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mem - [mainnet]

Module with methods for safe memory manipulation.

Functions

swap

Swap contents of two passed mutable references.

Move prevents from having two mutable references to the same value, so left and right references are always distinct.

public(friend) fun swap<T>(left: &mut T, right: &mut T)
Implementation
native friend fun swap<T>(left: &mut T, right: &mut T);

replace

Replace the value reference points to with the given new value, and return the value it had before.

public(friend) fun replace<T>(ref: &mut T, new: T): T
Implementation
friend fun replace<T>(ref: &mut T, new: T): T {
swap(ref, &mut new);
new
}

Specification

swap

public(friend) fun swap<T>(left: &mut T, right: &mut T)
pragma opaque;
aborts_if false;
ensures right == old(left);
ensures left == old(right);

replace

public(friend) fun replace<T>(ref: &mut T, new: T): T
pragma opaque;
aborts_if false;
ensures result == old(ref);
ensures ref == new;