ratetransposer.cpp

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inline uint RateTransposer::transpose(SAMPLETYPE *dest, const SAMPLETYPE *src, uint numSamples)
{
    if (uChannels == 2) 
    {
        return transposeStereo(dest, src, numSamples);
    } 
    else 
    {
        return transposeMono(dest, src, numSamples);
    }
}


// Sets the number of channels, 1 = mono, 2 = stereo
void RateTransposer::setChannels(const uint numchannels)
{
    if (uChannels == numchannels) return;

    assert(numchannels == 1 || numchannels == 2);
    uChannels = numchannels;

    storeBuffer.setChannels(uChannels);
    tempBuffer.setChannels(uChannels);
    outputBuffer.setChannels(uChannels);

    // Inits the linear interpolation registers
    resetRegisters();
}


// Clears all the samples in the object
void RateTransposer::clear()
{
    outputBuffer.clear();
    storeBuffer.clear();
}


// Returns nonzero if there aren't any samples available for outputting.
uint RateTransposer::isEmpty()
{
    int res;

    res = FIFOProcessor::isEmpty();
    if (res == 0) return 0;
    return storeBuffer.isEmpty();
}


//////////////////////////////////////////////////////////////////////////////
//
// RateTransposerInteger - integer arithmetic implementation
// 

/// fixed-point interpolation routine precision
#define SCALE    65536

// Constructor
RateTransposerInteger::RateTransposerInteger() : RateTransposer()
{
    // call these here as these are virtual functions; calling these
    // from the base class constructor wouldn't execute the overloaded
    // versions (<master yoda>peculiar C++ can be</my>).
    resetRegisters();
    setRate(1.0f);
}


RateTransposerInteger::~RateTransposerInteger()
{
}


void RateTransposerInteger::resetRegisters()
{
    iSlopeCount = 0;
    sPrevSampleL = 
    sPrevSampleR = 0;
}



// Transposes the sample rate of the given samples using linear interpolation. 
// 'Mono' version of the routine. Returns the number of samples returned in 
// the "dest" buffer
uint RateTransposerInteger::transposeMono(SAMPLETYPE *dest, const SAMPLETYPE *src, uint numSamples)
{
    unsigned int i, used;
    LONG_SAMPLETYPE temp, vol1;

    used = 0;    
    i = 0;

    // Process the last sample saved from the previous call first...
    while (iSlopeCount <= SCALE) 
    {
        vol1 = (LONG_SAMPLETYPE)(SCALE - iSlopeCount);
        temp = vol1 * sPrevSampleL + iSlopeCount * src[0];
        dest[i] = (SAMPLETYPE)(temp / SCALE);
        i++;
        iSlopeCount += uRate;
    }
    // now always (iSlopeCount > SCALE)
    iSlopeCount -= SCALE;

    while (1)
    {
        while (iSlopeCount > SCALE) 
        {
            iSlopeCount -= SCALE;
            used ++;
            if (used >= numSamples - 1) goto end;
        }
        vol1 = (LONG_SAMPLETYPE)(SCALE - iSlopeCount);
        temp = src[used] * vol1 + iSlopeCount * src[used + 1];
        dest[i] = (SAMPLETYPE)(temp / SCALE);

        i++;
        iSlopeCount += uRate;
    }
end:
    // Store the last sample for the next round
    sPrevSampleL = src[numSamples - 1];

    return i;
}


// Transposes the sample rate of the given samples using linear interpolation. 
// 'Mono' version of the routine. Returns the number of samples returned in 
// the "dest" buffer
uint RateTransposerInteger::transposeStereo(SAMPLETYPE *dest, const SAMPLETYPE *src, uint numSamples)
{
    unsigned int srcPos, i, used;
    LONG_SAMPLETYPE temp, vol1;

    if (numSamples == 0) return 0;  // no samples, no work

    used = 0;    
    i = 0;

    // Process the last sample saved from the sPrevSampleLious call first...
    while (iSlopeCount <= SCALE) 
    {
        vol1 = (LONG_SAMPLETYPE)(SCALE - iSlopeCount);
        temp = vol1 * sPrevSampleL + iSlopeCount * src[0];
        dest[2 * i] = (SAMPLETYPE)(temp / SCALE);
        temp = vol1 * sPrevSampleR + iSlopeCount * src[1];
        dest[2 * i + 1] = (SAMPLETYPE)(temp / SCALE);
        i++;
        iSlopeCount += uRate;
    }
    // now always (iSlopeCount > SCALE)
    iSlopeCount -= SCALE;

