rawvec.rs

pub struct RawVec<T> {
    mem: *mut T,
    cap: usize,
}

impl<T> RawVec<T> {
    pub fn with_capacity(cap: usize) -> RawVec<T> {
        let mut vec = Vec::<T>::with_capacity(cap);
        let ptr = vec.as_mut_ptr();
        mem::forget(vec);
        RawVec {
            mem: ptr,
            cap: cap,
        }
    }

    pub fn cap(&self) -> usize {
        self.cap
    }

    pub fn ptr(&self) -> *mut T {
        self.mem
    }

    pub fn reserve(&mut self, used_cap: usize, extra_cap: usize) {
        let mut vec = unsafe { Vec::<T>::from_raw_parts(self.mem, used_cap, self.cap) };
        vec.reserve(extra_cap);
        self.cap = vec.capacity();
        self.mem = vec.as_mut_ptr();
        mem::forget(vec);
    }
}


impl<T> Drop for RawVec<T> {
    fn drop(&mut self) {
        unsafe {
            Vec::from_raw_parts(self.mem, 0, self.cap);
        }
    }
}