Method Apply

libraries/lib-math/Dither.cpp:216–326

// stride number of samples.

void Dither::Apply(enum DitherType ditherType,
                   constSamplePtr source, sampleFormat sourceFormat,
                   samplePtr dest, sampleFormat destFormat,
                   unsigned int len,
                   unsigned int sourceStride /* = 1 */,
                   unsigned int destStride /* = 1 */)
{
    unsigned int i;

    // This code is not designed for 16-bit or 64-bit machine
    wxASSERT(sizeof(int) == 4);
    wxASSERT(sizeof(short) == 2);

    // Check parameters
    wxASSERT(source);
    wxASSERT(dest);
    wxASSERT(len >= 0);
    wxASSERT(sourceStride > 0);
    wxASSERT(destStride > 0);

    if (len == 0)
        return; // nothing to do

    if (destFormat == sourceFormat)
    {
        // No need to dither, because source and destination
        // format are the same. Just copy samples.
        if (destStride == 1 && sourceStride == 1)
            memcpy(dest, source, len * SAMPLE_SIZE(destFormat));
        else
        {
            if (sourceFormat == floatSample)
            {
                auto d = (float*)dest;
                auto s = (const float*)source;

                for (i = 0; i < len; i++, d += destStride, s += sourceStride)
                    *d = *s;
            } else
            if (sourceFormat == int24Sample)
            {
                auto d = (int*)dest;
                auto s = (const int*)source;

                for (i = 0; i < len; i++, d += destStride, s += sourceStride)
                    *d = *s;
            } else
            if (sourceFormat == int16Sample)
            {
                auto d = (short*)dest;
                auto s = (const short*)source;

                for (i = 0; i < len; i++, d += destStride, s += sourceStride)
                    *d = *s;
            } else {
                wxASSERT(false); // source format unknown
            }
        }