Hi, trying to implement ring buffer. I need to add offset of 1 * size_of::<T>() to get next free address where i can write value. Here is push implementation
pub fn push(&mut self, val: T) -> Result<(), Error> {
if size_of::<T>() == 0 {
panic!("No zero sized type");
}
println!("{}, {}", self.len, self.cap);
if self.len < self.cap {
unsafe {
self.head.as_ptr().write(val);
println!("wrote val {}", val);
println!("ptr * cap {:#?}", self.ptr.add(self.cap));
println!("head {:#?}", self.head);
if self.head.as_ptr().add(1) > self.ptr.as_ptr().add(self.cap) {
self.head = self.ptr;
} else {
self.head = self.head.add(1);
}
};
self.len += 1;
} else {
return Err(Error {
err_message: "Ringbuffer is full",
});
}
Ok(())
}
It should work on paper. At least looks good to me, but it prints this:
0, 4
wrote val 22
ptr * cap 0x00007ca8e4000b90
head 0x00007ca8e4000b70
1, 4
wrote val 44
ptr * cap 0x00007ca8e4000b90
head 0x00007ca8e4000b78
2, 4
wrote val 77
ptr * cap 0x00007ca8e4000b90
head 0x00007ca8e4000b80
3, 4
wrote val 99
ptr * cap 0x00007ca8e4000b90
head 0x00007ca8e4000b88
4, 4
Why do addresses go like 8 + 2 + 8 + 2 etc? How is that even possible?