audio/sdlaudio.c

/*
 * QEMU SDL audio driver
 *
 * Copyright (c) 2004-2005 Vassili Karpov (malc)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "qemu/osdep.h"
#include <SDL.h>
#include <SDL_thread.h>
#include "qemu/module.h"
#include "audio.h"

#ifndef _WIN32
#ifdef __sun__
#define _POSIX_PTHREAD_SEMANTICS 1
#elif defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__DragonFly__)
#include <pthread.h>
#endif
#endif

#define AUDIO_CAP "sdl"
#include "audio_int.h"

typedef struct SDLVoiceOut {
    HWVoiceOut hw;
} SDLVoiceOut;

static struct SDLAudioState {
    int exit;
    int initialized;
    bool driver_created;
    Audiodev *dev;
} glob_sdl;
typedef struct SDLAudioState SDLAudioState;

static void GCC_FMT_ATTR (1, 2) sdl_logerr (const char *fmt, ...)
{
    va_list ap;

    va_start (ap, fmt);
    AUD_vlog (AUDIO_CAP, fmt, ap);
    va_end (ap);

    AUD_log (AUDIO_CAP, "Reason: %s\n", SDL_GetError ());
}

static int aud_to_sdlfmt (AudioFormat fmt)
{
    switch (fmt) {
    case AUDIO_FORMAT_S8:
        return AUDIO_S8;

    case AUDIO_FORMAT_U8:
        return AUDIO_U8;

    case AUDIO_FORMAT_S16:
        return AUDIO_S16LSB;

    case AUDIO_FORMAT_U16:
        return AUDIO_U16LSB;

    default:
        dolog ("Internal logic error: Bad audio format %d\n", fmt);
#ifdef DEBUG_AUDIO
        abort ();
#endif
        return AUDIO_U8;
    }
}

static int sdl_to_audfmt(int sdlfmt, AudioFormat *fmt, int *endianness)
{
    switch (sdlfmt) {
    case AUDIO_S8:
        *endianness = 0;
        *fmt = AUDIO_FORMAT_S8;
        break;

    case AUDIO_U8:
        *endianness = 0;
        *fmt = AUDIO_FORMAT_U8;
        break;

    case AUDIO_S16LSB:
        *endianness = 0;
        *fmt = AUDIO_FORMAT_S16;
        break;

    case AUDIO_U16LSB:
        *endianness = 0;
        *fmt = AUDIO_FORMAT_U16;
        break;

    case AUDIO_S16MSB:
        *endianness = 1;
        *fmt = AUDIO_FORMAT_S16;
        break;

    case AUDIO_U16MSB:
        *endianness = 1;
        *fmt = AUDIO_FORMAT_U16;
        break;

    default:
        dolog ("Unrecognized SDL audio format %d\n", sdlfmt);
        return -1;
    }

    return 0;
}

static int sdl_open (SDL_AudioSpec *req, SDL_AudioSpec *obt)
{
    int status;
#ifndef _WIN32
    int err;
    sigset_t new, old;

    /* Make sure potential threads created by SDL don't hog signals.  */
    err = sigfillset (&new);
    if (err) {
        dolog ("sdl_open: sigfillset failed: %s\n", strerror (errno));
        return -1;
    }
    err = pthread_sigmask (SIG_BLOCK, &new, &old);
    if (err) {
        dolog ("sdl_open: pthread_sigmask failed: %s\n", strerror (err));
        return -1;
    }
#endif

    status = SDL_OpenAudio (req, obt);
    if (status) {
        sdl_logerr ("SDL_OpenAudio failed\n");
    }

#ifndef _WIN32
    err = pthread_sigmask (SIG_SETMASK, &old, NULL);
    if (err) {
        dolog ("sdl_open: pthread_sigmask (restore) failed: %s\n",
               strerror (errno));
        /* We have failed to restore original signal mask, all bets are off,
           so exit the process */
        exit (EXIT_FAILURE);
    }
#endif
    return status;
}

static void sdl_close (SDLAudioState *s)
{
    if (s->initialized) {
        SDL_LockAudio();
        s->exit = 1;
        SDL_UnlockAudio();
        SDL_PauseAudio (1);
        SDL_CloseAudio ();
        s->initialized = 0;
    }
}

static void sdl_callback (void *opaque, Uint8 *buf, int len)
{
    SDLVoiceOut *sdl = opaque;
    SDLAudioState *s = &glob_sdl;
    HWVoiceOut *hw = &sdl->hw;

    if (s->exit) {
        return;
    }

    /* dolog ("in callback samples=%zu live=%zu\n", samples, sdl->live); */

    while (hw->pending_emul && len) {
        size_t write_len;
        ssize_t start = ((ssize_t) hw->pos_emul) - hw->pending_emul;
        if (start < 0) {
            start += hw->size_emul;
        }
        assert(start >= 0 && start < hw->size_emul);

        write_len = MIN(MIN(hw->pending_emul, len),
                        hw->size_emul - start);

        memcpy(buf, hw->buf_emul + start, write_len);
        hw->pending_emul -= write_len;
        len -= write_len;
        buf += write_len;
    }

