postfish/feedback.c

   1 /*
   2  *
   3  *  postfish
   4  *
   5  *      Copyright (C) 2002-2005 Monty and Xiph.Org
   6  *
   7  *  Postfish is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; either version 2, or (at your option)
  10  *  any later version.
  11  *
  12  *  Postfish is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with Postfish; see the file COPYING.  If not, write to the
  19  *  Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  20  *
  21  *
  22  */
  23
  24 #include "postfish.h"
  25 #include "feedback.h"
  26
  27 static pthread_mutex_t feedback_mutex=PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
  28
  29 feedback_generic *feedback_new(feedback_generic_pool *pool,
  30                                feedback_generic *(*constructor)(void)){
  31   feedback_generic *ret;
  32
  33   pthread_mutex_lock(&feedback_mutex);
  34   if(pool->feedback_pool){
  35     ret=pool->feedback_pool;
  36     pool->feedback_pool=pool->feedback_pool->next;
  37     pthread_mutex_unlock(&feedback_mutex);
  38     return ret;
  39   }
  40   pthread_mutex_unlock(&feedback_mutex);
  41
  42   ret=constructor();
  43   return ret;
  44 }
  45
  46 void feedback_push(feedback_generic_pool *pool,
  47                    feedback_generic *f){
  48   f->next=NULL;
  49
  50   pthread_mutex_lock(&feedback_mutex);
  51   if(!pool->feedback_list_tail){
  52     pool->feedback_list_tail=f;
  53     pool->feedback_list_head=f;
  54   }else{
  55     pool->feedback_list_head->next=f;
  56     pool->feedback_list_head=f;
  57   }
  58   pthread_mutex_unlock(&feedback_mutex);
  59 }
  60
  61 feedback_generic *feedback_pull(feedback_generic_pool *pool){
  62   feedback_generic *f;
  63
  64   pthread_mutex_lock(&feedback_mutex);
  65   if(pool->feedback_list_tail){
  66
  67     f=pool->feedback_list_tail;
  68     pool->feedback_list_tail=pool->feedback_list_tail->next;
  69     if(!pool->feedback_list_tail)pool->feedback_list_head=0;
  70
  71   }else{
  72     pthread_mutex_unlock(&feedback_mutex);
  73     return 0;
  74   }
  75   pthread_mutex_unlock(&feedback_mutex);
  76   return(f);
  77 }
  78
  79 void feedback_old(feedback_generic_pool *pool,
  80                   feedback_generic *f){
  81
  82   pthread_mutex_lock(&feedback_mutex);
  83   f->next=pool->feedback_pool;
  84   pool->feedback_pool=f;
  85   pthread_mutex_unlock(&feedback_mutex);
  86 }
  87
  88 /* are there multiple feedback outputs waiting or just one (a metric
  89    of 'are we behind?') */
  90 int feedback_deep(feedback_generic_pool *pool){
  91   if(pool){
  92     pthread_mutex_lock(&feedback_mutex);
  93     if(pool->feedback_list_tail)
  94       if(pool->feedback_list_tail->next){
  95         pthread_mutex_unlock(&feedback_mutex);
  96         return 1;
  97       }
  98     pthread_mutex_unlock(&feedback_mutex);
  99   }
 100   return 0;
 101 }