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

/*
    bqresample

    A small library wrapping various audio sample rate conversion
    implementations in C++.

    Copyright 2007-2021 Particular Programs Ltd.

    Permission is hereby granted, free of charge, to any person
    obtaining a copy of this software and associated documentation
    files (the "Software"), to deal in the Software without
    restriction, including without limitation the rights to use, copy,
    modify, merge, publish, distribute, sublicense, and/or sell copies
    of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be
    included in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
    ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
    CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
    WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

    Except as contained in this notice, the names of Chris Cannam and
    Particular Programs Ltd shall not be used in advertising or
    otherwise to promote the sale, use or other dealings in this
    Software without prior written authorization.
*/

#include "bqresample/Resampler.h"

#include <cstdlib>
#include <cmath>

#include <iostream>
#include <algorithm>

#include <bqvec/Allocators.h>
#include <bqvec/VectorOps.h>

#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 HAVE_LIBRESAMPLE
#include <libresample.h>
#endif

#ifdef USE_SPEEX
#include "../speex/speex_resampler.h"
#endif

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

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

using namespace std;

namespace breakfastquay {

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 (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
    }

    return (int)data.output_frames_gen;
}

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

#endif /* HAVE_LIBSAMPLERATE */

#ifdef HAVE_LIBRESAMPLE

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

    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);

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

    void reset();

protected:
    void *m_src;
    float *m_iin;
    float *m_iout;
    double m_lastRatio;
    int m_channels;
    int m_iinsize;
    int m_ioutsize;
    int m_debugLevel;
};

D_Resample::D_Resample(Resampler::Quality quality,
                       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_debugLevel(debugLevel)
{
    if (m_debugLevel > 0) {
        cerr << "Resampler::Resampler: using implementation: libresample"
                  << endl;
    }

    float min_factor = 0.125f;
    float max_factor = 8.0f;

    m_src = resample_open(quality == Resampler::Best ? 1 : 0, min_factor, max_factor);

    if (!m_src) {
        cerr << "Resampler::Resampler: failed to create libresample resampler: " 
                  << endl;
        throw Resampler::ImplementationError; //!!! of course, need to catch this!
    }

    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_Resample::~D_Resample()
{
    resample_close(m_src);
    if (m_iinsize > 0) {
        deallocate(m_iin);
    }
    if (m_ioutsize > 0) {
        deallocate(m_iout);
    }
}

int
D_Resample::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)
{
    float *data_in;
    float *data_out;
    int input_frames, output_frames, end_of_input, source_used;
    float src_ratio;

    int outcount = (int)lrint(ceil(incount * ratio));

    if (m_channels == 1) {
        data_in = const_cast<float *>(*in); //!!!???
        data_out = *out;
    } else {
        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);
        data_in = m_iin;
        data_out = m_iout;
    }

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

    int output_frames_gen = resample_process(m_src,
                                             src_ratio,
                                             data_in,
                                             input_frames,
                                             end_of_input,
                                             &source_used,
                                             data_out,
                                             output_frames);

    if (output_frames_gen < 0) {
        cerr << "Resampler::process: libresample error: "
                  << endl;
        throw Resampler::ImplementationError; //!!! of course, need to catch this!
    }

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

    return output_frames_gen;
}

int
D_Resample::resampleInterleaved(float *const BQ_R__ out,
                                int outcount,
                                const float *const BQ_R__ in,
                                int incount,
                                double ratio,
                                bool final)
{
    int input_frames, output_frames, end_of_input, source_used;
    float src_ratio;

    int outcount = (int)lrint(ceil(incount * ratio));

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

    int output_frames_gen = resample_process(m_src,
                                             src_ratio,
                                             const_cast<float *>(in),
                                             input_frames,
                                             end_of_input,
                                             &source_used,
                                             out,
                                             output_frames);

    if (output_frames_gen < 0) {
        cerr << "Resampler::process: libresample error: "
                  << endl;
        throw Resampler::ImplementationError; //!!! of course, need to catch this!
    }

    return output_frames_gen;
}

void
D_Resample::reset()
{
}

#endif /* HAVE_LIBRESAMPLE */

#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 */

#ifdef USE_SPEEX
    
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.

    unsigned int big = 272408136U; 
    unsigned int denom = 1, num = 1;

    if (ratio < 1.f) {
        denom = big;
        double dnum = double(big) * double(ratio);
        num = (unsigned int)dnum;
    } else if (ratio > 1.f) {
        num = big;
        double ddenom = double(big) / double(ratio);
        denom = (unsigned int)ddenom;
    }
    
    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" 
             << 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)));
        if (actual < expected) {
            unsigned int final_out = expected - actual;
            unsigned int final_in = (unsigned int)(round(final_out / ratio));
            if (final_in > 0) {
                float *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);
                deallocate(pad);
                uoutcount += final_out;
                if (err) {
                    cerr << "Resampler::Resampler: Speex resampler returned error "
                         << err << endl;
#ifndef NO_EXCEPTIONS
                    throw Resampler::ImplementationError;
#endif
                }
            }
        }
    }
}

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_LIBRESAMPLE
        m_method = 3;
#endif
#ifdef USE_BQRESAMPLER
        m_method = 4;
#endif
#ifdef HAVE_LIBSAMPLERATE
        m_method = 1;
#endif
        break;

    case Resampler::FastestTolerable:
#ifdef HAVE_IPP
        m_method = 0;
#endif
#ifdef HAVE_LIBRESAMPLE
        m_method = 3;
#endif
#ifdef USE_SPEEX
        m_method = 2;
#endif
#ifdef USE_BQRESAMPLER
        m_method = 4;
#endif
#ifdef HAVE_LIBSAMPLERATE
        m_method = 1;
#endif
        break;

    case Resampler::Fastest:
#ifdef HAVE_IPP
        m_method = 0;
#endif
#ifdef HAVE_LIBRESAMPLE
        m_method = 3;
#endif
#ifdef USE_SPEEX
        m_method = 2;
#endif
#ifdef USE_BQRESAMPLER
        m_method = 4;
#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:
#ifdef USE_SPEEX
        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 HAVE_LIBRESAMPLE
        d = new Resamplers::D_Resample
            (params.quality, params.ratioChange,
             channels,
             params.initialSampleRate, params.maxBufferSize, params.debugLevel);
#else
        cerr << "Resampler::Resampler: No implementation available!" << endl;
        abort();
#endif
        break;

    case 4:
#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();
}

}
