Datasets:
File size: 1,960 Bytes
c62beea | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 | use vstd::prelude::*;
fn main() {}
verus!{
proof fn f1_lemma_vec_push<T>(vec: Seq<T>, i: T, l: usize)
requires
l == vec.len(),
ensures
forall|k: int| 0 <= k < vec.len() ==> #[trigger] vec[k] == vec.push(i)[k],
vec.push(i).index(l as int) == i,
{
}
fn f1_contains(str: &[u8], key: u8) -> (result: bool)
{
let mut i = 0;
while i < str.len()
{
if (str[i] == key) {
return true;
}
i += 1;
}
false
}
fn f1_remove_chars(str1: &[u8], str2: &[u8]) -> (result: Vec<u8>)
{
let mut output_str = Vec::new();
let mut index: usize = 0;
while index < str1.len()
{
if (!f1_contains(str2, str1[index])) {
output_str.push(str1[index]);
}
index += 1;
}
output_str
}
fn f2_contains_z(text: &[u8]) -> (result: bool)
{
let mut index = 0;
while index < text.len()
{
if text[index] == 90 || text[index] == 122 {
return true;
}
index += 1;
}
false
}
spec fn step1(__hp0: Seq<u8>, __hp1: Seq<u8>, outp: Seq<u8>) -> bool {
(forall|i: int|
0 <= i < outp.len() ==> (__hp0.contains(#[trigger] outp[i]) && !__hp1.contains(
#[trigger] outp[i],
)))
&& (forall|i: int|
0 <= i < __hp0.len() ==> (__hp1.contains(#[trigger] __hp0[i]) || outp.contains(
#[trigger] __hp0[i],
)))
}
spec fn step2(inp: Seq<u8>, outp: bool) -> bool {
(outp == (exists|i: int| 0 <= i < inp.len() && (inp[i] == 90 || inp[i] == 122)))
}
fn chain_driver(str1: &[u8], str2: &[u8]) -> (r_final: bool)
ensures
exists|v1: Seq<u8>| #[trigger] step1(str1@, str2@, v1) && step2(v1, r_final),
{
let x1 = f1_remove_chars(str1, str2);
let x2 = f2_contains_z(x1.as_slice());
proof {
assert(step1(str1@, str2@, x1@));
assert(step2(x1@, x2));
}
x2
}
} // verus!
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