mdw@git.distorted.org.uk Git - disorder/blob - clients/playrtp-mem.c

   1 /*
   2  * This file is part of DisOrder.
   3  * Copyright (C) 2007 Richard Kettlewell
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  18  * USA
  19  */
  20 /** @file clients/playrtp-mem.c
  21  * @brief RTP player memory management
  22  */
  23
  24 #include "common.h"
  25
  26 #include <pthread.h>
  27
  28 #include "mem.h"
  29 #include "vector.h"
  30 #include "heap.h"
  31 #include "playrtp.h"
  32
  33 /** @brief Linked list of free packets
  34  *
  35  * This is a linked list of formerly used packets.  For preference we re-use
  36  * packets that have already been used rather than unused ones, to limit the
  37  * size of the program's working set.  If there are no free packets in the list
  38  * we try @ref next_free_packet instead.
  39  *
  40  * Must hold @ref lock when accessing this.
  41  */
  42 static union free_packet *free_packets;
  43
  44 /** @brief Array of new free packets
  45  *
  46  * There are @ref count_free_packets ready to use at this address.  If there
  47  * are none left we allocate more memory.
  48  *
  49  * Must hold @ref lock when accessing this.
  50  */
  51 static union free_packet *next_free_packet;
  52
  53 /** @brief Count of new free packets at @ref next_free_packet
  54  *
  55  * Must hold @ref lock when accessing this.
  56  */
  57 static size_t count_free_packets;
  58
  59 /** @brief Lock protecting packet allocator */
  60 static pthread_mutex_t mem_lock = PTHREAD_MUTEX_INITIALIZER;
  61
  62 /** @brief Return a new packet */
  63 struct packet *playrtp_new_packet(void) {
  64   struct packet *p;
  65
  66   pthread_mutex_lock(&mem_lock);
  67   if(free_packets) {
  68     p = &free_packets->p;
  69     free_packets = free_packets->next;
  70   } else {
  71     if(!count_free_packets) {
  72       next_free_packet = xcalloc(1024, sizeof (union free_packet));
  73       count_free_packets = 1024;
  74     }
  75     p = &(next_free_packet++)->p;
  76     --count_free_packets;
  77   }
  78   pthread_mutex_unlock(&mem_lock);
  79   return p;
  80 }
  81
  82 /** @brief Free a packet */
  83 void playrtp_free_packet(struct packet *p) {
  84   union free_packet *u = (union free_packet *)p;
  85   pthread_mutex_lock(&mem_lock);
  86   u->next = free_packets;
  87   free_packets = u;
  88   pthread_mutex_unlock(&mem_lock);
  89 }
  90
  91
  92 /*
  93 Local Variables:
  94 c-basic-offset:2
  95 comment-column:40
  96 fill-column:79
  97 indent-tabs-mode:nil
  98 End:
  99 */