view src/audio/SDL_audiodev.c @ 2866:e532417a6977

Fixed SDL 1.2 compatibility problem. The API specifies that SDL_OpenAudio() will fill out the 'desired' audio spec with the correct samples and size set by the driver. This value is important since it may be used by applications that size audio buffers, etc. However, we want to allow advanced applications to call SDL_OpenAudioDevice() which gets passed a const 'desired' parameter, and have the correct data filled into the 'obtained' parameter, possibly allowing or not allowing format changes. So... 'obtained' becomes the audio format the user callback is expected to use, and we add flags to allow the application to specify which format changes are allowed. Note: We really need to add a way to query the 'obtained' audio spec.
author Sam Lantinga <slouken@libsdl.org>
date Sat, 13 Dec 2008 06:36:47 +0000
parents 99210400e8b9
children f7b03b6838cb
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/* Get the name of the audio device we use for output */

#if SDL_AUDIO_DRIVER_BSD || SDL_AUDIO_DRIVER_OSS || SDL_AUDIO_DRIVER_SUNAUDIO

#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>

#include "SDL_stdinc.h"
#include "SDL_audiodev_c.h"

#ifndef _PATH_DEV_DSP
#if defined(__NETBSD__) || defined(__OPENBSD__)
#define _PATH_DEV_DSP  "/dev/audio"
#else
#define _PATH_DEV_DSP  "/dev/dsp"
#endif
#endif
#ifndef _PATH_DEV_DSP24
#define _PATH_DEV_DSP24	"/dev/sound/dsp"
#endif
#ifndef _PATH_DEV_AUDIO
#define _PATH_DEV_AUDIO	"/dev/audio"
#endif

static inline void
test_device(const char *fname, int flags, int (*test) (int fd),
            char ***devices, int *devCount)
{
    struct stat sb;
    if ((stat(fname, &sb) == 0) && (S_ISCHR(sb.st_mode))) {
        int audio_fd = open(fname, flags, 0);
        if ((audio_fd >= 0) && (test(audio_fd))) {
            void *p =
                SDL_realloc(*devices, ((*devCount) + 1) * sizeof(char *));
            if (p != NULL) {
                size_t len = strlen(fname) + 1;
                char *str = (char *) SDL_malloc(len);
                *devices = (char **) p;
                if (str != NULL) {
                    SDL_strlcpy(str, fname, len);
                    (*devices)[(*devCount)++] = str;
                }
            }
            close(audio_fd);
        }
    }
}

void
SDL_FreeUnixAudioDevices(char ***devices, int *devCount)
{
    int i = *devCount;
    if ((i > 0) && (*devices != NULL)) {
        while (i--) {
            SDL_free((*devices)[i]);
        }
    }

    if (*devices != NULL) {
        SDL_free(*devices);
    }

    *devices = NULL;
    *devCount = 0;
}

static int
test_stub(int fd)
{
    return 1;
}

void
SDL_EnumUnixAudioDevices(int flags, int classic, int (*test) (int fd),
                         char ***devices, int *devCount)
{
    const char *audiodev;
    char audiopath[1024];

    if (test == NULL)
        test = test_stub;

    /* Figure out what our audio device is */
    if (((audiodev = SDL_getenv("SDL_PATH_DSP")) == NULL) &&
        ((audiodev = SDL_getenv("AUDIODEV")) == NULL)) {
        if (classic) {
            audiodev = _PATH_DEV_AUDIO;
        } else {
            struct stat sb;

            /* Added support for /dev/sound/\* in Linux 2.4 */
            if (((stat("/dev/sound", &sb) == 0) && S_ISDIR(sb.st_mode))
                && ((stat(_PATH_DEV_DSP24, &sb) == 0)
                    && S_ISCHR(sb.st_mode))) {
                audiodev = _PATH_DEV_DSP24;
            } else {
                audiodev = _PATH_DEV_DSP;
            }
        }
    }
    test_device(audiodev, flags, test, devices, devCount);

    if (SDL_strlen(audiodev) < (sizeof(audiopath) - 3)) {
        int instance = 0;
        while (instance++ <= 64) {
            SDL_snprintf(audiopath, SDL_arraysize(audiopath),
                         "%s%d", audiodev, instance);
            test_device(audiopath, flags, test, devices, devCount);
        }
    }
}

#endif /* Audio driver selection */
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