src/audio/windib/SDL_dibaudio.c

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2011 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/
#include "SDL_config.h"

/* Allow access to a raw mixing buffer */

#include "../../core/windows/SDL_windows.h"
#include <mmsystem.h>

#include "SDL_timer.h"
#include "SDL_audio.h"
#include "../SDL_audio_c.h"
#include "SDL_dibaudio.h"
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
#include "win_ce_semaphore.h"
#endif

#if defined(_WIN32_WCE)
#define WINDOWS_OS_NAME "Windows CE/PocketPC"
#elif defined(WIN64)
#define WINDOWS_OS_NAME "Win64"
#else
#define WINDOWS_OS_NAME "Win32"
#endif

/* The Win32 callback for filling the WAVE device */
static void CALLBACK
FillSound(HWAVEOUT hwo, UINT uMsg, DWORD_PTR dwInstance,
          DWORD dwParam1, DWORD dwParam2)
{
    SDL_AudioDevice *this = (SDL_AudioDevice *) dwInstance;

    /* Only service "buffer done playing" messages */
    if (uMsg != WOM_DONE)
        return;

    /* Signal that we are done playing a buffer */
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
    ReleaseSemaphoreCE(this->hidden->audio_sem, 1, NULL);
#else
    ReleaseSemaphore(this->hidden->audio_sem, 1, NULL);
#endif
}

static void
SetMMerror(char *function, MMRESULT code)
{
    size_t len;
    char errbuf[MAXERRORLENGTH];
    wchar_t werrbuf[MAXERRORLENGTH];

    SDL_snprintf(errbuf, SDL_arraysize(errbuf), "%s: ", function);
    len = SDL_strlen(errbuf);

    waveOutGetErrorText(code, werrbuf, MAXERRORLENGTH - len);
    WideCharToMultiByte(CP_ACP, 0, werrbuf, -1, errbuf + len,
                        MAXERRORLENGTH - len, NULL, NULL);

    SDL_SetError("%s", errbuf);
}

/* Set high priority for the audio thread */
static void
WINWAVEOUT_ThreadInit(_THIS)
{
    SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_HIGHEST);
}

void
WINWAVEOUT_WaitDevice(_THIS)
{
    /* Wait for an audio chunk to finish */
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
    WaitForSemaphoreCE(this->hidden->audio_sem, INFINITE);
#else
    WaitForSingleObject(this->hidden->audio_sem, INFINITE);
#endif
}

Uint8 *
WINWAVEOUT_GetDeviceBuf(_THIS)
{
    return (Uint8 *) (this->hidden->
                      wavebuf[this->hidden->next_buffer].lpData);
}

void
WINWAVEOUT_PlayDevice(_THIS)
{
    /* Queue it up */
    waveOutWrite(this->hidden->sound,
                 &this->hidden->wavebuf[this->hidden->next_buffer],
                 sizeof(this->hidden->wavebuf[0]));
    this->hidden->next_buffer = (this->hidden->next_buffer + 1) % NUM_BUFFERS;
}

void
WINWAVEOUT_WaitDone(_THIS)
{
    int i, left;

    do {
        left = NUM_BUFFERS;
        for (i = 0; i < NUM_BUFFERS; ++i) {
            if (this->hidden->wavebuf[i].dwFlags & WHDR_DONE) {
                --left;
            }
        }
        if (left > 0) {
            SDL_Delay(100);
        }
    } while (left > 0);
}

void
WINWAVEOUT_CloseDevice(_THIS)
{
    /* Close up audio */
    if (this->hidden != NULL) {
        int i;

        if (this->hidden->audio_sem) {
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
            CloseSynchHandle(this->hidden->audio_sem);
#else
            CloseHandle(this->hidden->audio_sem);
#endif
            this->hidden->audio_sem = 0;
        }

        if (this->hidden->sound) {
            waveOutClose(this->hidden->sound);
            this->hidden->sound = 0;
        }

        /* Clean up mixing buffers */
        for (i = 0; i < NUM_BUFFERS; ++i) {
            if (this->hidden->wavebuf[i].dwUser != 0xFFFF) {
                waveOutUnprepareHeader(this->hidden->sound,
                                       &this->hidden->wavebuf[i],
                                       sizeof(this->hidden->wavebuf[i]));
                this->hidden->wavebuf[i].dwUser = 0xFFFF;
            }
        }

        if (this->hidden->mixbuf != NULL) {
            /* Free raw mixing buffer */
            SDL_free(this->hidden->mixbuf);
            this->hidden->mixbuf = NULL;
        }

        SDL_free(this->hidden);
        this->hidden = NULL;
    }
}

int
WINWAVEOUT_OpenDevice(_THIS, const char *devname, int iscapture)
{
    SDL_AudioFormat test_format = SDL_FirstAudioFormat(this->spec.format);
    int valid_datatype = 0;
    MMRESULT result;
    WAVEFORMATEX waveformat;
    int i;

    /* 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));

