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|
//@ [coq] aeneas-args=-use-fuel
//@ [fstar] aeneas-args=-decreases-clauses -template-clauses
//@ [fstar] aeneas-args=-split-files
//@ [coq,fstar] subdir=misc
use std::vec::Vec;
/// No borrows
pub fn sum(max: u32) -> u32 {
let mut i = 0;
let mut s = 0;
while i < max {
s += i;
i += 1;
}
s *= 2;
s
}
/// Same as [sum], but we use borrows in order tocreate loans inside a loop
/// iteration, and those borrows will have to be ended by the end of the
/// iteration.
pub fn sum_with_mut_borrows(max: u32) -> u32 {
let mut i = 0;
let mut s = 0;
while i < max {
let ms = &mut s;
*ms += i;
let mi = &mut i;
*mi += 1;
}
s *= 2;
s
}
/// Similar to [sum_with_mut_borrows].
pub fn sum_with_shared_borrows(max: u32) -> u32 {
let mut i = 0;
let mut s = 0;
while i < max {
i += 1;
// We changed the order compared to [sum_with_mut_borrows]:
// we want to have a shared borrow surviving until the end
// of the iteration.
let mi = &i;
s += *mi;
}
s *= 2;
s
}
pub fn sum_array<const N: usize>(a: [u32; N]) -> u32 {
let mut i = 0;
let mut s = 0;
while i < N {
s += a[i];
i += 1;
}
s
}
/// This case is interesting, because the fixed point for the loop doesn't
/// introduce new abstractions.
pub fn clear(v: &mut Vec<u32>) {
let mut i = 0;
while i < v.len() {
v[i] = 0;
i += 1;
}
}
pub enum List<T> {
Cons(T, Box<List<T>>),
Nil,
}
/// The parameter `x` is a borrow on purpose
pub fn list_mem(x: &u32, mut ls: &List<u32>) -> bool {
while let List::Cons(y, tl) = ls {
if *y == *x {
return true;
} else {
ls = tl;
}
}
false
}
/// Same as [list_nth_mut] but with a loop
pub fn list_nth_mut_loop<T>(mut ls: &mut List<T>, mut i: u32) -> &mut T {
while let List::Cons(x, tl) = ls {
if i == 0 {
return x;
} else {
ls = tl;
i -= 1;
}
}
panic!()
}
/// Same as [list_nth_mut_loop] but with shared borrows
pub fn list_nth_shared_loop<T>(mut ls: &List<T>, mut i: u32) -> &T {
while let List::Cons(x, tl) = ls {
if i == 0 {
return x;
} else {
ls = tl;
i -= 1;
}
}
panic!()
}
pub fn get_elem_mut(slots: &mut Vec<List<usize>>, x: usize) -> &mut usize {
let mut ls = &mut slots[0];
loop {
match ls {
List::Nil => panic!(),
List::Cons(y, tl) => {
if *y == x {
return y;
} else {
ls = tl;
}
}
}
}
}
pub fn get_elem_shared(slots: &Vec<List<usize>>, x: usize) -> &usize {
let mut ls = &slots[0];
loop {
match ls {
List::Nil => panic!(),
List::Cons(y, tl) => {
if *y == x {
return y;
} else {
ls = tl;
}
}
}
}
}
pub fn id_mut<T>(ls: &mut List<T>) -> &mut List<T> {
ls
}
pub fn id_shared<T>(ls: &List<T>) -> &List<T> {
ls
}
/// Small variation of [list_nth_mut_loop]
pub fn list_nth_mut_loop_with_id<T>(ls: &mut List<T>, mut i: u32) -> &mut T {
let mut ls = id_mut(ls);
while let List::Cons(x, tl) = ls {
if i == 0 {
return x;
} else {
ls = tl;
i -= 1;
}
}
panic!()
}
/// Small variation of [list_nth_shared_loop]
pub fn list_nth_shared_loop_with_id<T>(ls: &List<T>, mut i: u32) -> &T {
let mut ls = id_shared(ls);
while let List::Cons(x, tl) = ls {
if i == 0 {
return x;
} else {
ls = tl;
i -= 1;
}
}
panic!()
}
/// Same as [list_nth_mut] but on a pair of lists.
