/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Rubber Band Library
    An audio time-stretching and pitch-shifting library.
    Copyright 2007-2023 Particular Programs Ltd.

    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation; either version 2 of the
    License, or (at your option) any later version.  See the file
    COPYING included with this distribution for more information.

    Alternatively, if you have a valid commercial licence for the
    Rubber Band Library obtained by agreement with the copyright
    holders, you may redistribute and/or modify it under the terms
    described in that licence.

    If you wish to distribute code using the Rubber Band Library
    under terms other than those of the GNU General Public License,
    you must obtain a valid commercial licence before doing so.
*/

#include "Resampler.h"

#include "Allocators.h"
#include "VectorOps.h"

#include "mathmisc.h"

#include <cstdlib>
#include <cmath>

#include <iostream>
#include <algorithm>

#ifdef HAVE_IPP
#include <ippversion.h>
#if (IPP_VERSION_MAJOR < 7)
#error Unsupported IPP version, must be >= 7
#else
#include <ipps.h>
#endif
#endif

#ifdef HAVE_SAMPLERATE
#define HAVE_LIBSAMPLERATE 1
#endif

#ifdef HAVE_LIBSAMPLERATE
#include <samplerate.h>
#endif

#ifdef USE_SPEEX
#include "../ext/speex/speex_resampler.h"
#else
#ifdef HAVE_LIBSPEEXDSP
#include <speex/speex_resampler.h>
#endif
#endif

#ifdef USE_BQRESAMPLER
#include "BQResampler.h"
#endif

#ifndef HAVE_IPP
#ifndef HAVE_LIBSAMPLERATE
#ifndef HAVE_LIBSPEEXDSP
#ifndef USE_SPEEX
#ifndef USE_BQRESAMPLER
#error No resampler implementation selected!
#endif
#endif
#endif
#endif
#endif

#define BQ_R__ R__

using std::cerr;
using std::endl;

namespace RubberBand {

class Resampler::Impl
{
public:
    virtual ~Impl() { }
    
    virtual int resample(float *const BQ_R__ *const BQ_R__ out,
                         int outcount,
                         const float *const BQ_R__ *const BQ_R__ in, 
                         int incount,
                         double ratio,
                         bool final) = 0;
    
    virtual int resampleInterleaved(float *const BQ_R__ out,
                                    int outcount,
                                    const float *const BQ_R__ in, 
                                    int incount,
                                    double ratio,
                                    bool final) = 0;

    virtual int getChannelCount() const = 0;
    virtual double getEffectiveRatio(double ratio) const = 0;

    virtual void reset() = 0;
};

namespace Resamplers {

#ifdef HAVE_IPP

class D_IPP : public Resampler::Impl
{
public:
    D_IPP(Resampler::Quality quality, Resampler::RatioChange,
          int channels, double initialSampleRate,
          int maxBufferSize, int debugLevel);
    ~D_IPP();

    int resample(float *const BQ_R__ *const BQ_R__ out,
                 int outcount,
                 const float *const BQ_R__ *const BQ_R__ in,
                 int incount,
                 double ratio,
                 bool final);

    int resampleInterleaved(float *const BQ_R__ out,
                            int outcount,
                            const float *const BQ_R__ in,
                            int incount,
                            double ratio,
                            bool final = false);

    int getChannelCount() const { return m_channels; }
    double getEffectiveRatio(double ratio) const { return ratio; }

    void reset();

protected:
    // to m_outbuf
    int doResample(int outcount, double ratio, bool final);
    
    IppsResamplingPolyphase_32f **m_state;
    double m_initialSampleRate;
    float **m_inbuf;
    size_t m_inbufsz;
    float **m_outbuf;
    size_t m_outbufsz;
    int m_bufsize;
    int m_channels;
    int m_window;
    float m_factor;
    int m_history;
    int *m_lastread;
    double *m_time;
    int m_debugLevel;
    
    void setBufSize(int);
};

D_IPP::D_IPP(Resampler::Quality /* quality */,
             Resampler::RatioChange /* ratioChange */,
             int channels, double initialSampleRate,
             int maxBufferSize, int debugLevel) :
    m_state(0),
    m_initialSampleRate(initialSampleRate),
    m_channels(channels),
    m_debugLevel(debugLevel)
{
    if (m_debugLevel > 0) {
        cerr << "Resampler::Resampler: using implementation: IPP" << endl;
    }

    m_window = 32;
    int nStep = 64;
    IppHintAlgorithm hint = ippAlgHintFast;
    m_factor = 8; // initial upper bound on m_ratio, may be amended later

    // This is largely based on the IPP docs and examples. Adapted
    // from the docs:
    //
    //    m_time defines the time value for which the first output
    //    sample is calculated. The input vector with indices less
    //    than m_time [whose initial value is m_history below]
    //    contains the history data of filters.
    //
    //    The history length is [(1/2) window * max(1, 1/factor) ]+1
    //    where window is the size of the ideal lowpass filter
    //    window. The input vector must contain the same number of
    //    elements with indices greater than m_time + length for the
    //    right filter wing for the last element.
    
