[gdal-dev] C++ template functions with raster bands

[Ari Jolma]

I want to write template functions like this:

template<typename cell_type>
void map(GDALRasterBand *b, mapper<cell_type> *mapper) {
...

This function would map the cell values of a band to new ones using some 
logic that is coded within the mapper object (and the logic depends on 
the cell_type).

I would like to catch errors which are due to mismatch between the band 
data type and the template cell_type. So far I've discovered this:

     band_wrapper band = band_initialize(b);
     if (band.info.size_of_data_type != sizeof(cell_type))
         goto fail_because_of_data_type_mismatch;

but it is not bullet proof since data types can have an equal size but 
be different. The band_initialize contains a switch statement, which 
sets the info element of the band wrapper.

Are there other ways to solve this problem? I could build long switch 
statements but it is not very appealing. And it gets messy when there is 
more than one band.

Ari