drivers/isdn/hardware/eicon/dqueue.c

   1 /* $Id: dqueue.c,v 1.5 2003/04/12 21:40:49 schindler Exp $
   2  *
   3  * Driver for Eicon DIVA Server ISDN cards.
   4  * User Mode IDI Interface
   5  *
   6  * Copyright 2000-2003 by Armin Schindler (mac@melware.de)
   7  * Copyright 2000-2003 Cytronics & Melware (info@melware.de)
   8  *
   9  * This software may be used and distributed according to the terms
  10  * of the GNU General Public License, incorporated herein by reference.
  11  */
  12
  13 #include "platform.h"
  14 #include "dqueue.h"
  15
  16 int
  17 diva_data_q_init(diva_um_idi_data_queue_t *q,
  18                  int max_length, int max_segments)
  19 {
  20         int i;
  21
  22         q->max_length = max_length;
  23         q->segments = max_segments;
  24
  25         for (i = 0; i < q->segments; i++) {
  26                 q->data[i] = NULL;
  27                 q->length[i] = 0;
  28         }
  29         q->read = q->write = q->count = q->segment_pending = 0;
  30
  31         for (i = 0; i < q->segments; i++) {
  32                 if (!(q->data[i] = diva_os_malloc(0, q->max_length))) {
  33                         diva_data_q_finit(q);
  34                         return (-1);
  35                 }
  36         }
  37
  38         return (0);
  39 }
  40
  41 int diva_data_q_finit(diva_um_idi_data_queue_t *q)
  42 {
  43         int i;
  44
  45         for (i = 0; i < q->segments; i++) {
  46                 if (q->data[i]) {
  47                         diva_os_free(0, q->data[i]);
  48                 }
  49                 q->data[i] = NULL;
  50                 q->length[i] = 0;
  51         }
  52         q->read = q->write = q->count = q->segment_pending = 0;
  53
  54         return (0);
  55 }
  56
  57 int diva_data_q_get_max_length(const diva_um_idi_data_queue_t *q)
  58 {
  59         return (q->max_length);
  60 }
  61
  62 void *diva_data_q_get_segment4write(diva_um_idi_data_queue_t *q)
  63 {
  64         if ((!q->segment_pending) && (q->count < q->segments)) {
  65                 q->segment_pending = 1;
  66                 return (q->data[q->write]);
  67         }
  68
  69         return NULL;
  70 }
  71
  72 void
  73 diva_data_q_ack_segment4write(diva_um_idi_data_queue_t *q, int length)
  74 {
  75         if (q->segment_pending) {
  76                 q->length[q->write] = length;
  77                 q->count++;
  78                 q->write++;
  79                 if (q->write >= q->segments) {
  80                         q->write = 0;
  81                 }
  82                 q->segment_pending = 0;
  83         }
  84 }
  85
  86 const void *diva_data_q_get_segment4read(const diva_um_idi_data_queue_t *
  87                                          q)
  88 {
  89         if (q->count) {
  90                 return (q->data[q->read]);
  91         }
  92         return NULL;
  93 }
  94
  95 int diva_data_q_get_segment_length(const diva_um_idi_data_queue_t *q)
  96 {
  97         return (q->length[q->read]);
  98 }
  99
 100 void diva_data_q_ack_segment4read(diva_um_idi_data_queue_t *q)
 101 {
 102         if (q->count) {
 103                 q->length[q->read] = 0;
 104                 q->count--;
 105                 q->read++;
 106                 if (q->read >= q->segments) {
 107                         q->read = 0;
 108                 }
 109         }
 110 }