    m_history = int(m_window * 0.5 * max(1.0, 1.0 / m_factor)) + 1;

    m_state = new IppsResamplingPolyphase_32f *[m_channels];

    m_lastread = new int[m_channels];
    m_time = new double[m_channels];

    m_inbufsz = 0;
    m_outbufsz = 0;
    m_inbuf = 0;
    m_outbuf = 0;
    m_bufsize = 0;
    
    setBufSize(maxBufferSize + m_history);

    if (m_debugLevel > 1) {
        cerr << "bufsize = " << m_bufsize << ", window = " << m_window << ", nStep = " << nStep << ", history = " << m_history << endl;
    }

    int specSize = 0;
    ippsResamplePolyphaseGetSize_32f(float(m_window),
                                     nStep,
                                     &specSize,
                                     hint);
    if (specSize == 0) {
#ifndef NO_EXCEPTIONS
        throw Resampler::ImplementationError;
#else        
        abort();
#endif
    }

    for (int c = 0; c < m_channels; ++c) {
        m_state[c] = (IppsResamplingPolyphase_32f *)ippsMalloc_8u(specSize);
        ippsResamplePolyphaseInit_32f(float(m_window),
                                      nStep,
                                      0.95f,
                                      9.0f,
                                      m_state[c],
                                      hint);
        
        m_lastread[c] = m_history;
        m_time[c] = m_history;
    }

    if (m_debugLevel > 1) {
        cerr << "Resampler init done" << endl;
    }
}

D_IPP::~D_IPP()
{
    for (int c = 0; c < m_channels; ++c) {
        ippsFree(m_state[c]);
    }

    deallocate_channels(m_inbuf, m_channels);
    deallocate_channels(m_outbuf, m_channels);

    delete[] m_lastread;
    delete[] m_time;
    delete[] m_state;
}

void
D_IPP::setBufSize(int sz)
{
    if (m_debugLevel > 1) {
        if (m_bufsize > 0) {
            cerr << "resize bufsize " << m_bufsize << " -> ";
        } else {
            cerr << "initialise bufsize to ";
        }
    }

    m_bufsize = sz;

    if (m_debugLevel > 1) {
        cerr << m_bufsize << endl;
    }

    int n1 = m_bufsize + m_history + 2;

    if (m_debugLevel > 1) {
        cerr << "inbuf allocating " << m_bufsize << " + " << m_history << " + 2 = " << n1 << endl;
    }

    int n2 = (int)lrintf(ceil((m_bufsize - m_history) * m_factor + 2));

    if (m_debugLevel > 1) {
        cerr << "outbuf allocating (" << m_bufsize << " - " << m_history << ") * " << m_factor << " + 2 = " << n2 << endl;
    }

    m_inbuf = reallocate_and_zero_extend_channels
        (m_inbuf, m_channels, m_inbufsz, m_channels, n1);

    m_outbuf = reallocate_and_zero_extend_channels
        (m_outbuf, m_channels, m_outbufsz, m_channels, n2);
            
    m_inbufsz = n1;
    m_outbufsz = n2;
}

int
D_IPP::resample(float *const BQ_R__ *const BQ_R__ out,
                int outspace,
                const float *const BQ_R__ *const BQ_R__ in,
                int incount,
                double ratio,
                bool final)
{
    if (ratio > m_factor) {
        m_factor = ratio;
        m_history = int(m_window * 0.5 * max(1.0, 1.0 / m_factor)) + 1;
    }

    if (m_debugLevel > 2) {
        cerr << "incount = " << incount << ", ratio = " << ratio << ", est space = " << lrintf(ceil(incount * ratio)) << ", outspace = " << outspace << ", final = " << final << endl;
    }

    for (int c = 0; c < m_channels; ++c) {
        if (m_lastread[c] + incount + m_history > m_bufsize) {
            setBufSize(m_lastread[c] + incount + m_history);
        }
    }

    for (int c = 0; c < m_channels; ++c) {
        for (int i = 0; i < incount; ++i) {
            m_inbuf[c][m_lastread[c] + i] = in[c][i];
        }
        m_lastread[c] += incount;
    }

    if (m_debugLevel > 2) {
        cerr << "lastread advanced to " << m_lastread[0] << endl;
    }

    int got = doResample(outspace, ratio, final);

    for (int c = 0; c < m_channels; ++c) {
        v_copy(out[c], m_outbuf[c], got);
    }

    return got;
}

int
D_IPP::resampleInterleaved(float *const BQ_R__ out,
                           int outspace,
                           const float *const BQ_R__ in,
                           int incount,
                           double ratio,
                           bool final)
{
    if (ratio > m_factor) {
        m_factor = ratio;
        m_history = int(m_window * 0.5 * max(1.0, 1.0 / m_factor)) + 1;
    }

