/************************** BEGIN dsp-combiner.h **************************
FAUST Architecture File
Copyright (C) 2003-2022 GRAME, Centre National de Creation Musicale
---------------------------------------------------------------------
This program 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 2.1 of the License, or
(at your option) any later version.

This program 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 this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

EXCEPTION : As a special exception, you may create a larger work
that contains this FAUST architecture section and distribute
that work under terms of your choice, so long as this FAUST
architecture section is not modified.
************************************************************************/

#ifndef __dsp_combiner__
#define __dsp_combiner__

#include <string.h>
#include <string>
#include <assert.h>
#include <sstream>

#include "faust/dsp/dsp.h"
#include "faust/gui/UI.h"

// Base class and common code for binary combiners

enum Layout { kVerticalGroup, kHorizontalGroup, kTabGroup };

class dsp_binary_combiner : public dsp {

    protected:

        dsp* fDSP1;
        dsp* fDSP2;
        int fBufferSize;
        Layout fLayout;
        std::string fLabel;

        void buildUserInterfaceAux(UI* ui_interface)
        {
            switch (fLayout) {
                case kHorizontalGroup:
                    ui_interface->openHorizontalBox(fLabel.c_str());
                    fDSP1->buildUserInterface(ui_interface);
                    fDSP2->buildUserInterface(ui_interface);
                    ui_interface->closeBox();
                    break;
                case kVerticalGroup:
                    ui_interface->openVerticalBox(fLabel.c_str());
                    fDSP1->buildUserInterface(ui_interface);
                    fDSP2->buildUserInterface(ui_interface);
                    ui_interface->closeBox();
                    break;
                case kTabGroup:
                    ui_interface->openTabBox(fLabel.c_str());
                    ui_interface->openVerticalBox("DSP1");
                    fDSP1->buildUserInterface(ui_interface);
                    ui_interface->closeBox();
                    ui_interface->openVerticalBox("DSP2");
                    fDSP2->buildUserInterface(ui_interface);
                    ui_interface->closeBox();
                    ui_interface->closeBox();
                    break;
            }
        }

        FAUSTFLOAT** allocateChannels(int num)
        {
            FAUSTFLOAT** channels = new FAUSTFLOAT*[num];
            for (int chan = 0; chan < num; chan++) {
                channels[chan] = new FAUSTFLOAT[fBufferSize];
                memset(channels[chan], 0, sizeof(FAUSTFLOAT) * fBufferSize);
            }
            return channels;
        }

        void deleteChannels(FAUSTFLOAT** channels, int num)
        {
            for (int chan = 0; chan < num; chan++) {
                delete [] channels[chan];
            }
            delete [] channels;
        }

     public:

        dsp_binary_combiner(dsp* dsp1, dsp* dsp2, int buffer_size, Layout layout, const std::string& label)
        :fDSP1(dsp1), fDSP2(dsp2), fBufferSize(buffer_size), fLayout(layout), fLabel(label)
        {}

        virtual ~dsp_binary_combiner()
        {
            delete fDSP1;
            delete fDSP2;
        }

        virtual int getSampleRate()
        {
            return fDSP1->getSampleRate();
        }
        virtual void init(int sample_rate)
        {
            fDSP1->init(sample_rate);
            fDSP2->init(sample_rate);
        }
        virtual void instanceInit(int sample_rate)
        {
            fDSP1->instanceInit(sample_rate);
            fDSP2->instanceInit(sample_rate);
        }
        virtual void instanceConstants(int sample_rate)
        {
            fDSP1->instanceConstants(sample_rate);
            fDSP2->instanceConstants(sample_rate);
        }

        virtual void instanceResetUserInterface()
        {
            fDSP1->instanceResetUserInterface();
            fDSP2->instanceResetUserInterface();
        }

        virtual void instanceClear()
        {
            fDSP1->instanceClear();
            fDSP2->instanceClear();
        }

        virtual void metadata(Meta* m)
        {
            fDSP1->metadata(m);
            fDSP2->metadata(m);
        }

};

// Combine two 'compatible' DSP in sequence

class dsp_sequencer : public dsp_binary_combiner {

    private:

