Wrong file data could give a large value for the number of vector elements
resulting in very large memory allocations.
Limit the allowed data range to UINT16_MAX (65535) elements
which hopefully should be sufficient for all use cases.
Changing the data type of the related member variables from int to
uint32_t allowed removing several type casts.
Signed-off-by: Stefan Weil <sw@weilnetz.de>