    if (m_debugLevel > 2) {
        cerr << "incount = " << incount << ", ratio = " << ratio << ", est space = " << lrintf(ceil(incount * ratio)) << ", outspace = " << outspace << ", final = " << final << endl;
    }

    for (int c = 0; c < m_channels; ++c) {
        if (m_lastread[c] + incount + m_history > m_bufsize) {
            setBufSize(m_lastread[c] + incount + m_history);
        }
    }

    for (int c = 0; c < m_channels; ++c) {
        for (int i = 0; i < incount; ++i) {
            m_inbuf[c][m_lastread[c] + i] = in[i * m_channels + c];
        }
        m_lastread[c] += incount;
    }

    if (m_debugLevel > 2) {
        cerr << "lastread advanced to " << m_lastread[0] << " after injection of "
             << incount << " samples" << endl;
    }

    int got = doResample(outspace, ratio, final);

    v_interleave(out, m_outbuf, m_channels, got);

    return got;
}

int
D_IPP::doResample(int outspace, double ratio, bool final)
{
    int outcount = 0;
    
    for (int c = 0; c < m_channels; ++c) {

        int n = m_lastread[c] - m_history - int(m_time[c]);

        if (c == 0 && m_debugLevel > 2) {
            cerr << "at start, lastread = " << m_lastread[c] << ", history = "
                 << m_history << ", time = " << m_time[c] << ", therefore n = "
                 << n << endl;
        }

        if (n <= 0) {
            if (c == 0 && m_debugLevel > 1) {
                cerr << "not enough input samples to do anything" << endl;
            }
            continue;
        }
        
        if (c == 0 && m_debugLevel > 2) {
            cerr << "before resample call, time = " << m_time[c] << endl;
        }

        // We're committed to not overrunning outspace, so we need to
        // offer the resampler only enough samples to ensure it won't

        int limit = int(floor(outspace / ratio));
        if (n > limit) {
            if (c == 0 && m_debugLevel > 1) {
                cerr << "trimming input samples from " << n << " to " << limit
                     << " to avoid overrunning " << outspace << " at output"
                     << endl;
            }
            n = limit;
        }
        
        ippsResamplePolyphase_32f(m_inbuf[c],
                                  n,
                                  m_outbuf[c],
                                  ratio,
                                  1.0f,
                                  &m_time[c],
                                  &outcount,
                                  m_state[c]);

        int t = int(floor(m_time[c]));
        
        int moveFrom = t - m_history;
        
        if (c == 0 && m_debugLevel > 2) {
            cerr << "converted " << n << " samples to " << outcount
                 << " (nb outbufsz = " << m_outbufsz
                 << "), time advanced to " << m_time[c] << endl;
            cerr << "rounding time to " << t << ", lastread = "
                 << m_lastread[c] << ", history = " << m_history << endl;
            cerr << "will move " << m_lastread[c] - moveFrom
                 << " unconverted samples back from index " << moveFrom
                 << " to 0" << endl;
        }

        if (moveFrom >= m_lastread[c]) {

            moveFrom = m_lastread[c];

            if (c == 0 && m_debugLevel > 2) {
                cerr << "number of samples to move is <= 0, "
                     << "not actually moving any" << endl;
            }
        } else {
        
            v_move(m_inbuf[c],
                   m_inbuf[c] + moveFrom,
                   m_lastread[c] - moveFrom);
        }

        m_lastread[c] -= moveFrom;
        m_time[c] -= moveFrom;

        if (c == 0 && m_debugLevel > 2) {
            cerr << "lastread reduced to " << m_lastread[c]
                 << ", time reduced to " << m_time[c]
                 << endl;
        }
        
        if (final && n < limit) {

            // Looks like this actually produces too many samples
            // (additionalcount is a few samples too large).

            // Also, we aren't likely to have enough space in the
            // output buffer as the caller won't have allowed for
            // all the samples we're retrieving here.

            // What to do?

            int additionalcount = 0;

            if (c == 0 && m_debugLevel > 2) {
                cerr << "final call, padding input with " << m_history
                     << " zeros (symmetrical with m_history)" << endl;
            }
            
            for (int i = 0; i < m_history; ++i) {
                m_inbuf[c][m_lastread[c] + i] = 0.f;
            }

            if (c == 0 && m_debugLevel > 2) {
                cerr << "before resample call, time = " << m_time[c] << endl;
            }

            int nAdditional = m_lastread[c] - int(m_time[c]);

            if (n + nAdditional > limit) {
                if (c == 0 && m_debugLevel > 1) {
                    cerr << "trimming final input samples from " << nAdditional
                         << " to " << (limit - n)
                         << " to avoid overrunning " << outspace << " at output"
                         << endl;
                }
                nAdditional = limit - n;
            }
            
            ippsResamplePolyphase_32f(m_inbuf[c],
                                      nAdditional,
                                      m_outbuf[c],
                                      ratio,
                                      1.0f,
                                      &m_time[c],
                                      &additionalcount,
                                      m_state[c]);
        
