/*
 * Name: DRV_VOX.C
 * 
 * Description: Mikmod driver for output on linux and FreeBSD Open Sound System
 * (OSS) (/dev/dsp)
 * 
 * Portability:  VoxWare/SS/OSS land. Linux, FreeBSD (NetBSD & SCO?)
 * 
 * New fragment configuration code done by Rao:
 * ============================================
 * 
 * You can use the environment variables 'MM_FRAGSIZE' and 'MM_NUMFRAGS' to
 * override the default size & number of audio buffer fragments. If you
 * experience crackles & pops, try experimenting with these values.
 * 
 * Read experimental.txt within the VoxWare package for information on these
 * options. They are _VERY_ important with relation to sound popping and
 * smooth playback.
 * 
 * In general, the slower your system, the higher these values need to be.
 * 
 * MM_NUMFRAGS is within the range 2 to 255 (decimal)
 * 
 * MM_FRAGSIZE is is within the range 7 to 17 (dec). The requested fragment size
 * will be 2^MM_FRAGSIZE
 * 
 * - This driver DOES work with MikMod 3.0 - modifed to use an ioctl() to figure
 * out how much data to do with each write, keeps us from blocking extensivly
 * 
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/stat.h>
#include <fcntl.h>
#ifdef __FreeBSD__
#include <machine/soundcard.h>
#else
#include <sys/soundcard.h>
#endif				/* __FreeBSD__ */
#include <sys/ioctl.h>
#include <sys/wait.h>
#include "mikmod.h"
#include "mmio.h"

#define DEFAULT_FRAGSIZE 17
#define DEFAULT_NUMFRAGS 4

static int      sndfd;
static int      fragmentsize;
static char    *audiobuffer;


static BOOL 
OSS_IsThere(void)
{
    return (access("/dev/dsp", W_OK) == 0);
}


static BOOL 
OSS_Init(void)
{
    char           *env;
    int             play_precision, play_stereo, play_rate;
    int             fragsize, numfrags;

    if ((sndfd = open("/dev/dsp", O_WRONLY)) < 0) {
		return 1;
    }
    fragsize = (env = getenv("MM_FRAGSIZE")) ? atoi(env) : DEFAULT_FRAGSIZE;
    numfrags = (env = getenv("MM_NUMFRAGS")) ? atoi(env) : DEFAULT_NUMFRAGS;

    if (fragsize < 7 || fragsize > 17)
		fragsize = DEFAULT_FRAGSIZE;

    if (numfrags < 2 || numfrags > 255)
		numfrags = DEFAULT_NUMFRAGS;

    fragmentsize = (numfrags << 16) | fragsize;

#ifndef __FreeBSD__
    if (ioctl(sndfd, SNDCTL_DSP_SETFRAGMENT, &fragmentsize) < 0) {
		close(sndfd);
		return 1;
    }
#endif				/* __FreeBSD__ */

    play_precision = (md_mode & DMODE_16BITS) ? 16 : 8;
    play_stereo = (md_mode & DMODE_STEREO) ? 1 : 0;
    play_rate = md_mixfreq;

    if (ioctl(sndfd, SNDCTL_DSP_SAMPLESIZE, &play_precision) == -1 ||
		ioctl(sndfd, SNDCTL_DSP_STEREO, &play_stereo) == -1 ||
		ioctl(sndfd, SNDCTL_DSP_SPEED, &play_rate) == -1) {
		
		close(sndfd);
		return 1;
    }

    ioctl(sndfd, SNDCTL_DSP_GETBLKSIZE, &fragmentsize);

    /*
     * Lose this for now - it will confuse ncurses etc... printf("Fragment
     * size is %ld\n",fragmentsize);
     */

    if (VC_Init()) {
		close(sndfd);
		return 1;
    }
    audiobuffer = (char *) _mm_malloc(fragmentsize * sizeof(char) * 2);

    if (audiobuffer == NULL) {
		VC_Exit();
		close(sndfd);
		return 1;
    }
    return 0;
}


static void 
OSS_Exit(void)
{
    free(audiobuffer);
    VC_Exit();
    close(sndfd);
}


static void 
OSS_Update(void)
{
    audio_buf_info  buffinf;

    ioctl(sndfd, SNDCTL_DSP_GETOSPACE, &buffinf);
    VC_WriteBytes(audiobuffer, buffinf.fragments * buffinf.fragsize);
    write(sndfd, audiobuffer, buffinf.fragments * buffinf.fragsize);
}

BOOL 
OSS_Reset(void)
{
    ioctl(sndfd, SNDCTL_DSP_RESET);
    VC_Exit();
    return VC_Init();
}


MDRIVER         drv_oss =
{
    NULL,
    "Open Sound System (OSS)",
    "Open Sound System (OSS) Driver v1.3 - by Rao & MikMak (with a little hacking from Pete)",
    0, 255,
    OSS_IsThere,
    VC_SampleLoad,
    VC_SampleUnload,
    VC_SampleSpace,
    VC_SampleLength,
    OSS_Init,
    OSS_Exit,
    OSS_Reset,
    VC_SetNumVoices,
    VC_PlayStart,
    VC_PlayStop,
    OSS_Update,
    VC_VoiceSetVolume,
    VC_VoiceSetFrequency,
    VC_VoiceSetPanning,
    VC_VoicePlay,
    VC_VoiceStop,
    VC_VoiceStopped,
    VC_VoiceReleaseSustain,
    VC_VoiceGetPosition,
    VC_VoiceRealVolume
};