purezen 0.0.2

Runtime for the Pure Data (Pd) audio programming language, implemented as an extensible audio library allowing full control over signal processing, message passing, and graph manipulation. Pure Data is a graph-based programming language environment creating interactive music and multimedia works.
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/*
 *  Copyright 2009,2010 Reality Jockey, Ltd.
 *                 info@rjdj.me
 *                 http://rjdj.me/
 * 
 *  This file is part of ZenGarden.
 *
 *  ZenGarden is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  ZenGarden is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *  
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with ZenGarden.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#include "ArrayArithmetic.h"
#include "DspDelayWrite.h"
#include "DspVariableDelay.h"
#include "PdGraph.h"

message::Object *DspVariableDelay::new_object(pd::Message *init_message, PdGraph *graph) {
  return new DspVariableDelay(init_message, graph);
}

DspVariableDelay::DspVariableDelay(pd::Message *init_message, PdGraph *graph) : DelayReceiver(0, 1, 0, 1, graph) {
  if (init_message->is_symbol(0)) {
    name = utils::copy_string(init_message->get_symbol(0));
    sample_rate = graph->get_sample_rate();
  } else {
    graph->print_err("vd~ requires the name of a delayline. None given.");
    name = NULL;
  }
}

DspVariableDelay::~DspVariableDelay() {
  // nothing to do
}

void DspVariableDelay::processDspWithIndex(int fromIndex, int toIndex) {
  int headIndex;
  int bufferLength;
  float *buffer = delayline->getBuffer(&headIndex, &bufferLength);
  float bufferLengthFloat = (float) bufferLength;
  
  float targetIndexBase = (float) (headIndex - block_sizeInt);
  #if __APPLE__
  float xArray[block_sizeInt];
  float targetIndexBaseArray[block_sizeInt];
  
  // calculate delay in samples (vector version of utils::millisecondsToSamples)
  float samplesPerMillisecond = sample_rate / 1000.0f;
  vDSP_vsmul(dspBufferAtInlet[0], 1, &samplesPerMillisecond, xArray, 1, block_sizeInt);
  
  float zero = 0.0f;
  float one = 1.0f;
  vDSP_vclip(xArray, 1, &zero, &bufferLengthFloat, xArray, 1, block_sizeInt); // clip the delay between 0 and the buffer length
  vDSP_vramp(&targetIndexBase, &one, targetIndexBaseArray, 1, block_sizeInt);  // create targetIndexBaseArray
  vDSP_vsub(xArray, 1, targetIndexBaseArray, 1, xArray, 1, block_sizeInt); // targetIndexBaseArray - xArray (== targetSampleIndex)
  
  // ensure that targetSampleIndex is positive
  // TODO(mhroth): vectorise this!
  for (int i = 0; i < block_sizeInt; i++) {
    if (xArray[i] < 0.0f) {
      xArray[i] += bufferLengthFloat;
    }
  }
  
  // do table lookup (in buffer) using xArray as indicies, with linear interpolation 
  vDSP_vlint(buffer, xArray, 1, dspBufferAtOutlet[0], 1, block_sizeInt, bufferLength);
  #else
  float *inputbuffer = dspBufferAtInlet[0];
  for (int i = 0; i < block_sizeInt; i++, targetIndexBase+=1.0f) {
    float delayInSamples = utils::millisecondsToSamples(inputbuffer[i], sample_rate);
    if (delayInSamples < 0.0f) {
      delayInSamples = 0.0f;
    } else if (delayInSamples > bufferLengthFloat) {
      delayInSamples = bufferLengthFloat;
    }
    
    float targetSampleIndex = targetIndexBase - delayInSamples;
    if (targetSampleIndex < 0.0f) {
      targetSampleIndex += bufferLengthFloat;
    }
    
    // 2-point linear interpolation (basic and fast)
    int x0 = (int) targetSampleIndex;
    float dx = targetSampleIndex - ((float) x0);
    float y0 = buffer[x0];
    float y1 = buffer[x0+1];
    float slope = (y1 - y0); // /(x1 - x0) == 1.0f!
    dspBufferAtOutlet[0][i] = (slope * dx) + y0;
  }
  #endif
}