            if (c == 0 && m_debugLevel > 2) {
                cerr << "converted " << n << " samples to " << additionalcount
                     << ", time advanced to " << m_time[c] << endl;
                cerr << "outcount = " << outcount << ", additionalcount = " << additionalcount << ", sum " << outcount + additionalcount << endl;
            }

            if (c == 0) {
                outcount += additionalcount;
            }
        }
    }

    if (m_debugLevel > 2) {
        cerr << "returning " << outcount << " samples" << endl;
    }
    
    return outcount;
}

void
D_IPP::reset()
{
    //!!!
}

#endif /* HAVE_IPP */

#ifdef HAVE_LIBSAMPLERATE

class D_SRC : public Resampler::Impl
{
public:
    D_SRC(Resampler::Quality quality, Resampler::RatioChange ratioChange,
          int channels, double initialSampleRate,
          int maxBufferSize, int m_debugLevel);
    ~D_SRC();

    int resample(float *const BQ_R__ *const BQ_R__ out,
                 int outcount,
                 const float *const BQ_R__ *const BQ_R__ in,
                 int incount,
                 double ratio,
                 bool final);

    int resampleInterleaved(float *const BQ_R__ out,
                            int outcount,
                            const float *const BQ_R__ in,
                            int incount,
                            double ratio,
                            bool final = false);

    int getChannelCount() const { return m_channels; }
    double getEffectiveRatio(double ratio) const { return ratio; }

    void reset();

protected:
    SRC_STATE *m_src;
    float *m_iin;
    float *m_iout;
    int m_channels;
    int m_iinsize;
    int m_ioutsize;
    double m_prevRatio;
    bool m_ratioUnset;
    bool m_smoothRatios;
    int m_debugLevel;
};

D_SRC::D_SRC(Resampler::Quality quality, Resampler::RatioChange ratioChange,
             int channels, double, int maxBufferSize, int debugLevel) :
    m_src(0),
    m_iin(0),
    m_iout(0),
    m_channels(channels),
    m_iinsize(0),
    m_ioutsize(0),
    m_prevRatio(1.0),
    m_ratioUnset(true),
    m_smoothRatios(ratioChange == Resampler::SmoothRatioChange),
    m_debugLevel(debugLevel)
{
    if (m_debugLevel > 0) {
        cerr << "Resampler::Resampler: using implementation: libsamplerate"
             << endl;
    }

    if (channels < 1) {
        cerr << "Resampler::Resampler: unable to create resampler: invalid channel count " << channels << " supplied" << endl;
#ifdef NO_EXCEPTIONS
        throw Resampler::ImplementationError;
#endif
        return;
    }
    
    int err = 0;
    m_src = src_new(quality == Resampler::Best ? SRC_SINC_BEST_QUALITY :
                    quality == Resampler::Fastest ? SRC_SINC_FASTEST :
                    SRC_SINC_MEDIUM_QUALITY,
                    channels, &err);

    if (err) {
        cerr << "Resampler::Resampler: failed to create libsamplerate resampler: " 
             << src_strerror(err) << endl;
#ifndef NO_EXCEPTIONS
        throw Resampler::ImplementationError;
#endif
        return;
    } else if (!m_src) {
        cerr << "Resampler::Resampler: failed to create libsamplerate resampler, but no error reported?" << endl;
#ifndef NO_EXCEPTIONS
        throw Resampler::ImplementationError;
#endif
        return;
    }

    if (maxBufferSize > 0 && m_channels > 1) {
        m_iinsize = maxBufferSize * m_channels;
        m_ioutsize = maxBufferSize * m_channels * 2;
        m_iin = allocate<float>(m_iinsize);
        m_iout = allocate<float>(m_ioutsize);
    }

    reset();
}

D_SRC::~D_SRC()
{
    src_delete(m_src);
    deallocate(m_iin);
    deallocate(m_iout);
}

int
D_SRC::resample(float *const BQ_R__ *const BQ_R__ out,
                int outcount,
                const float *const BQ_R__ *const BQ_R__ in,
                int incount,
                double ratio,
                bool final)
{
    if (m_channels == 1) {
        return resampleInterleaved(*out, outcount, *in, incount, ratio, final);
    }

    if (incount * m_channels > m_iinsize) {
        m_iin = reallocate<float>(m_iin, m_iinsize, incount * m_channels);
        m_iinsize = incount * m_channels;
    }
    if (outcount * m_channels > m_ioutsize) {
        m_iout = reallocate<float>(m_iout, m_ioutsize, outcount * m_channels);
        m_ioutsize = outcount * m_channels;
    }
    
    v_interleave(m_iin, in, m_channels, incount);

    int n = resampleInterleaved(m_iout, outcount, m_iin, incount, ratio, final);

    v_deinterleave(out, m_iout, m_channels, n);

    return n;
}

int
D_SRC::resampleInterleaved(float *const BQ_R__ out,
                           int outcount,
                           const float *const BQ_R__ in,
                           int incount,
                           double ratio,
                           bool final)
{
    SRC_DATA data;