    /* clear remaining buffer that we couldn't fill with data */
    if (len) {
        memset(buf, 0, len);
    }
}

#define SDL_WRAPPER_FUNC(name, ret_type, args_decl, args, fail, unlock) \
    static ret_type glue(sdl_, name)args_decl                           \
    {                                                                   \
        ret_type ret;                                                   \
                                                                        \
        SDL_LockAudio();                                                \
                                                                        \
        ret = glue(audio_generic_, name)args;                           \
                                                                        \
        SDL_UnlockAudio();                                              \
        return ret;                                                     \
    }

SDL_WRAPPER_FUNC(get_buffer_out, void *, (HWVoiceOut *hw, size_t *size),
                 (hw, size), *size = 0, sdl_unlock)
SDL_WRAPPER_FUNC(put_buffer_out_nowrite, size_t,
                 (HWVoiceOut *hw, void *buf, size_t size), (hw, buf, size),
                 /*nothing*/, sdl_unlock_and_post)
SDL_WRAPPER_FUNC(write, size_t,
                 (HWVoiceOut *hw, void *buf, size_t size), (hw, buf, size),
                 /*nothing*/, sdl_unlock_and_post)

#undef SDL_WRAPPER_FUNC

static void sdl_fini_out (HWVoiceOut *hw)
{
    (void) hw;

    sdl_close (&glob_sdl);
}

static int sdl_init_out(HWVoiceOut *hw, struct audsettings *as,
                        void *drv_opaque)
{
    SDLVoiceOut *sdl = (SDLVoiceOut *) hw;
    SDLAudioState *s = &glob_sdl;
    SDL_AudioSpec req, obt;
    int endianness;
    int err;
    AudioFormat effective_fmt;
    struct audsettings obt_as;

    req.freq = as->freq;
    req.format = aud_to_sdlfmt (as->fmt);
    req.channels = as->nchannels;
    req.samples = audio_buffer_samples(s->dev->u.sdl.out, as, 11610);
    req.callback = sdl_callback;
    req.userdata = sdl;

    if (sdl_open (&req, &obt)) {
        return -1;
    }

    err = sdl_to_audfmt(obt.format, &effective_fmt, &endianness);
    if (err) {
        sdl_close (s);
        return -1;
    }

    obt_as.freq = obt.freq;
    obt_as.nchannels = obt.channels;
    obt_as.fmt = effective_fmt;
    obt_as.endianness = endianness;

    audio_pcm_init_info (&hw->info, &obt_as);
    hw->samples = obt.samples;

    s->initialized = 1;
    s->exit = 0;
    SDL_PauseAudio (0);
    return 0;
}

static void sdl_enable_out(HWVoiceOut *hw, bool enable)
{
    SDL_PauseAudio(!enable);
}

static void *sdl_audio_init(Audiodev *dev)
{
    SDLAudioState *s = &glob_sdl;
    if (s->driver_created) {
        sdl_logerr("Can't create multiple sdl backends\n");
        return NULL;
    }

    if (SDL_InitSubSystem (SDL_INIT_AUDIO)) {
        sdl_logerr ("SDL failed to initialize audio subsystem\n");
        return NULL;
    }

    s->driver_created = true;
    s->dev = dev;
    return s;
}

static void sdl_audio_fini (void *opaque)
{
    SDLAudioState *s = opaque;
    sdl_close (s);
    SDL_QuitSubSystem (SDL_INIT_AUDIO);
    s->driver_created = false;
    s->dev = NULL;
}

static struct audio_pcm_ops sdl_pcm_ops = {
    .init_out = sdl_init_out,
    .fini_out = sdl_fini_out,
    .write    = sdl_write,
    .get_buffer_out = sdl_get_buffer_out,
    .put_buffer_out = sdl_put_buffer_out_nowrite,
    .enable_out = sdl_enable_out,
};

static struct audio_driver sdl_audio_driver = {
    .name           = "sdl",
    .descr          = "SDL http://www.libsdl.org",
    .init           = sdl_audio_init,
    .fini           = sdl_audio_fini,
    .pcm_ops        = &sdl_pcm_ops,
    .can_be_default = 1,
    .max_voices_out = 1,
    .max_voices_in  = 0,
    .voice_size_out = sizeof (SDLVoiceOut),
    .voice_size_in  = 0
};

static void register_audio_sdl(void)
{
    audio_driver_register(&sdl_audio_driver);
}
type_init(register_audio_sdl);