view src/audio/nas/SDL_nasaudio.c @ 3846:66fb40445587 SDL-ryan-multiple-audio-device

Removed distinction between "available" and "init" in audio backends, since both had to be checked for success as a pair at the higher level and several of the Available methods were just always-succeed placeholders anyhow. Now the availability check is done in the init code, and the higher level tries all possible drivers until one manages to initialize successfully.
author Ryan C. Gordon <icculus@icculus.org>
date Tue, 17 Oct 2006 09:09:21 +0000
parents 76c5a414b996
children
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 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

    This driver was written by:
    Erik Inge Bolsų
    knan@mo.himolde.no
*/
#include "SDL_config.h"

/* Allow access to a raw mixing buffer */

#include <signal.h>
#include <unistd.h>

#include "SDL_timer.h"
#include "SDL_audio.h"
#include "SDL_loadso.h"
#include "../SDL_audiomem.h"
#include "../SDL_audio_c.h"
#include "SDL_nasaudio.h"

/* The tag name used by nas audio */
#define NAS_DRIVER_NAME         "nas"

static struct SDL_PrivateAudioData *this2 = NULL;


static void (*NAS_AuCloseServer)(AuServer *);
static void (*NAS_AuNextEvent)(AuServer *, AuBool, AuEvent *);
static AuBool (*NAS_AuDispatchEvent)(AuServer *, AuEvent *);
static AuFlowID (*NAS_AuCreateFlow)(AuServer *, AuStatus *);
static void (*NAS_AuStartFlow)(AuServer *, AuFlowID, AuStatus *);
static void (*NAS_AuSetElements)
    (AuServer *, AuFlowID, AuBool, int, AuElement *, AuStatus *);
static void (*NAS_AuWriteElement)
    (AuServer *, AuFlowID, int, AuUint32, AuPointer, AuBool, AuStatus *);
static AuServer *(*NAS_AuOpenServer)
    (_AuConst char *, int, _AuConst char *, int, _AuConst char *, char **);
static AuEventHandlerRec *(*NAS_AuRegisterEventHandler)
    (AuServer *, AuMask, int, AuID, AuEventHandlerCallback, AuPointer);


#ifdef SDL_AUDIO_DRIVER_NAS_DYNAMIC

static const char *nas_library = SDL_AUDIO_DRIVER_NAS_DYNAMIC;
static void *nas_handle = NULL;

static int
load_nas_sym(const char *fn, void **addr)
{
    *addr = SDL_LoadFunction(nas_handle, fn);
    if (*addr == NULL) {
        return 0;
    }
    return 1;
}

/* cast funcs to char* first, to please GCC's strict aliasing rules. */
#define SDL_NAS_SYM(x) \
    if (!load_nas_sym(#x, (void **) (char *) &NAS_##x)) return -1
#else
#define SDL_NAS_SYM(x) NAS_##x = x
#endif

static int load_nas_syms(void)
{
    SDL_NAS_SYM(AuCloseServer);
    SDL_NAS_SYM(AuNextEvent);
    SDL_NAS_SYM(AuDispatchEvent);
    SDL_NAS_SYM(AuCreateFlow);
    SDL_NAS_SYM(AuStartFlow);
    SDL_NAS_SYM(AuSetElements);
    SDL_NAS_SYM(AuWriteElement);
    SDL_NAS_SYM(AuOpenServer);
    SDL_NAS_SYM(AuRegisterEventHandler);
    return 0;
}
#undef SDL_NAS_SYM

#ifdef SDL_AUDIO_DRIVER_NAS_DYNAMIC

static void
UnloadNASLibrary(void)
{
    if (nas_handle != NULL) {
        SDL_UnloadObject(nas_handle);
        nas_handle = NULL;
    }
}

static int
LoadNASLibrary(void)
{
    int retval = 0;
    if (nas_handle == NULL) {
        nas_handle = SDL_LoadObject(nas_library);
        if (nas_handle == NULL) {
            /* Copy error string so we can use it in a new SDL_SetError(). */
            char *origerr = SDL_GetError();
            size_t len = SDL_strlen(origerr) + 1;
            char *err = (char *) alloca(len);
            SDL_strlcpy(err, origerr, len);
            retval = -1;
            SDL_SetError("NAS: SDL_LoadObject('%s') failed: %s\n",
                          nas_library, err);
        } else {
            retval = load_nas_syms();
            if (retval < 0) {
                UnloadNASLibrary();
            }
        }
    }
    return retval;
}