        FAUSTFLOAT** fDSP1Outputs;

    public:

        dsp_sequencer(dsp* dsp1, dsp* dsp2,
                      int buffer_size = 4096,
                      Layout layout = Layout::kTabGroup,
                      const std::string& label = "Sequencer")
        :dsp_binary_combiner(dsp1, dsp2, buffer_size, layout, label)
        {
            fDSP1Outputs = allocateChannels(fDSP1->getNumOutputs());
        }

        virtual ~dsp_sequencer()
        {
            deleteChannels(fDSP1Outputs, fDSP1->getNumOutputs());
        }

        virtual int getNumInputs() { return fDSP1->getNumInputs(); }
        virtual int getNumOutputs() { return fDSP2->getNumOutputs(); }

        virtual void buildUserInterface(UI* ui_interface)
        {
            buildUserInterfaceAux(ui_interface);
        }

        virtual dsp* clone()
        {
            return new dsp_sequencer(fDSP1->clone(), fDSP2->clone(), fBufferSize, fLayout, fLabel);
        }

        virtual void compute(int count, FAUSTFLOAT** inputs, FAUSTFLOAT** outputs)
        {
            fDSP1->compute(count, inputs, fDSP1Outputs);
            fDSP2->compute(count, fDSP1Outputs, outputs);
        }

        virtual void compute(double date_usec, int count, FAUSTFLOAT** inputs, FAUSTFLOAT** outputs) { compute(count, inputs, outputs); }

};

// Combine two DSP in parallel

class dsp_parallelizer : public dsp_binary_combiner {

    private:

        FAUSTFLOAT** fDSP2Inputs;
        FAUSTFLOAT** fDSP2Outputs;

    public:

        dsp_parallelizer(dsp* dsp1, dsp* dsp2,
                     int buffer_size = 4096,
                     Layout layout = Layout::kTabGroup,
                     const std::string& label = "Parallelizer")
        :dsp_binary_combiner(dsp1, dsp2, buffer_size, layout, label)
        {
            fDSP2Inputs = new FAUSTFLOAT*[fDSP2->getNumInputs()];
            fDSP2Outputs = new FAUSTFLOAT*[fDSP2->getNumOutputs()];
        }

        virtual ~dsp_parallelizer()
        {
            delete [] fDSP2Inputs;
            delete [] fDSP2Outputs;
        }

        virtual int getNumInputs() { return fDSP1->getNumInputs() + fDSP2->getNumInputs(); }
        virtual int getNumOutputs() { return fDSP1->getNumOutputs() + fDSP2->getNumOutputs(); }

        virtual void buildUserInterface(UI* ui_interface)
        {
            buildUserInterfaceAux(ui_interface);
        }

        virtual dsp* clone()
        {
            return new dsp_parallelizer(fDSP1->clone(), fDSP2->clone(), fBufferSize, fLayout, fLabel);
        }

        virtual void compute(int count, FAUSTFLOAT** inputs, FAUSTFLOAT** outputs)
        {
            fDSP1->compute(count, inputs, outputs);

            // Shift inputs/outputs channels for fDSP2
            for (int chan = 0; chan < fDSP2->getNumInputs(); chan++) {
                fDSP2Inputs[chan] = inputs[fDSP1->getNumInputs() + chan];
            }
            for (int chan = 0; chan < fDSP2->getNumOutputs(); chan++) {
                fDSP2Outputs[chan] = outputs[fDSP1->getNumOutputs() + chan];
            }

            fDSP2->compute(count, fDSP2Inputs, fDSP2Outputs);
        }

        virtual void compute(double date_usec, int count, FAUSTFLOAT** inputs, FAUSTFLOAT** outputs) { compute(count, inputs, outputs); }

};

// Combine two 'compatible' DSP in splitter

class dsp_splitter : public dsp_binary_combiner {

    private:

        FAUSTFLOAT** fDSP1Outputs;
        FAUSTFLOAT** fDSP2Inputs;

    public:

        dsp_splitter(dsp* dsp1, dsp* dsp2,
                     int buffer_size = 4096,
                     Layout layout = Layout::kTabGroup,
                     const std::string& label = "Splitter")
        :dsp_binary_combiner(dsp1, dsp2, buffer_size, layout, label)
        {
            fDSP1Outputs = allocateChannels(fDSP1->getNumOutputs());
            fDSP2Inputs = new FAUSTFLOAT*[fDSP2->getNumInputs()];
        }

