Function perform_wavelet_transform

src/data_handler/data_handler.cpp:492–545

https://github.com/rafat/wavelib/wiki/DWT-Example-Code

// https://github.com/rafat/wavelib/wiki/DWT-Example-Code
int perform_wavelet_transform (double *data, int data_len, int wavelet, int decomposition_level,
    int extension, double *output_data, int *decomposition_lengths)
{
    std::string wavelet_str = get_wavelet_name (wavelet);
    std::string extension_str = get_extension_type (extension);
    if ((data == NULL) || (data_len <= 0) || (wavelet_str.empty ()) || (output_data == NULL) ||
        (extension_str.empty ()) || (decomposition_lengths == NULL) || (decomposition_level <= 0))
    {
        data_logger->error ("Please review arguments.");
        return (int)BrainFlowExitCodes::INVALID_ARGUMENTS_ERROR;
    }

    wave_object obj = NULL;
    wt_object wt = NULL;

    try
    {
        obj = wave_init (wavelet_str.c_str ());
        wt = wt_init (obj, "dwt", data_len, decomposition_level);
        setDWTExtension (wt, extension_str.c_str ());
        setWTConv (wt, "direct");
        dwt (wt, data);
        for (int i = 0; i < wt->outlength; i++)
        {
            output_data[i] = wt->output[i];
        }
        for (int i = 0; i < decomposition_level + 1; i++)
        {
            decomposition_lengths[i] = wt->length[i];
        }
        wave_free (obj);
        obj = NULL;
        wt_free (wt);
        wt = NULL;
    }
    catch (const std::exception &e)
    {
        if (obj)
        {
            wave_free (obj);
            obj = NULL;
        }
        if (wt)
        {
            wt_free (wt);
            wt = NULL;
        }
        // more likely exception here occured because input buffer is to small to perform wavelet
        // transform
        data_logger->error ("Exception in wavelib: {}", e.what ());
        return (int)BrainFlowExitCodes::INVALID_BUFFER_SIZE_ERROR;
    }
    return (int)BrainFlowExitCodes::STATUS_OK;
}

// inside wavelib inverse transform uses internal state from direct transform, dirty hack to restore
// it here