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extra_rwops.c
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/
extra_rwops.c
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/*
* SDL_sound -- An abstract sound format decoding API.
* Copyright (C) 2001 Ryan C. Gordon.
*
* This library 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 library 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 library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* Some extra RWops that are needed or are just handy to have.
*
* Please see the file COPYING in the source's root directory.
*
* This file written by Ryan C. Gordon. (icculus@clutteredmind.org)
*/
#include <stdio.h>
#include <stdlib.h>
#include "SDL.h"
/*
* The Reference Counter RWops...
*/
typedef struct
{
SDL_RWops *rw; /* The actual RWops we're refcounting... */
int refcount; /* The refcount; starts at 1. If goes to 0, delete. */
} RWRefCounterData;
/* Just pass through to the actual SDL_RWops's method... */
static int refcounter_seek(SDL_RWops *rw, int offset, int whence)
{
RWRefCounterData *data = (RWRefCounterData *) rw->hidden.unknown.data1;
return(data->rw->seek(data->rw, offset, whence));
} /* refcounter_seek */
/* Just pass through to the actual SDL_RWops's method... */
static int refcounter_read(SDL_RWops *rw, void *ptr, int size, int maxnum)
{
RWRefCounterData *data = (RWRefCounterData *) rw->hidden.unknown.data1;
return(data->rw->read(data->rw, ptr, size, maxnum));
} /* refcounter_read */
/* Just pass through to the actual SDL_RWops's method... */
static int refcounter_write(SDL_RWops *rw, const void *ptr, int size, int num)
{
RWRefCounterData *data = (RWRefCounterData *) rw->hidden.unknown.data1;
return(data->rw->write(data->rw, ptr, size, num));
} /* refcounter_write */
/*
* Decrement the reference count. If there are no more references, pass
* through to the actual SDL_RWops's method, and then clean ourselves up.
*/
static int refcounter_close(SDL_RWops *rw)
{
int retval = 0;
RWRefCounterData *data = (RWRefCounterData *) rw->hidden.unknown.data1;
data->refcount--;
if (data->refcount <= 0)
{
retval = data->rw->close(data->rw);
free(data);
SDL_FreeRW(rw);
} /* if */
return(retval);
} /* refcounter_close */
void RWops_RWRefCounter_addRef(SDL_RWops *rw)
{
RWRefCounterData *data = (RWRefCounterData *) rw->hidden.unknown.data1;
data->refcount++;
} /* RWops_RWRefCounter_addRef */
SDL_RWops *RWops_RWRefCounter_new(SDL_RWops *rw)
{
SDL_RWops *retval = NULL;
if (rw == NULL)
{
SDL_SetError("NULL argument to RWops_RWRefCounter_new().");
return(NULL);
} /* if */
retval = SDL_AllocRW();
if (retval != NULL)
{
RWRefCounterData *data;
data = (RWRefCounterData *) malloc(sizeof (RWRefCounterData));
if (data == NULL)
{
SDL_SetError("Out of memory.");
SDL_FreeRW(retval);
retval = NULL;
} /* if */
else
{
data->rw = rw;
data->refcount = 1;
retval->hidden.unknown.data1 = data;
retval->seek = refcounter_seek;
retval->read = refcounter_read;
retval->write = refcounter_write;
retval->close = refcounter_close;
} /* else */
} /* if */
return(retval);
} /* RWops_RWRefCounter_new */
/* end of extra_rwops.c ... */