/*

    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

    Modified in Oct 2004 by Hannu Savolainen 

    hannu@opensound.com

*/

#include "SDL_config.h"

/* Allow access to a raw mixing buffer */

#include <stdio.h>              /* For perror() */

#include <string.h>             /* For strerror() */

#include <errno.h>

#include <unistd.h>

#include <fcntl.h>

#include <signal.h>

#include <sys/time.h>

#include <sys/ioctl.h>

#include <sys/stat.h>

#if SDL_AUDIO_DRIVER_OSS_SOUNDCARD_H

/* This is installed on some systems */

#include <soundcard.h>

#else

/* This is recommended by OSS */

#include <sys/soundcard.h>

#endif

#include "SDL_timer.h"

#include "SDL_audio.h"

#include "../SDL_audiomem.h"

#include "../SDL_audio_c.h"

#include "../SDL_audiodev_c.h"

#include "SDL_dspaudio.h"

/* The tag name used by DSP audio */

#define DSP_DRIVER_NAME         "dsp"

/* Open the audio device for playback, and don't block if busy */

#define OPEN_FLAGS_OUTPUT    (O_WRONLY|O_NONBLOCK)

#define OPEN_FLAGS_INPUT    (O_RDONLY|O_NONBLOCK)

static char **outputDevices = NULL;

static int outputDeviceCount = 0;

static char **inputDevices = NULL;

static int inputDeviceCount = 0;

static inline void

free_device_list(char ***devs, int *count)

{

    SDL_FreeUnixAudioDevices(devs, count);

}

static inline void

build_device_list(int iscapture, char ***devs, int *count)

{

    const int flags = ((iscapture) ? OPEN_FLAGS_INPUT : OPEN_FLAGS_OUTPUT);

    free_device_list(devs, count);

    SDL_EnumUnixAudioDevices(flags, 0, NULL, devs, count);

}

static inline void

build_device_lists(void)

{

    build_device_list(0, &outputDevices, &outputDeviceCount);

    build_device_list(1, &inputDevices, &inputDeviceCount);

}

static inline void

free_device_lists(void)

{

    free_device_list(&outputDevices, &outputDeviceCount);

    free_device_list(&inputDevices, &inputDeviceCount);

}

static void

DSP_Deinitialize(void)

{

    free_device_lists();

}

static int

DSP_DetectDevices(int iscapture)

{

    if (iscapture) {

        build_device_list(1, &inputDevices, &inputDeviceCount);

        return inputDeviceCount;

    } else {

        build_device_list(0, &outputDevices, &outputDeviceCount);

        return outputDeviceCount;

    }

    return 0;  /* shouldn't ever hit this. */

}

static const char *

DSP_GetDeviceName(int index, int iscapture)

{

    if ((iscapture) && (index < inputDeviceCount)) {

        return inputDevices[index];

    } else if ((!iscapture) && (index < outputDeviceCount)) {

        return outputDevices[index];

    }

    SDL_SetError("No such device");

    return NULL;

}

static void

DSP_CloseDevice(_THIS)

{

    if (this->hidden != NULL) {

        if (this->hidden->mixbuf != NULL) {

            SDL_FreeAudioMem(this->hidden->mixbuf);

            this->hidden->mixbuf = NULL;

        }

        if (this->hidden->audio_fd >= 0) {

            close(this->hidden->audio_fd);

            this->hidden->audio_fd = -1;

        }

        SDL_free(this->hidden);

        this->hidden = NULL;

    }

}

static int

DSP_OpenDevice(_THIS, const char *devname, int iscapture)

{

    const int flags = ((iscapture) ? OPEN_FLAGS_INPUT : OPEN_FLAGS_OUTPUT);

    int format;

    int value;

    int frag_spec;

    SDL_AudioFormat test_format;

    /* We don't care what the devname is...we'll try to open anything. */

    /*  ...but default to first name in the list... */

    if (devname == NULL) {

        if ( ((iscapture) && (inputDeviceCount == 0)) ||

             ((!iscapture) && (outputDeviceCount == 0)) ) {

            SDL_SetError("No such audio device");

            return 0;

        }

        devname = ((iscapture) ? inputDevices[0] : outputDevices[0]);

    }

    /* 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));

    /* Open the audio device */

    this->hidden->audio_fd = open(devname, flags, 0);

    if (this->hidden->audio_fd < 0) {

        DSP_CloseDevice(this);

        SDL_SetError("Couldn't open %s: %s", devname, strerror(errno));

        return 0;

    }

    this->hidden->mixbuf = NULL;

    /* Make the file descriptor use blocking writes with fcntl() */

    {

        long ctlflags;

        ctlflags = fcntl(this->hidden->audio_fd, F_GETFL);

        ctlflags &= ~O_NONBLOCK;

        if (fcntl(this->hidden->audio_fd, F_SETFL, ctlflags) < 0) {

            DSP_CloseDevice(this);

            SDL_SetError("Couldn't set audio blocking mode");

            return 0;

        }

    }

    /* Get a list of supported hardware formats */

    if (ioctl(this->hidden->audio_fd, SNDCTL_DSP_GETFMTS, &value) < 0) {

        perror("SNDCTL_DSP_GETFMTS");

        DSP_CloseDevice(this);

        SDL_SetError("Couldn't get audio format list");

        return 0;

    }

    /* Try for a closest match on audio format */

    format = 0;

    for (test_format = SDL_FirstAudioFormat(this->spec.format);

         !format && test_format;) {

#ifdef DEBUG_AUDIO

        fprintf(stderr, "Trying format 0x%4.4x\n", test_format);

#endif

        switch (test_format) {

        case AUDIO_U8:

            if (value & AFMT_U8) {

                format = AFMT_U8;

            }

            break;

        case AUDIO_S16LSB:

            if (value & AFMT_S16_LE) {

                format = AFMT_S16_LE;

            }

            break;

        case AUDIO_S16MSB:

            if (value & AFMT_S16_BE) {

                format = AFMT_S16_BE;

            }

            break;

#if 0

/*

 * These formats are not used by any real life systems so they are not 

 * needed here.

