src/audio/windib/SDL_dibaudio.c

/*
    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
*/
#include "SDL_config.h"

/* Allow access to a raw mixing buffer */

#define WIN32_LEAN_AND_MEAN
#include <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


/* Audio driver functions */
static int DIB_OpenAudio(_THIS, SDL_AudioSpec * spec);
static void DIB_ThreadInit(_THIS);
static void DIB_WaitAudio(_THIS);
static Uint8 *DIB_GetAudioBuf(_THIS);
static void DIB_PlayAudio(_THIS);
static void DIB_WaitDone(_THIS);
static void DIB_CloseAudio(_THIS);

/* Audio driver bootstrap functions */

static int
Audio_Available(void)
{
    return (1);
}

static void
Audio_DeleteDevice(SDL_AudioDevice * device)
{
    SDL_free(device->hidden);
    SDL_free(device);
}

static SDL_AudioDevice *
Audio_CreateDevice(int devindex)
{
    SDL_AudioDevice *this;

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

    /* Set the function pointers */
    this->OpenAudio = DIB_OpenAudio;
    this->ThreadInit = DIB_ThreadInit;
    this->WaitAudio = DIB_WaitAudio;
    this->PlayAudio = DIB_PlayAudio;
    this->GetAudioBuf = DIB_GetAudioBuf;
    this->WaitDone = DIB_WaitDone;
    this->CloseAudio = DIB_CloseAudio;

    this->free = Audio_DeleteDevice;

    return this;
}

AudioBootStrap WAVEOUT_bootstrap = {
    "waveout", "Win95/98/NT/2000 WaveOut",
    Audio_Available, Audio_CreateDevice
};


/* 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(audio_sem, 1, NULL);
#else
    ReleaseSemaphore(audio_sem, 1, NULL);
#endif
}

static void
SetMMerror(char *function, MMRESULT code)
{
    size_t len;
    char errbuf[MAXERRORLENGTH];
#ifdef _WIN32_WCE
    wchar_t werrbuf[MAXERRORLENGTH];
#endif

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

#ifdef _WIN32_WCE
    /* UNICODE version */
    waveOutGetErrorText(code, werrbuf, MAXERRORLENGTH - len);
    WideCharToMultiByte(CP_ACP, 0, werrbuf, -1, errbuf + len,
                        MAXERRORLENGTH - len, NULL, NULL);
#else
    waveOutGetErrorText(code, errbuf + len, (UINT) (MAXERRORLENGTH - len));
#endif

    SDL_SetError("%s", errbuf);
}

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

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

Uint8 *
DIB_GetAudioBuf(_THIS)
{
    Uint8 *retval;

    retval = (Uint8 *) (wavebuf[next_buffer].lpData);
    return retval;
}

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

void
DIB_WaitDone(_THIS)
{
    int i, left;

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

void
DIB_CloseAudio(_THIS)
{
    int i;

    /* Close up audio */
    if (audio_sem) {
#if defined(_WIN32_WCE) && (_WIN32_WCE < 300)
        CloseSynchHandle(audio_sem);
#else
        CloseHandle(audio_sem);
#endif
    }
    if (sound) {
        waveOutClose(sound);
    }

    /* Clean up mixing buffers */
    for (i = 0; i < NUM_BUFFERS; ++i) {
        if (wavebuf[i].dwUser != 0xFFFF) {
            waveOutUnprepareHeader(sound, &wavebuf[i], sizeof(wavebuf[i]));
            wavebuf[i].dwUser = 0xFFFF;
        }
    }
    /* Free raw mixing buffer */
    if (mixbuf != NULL) {
        SDL_free(mixbuf);
        mixbuf = NULL;
    }
}

int
DIB_OpenAudio(_THIS, SDL_AudioSpec * spec)
{
    MMRESULT result;
    int i;
    WAVEFORMATEX waveformat;

    /* Initialize the wavebuf structures for closing */
    sound = NULL;
    audio_sem = NULL;
    for (i = 0; i < NUM_BUFFERS; ++i)
        wavebuf[i].dwUser = 0xFFFF;
    mixbuf = NULL;

    /* Set basic WAVE format parameters */
    SDL_memset(&waveformat, 0, sizeof(waveformat));
    waveformat.wFormatTag = WAVE_FORMAT_PCM;

    /* Determine the audio parameters from the AudioSpec */
    switch (spec->format & 0xFF) {
    case 8:
        /* Unsigned 8 bit audio data */
        spec->format = AUDIO_U8;
        waveformat.wBitsPerSample = 8;
        break;
    case 16:
        /* Signed 16 bit audio data */
        spec->format = AUDIO_S16;
        waveformat.wBitsPerSample = 16;
        break;
    default:
        SDL_SetError("Unsupported audio format");
        return (-1);
    }
    waveformat.nChannels = spec->channels;
    waveformat.nSamplesPerSec = 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 (spec->samples < (spec->freq / 4))
        spec->samples = ((spec->freq / 4) + 3) & ~3;

    /* Update the fragment size as size in bytes */
    SDL_CalculateAudioSpec(spec);

    /* Open the audio device */
    result = waveOutOpen(&sound, WAVE_MAPPER, &waveformat,
                         (DWORD_PTR) FillSound, (DWORD_PTR) this,
                         CALLBACK_FUNCTION);
    if (result != MMSYSERR_NOERROR) {
        SetMMerror("waveOutOpen()", result);
        return (-1);
    }
#ifdef SOUND_DEBUG
    /* Check the sound device we retrieved */
    {
        WAVEOUTCAPS caps;

        result = waveOutGetDevCaps((UINT) sound, &caps, sizeof(caps));
        if (result != MMSYSERR_NOERROR) {
            SetMMerror("waveOutGetDevCaps()", result);
            return (-1);
        }
        printf("Audio device: %s\n", caps.szPname);
    }
#endif

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

    /* Create the sound buffers */
    mixbuf = (Uint8 *) SDL_malloc(NUM_BUFFERS * spec->size);
    if (mixbuf == NULL) {
        SDL_SetError("Out of memory");
        return (-1);
    }
    for (i = 0; i < NUM_BUFFERS; ++i) {
        SDL_memset(&wavebuf[i], 0, sizeof(wavebuf[i]));
        wavebuf[i].lpData = (LPSTR) & mixbuf[i * spec->size];
        wavebuf[i].dwBufferLength = spec->size;
        wavebuf[i].dwFlags = WHDR_DONE;
        result = waveOutPrepareHeader(sound, &wavebuf[i], sizeof(wavebuf[i]));
        if (result != MMSYSERR_NOERROR) {
            SetMMerror("waveOutPrepareHeader()", result);
            return (-1);
        }
    }

    /* Ready to go! */
    next_buffer = 0;
    return (0);
}

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