        virtual ~dsp_splitter()
        {
            deleteChannels(fDSP1Outputs, fDSP1->getNumOutputs());
            delete [] fDSP2Inputs;
        }

        virtual int getNumInputs() { return fDSP1->getNumInputs(); }
        virtual int getNumOutputs() { return fDSP2->getNumOutputs(); }

        virtual void buildUserInterface(UI* ui_interface)
        {
            buildUserInterfaceAux(ui_interface);
        }

        virtual dsp* clone()
        {
            return new dsp_splitter(fDSP1->clone(), fDSP2->clone(), fBufferSize, fLayout, fLabel);
        }

        virtual void compute(int count, FAUSTFLOAT** inputs, FAUSTFLOAT** outputs)
        {
            fDSP1->compute(count, inputs, fDSP1Outputs);

            for (int chan = 0; chan < fDSP2->getNumInputs(); chan++) {
                 fDSP2Inputs[chan] = fDSP1Outputs[chan % fDSP1->getNumOutputs()];
            }

            fDSP2->compute(count, fDSP2Inputs, outputs);
        }
};

// Combine two 'compatible' DSP in merger

class dsp_merger : public dsp_binary_combiner {

    private:

        FAUSTFLOAT** fDSP1Inputs;
        FAUSTFLOAT** fDSP1Outputs;
        FAUSTFLOAT** fDSP2Inputs;

        void mix(int count, FAUSTFLOAT* dst, FAUSTFLOAT* src)
        {
            for (int frame = 0; frame < count; frame++) {
                dst[frame] += src[frame];
            }
        }

    public:

        dsp_merger(dsp* dsp1, dsp* dsp2,
                   int buffer_size = 4096,
                   Layout layout = Layout::kTabGroup,
                   const std::string& label = "Merger")
        :dsp_binary_combiner(dsp1, dsp2, buffer_size, layout, label)
        {
            fDSP1Inputs = allocateChannels(fDSP1->getNumInputs());
            fDSP1Outputs = allocateChannels(fDSP1->getNumOutputs());
            fDSP2Inputs = new FAUSTFLOAT*[fDSP2->getNumInputs()];
        }

        virtual ~dsp_merger()
        {
            deleteChannels(fDSP1Inputs, fDSP1->getNumInputs());
            deleteChannels(fDSP1Outputs, fDSP1->getNumOutputs());
            delete [] fDSP2Inputs;
        }

        virtual int getNumInputs() { return fDSP1->getNumInputs(); }
        virtual int getNumOutputs() { return fDSP2->getNumOutputs(); }

        virtual void buildUserInterface(UI* ui_interface)
        {
            buildUserInterfaceAux(ui_interface);
        }

        virtual dsp* clone()
        {
            return new dsp_merger(fDSP1->clone(), fDSP2->clone(), fBufferSize, fLayout, fLabel);
        }

        virtual void compute(int count, FAUSTFLOAT** inputs, FAUSTFLOAT** outputs)
        {
            fDSP1->compute(count, fDSP1Inputs, fDSP1Outputs);

            memset(fDSP2Inputs, 0, sizeof(FAUSTFLOAT*) * fDSP2->getNumInputs());

            for (int chan = 0; chan < fDSP1->getNumOutputs(); chan++) {
                int mchan = chan % fDSP2->getNumInputs();
                if (fDSP2Inputs[mchan]) {
                    mix(count, fDSP2Inputs[mchan], fDSP1Outputs[chan]);
                } else {
                    fDSP2Inputs[mchan] = fDSP1Outputs[chan];
                }
            }

            fDSP2->compute(count, fDSP2Inputs, outputs);
        }
};

// Combine two 'compatible' DSP in a recursive way

class dsp_recursiver : public dsp_binary_combiner {

    private:

        FAUSTFLOAT** fDSP1Inputs;
        FAUSTFLOAT** fDSP1Outputs;

