src/pulsecore/queue.c

   1 /***
   2   This file is part of PulseAudio.
   3
   4   Copyright 2004-2008 Lennart Poettering
   5
   6   PulseAudio 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   PulseAudio 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 PulseAudio; 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 <stdlib.h>
  27
  28 #include <pulse/xmalloc.h>
  29 #include <pulsecore/macro.h>
  30 #include <pulsecore/flist.h>
  31
  32 #include "queue.h"
  33
  34 PA_STATIC_FLIST_DECLARE(entries, 0, pa_xfree);
  35
  36 struct queue_entry {
  37     struct queue_entry *next;
  38     void *data;
  39 };
  40
  41 struct pa_queue {
  42     struct queue_entry *front, *back;
  43     unsigned length;
  44 };
  45
  46 pa_queue* pa_queue_new(void) {
  47     pa_queue *q = pa_xnew(pa_queue, 1);
  48
  49     q->front = q->back = NULL;
  50     q->length = 0;
  51
  52     return q;
  53 }
  54
  55 void pa_queue_free(pa_queue* q, pa_free2_cb_t free_func, void *userdata) {
  56     void *data;
  57     pa_assert(q);
  58
  59     while ((data = pa_queue_pop(q)))
  60         if (free_func)
  61             free_func(data, userdata);
  62
  63     pa_assert(!q->front);
  64     pa_assert(!q->back);
  65     pa_assert(q->length == 0);
  66
  67     pa_xfree(q);
  68 }
  69
  70 void pa_queue_push(pa_queue *q, void *p) {
  71     struct queue_entry *e;
  72
  73     pa_assert(q);
  74     pa_assert(p);
  75
  76     if (!(e = pa_flist_pop(PA_STATIC_FLIST_GET(entries))))
  77         e = pa_xnew(struct queue_entry, 1);
  78
  79     e->data = p;
  80     e->next = NULL;
  81
  82     if (q->back) {
  83         pa_assert(q->front);
  84         q->back->next = e;
  85     } else {
  86         pa_assert(!q->front);
  87         q->front = e;
  88     }
  89
  90     q->back = e;
  91     q->length++;
  92 }
  93
  94 void* pa_queue_pop(pa_queue *q) {
  95     void *p;
  96     struct queue_entry *e;
  97
  98     pa_assert(q);
  99
 100     if (!(e = q->front))
 101         return NULL;
 102
 103     q->front = e->next;
 104
 105     if (q->back == e) {
 106         pa_assert(!e->next);
 107         q->back = NULL;
 108     }
 109
 110     p = e->data;
 111
 112     if (pa_flist_push(PA_STATIC_FLIST_GET(entries), e) < 0)
 113         pa_xfree(e);
 114
 115     q->length--;
 116
 117     return p;
 118 }
 119
 120 int pa_queue_isempty(pa_queue *q) {
 121     pa_assert(q);
 122
 123     return q->length == 0;
 124 }