page: new library for reference counted buffers

1 files changed, 77 insertions, 0 deletions

diff --git a/src/page.c b/src/page.c
new file mode 100644
index 000000000..a4f52ae4a
--- /dev/null
+++ b/src/page.c
@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2003-2009 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "page.h"
+
+#include <glib.h>
+
+#include <assert.h>
+#include <string.h>
+
+/**
+ * Allocates a new #page object, without filling the data element.
+ */
+static struct page *
+page_new(size_t size)
+{
+	struct page *page = g_malloc(sizeof(*page) + size -
+				     sizeof(page->data));
+
+	assert(size > 0);
+
+	page->ref = 1;
+	page->size = size;
+	return page;
+}
+
+struct page *
+page_new_copy(const void *data, size_t size)
+{
+	struct page *page = page_new(size);
+
+	assert(data != NULL);
+
+	memcpy(page->data, data, size);
+	return page;
+}
+
+void
+page_ref(struct page *page)
+{
+	g_atomic_int_inc(&page->ref);
+}
+
+static void
+page_free(struct page *page)
+{
+	assert(page->ref == 0);
+
+	g_free(page);
+}
+
+bool
+page_unref(struct page *page)
+{
+	bool unused = g_atomic_int_dec_and_test(&page->ref);
+
+	if (unused)
+		page_free(page);
+
+	return unused;
+}