vlc/include/vlc_picture_pool.h

108 lines
3.7 KiB
C

/*****************************************************************************
* vlc_picture_pool.h: picture pool definitions
*****************************************************************************
* Copyright (C) 2009 VLC authors and VideoLAN
*
* Authors: Laurent Aimar <fenrir _AT_ videolan _DOT_ org>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser 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.
*****************************************************************************/
#ifndef VLC_PICTURE_POOL_H
#define VLC_PICTURE_POOL_H 1
/**
* \file
* This file defines picture pool structures and functions in vlc
*/
#include <vlc_picture.h>
/**
* Picture pool handle
*/
typedef struct picture_pool_t picture_pool_t;
/**
* Creates a pool of preallocated pictures. Free pictures can be allocated from
* the pool, and are returned to the pool when they are no longer referenced.
*
* This avoids allocating and deallocationg pictures repeatedly, and ensures
* that memory consumption remains within limits.
*
* To obtain a picture from the pool, use picture_pool_Get(). To increase and
* decrease the reference count, use picture_Hold() and picture_Release()
* respectively.
*
* @param count number of pictures in the array
* @param tab array of pictures
*
* @return a pointer to the new pool on success, or NULL on error
* (pictures are <b>not</b> released on error)
*/
VLC_API picture_pool_t * picture_pool_New(unsigned count,
picture_t *const *tab) VLC_USED;
/**
* Allocates pictures from the heap and creates a picture pool with them.
* This is a convenience wrapper for picture_NewFromFormat() and
* picture_pool_New().
*
* @param fmt video format of pictures to allocate from the heap
* @param count number of pictures to allocate
*
* @return a pointer to the new pool on success, NULL on error
*/
VLC_API picture_pool_t * picture_pool_NewFromFormat(const video_format_t *fmt,
unsigned count) VLC_USED;
/**
* Releases a pool created by picture_pool_New()
* or picture_pool_NewFromFormat().
*
* @note If there are no pending references to the pooled pictures, and the
* picture_resource_t.pf_destroy callback was not NULL, it will be invoked.
* Otherwise the default callback will be used.
*
* @warning If there are pending references (a.k.a. late pictures), the
* pictures will remain valid until the all pending references are dropped by
* picture_Release().
*/
VLC_API void picture_pool_Release( picture_pool_t * );
/**
* Obtains a picture from a pool if any is immediately available.
*
* The picture must be released with picture_Release().
*
* @return a picture, or NULL if all pictures in the pool are allocated
*
* @note This function is thread-safe.
*/
VLC_API picture_t * picture_pool_Get( picture_pool_t * ) VLC_USED;
/**
* Obtains a picture from a pool.
*
* The picture must be released with picture_Release().
*
* @return a picture or NULL on memory error
*
* @note This function is thread-safe.
*/
VLC_API picture_t *picture_pool_Wait(picture_pool_t *) VLC_USED;
#endif /* VLC_PICTURE_POOL_H */