Accessing grdecl grid cells without allocating memory for the whole file?

I tried libecl to access grdecl files from C/C++.

From grdecl files, i need to extract the cell corners coordinates, to find wether a cell is present or not, and the values for some properties for each cell. But i am having issues of excessive memory consumption. Trying to open a 4GB grdecl file is crashing my computer (16GB RAM) with too big allocs (grid ix about 500x500x500).

What i do is
- Load the various properties using ecl_kw_fscanf_alloc_grdecl_dynamic__(). This stores values in binary format, but uncompresses the '5*-9999' elements, so the buffer for the COORD, ACTNUM, & ZCORN is still 4GB in memory
- call ecl_grid_alloc_GRDECL_kw() to create an ecl_grid_type. This crashes the computer for the big file.

As i understand, this will always allocate a buffer of nx*ny*nz cells. And the structure for a cell is about 250 bytes each. For a 500x500x500 grid, this only already needs 31GB or RAM.

I don't even need to have all cells in memory at a given time. I could just go with "cell iterator", that from raw ecl_kw_type buffers, gives me access to the corner coordinates for each cell sucesssive cell, so i can store them in an other format.
Is there a way to access the cells geometry information and properties values without the need to have this much data in memory?