src/page.c

   1 /*
   2  * Copyright (C) 2003-2010 The Music Player Daemon Project
   3  * http://www.musicpd.org
   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,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include "config.h"
  21 #include "page.h"
  22
  23 #include <glib.h>
  24
  25 #include <assert.h>
  26 #include <string.h>
  27
  28 /**
  29  * Allocates a new #page object, without filling the data element.
  30  */
  31 static struct page *
  32 page_new(size_t size)
  33 {
  34         struct page *page = g_malloc(sizeof(*page) + size -
  35                                      sizeof(page->data));
  36
  37         assert(size > 0);
  38
  39         page->ref = 1;
  40         page->size = size;
  41         return page;
  42 }
  43
  44 struct page *
  45 page_new_copy(const void *data, size_t size)
  46 {
  47         struct page *page = page_new(size);
  48
  49         assert(data != NULL);
  50
  51         memcpy(page->data, data, size);
  52         return page;
  53 }
  54
  55 struct page *
  56 page_new_concat(const struct page *a, const struct page *b)
  57 {
  58         struct page *page = page_new(a->size + b->size);
  59
  60         memcpy(page->data, a->data, a->size);
  61         memcpy(page->data + a->size, b->data, b->size);
  62
  63         return page;
  64 }
  65
  66 void
  67 page_ref(struct page *page)
  68 {
  69         g_atomic_int_inc(&page->ref);
  70 }
  71
  72 static void
  73 page_free(struct page *page)
  74 {
  75         assert(page->ref == 0);
  76
  77         g_free(page);
  78 }
  79
  80 bool
  81 page_unref(struct page *page)
  82 {
  83         bool unused = g_atomic_int_dec_and_test(&page->ref);
  84
  85         if (unused)
  86                 page_free(page);
  87
  88         return unused;
  89 }