mirror of
https://github.com/Telecominfraproject/OpenCellular.git
synced 2025-12-27 10:14:57 +00:00
a9541220dc
For simplicity of the code, we don't allow (head == tail) when the queue is full. But currently we are wasting the size of a single unit, while we can actually just waste 1 byte. Let's fix this. BUG=None TEST=Pass the unit test. BRANCH=None Change-Id: Id09c20a9345ebb3ec0cad659afe36e25b422e688 Signed-off-by: Vic Yang <victoryang@chromium.org> Reviewed-on: https://gerrit.chromium.org/gerrit/58058 Reviewed-by: Yung-Chieh Lo <yjlou@chromium.org>
58 lines
1.2 KiB
C
58 lines
1.2 KiB
C
/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
|
|
* Use of this source code is governed by a BSD-style license that can be
|
|
* found in the LICENSE file.
|
|
*
|
|
* Queue data structure implementation.
|
|
*/
|
|
#include "queue.h"
|
|
#include "util.h"
|
|
|
|
void queue_reset(struct queue *queue)
|
|
{
|
|
queue->head = queue->tail = 0;
|
|
}
|
|
|
|
int queue_is_empty(const struct queue *q)
|
|
{
|
|
return q->head == q->tail;
|
|
}
|
|
|
|
int queue_has_space(const struct queue *q, int unit_count)
|
|
{
|
|
if (q->tail >= q->head)
|
|
return (q->tail + unit_count * q->unit_bytes) <=
|
|
(q->head + q->buf_bytes - 1);
|
|
else
|
|
return (q->tail + unit_count * q->unit_bytes) <=
|
|
(q->head - 1);
|
|
}
|
|
|
|
void queue_add_units(struct queue *q, const void *src, int unit_count)
|
|
{
|
|
const uint8_t *s = (const uint8_t *)src;
|
|
|
|
if (!queue_has_space(q, unit_count))
|
|
return;
|
|
|
|
for (unit_count *= q->unit_bytes; unit_count; unit_count--) {
|
|
q->buf[q->tail++] = *(s++);
|
|
q->tail %= q->buf_bytes;
|
|
}
|
|
}
|
|
|
|
int queue_remove_unit(struct queue *q, void *dest)
|
|
{
|
|
int count;
|
|
uint8_t *d = (uint8_t *)dest;
|
|
|
|
if (queue_is_empty(q))
|
|
return 0;
|
|
|
|
for (count = q->unit_bytes; count; count--) {
|
|
*(d++) = q->buf[q->head++];
|
|
q->head %= q->buf_bytes;
|
|
}
|
|
|
|
return 1;
|
|
}
|