        FAUSTFLOAT** fDSP2Inputs;
        FAUSTFLOAT** fDSP2Outputs;

    public:

        dsp_recursiver(dsp* dsp1, dsp* dsp2,
                       Layout layout = Layout::kTabGroup,
                       const std::string& label = "Recursiver")
        :dsp_binary_combiner(dsp1, dsp2, 1, layout, label)
        {
            fDSP1Inputs = allocateChannels(fDSP1->getNumInputs());
            fDSP1Outputs = allocateChannels(fDSP1->getNumOutputs());
            fDSP2Inputs = allocateChannels(fDSP2->getNumInputs());
            fDSP2Outputs = allocateChannels(fDSP2->getNumOutputs());
        }

        virtual ~dsp_recursiver()
        {
            deleteChannels(fDSP1Inputs, fDSP1->getNumInputs());
            deleteChannels(fDSP1Outputs, fDSP1->getNumOutputs());
            deleteChannels(fDSP2Inputs, fDSP2->getNumInputs());
            deleteChannels(fDSP2Outputs, fDSP2->getNumOutputs());
        }

        virtual int getNumInputs() { return fDSP1->getNumInputs() - fDSP2->getNumOutputs(); }
        virtual int getNumOutputs() { return fDSP1->getNumOutputs(); }

        virtual void buildUserInterface(UI* ui_interface)
        {
            buildUserInterfaceAux(ui_interface);
        }

        virtual dsp* clone()
        {
            return new dsp_recursiver(fDSP1->clone(), fDSP2->clone(), fLayout, fLabel);
        }

        virtual void compute(int count, FAUSTFLOAT** inputs, FAUSTFLOAT** outputs)
        {
            for (int frame = 0; (frame < count); frame++) {

                for (int chan = 0; chan < fDSP2->getNumOutputs(); chan++) {
                    fDSP1Inputs[chan][0] = fDSP2Outputs[chan][0];
                }

                for (int chan = 0; chan < fDSP1->getNumInputs() - fDSP2->getNumOutputs(); chan++) {
                    fDSP1Inputs[chan + fDSP2->getNumOutputs()][0] = inputs[chan][frame];
                }

                fDSP1->compute(1, fDSP1Inputs, fDSP1Outputs);

                for (int chan = 0; chan < fDSP1->getNumOutputs(); chan++) {
                    outputs[chan][frame] = fDSP1Outputs[chan][0];
                }

                for (int chan = 0; chan < fDSP2->getNumInputs(); chan++) {
                    fDSP2Inputs[chan][0] = fDSP1Outputs[chan][0];
                }

                fDSP2->compute(1, fDSP2Inputs, fDSP2Outputs);
            }
        }

        virtual void compute(double date_usec, int count, FAUSTFLOAT** inputs, FAUSTFLOAT** outputs) { compute(count, inputs, outputs); }

};

/*
 Crossfade between two DSP.
 When fCrossfade = 1, the first DSP only is computed, when fCrossfade = 0,
 the second DSP only is computed, otherwise both DSPs are computed and mixed.
*/

class dsp_crossfader: public dsp_binary_combiner {

    private:
    
        FAUSTFLOAT fCrossfade;
        FAUSTFLOAT** fDSPOutputs1;
        FAUSTFLOAT** fDSPOutputs2;
    
    public:
    
        dsp_crossfader(dsp* dsp1, dsp* dsp2,
                       Layout layout = Layout::kTabGroup,
                       const std::string& label = "Crossfade")
        :dsp_binary_combiner(dsp1, dsp2, 4096, layout, label),fCrossfade(FAUSTFLOAT(0.5))
        {
            fDSPOutputs1 = allocateChannels(fDSP1->getNumOutputs());
            fDSPOutputs2 = allocateChannels(fDSP1->getNumOutputs());
        }
    
        virtual ~dsp_crossfader()
        {
            deleteChannels(fDSPOutputs1, fDSP1->getNumInputs());
            deleteChannels(fDSPOutputs2, fDSP1->getNumOutputs());
        }
    
        virtual int getNumInputs() { return fDSP1->getNumInputs(); }
        virtual int getNumOutputs() { return fDSP1->getNumOutputs(); }

