Method TestSignChanges

src/VoiceKey.cpp:895–936

double VoiceKey::TestSignChanges(
   const WaveChannel & t, sampleCount start, sampleCount len)
{


   auto s = start;                                //Keep track of start
   auto originalLen = len;                        //Keep track of the length of block to process (its not the length of t)
   const auto blockSize = limitSampleBufferSize(
      t.GetMaxBlockSize(), len);               //Determine size of sampling buffer
   unsigned long signchanges = 1;
   int currentsign=0;

   Floats buffer{ blockSize };       //Get a sampling buffer

   while(len > 0) {
      //Figure out how much to grab
      auto block = limitSampleBufferSize ( t.GetBestBlockSize(s), len );

      t.GetFloats(buffer.get(), s, block);                      //grab the block;

      if  (len == originalLen)
         {
            //The first time through, set stuff up special.
            currentsign = sgn(buffer[0]);
         }

      //Now, go through the block and calculate zero crossings

      for(decltype(block) i = 0; i< block; i++)
         {
            if( sgn(buffer[i]) != currentsign)
               {
                  currentsign = sgn(buffer[i]);
                  signchanges++;
               }

         }
      len -= block;
      s += block;
   }
   return (double)signchanges / originalLen.as_double();
}

void VoiceKey::TestSignChangesUpdate(double & currentsignchanges, int len,
                                     const float & a1,