    while (1)
    {
        while (iSlopeCount > SCALE) 
        {
            iSlopeCount -= SCALE;
            used ++;
            if (used >= numSamples - 1) goto end;
        }
        srcPos = 2 * used;
        vol1 = (LONG_SAMPLETYPE)(SCALE - iSlopeCount);
        temp = src[srcPos] * vol1 + iSlopeCount * src[srcPos + 2];
        dest[2 * i] = (SAMPLETYPE)(temp / SCALE);
        temp = src[srcPos + 1] * vol1 + iSlopeCount * src[srcPos + 3];
        dest[2 * i + 1] = (SAMPLETYPE)(temp / SCALE);

        i++;
        iSlopeCount += uRate;
    }
end:
    // Store the last sample for the next round
    sPrevSampleL = src[2 * numSamples - 2];
    sPrevSampleR = src[2 * numSamples - 1];

    return i;
}


// Sets new target uRate. Normal uRate = 1.0, smaller values represent slower 
// uRate, larger faster uRates.
void RateTransposerInteger::setRate(float newRate)
{
    uRate = (int)(newRate * SCALE + 0.5f);
    RateTransposer::setRate(newRate);
}


//////////////////////////////////////////////////////////////////////////////
//
// RateTransposerFloat - floating point arithmetic implementation
// 
//////////////////////////////////////////////////////////////////////////////

// Constructor
RateTransposerFloat::RateTransposerFloat() : RateTransposer()
{
    // call these here as these are virtual functions; calling these
    // from the base class constructor wouldn't execute the overloaded
    // versions (<master yoda>peculiar C++ can be</my>).
    resetRegisters();
    setRate(1.0f);
}


RateTransposerFloat::~RateTransposerFloat()
{
}


void RateTransposerFloat::resetRegisters()
{
    fSlopeCount = 0;
    sPrevSampleL = 
    sPrevSampleR = 0;
}



// Transposes the sample rate of the given samples using linear interpolation. 
// 'Mono' version of the routine. Returns the number of samples returned in 
// the "dest" buffer
uint RateTransposerFloat::transposeMono(SAMPLETYPE *dest, const SAMPLETYPE *src, uint numSamples)
{
    unsigned int i, used;

    used = 0;    
    i = 0;

    // Process the last sample saved from the previous call first...
    while (fSlopeCount <= 1.0f) 
    {
        dest[i] = (SAMPLETYPE)((1.0f - fSlopeCount) * sPrevSampleL + fSlopeCount * src[0]);
        i++;
        fSlopeCount += fRate;
    }
    fSlopeCount -= 1.0f;

    while (1)
    {
        while (fSlopeCount > 1.0f) 
        {
            fSlopeCount -= 1.0f;
            used ++;
            if (used >= numSamples - 1) goto end;
        }
        dest[i] = (SAMPLETYPE)((1.0f - fSlopeCount) * src[used] + fSlopeCount * src[used + 1]);
        i++;
        fSlopeCount += fRate;
    }
end:
    // Store the last sample for the next round
    sPrevSampleL = src[numSamples - 1];

    return i;
}


// Transposes the sample rate of the given samples using linear interpolation. 
// 'Mono' version of the routine. Returns the number of samples returned in 
// the "dest" buffer
uint RateTransposerFloat::transposeStereo(SAMPLETYPE *dest, const SAMPLETYPE *src, uint numSamples)
{
    unsigned int srcPos, i, used;

    if (numSamples == 0) return 0;  // no samples, no work

    used = 0;    
    i = 0;

    // Process the last sample saved from the sPrevSampleLious call first...
    while (fSlopeCount <= 1.0f) 
    {
        dest[2 * i] = (SAMPLETYPE)((1.0f - fSlopeCount) * sPrevSampleL + fSlopeCount * src[0]);
        dest[2 * i + 1] = (SAMPLETYPE)((1.0f - fSlopeCount) * sPrevSampleR + fSlopeCount * src[1]);
        i++;
        fSlopeCount += fRate;
    }
    // now always (iSlopeCount > 1.0f)
    fSlopeCount -= 1.0f;

    while (1)
    {
        while (fSlopeCount > 1.0f) 
        {
            fSlopeCount -= 1.0f;
            used ++;
            if (used >= numSamples - 1) goto end;
        }
        srcPos = 2 * used;

        dest[2 * i] = (SAMPLETYPE)((1.0f - fSlopeCount) * src[srcPos] 
            + fSlopeCount * src[srcPos + 2]);
        dest[2 * i + 1] = (SAMPLETYPE)((1.0f - fSlopeCount) * src[srcPos + 1] 
            + fSlopeCount * src[srcPos + 3]);

        i++;
        fSlopeCount += fRate;
    }
end:
    // Store the last sample for the next round
    sPrevSampleL = src[2 * numSamples - 2];
    sPrevSampleR = src[2 * numSamples - 1];

    return i;
}