#define BYTES_TO_READ 2048

size_t bytes_read = 0;
size_t i ;

unsigned char buffer [BYTES_TO_READ] ;

while ((bytes_read = fread (buffer,1,BYTES_TO_READ,fromfile)) > 0) {
    for (i = 0; i < bytes_read; ++i) {
        apdoroti_chara (buffer [i]) ;
    }
}