code.delx.au - pulseaudio/blob - polyp/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 General Public License as published
   8   by the Free Software Foundation; either version 2 of the License,
   9   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   General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   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 "queue.h"
  30
  31 struct queue_entry {
  32     struct queue_entry *next;
  33     void *data;
  34 };
  35
  36 struct pa_queue {
  37     struct queue_entry *front, *back;
  38     unsigned length;
  39 };
  40
  41 struct pa_queue* pa_queue_new(void) {
  42     struct pa_queue *q = malloc(sizeof(struct pa_queue));
  43     assert(q);
  44     q->front = q->back = NULL;
  45     q->length = 0;
  46     return q;
  47 }
  48
  49 void pa_queue_free(struct pa_queue* q, void (*destroy)(void *p, void *userdata), void *userdata) {
  50     struct queue_entry *e;
  51     assert(q);
  52
  53     e = q->front;
  54     while (e) {
  55         struct queue_entry *n = e->next;
  56
  57         if (destroy)
  58             destroy(e->data, userdata);
  59
  60         free(e);
  61         e = n;
  62     }
  63
  64     free(q);
  65 }
  66
  67 void pa_queue_push(struct pa_queue *q, void *p) {
  68     struct queue_entry *e;
  69
  70     e = malloc(sizeof(struct queue_entry));
  71
  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(struct 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     free(e);
 100
 101     q->length--;
 102
 103     return p;
 104 }
 105
 106 int pa_queue_is_empty(struct pa_queue *q) {
 107     assert(q);
 108     return q->length == 0;
 109 }