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

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of PulseAudio.
   5
   6   Copyright 2004-2006 Lennart Poettering
   7
   8   PulseAudio is free software; you can redistribute it and/or modify
   9   it under the terms of the GNU Lesser General Public License as
  10   published by the Free Software Foundation; either version 2.1 of the
  11   License, or (at your option) any later version.
  12
  13   PulseAudio is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public
  19   License along with PulseAudio; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  21   USA.
  22 ***/
  23
  24 #ifdef HAVE_CONFIG_H
  25 #include <config.h>
  26 #endif
  27
  28 #include <assert.h>
  29 #include <stdlib.h>
  30
  31 #include <pulse/xmalloc.h>
  32
  33 #include "queue.h"
  34
  35 struct queue_entry {
  36     struct queue_entry *next;
  37     void *data;
  38 };
  39
  40 struct pa_queue {
  41     struct queue_entry *front, *back;
  42     unsigned length;
  43 };
  44
  45 pa_queue* pa_queue_new(void) {
  46     pa_queue *q = pa_xnew(pa_queue, 1);
  47     q->front = q->back = NULL;
  48     q->length = 0;
  49     return q;
  50 }
  51
  52 void pa_queue_free(pa_queue* q, void (*destroy)(void *p, void *userdata), void *userdata) {
  53     struct queue_entry *e;
  54     assert(q);
  55
  56     e = q->front;
  57     while (e) {
  58         struct queue_entry *n = e->next;
  59
  60         if (destroy)
  61             destroy(e->data, userdata);
  62
  63         pa_xfree(e);
  64         e = n;
  65     }
  66
  67     pa_xfree(q);
  68 }
  69
  70 void pa_queue_push(pa_queue *q, void *p) {
  71     struct queue_entry *e;
  72
  73     e = pa_xnew(struct queue_entry, 1);
  74     e->data = p;
  75     e->next = NULL;
  76
  77     if (q->back)
  78         q->back->next = e;
  79     else {
  80         assert(!q->front);
  81         q->front = e;
  82     }
  83
  84     q->back = e;
  85     q->length++;
  86 }
  87
  88 void* pa_queue_pop(pa_queue *q) {
  89     void *p;
  90     struct queue_entry *e;
  91     assert(q);
  92
  93     if (!(e = q->front))
  94         return NULL;
  95
  96     q->front = e->next;
  97     if (q->back == e)
  98         q->back = NULL;
  99
 100     p = e->data;
 101     pa_xfree(e);
 102
 103     q->length--;
 104
 105     return p;
 106 }
 107
 108 int pa_queue_is_empty(pa_queue *q) {
 109     assert(q);
 110     return q->length == 0;
 111 }