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/*
* buffer.c
*
* Copyright (C) Thomas Oestreich - June 2001
*
* This file is part of transcode, a video stream processing tool
*
* transcode 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, or (at your option)
* any later version.
*
* transcode 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 GNU Make; see the file COPYING. If not, write to
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include "buffer.h"
#include <stdlib.h>
#include <unistd.h>
buffer_list_t *buffer_list_head;
buffer_list_t *buffer_list_tail;
buffer_list_t *buffer_register(int id)
{
/* objectives:
===========
register new buffer
allocate space for new buffer and establish backward reference
*/
buffer_list_t *ptr;
// retrive a valid pointer from the pool
if((ptr = malloc(sizeof(buffer_list_t))) == NULL) return(NULL);
if((ptr->data = (char *) malloc(MAX_PCM_BUFFER)) == NULL) return(NULL);
ptr->status = BUFFER_EMPTY;
ptr->next = NULL;
ptr->prev = NULL;
ptr->id = id;
if(buffer_list_tail != NULL)
{
buffer_list_tail->next = ptr;
ptr->prev = buffer_list_tail;
}
buffer_list_tail = ptr;
/* first buffer registered must set buffer_list_head */
if(buffer_list_head == NULL) buffer_list_head = ptr;
return(ptr);
}
/* ------------------------------------------------------------------ */
void buffer_remove(buffer_list_t *ptr)
{
/* objectives:
===========
remove buffer from chained list
*/
if(ptr == NULL) return; // do nothing if null pointer
if(ptr->prev != NULL) (ptr->prev)->next = ptr->next;
if(ptr->next != NULL) (ptr->next)->prev = ptr->prev;
if(ptr == buffer_list_tail) buffer_list_tail = ptr->prev;
if(ptr == buffer_list_head) buffer_list_head = ptr->next;
// release valid pointer to pool
ptr->status = BUFFER_EMPTY;
free(ptr->data);
free(ptr);
ptr=NULL;
}
/* ------------------------------------------------------------------ */
buffer_list_t *buffer_retrieve()
{
/* objectives:
===========
get pointer to next full buffer
*/
buffer_list_t *ptr;
ptr = buffer_list_head;
/* move along the chain and check for status */
while(ptr != NULL)
{
if(ptr->status == BUFFER_READY)
{
return(ptr);
}
ptr = ptr->next;
}
return(NULL);
}
/*************************************************************************/
/*
* Local variables:
* c-file-style: "stroustrup"
* c-file-offsets: ((case-label . *) (statement-case-intro . *))
* indent-tabs-mode: nil
* End:
*
* vim: expandtab shiftwidth=4:
*/
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