        void buildUserInterface(UI* ui_interface)
        {
            switch (fLayout) {
                case kHorizontalGroup:
                    ui_interface->openHorizontalBox(fLabel.c_str());
                    ui_interface->addHorizontalSlider("Crossfade", &fCrossfade, FAUSTFLOAT(0.5), FAUSTFLOAT(0), FAUSTFLOAT(1), FAUSTFLOAT(0.01));
                    fDSP1->buildUserInterface(ui_interface);
                    fDSP2->buildUserInterface(ui_interface);
                    ui_interface->closeBox();
                    break;
                case kVerticalGroup:
                    ui_interface->openVerticalBox(fLabel.c_str());
                    ui_interface->addHorizontalSlider("Crossfade", &fCrossfade, FAUSTFLOAT(0.5), FAUSTFLOAT(0), FAUSTFLOAT(1), FAUSTFLOAT(0.01));
                    fDSP1->buildUserInterface(ui_interface);
                    fDSP2->buildUserInterface(ui_interface);
                    ui_interface->closeBox();
                    break;
                case kTabGroup:
                    ui_interface->openTabBox(fLabel.c_str());
                    ui_interface->openVerticalBox("Crossfade");
                    ui_interface->addHorizontalSlider("Crossfade", &fCrossfade, FAUSTFLOAT(0.5), FAUSTFLOAT(0), FAUSTFLOAT(1), FAUSTFLOAT(0.01));
                    ui_interface->closeBox();
                    ui_interface->openVerticalBox("DSP1");
                    fDSP1->buildUserInterface(ui_interface);
                    ui_interface->closeBox();
                    ui_interface->openVerticalBox("DSP2");
                    fDSP2->buildUserInterface(ui_interface);
                    ui_interface->closeBox();
                    ui_interface->closeBox();
                    break;
            }
        }
    
        virtual dsp* clone()
        {
            return new dsp_crossfader(fDSP1->clone(), fDSP2->clone(), fLayout, fLabel);
        }
    
        virtual void compute(int count, FAUSTFLOAT** inputs, FAUSTFLOAT** outputs)
        {
            if (fCrossfade == FAUSTFLOAT(1)) {
                fDSP1->compute(count, inputs, outputs);
            } else if (fCrossfade == FAUSTFLOAT(0)) {
                fDSP2->compute(count, inputs, outputs);
            } else {
                // Compute each effect
                fDSP1->compute(count, inputs, fDSPOutputs1);
                fDSP2->compute(count, inputs, fDSPOutputs2);
                // Mix between the two effects
                FAUSTFLOAT gain1 = fCrossfade;
                FAUSTFLOAT gain2 = FAUSTFLOAT(1) - gain1;
                for (int frame = 0; (frame < count); frame++) {
                    for (int chan = 0; chan < fDSP1->getNumOutputs(); chan++) {
                        outputs[chan][frame] = fDSPOutputs1[chan][frame] * gain1 + fDSPOutputs2[chan][frame] * gain2;
                    }
                }
            }
        }
    
        virtual void compute(double date_usec, int count, FAUSTFLOAT** inputs, FAUSTFLOAT** outputs) { compute(count, inputs, outputs); }
};

#ifndef __dsp_algebra_api__
#define __dsp_algebra_api__

// DSP algebra API
/*
 Each operation takes two DSP and a optional Layout and Label parameters, returns the combined DSPs, or null if failure with an error message.
 */

static dsp* createDSPSequencer(dsp* dsp1, dsp* dsp2,
                               std::string& error,
                               Layout layout = Layout::kTabGroup,
                               const std::string& label = "Sequencer")
{
    if (dsp1->getNumOutputs() != dsp2->getNumInputs()) {
        std::stringstream error_aux;
        error_aux << "Connection error in dsp_sequencer : the number of outputs ("
                  << dsp1->getNumOutputs() << ") of A "
                  << "must be equal to the number of inputs (" << dsp2->getNumInputs() << ") of B" << std::endl;
        error = error_aux.str();
        return nullptr;
    } else {
        return new dsp_sequencer(dsp1, dsp2, 4096, layout, label);
    }
}

static dsp* createDSPParallelizer(dsp* dsp1, dsp* dsp2,
                                  std::string& error,
                                  Layout layout = Layout::kTabGroup,
                                  const std::string& label = "Parallelizer")
{
    return new dsp_parallelizer(dsp1, dsp2, 4096, layout, label);
}

