private void findColumns(Cursor c, String[] from) {
        if (c != null) {
            int i;
            int count = from.length;
            if (mFrom == null || mFrom.length != count) {
                mFrom = new int[count];
            }
            for (i = 0; i < count; i++) {
                mFrom[i] = c.getColumnIndexOrThrow(from[i]);
            }
        } else {
            mFrom = null;
        }
    }
Create a map from an array of strings to an array of column-id integers in cursor c.
If c is null, the array will be discarded.

@param c the cursor to find the columns from
@param from the Strings naming the columns of interest
third_party/DragSortListView/src/com/mobeta/android/dslv/SimpleDragSortCursorAdapter.java