Function nstd_sys::alloc::nstd_alloc_reallocate

#[no_mangle]
pub unsafe extern "C" fn nstd_alloc_reallocate(
    ptr: &mut NSTDAnyMut,
    size: NSTDUInt,
    new_size: NSTDUInt
) -> NSTDAllocError

Available on crate feature nstd_alloc only.

Reallocates a block of memory previously allocated by nstd_alloc_allocate[_zeroed].

If everything goes right, the pointer will point to the new memory location and 0 will be returned. If this is not the case and allocation fails, the pointer will remain untouched and a value of nonzero is returned.

Parameters:

• NSTDAnyMut *ptr - A pointer to the allocated memory.

• NSTDUInt size - The number of bytes currently allocated.

• NSTDUInt new_size - The number of bytes to reallocate.

Returns

NSTDAllocError errc - The allocation operation error code.

Safety

• Behavior is undefined if new_size is zero.

• Behavior is undefined if ptr is not a value returned by nstd_alloc_allocate[_zeroed].

• size must be the same value that was used to allocate the memory buffer.

Example

use nstd_sys::alloc::{
    nstd_alloc_allocate_zeroed, nstd_alloc_deallocate, nstd_alloc_reallocate,
    NSTDAllocError::NSTD_ALLOC_ERROR_NONE,
};

const SIZE: usize = core::mem::size_of::<[u64; 64]>();

unsafe {
    let mut mem = nstd_alloc_allocate_zeroed(SIZE);
    assert!(!mem.is_null());
    assert!(*mem.cast::<[u64; 64]>() == [0u64; 64]);

    assert!(nstd_alloc_reallocate(&mut mem, SIZE, SIZE / 2) == NSTD_ALLOC_ERROR_NONE);
    assert!(*mem.cast::<[u64; 32]>() == [0u64; 32]);

    nstd_alloc_deallocate(&mut mem, SIZE);
}