#else

static void
UnloadNASLibrary(void)
{
}

static int
LoadNASLibrary(void)
{
    load_nas_syms();
    return 0;
}

#endif /* SDL_AUDIO_DRIVER_NAS_DYNAMIC */

/* This function waits until it is possible to write a full sound buffer */
static void
NAS_WaitDevice(_THIS)
{
    while (this->hidden->buf_free < this->hidden->mixlen) {
        AuEvent ev;
        NAS_AuNextEvent(this->hidden->aud, AuTrue, &ev);
        NAS_AuDispatchEvent(this->hidden->aud, &ev);
    }
}

static void
NAS_PlayDevice(_THIS)
{
    while (this->hidden->mixlen > this->hidden->buf_free) {
        /*
         * We think the buffer is full? Yikes! Ask the server for events,
         *  in the hope that some of them is LowWater events telling us more
         *  of the buffer is free now than what we think.
         */
        AuEvent ev;
        NAS_AuNextEvent(this->hidden->aud, AuTrue, &ev);
        NAS_AuDispatchEvent(this->hidden->aud, &ev);
    }
    this->hidden->buf_free -= this->hidden->mixlen;

    /* Write the audio data */
    NAS_AuWriteElement(this->hidden->aud, this->hidden->flow, 0,
                   this->hidden->mixlen, this->hidden->mixbuf, AuFalse, NULL);

    this->hidden->written += this->hidden->mixlen;

#ifdef DEBUG_AUDIO
    fprintf(stderr, "Wrote %d bytes of audio data\n", this->hidden->mixlen);
#endif
}

static Uint8 *
NAS_GetDeviceBuf(_THIS)
{
    return (this->hidden->mixbuf);
}

static void
NAS_CloseDevice(_THIS)
{
    if (this->hidden != NULL) {
        if (this->hidden->mixbuf != NULL) {
            SDL_FreeAudioMem(this->hidden->mixbuf);
            this->hidden->mixbuf = NULL;
        }
        if (this->hidden->aud) {
            NAS_AuCloseServer(this->hidden->aud);
            this->hidden->aud = 0;
        }
        SDL_free(this->hidden);
        this2 = this->hidden = NULL;
    }
}

static unsigned char
sdlformat_to_auformat(unsigned int fmt)
{
    switch (fmt) {
    case AUDIO_U8:
        return AuFormatLinearUnsigned8;
    case AUDIO_S8:
        return AuFormatLinearSigned8;
    case AUDIO_U16LSB:
        return AuFormatLinearUnsigned16LSB;
    case AUDIO_U16MSB:
        return AuFormatLinearUnsigned16MSB;
    case AUDIO_S16LSB:
        return AuFormatLinearSigned16LSB;
    case AUDIO_S16MSB:
        return AuFormatLinearSigned16MSB;
    }
    return AuNone;
}

static AuBool
event_handler(AuServer * aud, AuEvent * ev, AuEventHandlerRec * hnd)
{
    switch (ev->type) {
    case AuEventTypeElementNotify:
        {
            AuElementNotifyEvent *event = (AuElementNotifyEvent *) ev;

            switch (event->kind) {
            case AuElementNotifyKindLowWater:
                if (this2->buf_free >= 0) {
                    this2->really += event->num_bytes;
                    gettimeofday(&this2->last_tv, 0);
                    this2->buf_free += event->num_bytes;
                } else {
                    this2->buf_free = event->num_bytes;
                }
                break;
            case AuElementNotifyKindState:
                switch (event->cur_state) {
                case AuStatePause:
                    if (event->reason != AuReasonUser) {
                        if (this2->buf_free >= 0) {
                            this2->really += event->num_bytes;
                            gettimeofday(&this2->last_tv, 0);
                            this2->buf_free += event->num_bytes;
                        } else {
                            this2->buf_free = event->num_bytes;
                        }
                    }
                    break;
                }
            }
        }
    }
    return AuTrue;
}

static AuDeviceID
find_device(_THIS, int nch)
{
    /* These "Au" things are all macros, not functions... */
    int i;
    for (i = 0; i < AuServerNumDevices(this->hidden->aud); i++) {
        if ((AuDeviceKind(AuServerDevice(this->hidden->aud, i)) ==
             AuComponentKindPhysicalOutput) &&
            AuDeviceNumTracks(AuServerDevice(this->hidden->aud, i)) == nch) {
            return AuDeviceIdentifier(AuServerDevice(this->hidden->aud, i));
        }
    }
    return AuNone;
}

static int
NAS_OpenDevice(_THIS, const char *devname, int iscapture)
{
    AuElement elms[3];
    int buffer_size;
    SDL_AudioFormat test_format, format;

