sparc_audiodrv.cpp

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//
// 1997/09/27 21:38:01
//

#include "audiodrv.h"

audioDriver::audioDriver()
{
        // Reset everything.
        errorString = "None";
        frequency = 0;
        channels = 0;
        encoding = 0;
        precision = 0;
        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 inFragSizeBase)
{
        if ((audioHd=open(AUDIODEVICE,O_WRONLY,0)) == (-1))
    {
                errorString = "AUDIO: Could not open audio device.";
                return false;
    }

        // Transfer input parameters to this object.
        // May later be replaced with driver defaults.
        frequency = inFreq;
        channels = inChannels;
        precision = inPrecision;

#ifdef CHECKFORSPEAKERBOX  
        int hwdevice;
        if ( ioctl(audioHd,AUDIO_GETDEV,&hwdevice) == -1)
    {
                errorString = "AUDIO: No audio hardware device installed.";
                return false;
    }
        if ( hwdevice != AUDIO_DEV_SPEAKERBOX )
    {
                audioHd = -1;
                errorString = "AUDIO: Speakerbox not installed/enabled.";
                return false;
    }
#endif
        
        // Choose the nearest possible frequency.
        int dbrifreqs[] = 
        {
                8000, 9600, 11025, 16000, 18900, 22050, 32000, 37800, 44100, 48000, 0
        };
        int dbrifsel = 0;
        int dbrifreqdiff = 100000;
        int dbrifrequency = frequency;
        do
    {  
                int dbrifreqdiff2 = frequency - dbrifreqs[dbrifsel];
                dbrifreqdiff2 < 0 ? dbrifreqdiff2 = 0 - dbrifreqdiff2 : dbrifreqdiff2 += 0;
                if ( dbrifreqdiff2 < dbrifreqdiff )  
                {
                        dbrifreqdiff = dbrifreqdiff2;
                        dbrifrequency = dbrifreqs[dbrifsel];
                }
                dbrifsel++;
    }  while ( dbrifreqs[dbrifsel] != 0 );
        frequency = dbrifrequency;
        
        precision = SIDEMU_16BIT;  // Only poor audio capabilities for 8-bit.
        // Sparcstations 5 and 10 tend to be 16-bit only at rates above 8000 Hz.
        encoding = SIDEMU_SIGNED_PCM;
        blockSize = frequency;  // dumb mode
        audio_info myaudio_info;
        if ( ioctl(audioHd,AUDIO_GETINFO,&myaudio_info) == (-1))
    {
                errorString = "AUDIO: Could not get audio info.";
                return false;
    }
        AUDIO_INITINFO( &myaudio_info );
        myaudio_info.play.sample_rate = frequency;
        //myaudio_info.play.buffer_size = blockSize;  // does not work ?
        if (channels == SIDEMU_STEREO)
                myaudio_info.play.channels = 2;
        else  // if (channels == SIDEMU_MONO)
                myaudio_info.play.channels = 1;
        myaudio_info.play.precision = precision;
        myaudio_info.play.encoding = AUDIO_ENCODING_LINEAR;
        myaudio_info.output_muted = 0;
        if ( ioctl(audioHd,AUDIO_SETINFO,&myaudio_info) == (-1))
    {
                errorString = "AUDIO: Could not set audio info.";
                return false;
    }

        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))
        {
                write(audioHd,pBuffer,bufferSize);
        }
}

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