level_10/45.rs

use vstd::prelude::*;
fn main() {}
verus!{



spec fn f1_is_lower_case(c: u8) -> bool {
    c >= 97 && c <= 122
}

spec fn f1_shift_minus_32_spec(c: u8) -> u8 {
    (c - 32) as u8
}

fn f1_to_uppercase(str1: &[u8]) -> (result: Vec<u8>)
{
    let mut upper_case: Vec<u8> = Vec::with_capacity(str1.len());
    let mut index = 0;
    while index < str1.len()
    {
        if (str1[index] >= 97 && str1[index] <= 122) {
            upper_case.push((str1[index] - 32) as u8);
        } else {
            upper_case.push(str1[index]);
        }
        index += 1;
    }
    upper_case
}





spec fn f2_is_upper_case(c: u8) -> bool {
    c >= 65 && c <= 90
}

spec fn f2_shift32_spec(c: u8) -> u8 {
    (c + 32) as u8
}

spec fn f2_is_lower_case(c: u8) -> bool {
    c >= 97 && c <= 122
}

spec fn f2_shift_minus_32_spec(c: u8) -> u8 {
    (c - 32) as u8
}

spec fn f2_to_toggle_case_spec(s: u8) -> u8 {
    if f2_is_lower_case(s) {
        f2_shift_minus_32_spec(s)
    } else if f2_is_upper_case(s) {
        f2_shift32_spec(s)
    } else {
        s
    }
}

fn f2_to_toggle_case(str1: &[u8]) -> (toggle_case: Vec<u8>)
{
    let mut toggle_case = Vec::with_capacity(str1.len());

    let mut index = 0;
    while index < str1.len()
    {
        if (str1[index] >= 97 && str1[index] <= 122) {
            toggle_case.push((str1[index] - 32) as u8);
        } else if (str1[index] >= 65 && str1[index] <= 90) {
            toggle_case.push((str1[index] + 32) as u8);
        } else {
            toggle_case.push(str1[index]);
        }
        index += 1;

    }
    toggle_case
}





fn f3_replace_blanks_with_chars(str1: &[u8], ch: u8) -> (result: Vec<u8>)
{
    let mut out_str: Vec<u8> = Vec::with_capacity(str1.len());
    let mut index = 0;
    while index < str1.len()
    {
        if (str1[index] == 32) {  // 32 is ASCII Space as u8
            out_str.push(ch);
        } else {
            out_str.push(str1[index]);
        }
        index += 1;
    }
    out_str
}





// ASCII --> space=32, comma=44 , dot=46 , colon=58
spec fn f4_is_space_comma_dot_spec(c: u8) -> bool {
    (c == 32) || (c == 44) || (c == 46)
}

fn f4_replace_with_colon(str1: &[u8]) -> (result: Vec<u8>)
{
    let mut result: Vec<u8> = Vec::with_capacity(str1.len());
    let mut index = 0;
    while index < str1.len()
    {
        if ((str1[index] == 32) || (str1[index] == 44) || (str1[index] == 46)) {
            result.push(58);  //ASCII -> colon=58
        } else {
            result.push(str1[index]);
        }
        index += 1;
    }
    result
}





fn f5_replace_chars(str1: &[u8], old_char: u8, new_char: u8) -> (result: Vec<u8>)
{
    let mut result_str = Vec::with_capacity(str1.len());
    let mut index = 0;
    while index < str1.len()
    {
        if str1[index] == old_char {
            result_str.push(new_char);
        } else {
            result_str.push(str1[index]);
        }
        index += 1;
    }
    result_str
}





// ASCII --> space=32, comma=44 , dot=46 , colon=58
spec fn f6_is_space_comma_dot_spec(c: u8) -> bool {
    (c == 32) || (c == 44) || (c == 46)
}

fn f6_replace_with_colon(str1: &[u8]) -> (result: Vec<u8>)
{
    let mut result: Vec<u8> = Vec::with_capacity(str1.len());
    let mut index = 0;
    while index < str1.len()
    {
        if ((str1[index] == 32) || (str1[index] == 44) || (str1[index] == 46)) {
            result.push(58);  //ASCII -> colon=58
        } else {
            result.push(str1[index]);
        }
        index += 1;
    }
    result
}





