code.delx.au - pulseaudio/blob - src/polypcore/queue.c

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of polypaudio.
   5
   6   polypaudio is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU Lesser General Public License as
   8   published by the Free Software Foundation; either version 2.1 of the
   9   License, or (at your option) any later version.
  10
  11   polypaudio is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public
  17   License along with polypaudio; if not, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19   USA.
  20 ***/
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <assert.h>
  27 #include <stdlib.h>
  28
  29 #include <polyp/xmalloc.h>
  30
  31 #include "queue.h"
  32
  33 struct queue_entry {
  34     struct queue_entry *next;
  35     void *data;
  36 };
  37
  38 struct pa_queue {
  39     struct queue_entry *front, *back;
  40     unsigned length;
  41 };
  42
  43 pa_queue* pa_queue_new(void) {
  44     pa_queue *q = pa_xnew(pa_queue, 1);
  45     q->front = q->back = NULL;
  46     q->length = 0;
  47     return q;
  48 }
  49
  50 void pa_queue_free(pa_queue* q, void (*destroy)(void *p, void *userdata), void *userdata) {
  51     struct queue_entry *e;
  52     assert(q);
  53
  54     e = q->front;
  55     while (e) {
  56         struct queue_entry *n = e->next;
  57
  58         if (destroy)
  59             destroy(e->data, userdata);
  60
  61         pa_xfree(e);
  62         e = n;
  63     }
  64
  65     pa_xfree(q);
  66 }
  67
  68 void pa_queue_push(pa_queue *q, void *p) {
  69     struct queue_entry *e;
  70
  71     e = pa_xnew(struct queue_entry, 1);
  72     e->data = p;
  73     e->next = NULL;
  74
  75     if (q->back)
  76         q->back->next = e;
  77     else {
  78         assert(!q->front);
  79         q->front = e;
  80     }
  81
  82     q->back = e;
  83     q->length++;
  84 }
  85
  86 void* pa_queue_pop(pa_queue *q) {
  87     void *p;
  88     struct queue_entry *e;
  89     assert(q);
  90
  91     if (!(e = q->front))
  92         return NULL;
  93
  94     q->front = e->next;
  95     if (q->back == e)
  96         q->back = NULL;
  97
  98     p = e->data;
  99     pa_xfree(e);
 100
 101     q->length--;
 102
 103     return p;
 104 }
 105
 106 int pa_queue_is_empty(pa_queue *q) {
 107     assert(q);
 108     return q->length == 0;
 109 }