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// --------------------------------------------------------------------------
// ``Open Sound System (OSS)'' specific audio driver interface.
// --------------------------------------------------------------------------
#include "audiodrv.h"
#if defined(HAVE_OPENBSD)
const char audioDriver::AUDIODEVICE[] = "/dev/audio";
#elif defined(HAVE_NETBSD)
const char audioDriver::AUDIODEVICE[] = "/dev/sound";
#else
const char audioDriver::AUDIODEVICE[] = "/dev/dsp";
#endif
audioDriver::audioDriver()
{
// Reset everything.
errorString = "None";
frequency = 0;
channels = 0;
encoding = 0;
precision = 0;
swapEndian = false;
audioHd = (-1);
}
bool audioDriver::IsThere()
{
// Check device availability and write permissions.
return (access(AUDIODEVICE,W_OK)==0);
}
bool audioDriver::Open(udword inFreq, int inPrecision, int inChannels,
int inFragments, int inFragBase)
{
if ((audioHd=open(AUDIODEVICE,O_WRONLY,0)) == (-1))
{
perror(AUDIODEVICE);
errorString = "ERROR: Could not open audio device.";
return false;
}
// Transfer input parameters to this object.
// May later be replaced with driver defaults.
frequency = inFreq;
precision = inPrecision;
channels = inChannels;
fragments = inFragments;
fragSizeBase = inFragBase;
int mask;
// Query supported sample formats.
if (ioctl(audioHd,SNDCTL_DSP_GETFMTS,&mask) == (-1))
{
perror(AUDIODEVICE);
errorString = "AUDIO: Could not get sample formats.";
return false;
}
// Assume CPU and soundcard have same endianess.
swapEndian = false;
struct DriverCaps
{
int format;
int encoding;
int precision;
bool swapEndian;
};
DriverCaps driverCaps16[] =
{
#if defined(WORDS_BIGENDIAN)
{ AFMT_S16_BE, SIDEMU_SIGNED_PCM, SIDEMU_16BIT, false },
{ AFMT_U16_BE, SIDEMU_UNSIGNED_PCM, SIDEMU_16BIT, false },
{ AFMT_S16_LE, SIDEMU_SIGNED_PCM, SIDEMU_16BIT, true },
{ AFMT_U16_LE, SIDEMU_UNSIGNED_PCM, SIDEMU_16BIT, true },
#else
{ AFMT_S16_LE, SIDEMU_SIGNED_PCM, SIDEMU_16BIT, false },
{ AFMT_U16_LE, SIDEMU_UNSIGNED_PCM, SIDEMU_16BIT, false },
{ AFMT_S16_BE, SIDEMU_SIGNED_PCM, SIDEMU_16BIT, true },
{ AFMT_U16_BE, SIDEMU_UNSIGNED_PCM, SIDEMU_16BIT, true },
#endif
{ AFMT_S8, SIDEMU_SIGNED_PCM, SIDEMU_8BIT, false },
{ AFMT_U8, SIDEMU_UNSIGNED_PCM, SIDEMU_8BIT, false }
};
DriverCaps driverCaps8[] =
{
{ AFMT_S8, SIDEMU_SIGNED_PCM, SIDEMU_8BIT, false },
{ AFMT_U8, SIDEMU_UNSIGNED_PCM, SIDEMU_8BIT, false },
#if defined(WORDS_BIGENDIAN)
{ AFMT_S16_BE, SIDEMU_SIGNED_PCM, SIDEMU_16BIT, false },
{ AFMT_U16_BE, SIDEMU_UNSIGNED_PCM, SIDEMU_16BIT, false },
{ AFMT_S16_LE, SIDEMU_SIGNED_PCM, SIDEMU_16BIT, true },
{ AFMT_U16_LE, SIDEMU_UNSIGNED_PCM, SIDEMU_16BIT, true },
#else
{ AFMT_S16_LE, SIDEMU_SIGNED_PCM, SIDEMU_16BIT, false },
{ AFMT_U16_LE, SIDEMU_UNSIGNED_PCM, SIDEMU_16BIT, false },
{ AFMT_S16_BE, SIDEMU_SIGNED_PCM, SIDEMU_16BIT, true },
{ AFMT_U16_BE, SIDEMU_UNSIGNED_PCM, SIDEMU_16BIT, true }
#endif
};
int wantedFormat = 0;
// Set sample precision and type of encoding.