    /* Initialize all variables that we clean on shutdown */
    this->hidden = (struct SDL_PrivateAudioData *)
                        SDL_malloc((sizeof *this->hidden));
    if (this->hidden == NULL) {
        SDL_OutOfMemory();
        return 0;
    }
    SDL_memset(this->hidden, 0, (sizeof *this->hidden));

    /* Try for a closest match on audio format */
    format = 0;
    for (test_format = SDL_FirstAudioFormat(this->spec.format);
         !format && test_format;) {
        format = sdlformat_to_auformat(test_format);
        if (format == AuNone) {
            test_format = SDL_NextAudioFormat();
        }
    }
    if (format == 0) {
        NAS_CloseDevice(this);
        SDL_SetError("NAS: Couldn't find any hardware audio formats");
        return 0;
    }
    this->spec.format = test_format;

    this->hidden->aud = NAS_AuOpenServer("", 0, NULL, 0, NULL, NULL);
    if (this->hidden->aud == 0) {
        NAS_CloseDevice(this);
        SDL_SetError("NAS: Couldn't open connection to NAS server");
        return 0;
    }

    this->hidden->dev = find_device(this, this->spec.channels);
    if ((this->hidden->dev == AuNone)
        || (!(this->hidden->flow = NAS_AuCreateFlow(this->hidden->aud, 0)))) {
        NAS_CloseDevice(this);
        SDL_SetError("NAS: Couldn't find a fitting device on NAS server");
        return 0;
    }

    buffer_size = this->spec.freq;
    if (buffer_size < 4096)
        buffer_size = 4096;

    if (buffer_size > 32768)
        buffer_size = 32768;    /* So that the buffer won't get unmanageably big. */

    /* Calculate the final parameters for this audio specification */
    SDL_CalculateAudioSpec(&this->spec);

    this2 = this->hidden;

    AuMakeElementImportClient(elms,this->spec.freq,format,this->spec.channels,
                              AuTrue, buffer_size, buffer_size / 4, 0, NULL);
    AuMakeElementExportDevice(elms + 1, 0, this->hidden->dev, this->spec.freq,
                              AuUnlimitedSamples, 0, NULL);
    NAS_AuSetElements(this->hidden->aud, this->hidden->flow,
                      AuTrue, 2, elms, NULL);
    NAS_AuRegisterEventHandler(this->hidden->aud, AuEventHandlerIDMask, 0,
                               this->hidden->flow, event_handler,
                               (AuPointer) NULL);

    NAS_AuStartFlow(this->hidden->aud, this->hidden->flow, NULL);

    /* Allocate mixing buffer */
    this->hidden->mixlen = this->spec.size;
    this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(this->hidden->mixlen);
    if (this->hidden->mixbuf == NULL) {
        NAS_CloseDevice(this);
        SDL_OutOfMemory();
        return 0;
    }
    SDL_memset(this->hidden->mixbuf, this->spec.silence, this->spec.size);

    /* We're ready to rock and roll. :-) */
    return 1;
}

static void
NAS_Deinitialize(void)
{
    UnloadNASLibrary();
}

static int
NAS_Init(SDL_AudioDriverImpl *impl)
{
    if (LoadNASLibrary() < 0) {
        return 0;
    } else {
        AuServer *aud = NAS_AuOpenServer("", 0, NULL, 0, NULL, NULL);
        if (aud == NULL) {
            SDL_SetError("NAS: AuOpenServer() failed (no audio server?)");
            return 0;
        }
        NAS_AuCloseServer(aud);
    }

    /* Set the function pointers */
    impl->OpenDevice = NAS_OpenDevice;
    impl->PlayDevice = NAS_PlayDevice;
    impl->WaitDevice = NAS_WaitDevice;
    impl->GetDeviceBuf = NAS_GetDeviceBuf;
    impl->CloseDevice = NAS_CloseDevice;
    impl->Deinitialize = NAS_Deinitialize;
    impl->OnlyHasDefaultOutputDevice = 1;  /* !!! FIXME: is this true? */

    return 1;
}

AudioBootStrap NAS_bootstrap = {
    NAS_DRIVER_NAME, "Network Audio System", NAS_Init, 0
};

/* vi: set ts=4 sw=4 expandtab: */