    // libsamplerate smooths the filter change over the duration of
    // the processing block to avoid artifacts due to sudden changes,
    // and it uses outcount to determine how long to smooth the change
    // over. This is a good thing, but it does mean (a) we should
    // never pass outcount significantly longer than the actual
    // expected output, and (b) when the ratio has just changed, we
    // should aim to supply a shortish block next
    
    if (!final && (outcount > int(ceil(incount * ratio) + 5))) {
        outcount = int(ceil(incount * ratio) + 5);
    }

    if (m_ratioUnset || !m_smoothRatios) {

        // The first time we set a ratio, we want to do it directly
        src_set_ratio(m_src, ratio);
        m_ratioUnset = false;
        m_prevRatio = ratio;

    } else if (ratio != m_prevRatio) {

        // If we are processing a block of appreciable length, turn it
        // into two recursive calls, one for the short smoothing block
        // and the other for the rest. Update m_prevRatio before doing
        // this so that the calls don't themselves recurse!
        m_prevRatio = ratio;

        int shortBlock = 200;
        if (outcount > shortBlock * 2) {
            int shortIn = int(floor(shortBlock / ratio));
            if (shortIn >= 10) {
                int shortOut =
                    resampleInterleaved(out, shortBlock,
                                        in, shortIn,
                                        ratio, false);
                int remainingOut = 0;
                if (shortOut < outcount) {
                    remainingOut =
                        resampleInterleaved(out + shortOut * m_channels,
                                            outcount - shortOut,
                                            in + shortIn * m_channels,
                                            incount - shortIn,
                                            ratio, final);
                }
                return shortOut + remainingOut;
            }
        }
    }

    data.data_in = const_cast<float *>(in);
    data.data_out = out;

    data.input_frames = incount;
    data.output_frames = outcount;
    data.src_ratio = ratio;
    data.end_of_input = (final ? 1 : 0);

    int err = src_process(m_src, &data);

    if (err) {
        cerr << "Resampler::process: libsamplerate error: "
             << src_strerror(err) << endl;
#ifndef NO_EXCEPTIONS
        throw Resampler::ImplementationError;
#endif
    }

//    cerr << "Resampler::process: final = " << final << ", incount = "
//         << incount << ", outcount = " << outcount << ", ratio = "
//         << ratio << ", gen = " << data.output_frames_gen << endl;
    
    return (int)data.output_frames_gen;
}

void
D_SRC::reset()
{
    src_reset(m_src);
    m_ratioUnset = true;
}

#endif /* HAVE_LIBSAMPLERATE */

#ifdef USE_BQRESAMPLER
    
class D_BQResampler : public Resampler::Impl
{
public:
    D_BQResampler(Resampler::Parameters params, int channels);
    ~D_BQResampler();

    int resample(float *const BQ_R__ *const BQ_R__ out,
                 int outcount,
                 const float *const BQ_R__ *const BQ_R__ in,
                 int incount,
                 double ratio,
                 bool final);

    int resampleInterleaved(float *const BQ_R__ out,
                            int outcount,
                            const float *const BQ_R__ in,
                            int incount,
                            double ratio,
                            bool final = false);

    int getChannelCount() const {
        return m_channels;
    }

    double getEffectiveRatio(double ratio) const {
        return m_resampler->getEffectiveRatio(ratio);
    }

    void reset();

protected:
    BQResampler *m_resampler;
    float *m_iin;
    float *m_iout;
    int m_channels;
    int m_iinsize;
    int m_ioutsize;
    int m_debugLevel;
};

D_BQResampler::D_BQResampler(Resampler::Parameters params, int channels) :
    m_resampler(0),
    m_iin(0),
    m_iout(0),
    m_channels(channels),
    m_iinsize(0),
    m_ioutsize(0),
    m_debugLevel(params.debugLevel)
{
    if (m_debugLevel > 0) {
        cerr << "Resampler::Resampler: using implementation: BQResampler" << endl;
    }

    BQResampler::Parameters rparams;
    switch (params.quality) {
    case Resampler::Best:
        rparams.quality = BQResampler::Best;
        break;
    case Resampler::FastestTolerable:
        rparams.quality = BQResampler::FastestTolerable;
        break;
    case Resampler::Fastest:
        rparams.quality = BQResampler::Fastest;
        break;
    }
    switch (params.dynamism) {
    case Resampler::RatioOftenChanging:
        rparams.dynamism = BQResampler::RatioOftenChanging;
        break;
    case Resampler::RatioMostlyFixed:
        rparams.dynamism = BQResampler::RatioMostlyFixed;
        break;
    }
    switch (params.ratioChange) {
    case Resampler::SmoothRatioChange:
        rparams.ratioChange = BQResampler::SmoothRatioChange;
        break;
    case Resampler::SuddenRatioChange:
        rparams.ratioChange = BQResampler::SuddenRatioChange;
        break;
    }
    rparams.referenceSampleRate = params.initialSampleRate;
    rparams.debugLevel = params.debugLevel;

    m_resampler = new BQResampler(rparams, m_channels);
    
    if (params.maxBufferSize > 0 && m_channels > 1) {
        m_iinsize = params.maxBufferSize * m_channels;
        m_ioutsize = params.maxBufferSize * m_channels * 2;
        m_iin = allocate<float>(m_iinsize);
        m_iout = allocate<float>(m_ioutsize);
    }
}

