//
//  Vrml 97 library
//  Copyright (C) 1998 Chris Morley
//
//
//  Audio.h
//    contributed by Kumaran Santhanam

#ifndef _AUDIO_
#define _AUDIO_

//
//  Audio document class
//
#include <stdio.h>
#include <math.h>

class  Doc;

enum AudioEncoding
{
    AUDIO_LINEAR,
    AUDIO_ULAW
};


class Audio
{
  public:
    Audio (const char *url = 0, Doc *relative = 0);
    ~Audio ();

    bool setURL (const char *url, Doc *relative = 0);
    bool tryURLs (int nUrls, const char * const *urls, Doc *relative = 0);

    const char *url() const;

    AudioEncoding encoding() const        { return _encoding; }
    int channels() const                  { return _channels; }
    int bitsPerSample() const             { return _bits_per_sample; }
    int samplesPerSec() const             { return _samples_per_sec; }
    int sampleBlockSize() const           { return _sample_blocksize; }
    int numSamples() const                { return _num_samples; }

    int numBytes() const         { return _num_samples * _sample_blocksize; }
    const unsigned char *samples() const  { return _samples; }

    double duration() const  {
        if (_samples_per_sec > 0)
            return (double)_num_samples/(double)_samples_per_sec;
        else
            return 0;
    }

    // Get the sample index given a floating point time index
    // If the time index is greater than the duration, the sample
    // index is wrapped back to the beginning of the sample.
    // From: Alex Funk <Alexander.Funk@nord-com.net>
    // Avoid int overflow when multiplying time_index by samples_per_sec
    // Modified to use fmod() by Kumaran Santhanam.
    int getByteIndex(double time_index) const  {
      if (_num_samples > 0 && _samples_per_sec > 0)
	return _sample_blocksize *
	  (int)(fmod(time_index, duration()) * (double)_samples_per_sec);
      else
	return -1;
    }


  private:
    Doc *           _doc;

    AudioEncoding   _encoding;
    int             _channels;
    int             _bits_per_sample;
    int             _samples_per_sec;

    // Samples are stored in aligned blocks.  Sometimes, the
    // block will be larger than the sample itself.  Usually,
    // however, an 8-bit sample will be in a 1-byte block and
    // a 16-bit sample will be in a 2-byte block.
    int             _sample_blocksize;

    int             _num_samples;
    unsigned char * _samples;


    bool wavread (FILE *fp);
};


#endif // _AUDIO_