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 size_t pthread_mq_vacant(pthread_mq_t *mq) {
  43         return (mq->msg_count_max - mq->msg_count);
  44 }
  45
  46 bool pthread_mq_reset(pthread_mq_t *mq) {
  47         if(pthread_mutex_lock(&mq->lock)) return false;
  48         mq->msg_count = 0;
  49         mq->head_idx = 0;
  50         pthread_mq_cond(mq);
  51         pthread_mutex_unlock(&mq->lock);
  52         return true;
  53 }
  54
  55 bool pthread_mq_send_generic(pthread_mq_t *mq, void * data, pthread_mq_flags_t flags, const struct timespec *restrict abs_timeout) {
  56         //printf("S-Timed: %p\n", abs_timeout);
  57         int ret;
  58
  59         //Lock queue
  60         if(pthread_mutex_timedlock(&mq->lock, abs_timeout)) return false;
  61
  62         //Wait for queue to be in writable condition
  63         while(!pthread_mq_writable(mq)) {
  64                 //printf("S+Timed: %p\n", abs_timeout);
  65                 if(abs_timeout == NULL) {
  66                         ret = pthread_cond_wait(&mq->cond_writable, &mq->lock);
  67                 } else {
  68                         //printf("STimed: %p\n", abs_timeout);
  69                         //assert(abs_timeout != NULL);
  70                         ret = pthread_cond_timedwait(&mq->cond_writable, &mq->lock, abs_timeout);
  71                 }
  72                 if(ret) {
  73                         pthread_mutex_unlock(&mq->lock);
  74                         return false;
  75                 }
  76         }
  77
  78         //Write data to queue
  79         bool to_front = (flags & PTHREAD_XMQ_FRONT);
  80         size_t idx = ( ( mq->head_idx + (to_front?mq->msg_count_max-1:mq->msg_count) ) % mq->msg_count_max );
  81         void *ptr = mq->data + (idx * mq->msg_size);
  82         mq->msg_count++;
  83         if(to_front) mq->head_idx = (mq->msg_count_max + mq->head_idx - 1) % mq->msg_count_max;
  84         memcpy(ptr, data, mq->msg_size);
  85
  86         //Signal conditions and unlock
  87         pthread_mq_cond(mq);
  88         pthread_mutex_unlock(&mq->lock);
  89         return true;
  90 }
  91
  92 bool pthread_mq_receive_generic(pthread_mq_t *mq, void * data, pthread_mq_flags_t flags, const struct timespec *restrict abs_timeout) {
  93         int ret;
  94
  95         //Lock queue
  96         if(pthread_mutex_timedlock(&mq->lock, abs_timeout)) return false;
  97
  98         //Wait for queue to be in readable condition
  99         while(!pthread_mq_readable(mq)) {
 100                 if(abs_timeout == NULL) {
 101                         ret = pthread_cond_wait(&mq->cond_readable, &mq->lock);
 102                 } else {
 103                         //printf("RTimed: %p\n", abs_timeout);
 104                         //assert(abs_timeout != NULL);
 105                         ret = pthread_cond_timedwait(&mq->cond_readable, &mq->lock, abs_timeout);
 106                 }
 107                 if(ret) {
 108                         pthread_mutex_unlock(&mq->lock);
 109                         return false;
 110                 }
 111         }
 112
 113         //Read data from queue
 114         void *ptr = mq->data + (mq->head_idx * mq->msg_size);
 115         memcpy(data, ptr, mq->msg_size);
 116
 117         //Delete data from queue if not peeking
 118         bool peek = (flags & PTHREAD_XMQ_PEEK);
 119         if(!peek) {
 120                 mq->msg_count--;
 121                 mq->head_idx = (mq->head_idx+1) % mq->msg_count_max;
 122         }
 123
 124         //Signal conditions and unlock
 125         pthread_mq_cond(mq);
 126         pthread_mutex_unlock(&mq->lock);
 127         return true;
 128 }