D_BQResampler::~D_BQResampler()
{
    delete m_resampler;
    deallocate(m_iin);
    deallocate(m_iout);
}

int
D_BQResampler::resample(float *const BQ_R__ *const BQ_R__ out,
                        int outcount,
                        const float *const BQ_R__ *const BQ_R__ in,
                        int incount,
                        double ratio,
                        bool final)
{
    if (m_channels == 1) {
        return resampleInterleaved(*out, outcount, *in, incount, ratio, final);
    }

    if (incount * m_channels > m_iinsize) {
        m_iin = reallocate<float>(m_iin, m_iinsize, incount * m_channels);
        m_iinsize = incount * m_channels;
    }
    if (outcount * m_channels > m_ioutsize) {
        m_iout = reallocate<float>(m_iout, m_ioutsize, outcount * m_channels);
        m_ioutsize = outcount * m_channels;
    }
    
    v_interleave(m_iin, in, m_channels, incount);
    
    int n = resampleInterleaved(m_iout, outcount, m_iin, incount, ratio, final);

    v_deinterleave(out, m_iout, m_channels, n);

    return n;
}

int
D_BQResampler::resampleInterleaved(float *const BQ_R__ out,
                                   int outcount,
                                   const float *const BQ_R__ in,
                                   int incount,
                                   double ratio,
                                   bool final)
{
    return m_resampler->resampleInterleaved(out, outcount,
                                            in, incount,
                                            ratio, final);
}

void
D_BQResampler::reset()
{
    m_resampler->reset();
}

#endif /* USE_BQRESAMPLER */

#if defined(USE_SPEEX) || defined(HAVE_LIBSPEEXDSP)
    
class D_Speex : public Resampler::Impl
{
public:
    D_Speex(Resampler::Quality quality, Resampler::RatioChange,
            int channels, double initialSampleRate,
            int maxBufferSize, int debugLevel);
    ~D_Speex();

    int resample(float *const BQ_R__ *const BQ_R__ out,
                 int outcount,
                 const float *const BQ_R__ *const BQ_R__ in,
                 int incount,
                 double ratio,
                 bool final);

    int resampleInterleaved(float *const BQ_R__ out,
                            int outcount,
                            const float *const BQ_R__ in,
                            int incount,
                            double ratio,
                            bool final = false);

    int getChannelCount() const { return m_channels; }
    double getEffectiveRatio(double ratio) const { return ratio; }

    void reset();

protected:
    SpeexResamplerState *m_resampler;
    double m_initialSampleRate;
    float *m_iin;
    float *m_iout;
    int m_channels;
    int m_iinsize;
    int m_ioutsize;
    double m_lastratio;
    bool m_initial;
    int m_debugLevel;

    void setRatio(double);
    void doResample(const float *in, unsigned int &incount,
                    float *out, unsigned int &outcount,
                    double ratio, bool final);
};

D_Speex::D_Speex(Resampler::Quality quality, Resampler::RatioChange,
                 int channels, double initialSampleRate,
                 int maxBufferSize, int debugLevel) :
    m_resampler(0),
    m_initialSampleRate(initialSampleRate),
    m_iin(0),
    m_iout(0),
    m_channels(channels),
    m_iinsize(0),
    m_ioutsize(0),
    m_lastratio(-1.0),
    m_initial(true),
    m_debugLevel(debugLevel)
{
    int q = (quality == Resampler::Best ? 10 :
             quality == Resampler::Fastest ? 0 : 4);

    if (m_debugLevel > 0) {
        cerr << "Resampler::Resampler: using implementation: Speex with q = "
             << q << endl;
    }

    int rrate = int(round(m_initialSampleRate));
    
    int err = 0;
    m_resampler = speex_resampler_init_frac(m_channels,
                                            1, 1,
                                            rrate, rrate,
                                            q,
                                            &err);
    

    if (err) {
        cerr << "Resampler::Resampler: failed to create Speex resampler" 
             << endl;
#ifndef NO_EXCEPTIONS
        throw Resampler::ImplementationError;
#endif
    }

    if (maxBufferSize > 0 && m_channels > 1) {
        m_iinsize = maxBufferSize * m_channels;
        m_ioutsize = maxBufferSize * m_channels * 2;
        m_iin = allocate<float>(m_iinsize);
        m_iout = allocate<float>(m_ioutsize);
    }
}

