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//
// queue.c
//
// Message queue
//
// Copyright (C) 2002 Michael Ringgaard. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// 3. Neither the name of the project nor the names of its contributors
// may be used to endorse or promote products derived from this software
// without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
// SUCH DAMAGE.
//
#include <os/krnl.h>
struct queue *alloc_queue(int size) {
struct queue *q = (struct queue *) kmalloc(sizeof(struct queue));
if (!q) return q;
q->elems = (void **) kmalloc(size * sizeof(void *));
if (!q->elems) {
kfree(q);
return NULL;
}
init_sem(&q->notfull, size);
init_sem(&q->notempty, 0);
q->size = size;
q->in = 0;
q->out = 0;
return q;
}
void free_queue(struct queue *q) {
kfree(q->elems);
kfree(q);
}
int enqueue(struct queue *q, void *msg, unsigned int timeout) {
if (wait_for_object(&q->notfull, timeout) < 0) return -ETIMEOUT;
q->elems[q->in++] = msg;
if (q->in == q->size) q->in = 0;
release_sem(&q->notempty, 1);
return 0;
}
void *dequeue(struct queue *q, unsigned int timeout) {
void *msg;
if (wait_for_object(&q->notempty, timeout) < 0) return NULL;
msg = q->elems[q->out++];
if (q->out == q->size) q->out = 0;
release_sem(&q->notfull, 1);
return msg;
}