Function sp_conv_init

src/core/_SoundPipe_FFT.cpp:343–429

}

int sp_conv_init(sp_data * sp, sp_conv * p, sp_ftbl * ft, SPFLOAT iPartLen)
{
    int i, j, k, n, nBytes, skipSamples;
    SPFLOAT FFTscale;

    p->iTotLen = ft->size;
    p->iSkipSamples = 0;
    p->iPartLen = iPartLen;

    p->nChannels = 1;
    /* partition length */
    p->partSize = (int) lrintf(p->iPartLen);
    if (p->partSize < 4 || (p->partSize & (p->partSize - 1)) != 0)
    {
        fprintf(stderr, "conv: invalid partition size.\n");
        return SP_NOT_OK;
    }

    sp_fft_init(&p->fft, (int) log2(p->partSize << 1));
    n = (int) ft->size / p->nChannels;
    skipSamples = (int) lrintf(p->iSkipSamples);
    n -= skipSamples;

    if (lrintf(p->iTotLen) > 0 && n > lrintf(p->iTotLen))
    {
        n = (int) lrintf(p->iTotLen);
    }

    if (n <= 0)
    {
        fprintf(stderr, "uh oh.\n");
        return SP_NOT_OK;
    }

    p->nPartitions = (n + (p->partSize - 1)) / p->partSize;
    /* calculate the amount of aux space to allocate (in bytes) */
    nBytes = buf_bytes_alloc(p->nChannels, p->partSize, p->nPartitions);
    sp_auxdata_alloc(&p->auxData, nBytes);
    /* if skipping samples: check for possible truncation of IR */
    /* initialise buffer pointers */
    set_buf_pointers(p, p->nChannels, p->partSize, p->nPartitions);
    /* clear ring buffer to zero */
    n = (p->partSize << 1) * p->nPartitions;
    memset(p->ringBuf, 0, n * sizeof(SPFLOAT));
    p->cnt = 0;
    p->rbCnt = 0;
    FFTscale = 1.0;
    for (j = 0; j < p->nChannels; j++)
    {
        /* table read position */
        i = (skipSamples * p->nChannels) + j;
        /* IR write position */
        n = (p->partSize << 1) * (p->nPartitions - 1);
        do
        {
            for (k = 0; k < p->partSize; k++)
            {
                if (i >= 0 && i < (int) ft->size)