///
/// This test checks that we manage to decompose a loop into disjoint regions.
pub fn list_nth_mut_loop_pair<'a, 'b, T>(
mut ls0: &'a mut List<T>,
mut ls1: &'b mut List<T>,
mut i: u32,
) -> (&'a mut T, &'b mut T) {
loop {
match (ls0, ls1) {
(List::Nil, _) | (_, List::Nil) => {
panic!()
}
(List::Cons(x0, tl0), List::Cons(x1, tl1)) => {
if i == 0 {
return (x0, x1);
} else {
ls0 = tl0;
ls1 = tl1;
i -= 1;
}
}
}
}
}
/// Same as [list_nth_mut_loop_pair] but with shared borrows.
pub fn list_nth_shared_loop_pair<'a, 'b, T>(
mut ls0: &'a List<T>,
mut ls1: &'b List<T>,
mut i: u32,
) -> (&'a T, &'b T) {
loop {
match (ls0, ls1) {
(List::Nil, _) | (_, List::Nil) => {
panic!()
}
(List::Cons(x0, tl0), List::Cons(x1, tl1)) => {
if i == 0 {
return (x0, x1);
} else {
ls0 = tl0;
ls1 = tl1;
i -= 1;
}
}
}
}
}
/// Same as [list_nth_mut_loop_pair] but this time we force the two loop
/// regions to be merged.
pub fn list_nth_mut_loop_pair_merge<'a, T>(
mut ls0: &'a mut List<T>,
mut ls1: &'a mut List<T>,
mut i: u32,
) -> (&'a mut T, &'a mut T) {
while let (List::Cons(x0, tl0), List::Cons(x1, tl1)) = (ls0, ls1) {
if i == 0 {
return (x0, x1);
} else {
ls0 = tl0;
ls1 = tl1;
i -= 1;
}
}
panic!()
}
/// Same as [list_nth_mut_loop_pair_merge] but with shared borrows.
pub fn list_nth_shared_loop_pair_merge<'a, T>(
mut ls0: &'a List<T>,
mut ls1: &'a List<T>,
mut i: u32,
) -> (&'a T, &'a T) {
while let (List::Cons(x0, tl0), List::Cons(x1, tl1)) = (ls0, ls1) {
if i == 0 {
return (x0, x1);
} else {
ls0 = tl0;
ls1 = tl1;
i -= 1;
}
}
panic!()
}
/// Mixing mutable and shared borrows.
pub fn list_nth_mut_shared_loop_pair<'a, 'b, T>(
mut ls0: &'a mut List<T>,
mut ls1: &'b List<T>,
mut i: u32,
) -> (&'a mut T, &'b T) {
while let (List::Cons(x0, tl0), List::Cons(x1, tl1)) = (ls0, ls1) {
if i == 0 {
return (x0, x1);
} else {
ls0 = tl0;
ls1 = tl1;
i -= 1;
}
}
panic!()
}
/// Same as [list_nth_mut_shared_loop_pair] but this time we force the two loop
/// regions to be merged.
pub fn list_nth_mut_shared_loop_pair_merge<'a, T>(
mut ls0: &'a mut List<T>,
mut ls1: &'a List<T>,
mut i: u32,
) -> (&'a mut T, &'a T) {
while let (List::Cons(x0, tl0), List::Cons(x1, tl1)) = (ls0, ls1) {
if i == 0 {
return (x0, x1);
} else {
ls0 = tl0;
ls1 = tl1;
i -= 1;
}
}
panic!()
}
/// Same as [list_nth_mut_shared_loop_pair], but we switched the positions of
/// the mutable and shared borrows.
pub fn list_nth_shared_mut_loop_pair<'a, 'b, T>(
mut ls0: &'a List<T>,
mut ls1: &'b mut List<T>,
mut i: u32,
) -> (&'a T, &'b mut T) {
while let (List::Cons(x0, tl0), List::Cons(x1, tl1)) = (ls0, ls1) {
if i == 0 {
return (x0, x1);
} else {
ls0 = tl0;
ls1 = tl1;
i -= 1;
}
}
panic!()
}
/// Same as [list_nth_mut_shared_loop_pair_merge], but we switch the positions of
/// the mutable and shared borrows.
pub fn list_nth_shared_mut_loop_pair_merge<'a, T>(
mut ls0: &'a List<T>,
mut ls1: &'a mut List<T>,
mut i: u32,
) -> (&'a T, &'a mut T) {
while let (List::Cons(x0, tl0), List::Cons(x1, tl1)) = (ls0, ls1) {
if i == 0 {
return (x0, x1);
} else {
ls0 = tl0;
ls1 = tl1;
i -= 1;
}
}
panic!()
}
// We do not use the input borrow inside the loop
#[allow(clippy::empty_loop)]
pub fn ignore_input_mut_borrow(_a: &mut u32, mut i: u32) {
while i > 0 {
i -= 1;
}
}
// We do not use the input borrow inside the loop
#[allow(clippy::empty_loop)]
pub fn incr_ignore_input_mut_borrow(a: &mut u32, mut i: u32) {
*a += 1;
while i > 0 {
i -= 1;
}
}
// We do not use the input borrow inside the loop
#[allow(clippy::empty_loop)]
pub fn ignore_input_shared_borrow(_a: &mut u32, mut i: u32) {
while i > 0 {
i -= 1;
}
}
|