 */

        case AUDIO_S8:

            if (value & AFMT_S8) {

                format = AFMT_S8;

            }

            break;

        case AUDIO_U16LSB:

            if (value & AFMT_U16_LE) {

                format = AFMT_U16_LE;

            }

            break;

        case AUDIO_U16MSB:

            if (value & AFMT_U16_BE) {

                format = AFMT_U16_BE;

            }

            break;

#endif

        default:

            format = 0;

            break;

        }

        if (!format) {

            test_format = SDL_NextAudioFormat();

        }

    }

    if (format == 0) {

        DSP_CloseDevice(this);

        SDL_SetError("Couldn't find any hardware audio formats");

        return 0;

    }

    this->spec.format = test_format;

    /* Set the audio format */

    value = format;

    if ( (ioctl(this->hidden->audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) ||

         (value != format) ) {

        perror("SNDCTL_DSP_SETFMT");

        DSP_CloseDevice(this);

        SDL_SetError("Couldn't set audio format");

        return 0;

    }

    /* Set the number of channels of output */

    value = this->spec.channels;

    if (ioctl(this->hidden->audio_fd, SNDCTL_DSP_CHANNELS, &value) < 0) {

        perror("SNDCTL_DSP_CHANNELS");

        DSP_CloseDevice(this);

        SDL_SetError("Cannot set the number of channels");

        return 0;

    }

    this->spec.channels = value;

    /* Set the DSP frequency */

    value = this->spec.freq;

    if (ioctl(this->hidden->audio_fd, SNDCTL_DSP_SPEED, &value) < 0) {

        perror("SNDCTL_DSP_SPEED");

        DSP_CloseDevice(this);

        SDL_SetError("Couldn't set audio frequency");

        return 0;

    }

    this->spec.freq = value;

    /* Calculate the final parameters for this audio specification */

    SDL_CalculateAudioSpec(&this->spec);

    /* Determine the power of two of the fragment size */

    for (frag_spec = 0; (0x01U << frag_spec) < this->spec.size; ++frag_spec);

    if ((0x01U << frag_spec) != this->spec.size) {

        DSP_CloseDevice(this);

        SDL_SetError("Fragment size must be a power of two");

        return 0;

    }

    frag_spec |= 0x00020000;    /* two fragments, for low latency */

    /* Set the audio buffering parameters */

#ifdef DEBUG_AUDIO

    fprintf(stderr, "Requesting %d fragments of size %d\n",

            (frag_spec >> 16), 1 << (frag_spec & 0xFFFF));

#endif

    if (ioctl(this->hidden->audio_fd, SNDCTL_DSP_SETFRAGMENT, &frag_spec) < 0) {

        perror("SNDCTL_DSP_SETFRAGMENT");

    }

#ifdef DEBUG_AUDIO

    {

        audio_buf_info info;

        ioctl(this->hidden->audio_fd, SNDCTL_DSP_GETOSPACE, &info);

        fprintf(stderr, "fragments = %d\n", info.fragments);

        fprintf(stderr, "fragstotal = %d\n", info.fragstotal);

        fprintf(stderr, "fragsize = %d\n", info.fragsize);

        fprintf(stderr, "bytes = %d\n", info.bytes);

    }

#endif

    /* Allocate mixing buffer */

    this->hidden->mixlen = this->spec.size;

    this->hidden->mixbuf = (Uint8 *) SDL_AllocAudioMem(this->hidden->mixlen);

    if (this->hidden->mixbuf == NULL) {

        DSP_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

DSP_PlayDevice(_THIS)

{

    const Uint8 *mixbuf = this->hidden->mixbuf;

    const int mixlen = this->hidden->mixlen;

    if (write(this->hidden->audio_fd, mixbuf, mixlen) == -1) {

        perror("Audio write");

        this->enabled = 0;

    }

#ifdef DEBUG_AUDIO

    fprintf(stderr, "Wrote %d bytes of audio data\n", mixlen);

#endif

}

static Uint8 *

DSP_GetDeviceBuf(_THIS)

{

    return (this->hidden->mixbuf);

}

static int

DSP_Init(SDL_AudioDriverImpl *impl)

{

    /* Set the function pointers */

    impl->DetectDevices = DSP_DetectDevices;

    impl->GetDeviceName = DSP_GetDeviceName;

    impl->OpenDevice = DSP_OpenDevice;

    impl->PlayDevice = DSP_PlayDevice;

    impl->GetDeviceBuf = DSP_GetDeviceBuf;

    impl->CloseDevice = DSP_CloseDevice;

    impl->Deinitialize = DSP_Deinitialize;

    build_device_lists();

    return 1;

}

AudioBootStrap DSP_bootstrap = {

    DSP_DRIVER_NAME, "OSS /dev/dsp standard audio", DSP_Init, 0

};

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