//
// Programmer:    Craig Stuart Sapp <craig@ccrma.stanford.edu>
// Creation Date: Wed Jun 27 12:28:03 PDT 2001
// Last Modified: Wed Jun 27 12:28:16 PDT 2001
// Filename:      ...sig/maint/code/audio/AudioIO/oss/DspIO_oss.cpp
// Web Address:   http://sig.sapp.org/src/sig/DspIO_oss.cpp
// Syntax:        C++ 
//
// Description:   Basic Audio input/output functionality for the 
//                Linux OSS audio device /dev/dsp.  This class
//                is inherited by the classes AudioIn_oss and
//                AudioOut_oss.  Only one device is allowed
//                at this time.
//

#ifdef LINUX

#include "DspIO_oss.h"

#include <sys/ioctl.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/soundcard.h>

#include <stdlib.h>
#include <string.h>

#ifndef OLDCPP
   #include <iostream>
   using namespace std;
#else
   #include <iostream.h>
#endif

// define static variables:
const char* DspIO_oss::dsp                  = "/dev/dsp";
int         DspIO_oss::dsp_fd               = -1;
int         DspIO_oss::openQ                =  0;
int         DspIO_oss::numchans             =  0;
int         DspIO_oss::srate                =  0;
int         DspIO_oss::format               =  0;
int         DspIO_oss::class_count          =  0;


///////////////////////////////
//
// DspIO_oss::DspIO_oss --
//	default value: autoOpen = 1;
//

DspIO_oss::DspIO_oss(void) {
   class_count++;
}



//////////////////////////////
//
// DspIO_oss::~DspIO_oss --
//

DspIO_oss::~DspIO_oss() {
   class_count--;

   if (class_count == 0) {
      close();
   } else if (class_count < 0) {
      cerr << "Unusual class instatiation count: " << class_count << endl;
      exit(1);
   }
}



//////////////////////////////
//
// DspIO_oss::close -- close the dsp device.  The device
//   automatically closes once the program ends, but you can close it
//   so that other programs can use it.
//

void DspIO_oss::close(void) {
   if (getFd() >= 0) {
      ::close(getFd());
      dsp_fd = -1;
   }

   openQ = 0;
}



/////////////////////////////
//
// DspIO_oss::is_open -- returns true if the device
//	is already open, false if closed.
//

int DspIO_oss::is_open(void) {
   return openQ;
}

   

/////////////////////////////
//
// DspIO_oss::open -- returns true if the device
//	was successfully opended (or already opened)
//

int DspIO_oss::open(void) {
   if (getFd() < 0) {
      dsp_fd = ::open(dsp, O_RDONLY, 0);
      if (getFd() >= 0) openQ = 1;
      else openQ = 0;
   }
   
   return is_open();
}


   
//////////////////////////////
//
// DspIO_oss::open16LSB --
//     default values:  channels = 1; samplingrate = 44100.0
//

int DspIO_oss::open16LSB(int channels, double samplingrate) {
   if (is_open()) {
      close();
   }
   open(); 

   // (1) set the sample format
   DspIO_oss::format = AFMT_S16_LE;  // know this one works on my computer
   if (ioctl(dsp_fd, SNDCTL_DSP_SETFMT, &format) == -1) {
      cout << "Error seting sound input to 16bit little endian" << endl;
      exit(1);
   }
   if (format != AFMT_S16_LE) {
      cout << "Error: cannot handle 16-bit little endian input" << endl;
      exit(1);
   }

   // (2) set the number of channels
   DspIO_oss::numchans = channels;
   if (channels < 1) {
      channels = 1;
   }

   if (ioctl(dsp_fd, SNDCTL_DSP_CHANNELS, &channels) == -1) {
      cout << "Error: cannot set input to " << channels << " channels " << endl;
      exit(1);
   }
   if (channels != 1) {
      cout << "Error: cannot set input to specified channels" << endl;
      cout << "Can do " << channels << " channels however" << endl;
      exit(1);
   }

   // (3) set the sampling rate
   DspIO_oss::srate = (int)samplingrate;
   if (ioctl(dsp_fd, SNDCTL_DSP_SPEED, &srate) == -1) {
     cout << "Error setting the speed of the recording to " << srate << endl;
   }
   if (abs(srate - (int)samplingrate ) > samplingrate/20) {
     cout << "Error: " << samplingrate 
          << " sampling rate not supported" << endl;
     exit(1);
   }

   return getFd();
}



//////////////////////////////
//
// DspIO_oss::read -- reads audio data.
//
 
void DspIO_oss::read(uchar* buf, int aSize) {
   ::read(getFd(), buf, aSize);
}



//////////////////////////////
//
// DspIO_oss::getFd -- returns the file descriptor of the device.
//

int DspIO_oss::getFd(void) {
   return dsp_fd;
}


#endif /* LINUX */

// md5sum: 73b5d8dc50870ea986a7f5cde8fedb4a DspIO_oss.cpp [20050403]