if (precision == SIDEMU_16BIT)
{
for ( int d=0; d<sizeof(driverCaps16)/sizeof(DriverCaps); d++ )
{
if ( mask&driverCaps16[d].format )
{
wantedFormat = driverCaps16[d].format;
precision = driverCaps16[d].precision;
encoding = driverCaps16[d].encoding;
swapEndian = driverCaps16[d].swapEndian;
break;
}
}
}
else // if (precision == SIDEMU_8BIT)
{
for ( int d=0; d<sizeof(driverCaps8)/sizeof(DriverCaps); d++ )
{
if ( mask&driverCaps8[d].format )
{
wantedFormat = driverCaps8[d].format;
precision = driverCaps8[d].precision;
encoding = driverCaps8[d].encoding;
swapEndian = driverCaps8[d].swapEndian;
break;
}
}
}
if ( !(mask&wantedFormat) || !wantedFormat )
{
errorString = "AUDIO: Desired sample encoding not supported.";
return false;
}
int format = wantedFormat;
if (ioctl(audioHd,SNDCTL_DSP_SETFMT,&format) == (-1))
{
perror(AUDIODEVICE);
errorString = "AUDIO: Could not set sample format.";
return false;
}
if (format != wantedFormat)
{
errorString = "AUDIO: Audio driver did not accept sample format.";
return false;
}
// Set mono/stereo.
int dsp_stereo;
if (channels == SIDEMU_STEREO)
dsp_stereo = 1;
else // if (channels == SIDEMU_MONO)
dsp_stereo = 0;
if (ioctl(audioHd,SNDCTL_DSP_STEREO,&dsp_stereo) == (-1))
{
perror(AUDIODEVICE);
errorString = "AUDIO: Could not set mono/stereo.";
return false;
}
// Verify and accept the number of channels the driver accepted.
if (dsp_stereo == 1)
channels = SIDEMU_STEREO;
else if (dsp_stereo == 0)
channels = SIDEMU_MONO;
else
{
errorString = "AUDIO: Could not set mono/stereo.";
return false;
}
// Set frequency.
int dsp_speed = frequency;
if (ioctl(audioHd,SNDCTL_DSP_SPEED,&dsp_speed) == (-1))
{
perror(AUDIODEVICE);
errorString = "AUDIO: Could not set frequency.";
return false;
}
// Accept the frequency the driver accepted.
frequency = dsp_speed;
// N fragments of size (2 ^ S) bytes
// NNNNSSSS
// e.g. frag = 0x0004000e;
// fragments should be out of [2,3,..,255]
// fragSizeBase should be out of [7,8,...,17]
// depending on the kernel audio driver buffer size
int frag = (fragments << 16) | fragSizeBase;
ioctl(audioHd,SNDCTL_DSP_SETFRAGMENT,&frag);
ioctl(audioHd,SNDCTL_DSP_GETBLKSIZE,&blockSize);
audio_buf_info myAudInfo;
if (ioctl(audioHd,SNDCTL_DSP_GETOSPACE,&myAudInfo) == (-1))
{
perror(AUDIODEVICE);
errorString = "AUDIO: Could not get audio_buf_info.";
return false;
}
fragments = myAudInfo.fragstotal;
//cout << "fragsize = " << (int)myAudInfo.fragsize << endl;
//cout << "bytes = " << (int)myAudInfo.bytes << endl;
return true;
}
// Close an opened audio device, free any allocated buffers and
// reset any variables that reflect the current state.
void audioDriver::Close()
{
if (audioHd != (-1))
{
close(audioHd);
audioHd = (-1);
}
}
void audioDriver::Play(ubyte* pBuffer, int bufferSize)
{
if (audioHd != (-1))
{
if (swapEndian)
{
for (int n=0; n<bufferSize; n+=2)
{
ubyte tmp = pBuffer[n+0];
pBuffer[n+0] = pBuffer[n+1];
pBuffer[n+1] = tmp;
}
}
write(audioHd,pBuffer,bufferSize);
}
}
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