D_Speex::~D_Speex()
{
    speex_resampler_destroy(m_resampler);
    deallocate<float>(m_iin);
    deallocate<float>(m_iout);
}

void
D_Speex::setRatio(double ratio)
{
    // Speex wants a ratio of two unsigned integers, not a single
    // float.  Let's do that.

    int max_denom = 48000;
    if (ratio > 1.0) {
        max_denom = int(ceil(48000 / ratio));
    }

    int inum, idenom;
    pickNearestRational(ratio, max_denom, inum, idenom);

    if (inum < 0 || idenom < 0) {
        cerr << "Resampler::setRatio: Internal error: "
             << "numerator or denominator < 0 ("
             << inum << "/" << idenom << ")" << endl;
        return;
    }
    
    unsigned int num = inum, denom = idenom;
    
    if (m_debugLevel > 1) {
        cerr << "D_Speex: Desired ratio " << ratio << ", requesting ratio "
             << num << "/" << denom << " = " << float(double(num)/double(denom))
             << endl;
    }

    int fromRate = int(round(m_initialSampleRate));
    int toRate = int(round(m_initialSampleRate * ratio));
    
    int err = speex_resampler_set_rate_frac
        (m_resampler, denom, num, fromRate, toRate);

    if (err) {
        cerr << "Resampler::Resampler: failed to set rate on Speex resampler"
             << " (with ratio = " << ratio << " [ratio-1 = " << ratio - 1.0
             << "], denom = " << denom
             << ", num = " << num << ", fromRate = " << fromRate
             << ", toRate = " << toRate << ", err = " << err
             << ")" << endl;
#ifndef NO_EXCEPTIONS
        throw Resampler::ImplementationError;
#endif
    }
    
    speex_resampler_get_ratio(m_resampler, &denom, &num);
    
    if (m_debugLevel > 1) {
        cerr << "D_Speex: Desired ratio " << ratio << ", got ratio "
             << num << "/" << denom << " = " << float(double(num)/double(denom))
             << endl;
    }
    
    m_lastratio = ratio;

    if (m_initial) {
        speex_resampler_skip_zeros(m_resampler);
        m_initial = false;
    }
}

int
D_Speex::resample(float *const BQ_R__ *const BQ_R__ out,
                  int outcount,
                  const float *const BQ_R__ *const BQ_R__ in,
                  int incount,
                  double ratio,
                  bool final)
{
    if (ratio != m_lastratio) {
        setRatio(ratio);
    }

    unsigned int uincount = incount;
    unsigned int uoutcount = outcount;

    float *data_in, *data_out;

    if (m_channels == 1) {
        data_in = const_cast<float *>(*in);
        data_out = *out;
    } else {
        if (int(incount * m_channels) > m_iinsize) {
            m_iin = reallocate<float>(m_iin, m_iinsize, incount * m_channels);
            m_iinsize = incount * m_channels;
        }
        if (int(outcount * m_channels) > m_ioutsize) {
            m_iout = reallocate<float>(m_iout, m_ioutsize, outcount * m_channels);
            m_ioutsize = outcount * m_channels;
        }
        v_interleave(m_iin, in, m_channels, incount);
        data_in = m_iin;
        data_out = m_iout;
    }

    doResample(data_in, uincount, data_out, uoutcount, ratio, final);

    if (m_channels > 1) {
        v_deinterleave(out, m_iout, m_channels, uoutcount);
    }

    return uoutcount;
}

int
D_Speex::resampleInterleaved(float *const BQ_R__ out,
                             int outcount,
                             const float *const BQ_R__ in,
                             int incount,
                             double ratio,
                             bool final)
{
    if (ratio != m_lastratio) {
        setRatio(ratio);
    }

    unsigned int uincount = incount;
    unsigned int uoutcount = outcount;

    float *data_in = const_cast<float *>(in);
    float *data_out = out;

    doResample(data_in, uincount, data_out, uoutcount, ratio, final);
    
    return uoutcount;
}

void
D_Speex::doResample(const float *data_in, unsigned int &uincount,
                    float *data_out, unsigned int &uoutcount,
                    double ratio, bool final)
{
    int initial_outcount = int(uoutcount);
    
    int err = speex_resampler_process_interleaved_float
        (m_resampler,
         data_in, &uincount,
         data_out, &uoutcount);
    
    if (err) {
        cerr << "Resampler::Resampler: Speex resampler returned error "
             << err << endl;
#ifndef NO_EXCEPTIONS
        throw Resampler::ImplementationError;
#endif
    }

