Struct CVec 

#[repr(C)]
pub struct CVec {
    pub ptr: *mut c_void,
    pub len: usize,
    pub cap: usize,
}

CVec is a C compatible struct that stores an opaque pointer to a block of memory, its length and the capacity of the vector it was allocated from.

Safety

Changing the values here may lead to undefined behavior when the memory is dropped.

Fields

ptr: *mut c_void

Opaque pointer to block of memory storing elements to access the elements cast it to the underlying type.

len: usize

The number of elements in the block.

cap: usize

The capacity of vector from which it was allocated. Used when deallocating the memory

Implementations

impl CVec

pub fn empty() -> Self

Returns an empty CVec.

This is primarily useful for constructing a sentinel value that represents the absence of data when crossing the FFI boundary.

Uses a dangling pointer (like Vec::new()) rather than null to satisfy Vec::from_raw_parts preconditions when the CVec is later dropped.

pub unsafe fn into_vec<T>(self) -> Vec<T>

Reconstructs and consumes the Rust vector represented by this value.

Safety

For non-zero capacity, ptr, len, and cap must describe exactly one live allocation originally created by Vec<T> with len initialized elements. The allocation must not be accessed or reconstructed again after this call.

Panics

Panics if len > cap, len != 0 when cap == 0, or a non-empty allocation has a null pointer.

pub unsafe fn as_slice<T>(&self) -> &[T]

Borrows the initialized elements represented by this value.

Safety

For non-zero length, ptr must point to len initialized, properly aligned T values that remain valid and are not mutated for the returned slice’s lifetime.

Panics

Panics if len > cap or a non-empty slice has a null pointer.

Trait Implementations

impl Debug for CVec

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for CVec

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> From<Vec<T>> for CVec

Consumes and leaks the Vec, returning a mutable pointer to the contents as a CVec. The memory has been leaked and now exists for the lifetime of the program unless dropped manually. Note: drop the memory by reconstructing the vec using from_raw_parts method as shown in the test below.

fn from(data: Vec<T>) -> Self

Converts to this type from the input type.