linux/drivers/isdn/hardware/eicon/dqueue.c

111 lines
2.1 KiB
C

/* $Id: dqueue.c,v 1.5 2003/04/12 21:40:49 schindler Exp $
*
* Driver for Eicon DIVA Server ISDN cards.
* User Mode IDI Interface
*
* Copyright 2000-2003 by Armin Schindler (mac@melware.de)
* Copyright 2000-2003 Cytronics & Melware (info@melware.de)
*
* This software may be used and distributed according to the terms
* of the GNU General Public License, incorporated herein by reference.
*/
#include "platform.h"
#include "dqueue.h"
int
diva_data_q_init(diva_um_idi_data_queue_t *q,
int max_length, int max_segments)
{
int i;
q->max_length = max_length;
q->segments = max_segments;
for (i = 0; i < q->segments; i++) {
q->data[i] = NULL;
q->length[i] = 0;
}
q->read = q->write = q->count = q->segment_pending = 0;
for (i = 0; i < q->segments; i++) {
if (!(q->data[i] = diva_os_malloc(0, q->max_length))) {
diva_data_q_finit(q);
return (-1);
}
}
return (0);
}
int diva_data_q_finit(diva_um_idi_data_queue_t *q)
{
int i;
for (i = 0; i < q->segments; i++) {
if (q->data[i]) {
diva_os_free(0, q->data[i]);
}
q->data[i] = NULL;
q->length[i] = 0;
}
q->read = q->write = q->count = q->segment_pending = 0;
return (0);
}
int diva_data_q_get_max_length(const diva_um_idi_data_queue_t *q)
{
return (q->max_length);
}
void *diva_data_q_get_segment4write(diva_um_idi_data_queue_t *q)
{
if ((!q->segment_pending) && (q->count < q->segments)) {
q->segment_pending = 1;
return (q->data[q->write]);
}
return NULL;
}
void
diva_data_q_ack_segment4write(diva_um_idi_data_queue_t *q, int length)
{
if (q->segment_pending) {
q->length[q->write] = length;
q->count++;
q->write++;
if (q->write >= q->segments) {
q->write = 0;
}
q->segment_pending = 0;
}
}
const void *diva_data_q_get_segment4read(const diva_um_idi_data_queue_t *
q)
{
if (q->count) {
return (q->data[q->read]);
}
return NULL;
}
int diva_data_q_get_segment_length(const diva_um_idi_data_queue_t *q)
{
return (q->length[q->read]);
}
void diva_data_q_ack_segment4read(diva_um_idi_data_queue_t *q)
{
if (q->count) {
q->length[q->read] = 0;
q->count--;
q->read++;
if (q->read >= q->segments) {
q->read = 0;
}
}
}