    /* Initialize the wavebuf structures for closing */
    for (i = 0; i < NUM_BUFFERS; ++i)
        this->hidden->wavebuf[i].dwUser = 0xFFFF;

    while ((!valid_datatype) && (test_format)) {
        valid_datatype = 1;
        this->spec.format = test_format;
        switch (test_format) {
        case AUDIO_U8:
        case AUDIO_S16:
        case AUDIO_S32:
            break;              /* valid. */

        default:
            valid_datatype = 0;
            test_format = SDL_NextAudioFormat();
            break;
        }
    }

    if (!valid_datatype) {
        WINWAVEOUT_CloseDevice(this);
        SDL_SetError("Unsupported audio format");
        return 0;
    }

    /* Set basic WAVE format parameters */
    SDL_memset(&waveformat, '\0', sizeof(waveformat));
    waveformat.wFormatTag = WAVE_FORMAT_PCM;
    waveformat.wBitsPerSample = SDL_AUDIO_BITSIZE(this->spec.format);

    if (this->spec.channels > 2)
        this->spec.channels = 2;        /* !!! FIXME: is this right? */

    waveformat.nChannels = this->spec.channels;
    waveformat.nSamplesPerSec = this->spec.freq;
    waveformat.nBlockAlign =
        waveformat.nChannels * (waveformat.wBitsPerSample / 8);
    waveformat.nAvgBytesPerSec =
        waveformat.nSamplesPerSec * waveformat.nBlockAlign;

    /* Check the buffer size -- minimum of 1/4 second (word aligned) */
    if (this->spec.samples < (this->spec.freq / 4))
        this->spec.samples = ((this->spec.freq / 4) + 3) & ~3;

    /* Update the fragment size as size in bytes */
    SDL_CalculateAudioSpec(&this->spec);

    /* Open the audio device */
    result = waveOutOpen(&this->hidden->sound, WAVE_MAPPER, &waveformat,
                         (DWORD_PTR) FillSound, (DWORD_PTR) this,
                         CALLBACK_FUNCTION);
    if (result != MMSYSERR_NOERROR) {
        WINWAVEOUT_CloseDevice(this);
        SetMMerror("waveOutOpen()", result);
        return 0;
    }
#ifdef SOUND_DEBUG
    /* Check the sound device we retrieved */
    {
        WAVEOUTCAPS caps;

        result = waveOutGetDevCaps((UINT) this->hidden->sound,
                                   &caps, sizeof(caps));
        if (result != MMSYSERR_NOERROR) {
            WINWAVEOUT_CloseDevice(this);
            SetMMerror("waveOutGetDevCaps()", result);
            return 0;
        }
        printf("Audio device: %s\n", caps.szPname);
    }
#endif

    /* Create the audio buffer semaphore */
    this->hidden->audio_sem =
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
        CreateSemaphoreCE(NULL, NUM_BUFFERS - 1, NUM_BUFFERS, NULL);
#else
        CreateSemaphore(NULL, NUM_BUFFERS - 1, NUM_BUFFERS, NULL);
#endif
    if (this->hidden->audio_sem == NULL) {
        WINWAVEOUT_CloseDevice(this);
        SDL_SetError("Couldn't create semaphore");
        return 0;
    }

    /* Create the sound buffers */
    this->hidden->mixbuf =
        (Uint8 *) SDL_malloc(NUM_BUFFERS * this->spec.size);
    if (this->hidden->mixbuf == NULL) {
        WINWAVEOUT_CloseDevice(this);
        SDL_OutOfMemory();
        return 0;
    }
    for (i = 0; i < NUM_BUFFERS; ++i) {
        SDL_memset(&this->hidden->wavebuf[i], '\0',
                   sizeof(this->hidden->wavebuf[i]));
        this->hidden->wavebuf[i].dwBufferLength = this->spec.size;
        this->hidden->wavebuf[i].dwFlags = WHDR_DONE;
        this->hidden->wavebuf[i].lpData =
            (LPSTR) & this->hidden->mixbuf[i * this->spec.size];
        result = waveOutPrepareHeader(this->hidden->sound,
                                      &this->hidden->wavebuf[i],
                                      sizeof(this->hidden->wavebuf[i]));
        if (result != MMSYSERR_NOERROR) {
            WINWAVEOUT_CloseDevice(this);
            SetMMerror("waveOutPrepareHeader()", result);
            return 0;
        }
    }

    return 1;                   /* Ready to go! */
}


static int
WINWAVEOUT_Init(SDL_AudioDriverImpl * impl)
{
    /* Set the function pointers */
    impl->OpenDevice = WINWAVEOUT_OpenDevice;
    impl->ThreadInit = WINWAVEOUT_ThreadInit;
    impl->PlayDevice = WINWAVEOUT_PlayDevice;
    impl->WaitDevice = WINWAVEOUT_WaitDevice;
    impl->WaitDone = WINWAVEOUT_WaitDone;
    impl->GetDeviceBuf = WINWAVEOUT_GetDeviceBuf;
    impl->CloseDevice = WINWAVEOUT_CloseDevice;
    impl->OnlyHasDefaultOutputDevice = 1;       /* !!! FIXME: Is this true? */

    return 1;   /* this audio target is available. */
}

AudioBootStrap WINWAVEOUT_bootstrap = {
    "waveout", WINDOWS_OS_NAME " WaveOut", WINWAVEOUT_Init, 0
};

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