static dsp* createDSPSplitter(dsp* dsp1, dsp* dsp2, std::string& error, Layout layout = Layout::kTabGroup, const std::string& label = "Splitter")
{
    if (dsp1->getNumOutputs() == 0) {
        error = "Connection error in dsp_splitter : the first expression has no outputs\n";
        return nullptr;
    } else if (dsp2->getNumInputs() == 0) {
        error = "Connection error in dsp_splitter : the second expression has no inputs\n";
        return nullptr;
    } else if (dsp2->getNumInputs() % dsp1->getNumOutputs() != 0) {
        std::stringstream error_aux;
        error_aux << "Connection error in dsp_splitter : the number of outputs (" << dsp1->getNumOutputs()
                  << ") of the first expression should be a divisor of the number of inputs ("
                  << dsp2->getNumInputs()
                  << ") of the second expression" << std::endl;
        error = error_aux.str();
        return nullptr;
    } else if (dsp2->getNumInputs() == dsp1->getNumOutputs()) {
        return new dsp_sequencer(dsp1, dsp2, 4096, layout, label);
    } else {
        return new dsp_splitter(dsp1, dsp2, 4096, layout, label);
    }
}

static dsp* createDSPMerger(dsp* dsp1, dsp* dsp2,
                            std::string& error,
                            Layout layout = Layout::kTabGroup,
                            const std::string& label = "Merger")
{
    if (dsp1->getNumOutputs() == 0) {
        error = "Connection error in dsp_merger : the first expression has no outputs\n";
        return nullptr;
    } else if (dsp2->getNumInputs() == 0) {
        error = "Connection error in dsp_merger : the second expression has no inputs\n";
        return nullptr;
    } else if (dsp1->getNumOutputs() % dsp2->getNumInputs() != 0) {
        std::stringstream error_aux;
        error_aux << "Connection error in dsp_merger : the number of outputs (" << dsp1->getNumOutputs()
                  << ") of the first expression should be a multiple of the number of inputs ("
                  << dsp2->getNumInputs()
                  << ") of the second expression" << std::endl;
        error = error_aux.str();
        return nullptr;
    } else if (dsp2->getNumInputs() == dsp1->getNumOutputs()) {
        return new dsp_sequencer(dsp1, dsp2, 4096, layout, label);
    } else {
        return new dsp_merger(dsp1, dsp2, 4096, layout, label);
    }
}

static dsp* createDSPRecursiver(dsp* dsp1, dsp* dsp2,
                                std::string& error,
                                Layout layout = Layout::kTabGroup,
                                const std::string& label = "Recursiver")
{
    if ((dsp2->getNumInputs() > dsp1->getNumOutputs()) || (dsp2->getNumOutputs() > dsp1->getNumInputs())) {
        std::stringstream error_aux;
        error_aux << "Connection error in : dsp_recursiver" << std::endl;
        if (dsp2->getNumInputs() > dsp1->getNumOutputs()) {
            error_aux << "The number of outputs " << dsp1->getNumOutputs()
                      << " of the first expression should be greater or equal to the number of inputs ("
                      << dsp2->getNumInputs()
                      << ") of the second expression" << std::endl;
        }
        if (dsp2->getNumOutputs() > dsp1->getNumInputs()) {
            error_aux << "The number of inputs " << dsp1->getNumInputs()
                      << " of the first expression should be greater or equal to the number of outputs ("
                      << dsp2->getNumOutputs()
                      << ") of the second expression" << std::endl;
        }
        error = error_aux.str();
        return nullptr;
    } else {
        return new dsp_recursiver(dsp1, dsp2, layout, label);
    }
}

static dsp* createDSPCrossfader(dsp* dsp1, dsp* dsp2,
                                 std::string& error,
                                 Layout layout = Layout::kTabGroup,
                                 const std::string& label = "Crossfade")
{
    if (dsp1->getNumInputs() != dsp2->getNumInputs()) {
        std::stringstream error_aux;
        error_aux << "Connection error in dsp_crossfader : the number of inputs ("
        << dsp1->getNumInputs() << ") of A "
        << "must be equal to the number of inputs (" << dsp2->getNumInputs() << ") of B" << std::endl;
        error = error_aux.str();
        return nullptr;
    } else if (dsp1->getNumOutputs() != dsp2->getNumOutputs()) {
        std::stringstream error_aux;
        error_aux << "Connection error in dsp_crossfader : the number of outputs ("
        << dsp1->getNumOutputs() << ") of A "
        << "must be equal to the number of outputs (" << dsp2->getNumOutputs() << ") of B" << std::endl;
        error = error_aux.str();
        return nullptr;
    } else {
        return new dsp_crossfader(dsp1, dsp2, layout, label);
    }
}

#endif

#endif
/************************** END dsp-combiner.h **************************/
