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Diffstat (limited to 'src/page.h')
-rw-r--r-- | src/page.h | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/src/page.h b/src/page.h new file mode 100644 index 000000000..6bee4996f --- /dev/null +++ b/src/page.h @@ -0,0 +1,85 @@ +/* + * 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. + */ + +/** \file + * + * This is a library which manages reference counted buffers. + */ + +#ifndef MPD_PAGE_H +#define MPD_PAGE_H + +#include <stddef.h> +#include <stdbool.h> + +/** + * A dynamically allocated buffer which keeps track of its reference + * count. This is useful for passing buffers around, when several + * instances hold references to one buffer. + */ +struct page { + /** + * The number of references to this buffer. This library uses + * atomic functions to access it, i.e. no locks are required. + * As soon as this attribute reaches zero, the buffer is + * freed. + */ + int ref; + + /** + * The size of this buffer in bytes. + */ + size_t size; + + /** + * Dynamic array containing the buffer data. + */ + unsigned char data[sizeof(long)]; +}; + +/** + * Creates a new #page object, and copies data from the specified + * buffer. It is initialized with a reference count of 1. + * + * @param data the source buffer + * @param size the size of the source buffer + * @return the new #page object + */ +struct page * +page_new_copy(const void *data, size_t size); + +/** + * Increases the reference counter. + * + * @param page the #page object + */ +void +page_ref(struct page *page); + +/** + * Decreases the reference counter. If it reaches zero, the #page is + * freed. + * + * @param page the #page object + * @return true if the #page has been freed + */ +bool +page_unref(struct page *page); + +#endif |