/project/jni/sdl_sound/extra_rwops.c

  1/*
  2 * SDL_sound -- An abstract sound format decoding API.
  3 * Copyright (C) 2001  Ryan C. Gordon.
  4 *
  5 * This library is free software; you can redistribute it and/or
  6 * modify it under the terms of the GNU Lesser General Public
  7 * License as published by the Free Software Foundation; either
  8 * version 2.1 of the License, or (at your option) any later version.
  9 *
 10 * This library is distributed in the hope that it will be useful,
 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 13 * Lesser General Public License for more details.
 14 *
 15 * You should have received a copy of the GNU Lesser General Public
 16 * License along with this library; if not, write to the Free Software
 17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 18 */
 19
 20/*
 21 * Some extra RWops that are needed or are just handy to have.
 22 *
 23 * Please see the file COPYING in the source's root directory.
 24 *
 25 *  This file written by Ryan C. Gordon. (icculus@icculus.org)
 26 */
 27
 28#include <stdio.h>
 29#include <stdlib.h>
 30#include "SDL.h"
 31
 32
 33    /*
 34     * The Reference Counter RWops...
 35     */
 36
 37
 38typedef struct
 39{
 40    SDL_RWops *rw;  /* The actual RWops we're refcounting... */
 41    int refcount;   /* The refcount; starts at 1. If goes to 0, delete. */
 42} RWRefCounterData;
 43
 44
 45/* Just pass through to the actual SDL_RWops's method... */
 46static int refcounter_seek(SDL_RWops *rw, int offset, int whence)
 47{
 48    RWRefCounterData *data = (RWRefCounterData *) rw->hidden.unknown.data1;
 49    return(data->rw->seek(data->rw, offset, whence));
 50} /* refcounter_seek */
 51
 52
 53/* Just pass through to the actual SDL_RWops's method... */
 54static int refcounter_read(SDL_RWops *rw, void *ptr, int size, int maxnum)
 55{
 56    RWRefCounterData *data = (RWRefCounterData *) rw->hidden.unknown.data1;
 57    return(data->rw->read(data->rw, ptr, size, maxnum));
 58} /* refcounter_read */
 59
 60
 61/* Just pass through to the actual SDL_RWops's method... */
 62static int refcounter_write(SDL_RWops *rw, const void *ptr, int size, int num)
 63{
 64    RWRefCounterData *data = (RWRefCounterData *) rw->hidden.unknown.data1;
 65    return(data->rw->write(data->rw, ptr, size, num));
 66} /* refcounter_write */
 67
 68
 69/*
 70 * Decrement the reference count. If there are no more references, pass
 71 *   through to the actual SDL_RWops's method, and then clean ourselves up.
 72 */
 73static int refcounter_close(SDL_RWops *rw)
 74{
 75    int retval = 0;
 76    RWRefCounterData *data = (RWRefCounterData *) rw->hidden.unknown.data1;
 77    data->refcount--;
 78    if (data->refcount <= 0)
 79    {
 80        retval = data->rw->close(data->rw);
 81        free(data);
 82        SDL_FreeRW(rw);
 83    } /* if */
 84
 85    return(retval);
 86} /* refcounter_close */
 87
 88
 89void RWops_RWRefCounter_addRef(SDL_RWops *rw)
 90{
 91    RWRefCounterData *data = (RWRefCounterData *) rw->hidden.unknown.data1;
 92    data->refcount++;
 93} /* RWops_RWRefCounter_addRef */
 94
 95
 96SDL_RWops *RWops_RWRefCounter_new(SDL_RWops *rw)
 97{
 98    SDL_RWops *retval = NULL;
 99
100    if (rw == NULL)
101    {
102        SDL_SetError("NULL argument to RWops_RWRefCounter_new().");
103        return(NULL);
104    } /* if */
105
106    retval = SDL_AllocRW();
107    if (retval != NULL)
108    {
109        RWRefCounterData *data;
110        data = (RWRefCounterData *) malloc(sizeof (RWRefCounterData));
111        if (data == NULL)
112        {
113            SDL_SetError("Out of memory.");
114            SDL_FreeRW(retval);
115            retval = NULL;
116        } /* if */
117        else
118        {
119            data->rw = rw;
120            data->refcount = 1;
121            retval->hidden.unknown.data1 = data;
122            retval->seek = refcounter_seek;
123            retval->read = refcounter_read;
124            retval->write = refcounter_write;
125            retval->close = refcounter_close;
126        } /* else */
127    } /* if */
128
129    return(retval);
130} /* RWops_RWRefCounter_new */
131
132
133/* end of extra_rwops.c ... */
134
135