    if (final) {
        int actual = int(uoutcount);
        int expected = std::min(initial_outcount, int(round(uincount * ratio)));
        float *pad = nullptr;
        while (actual < expected) {
            unsigned int final_out = expected - actual;
            unsigned int final_in = (unsigned int)(round(final_out / ratio));
            if (final_in == 0) {
                break;
            } else {
                if (!pad) {
                    pad = allocate_and_zero<float>(final_in * m_channels);
                }
                err = speex_resampler_process_interleaved_float
                    (m_resampler,
                     pad, &final_in,
                     data_out + actual * m_channels, &final_out);
                actual += final_out;
                uoutcount += final_out;
                if (err) {
                    cerr << "Resampler::Resampler: Speex resampler returned error "
                         << err << endl;
                    if (pad) {
                        deallocate(pad);
                    }
#ifndef NO_EXCEPTIONS
                    throw Resampler::ImplementationError;
#endif
                }
            }
        }
        if (pad) {
            deallocate(pad);
        }
    }
}

void
D_Speex::reset()
{
    m_lastratio = -1.0; // force reset of ratio
    m_initial = true;
    speex_resampler_reset_mem(m_resampler);
}

#endif

} /* end namespace Resamplers */

Resampler::Resampler(Resampler::Parameters params, int channels)
{
    m_method = -1;

    if (params.initialSampleRate == 0) {
        params.initialSampleRate = 44100;
    }
    
    switch (params.quality) {

    case Resampler::Best:
#ifdef HAVE_IPP
        m_method = 0;
#endif
#ifdef USE_SPEEX
        m_method = 2;
#endif
#ifdef HAVE_LIBSPEEXDSP
        m_method = 2;
#endif
#ifdef USE_BQRESAMPLER
        m_method = 3;
#endif
#ifdef HAVE_LIBSAMPLERATE
        m_method = 1;
#endif
        break;

    case Resampler::FastestTolerable:
#ifdef HAVE_IPP
        m_method = 0;
#endif
#ifdef USE_SPEEX
        m_method = 2;
#endif
#ifdef HAVE_LIBSPEEXDSP
        m_method = 2;
#endif
#ifdef USE_BQRESAMPLER
        m_method = 3;
#endif
#ifdef HAVE_LIBSAMPLERATE
        m_method = 1;
#endif
        break;

    case Resampler::Fastest:
#ifdef HAVE_IPP
        m_method = 0;
#endif
#ifdef USE_SPEEX
        m_method = 2;
#endif
#ifdef HAVE_LIBSPEEXDSP
        m_method = 2;
#endif
#ifdef USE_BQRESAMPLER
        m_method = 3;
#endif
#ifdef HAVE_LIBSAMPLERATE
        m_method = 1;
#endif
        break;
    }

    if (m_method == -1) {
        cerr << "Resampler::Resampler: No implementation available!" << endl;
        abort();
    }

    switch (m_method) {
    case 0:
#ifdef HAVE_IPP
        d = new Resamplers::D_IPP
            (params.quality, params.ratioChange,
             channels,
             params.initialSampleRate, params.maxBufferSize, params.debugLevel);
#else
        cerr << "Resampler::Resampler: No implementation available!" << endl;
        abort();
#endif
        break;

    case 1:
#ifdef HAVE_LIBSAMPLERATE
        d = new Resamplers::D_SRC
            (params.quality, params.ratioChange,
             channels,
             params.initialSampleRate, params.maxBufferSize, params.debugLevel);
#else
        cerr << "Resampler::Resampler: No implementation available!" << endl;
        abort();
#endif
        break;

    case 2:
#if defined(USE_SPEEX) || defined(HAVE_LIBSPEEXDSP)
        d = new Resamplers::D_Speex
            (params.quality, params.ratioChange,
             channels,
             params.initialSampleRate, params.maxBufferSize, params.debugLevel);
#else
        cerr << "Resampler::Resampler: No implementation available!" << endl;
        abort();
#endif
        break;

    case 3:
#ifdef USE_BQRESAMPLER
        d = new Resamplers::D_BQResampler(params, channels);
#else
        cerr << "Resampler::Resampler: No implementation available!" << endl;
        abort();
#endif
        break;
    }

    if (!d) {
        cerr << "Resampler::Resampler: Internal error: No implementation selected"
             << endl;
        abort();
    }
}

Resampler::~Resampler()
{
    delete d;
}

int 
Resampler::resample(float *const BQ_R__ *const BQ_R__ out,
                    int outcount,
                    const float *const BQ_R__ *const BQ_R__ in,
                    int incount,
                    double ratio,
                    bool final)
{
    return d->resample(out, outcount, in, incount, ratio, final);
}

int 
Resampler::resampleInterleaved(float *const BQ_R__ out,
                               int outcount,
                               const float *const BQ_R__ in,
                               int incount,
                               double ratio,
                               bool final)
{
    return d->resampleInterleaved(out, outcount, in, incount, ratio, final);
}

int
Resampler::getChannelCount() const
{
    return d->getChannelCount();
}

double
Resampler::getEffectiveRatio(double ratio) const
{
    return d->getEffectiveRatio(ratio);
}

void
Resampler::reset()
{
    d->reset();
}

}
