Commit d18edcd7 authored by Steve Lhomme's avatar Steve Lhomme

core: add a set of functions to use a plain FIFO

It's similar to the block FIFO but with no locking.
parent a3c904e5
/*****************************************************************************
* vlc_fifo_helper.h: Basic FIFO helper functions
*****************************************************************************
* Copyright (C) 2017 VLC authors and VideoLAN
*
* Authors: Steve Lhomme <robux4@gmail.com>
*
* 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_FIFO_HELPER_H
#define VLC_FIFO_HELPER_H 1
typedef struct FIFO_ITEM {
struct FIFO_ITEM *p_next;
} fifo_item_t;
typedef struct
{
fifo_item_t *p_first;
fifo_item_t **pp_last;
size_t i_depth;
} fifo_t;
static inline void fifo_Init(fifo_t *p_fifo)
{
p_fifo->p_first = NULL;
p_fifo->pp_last = &p_fifo->p_first;
p_fifo->i_depth = 0;
}
static inline void fifo_Release(fifo_t *fifo)
{
assert(fifo->i_depth == 0); /* we should have poped all the items */
}
static inline size_t fifo_GetCount(fifo_t *fifo)
{
return fifo->i_depth;
}
static inline fifo_item_t *fifo_Show(fifo_t *p_fifo)
{
fifo_item_t *b;
assert(p_fifo->p_first != NULL);
b = p_fifo->p_first;
return b;
}
static inline fifo_item_t *fifo_Get(fifo_t *fifo)
{
fifo_item_t *block = fifo->p_first;
if (block == NULL)
return NULL; /* Nothing to do */
fifo->p_first = block->p_next;
if (block->p_next == NULL)
fifo->pp_last = &fifo->p_first;
block->p_next = NULL;
assert(fifo->i_depth > 0);
fifo->i_depth--;
return block;
}
static inline void fifo_Put(fifo_t *fifo, fifo_item_t *p_item)
{
*(fifo->pp_last) = p_item;
while (p_item != NULL)
{
fifo->pp_last = &p_item->p_next;
fifo->i_depth++;
p_item = p_item->p_next;
}
}
/* macro to get the proper item type in/out of the FIFO
* The item type must have a field fifo_item_t named fifo
*/
#define TYPED_FIFO(type, prefix) \
static inline void prefix ## _fifo_Init(fifo_t *p_fifo) \
{ \
fifo_Init(p_fifo); \
} \
static inline void prefix ## _fifo_Release(fifo_t *p_fifo) \
{ \
fifo_Release(p_fifo); \
} \
static inline void prefix ## _fifo_Put(fifo_t *p_fifo, type *p_item) \
{ \
fifo_Put(p_fifo, &p_item->fifo); \
} \
static inline type *prefix ## _fifo_Get(fifo_t *p_fifo) \
{ \
return (type*)fifo_Get(p_fifo); \
} \
static inline type *prefix ## _fifo_Show(fifo_t *p_fifo) \
{ \
return (type*)fifo_Show(p_fifo); \
} \
static inline size_t prefix ## _fifo_GetCount(fifo_t *fifo) \
{ \
return fifo->i_depth; \
}
#endif /* VLC_FIFO_HELPER_H */
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