait for queue to be in readable condition
  90         while(!pthread_mq_readable(mq)) {
  91                 if(abs_timeout == NULL) {
  92                         ret = pthread_cond_wait(&mq->cond_readable, &mq->lock);
  93                 } else {
  94                         ret = pthread_cond_timedwait(&mq->cond_readable, &mq->lock, abs_timeout);
  95                 }
  96                 if(ret) {
  97                         pthread_mutex_unlock(&mq->lock);
  98                         return false;
  99                 }
 100         }
 101
 102         //Read data from queue
 103         void *ptr = mq->data + (mq->head_idx * mq->msg_size);
 104         memcpy(data, ptr, mq->msg_size);
 105
 106         //Delete data from queue if not peeking
 107         if(!peek) {
 108                 mq->msg_count--;
 109                 mq->head_idx = (mq->head_idx+1) % mq->msg_count_max;
 110         }
 111
 112         //Signal conditions and unlock
 113         pthread_mq_cond(mq);
 114         pthread_mutex_unlock(&mq->lock);
 115         return true;
 116 }