spec fn f7_is_upper_case(c: u8) -> bool {
    c >= 65 && c <= 90
}

spec fn f7_shift32_spec(c: u8) -> u8 {
    (c + 32) as u8
}

spec fn f7_is_lower_case(c: u8) -> bool {
    c >= 97 && c <= 122
}

spec fn f7_shift_minus_32_spec(c: u8) -> u8 {
    (c - 32) as u8
}

spec fn f7_to_toggle_case_spec(s: u8) -> u8 {
    if f7_is_lower_case(s) {
        f7_shift_minus_32_spec(s)
    } else if f7_is_upper_case(s) {
        f7_shift32_spec(s)
    } else {
        s
    }
}

fn f7_to_toggle_case(str1: &[u8]) -> (toggle_case: Vec<u8>)
{
    let mut toggle_case = Vec::with_capacity(str1.len());

    let mut index = 0;
    while index < str1.len()
    {
        if (str1[index] >= 97 && str1[index] <= 122) {
            toggle_case.push((str1[index] - 32) as u8);
        } else if (str1[index] >= 65 && str1[index] <= 90) {
            toggle_case.push((str1[index] + 32) as u8);
        } else {
            toggle_case.push(str1[index]);
        }
        index += 1;

    }
    toggle_case
}





spec fn f8_is_lower_case(c: u8) -> bool {
    c >= 97 && c <= 122
}

spec fn f8_shift_minus_32_spec(c: u8) -> u8 {
    (c - 32) as u8
}

fn f8_to_uppercase(str1: &[u8]) -> (result: Vec<u8>)
{
    let mut upper_case: Vec<u8> = Vec::with_capacity(str1.len());
    let mut index = 0;
    while index < str1.len()
    {
        if (str1[index] >= 97 && str1[index] <= 122) {
            upper_case.push((str1[index] - 32) as u8);
        } else {
            upper_case.push(str1[index]);
        }
        index += 1;
    }
    upper_case
}





fn f9_replace_chars(str1: &[u8], old_char: u8, new_char: u8) -> (result: Vec<u8>)
{
    let mut result_str = Vec::with_capacity(str1.len());
    let mut index = 0;
    while index < str1.len()
    {
        if str1[index] == old_char {
            result_str.push(new_char);
        } else {
            result_str.push(str1[index]);
        }
        index += 1;
    }
    result_str
}





spec fn f10_is_digit(c: u8) -> bool {
    (c >= 48 && c <= 57)
}

spec fn f10_count_digits_recursively(seq: Seq<u8>) -> int
    decreases seq.len(),
{
    if seq.len() == 0 {
        0
    } else {
        f10_count_digits_recursively(seq.drop_last()) + if f10_is_digit(seq.last()) {
            1 as int
        } else {
            0 as int
        }
    }
}

fn f10_count_digits(text: &[u8]) -> (count: usize)
{
    let mut count = 0;
    let mut index = 0;

    while index < text.len()
    {
        if (text[index] >= 48 && text[index] <= 57) {
            count += 1;
        }
        index += 1;
    }
    count
}



spec fn step1(__hp0: Seq<u8>, outp: Seq<u8>) -> bool {
    (__hp0.len() == outp.len())
    && (forall|i: int|
            0 <= i < __hp0.len() ==> (outp[i] == (if f1_is_lower_case(#[trigger] __hp0[i]) {
                f1_shift_minus_32_spec(__hp0[i])
            } else {
                __hp0[i]
            })))
}

spec fn step2(inp: Seq<u8>, outp: Seq<u8>) -> bool {
    (inp.len() == outp.len())
    && (forall|i: int|
            0 <= i < inp.len() ==> outp[i] == f2_to_toggle_case_spec(#[trigger] inp[i]))
}

spec fn step3(inp: Seq<u8>, p3_ch: u8, outp: Seq<u8>) -> bool {
    (inp.len() == outp.len())
    && (forall|i: int|
            0 <= i < inp.len() ==> outp[i] == (if inp[i] == 32 {
                p3_ch
            } else {
                inp[i]
            }))
}

spec fn step4(inp: Seq<u8>, outp: Seq<u8>) -> bool {
    (inp.len() == outp.len())
    && (forall|k: int|
            0 <= k < outp.len() ==> #[trigger] outp[k] == (if f4_is_space_comma_dot_spec(inp[k]) {
                58  //ASCII -> colon=58

            } else {
                inp[k]
            }))
}

spec fn step5(inp: Seq<u8>, p5_old_char: u8, p5_new_char: u8, outp: Seq<u8>) -> bool {
    (inp.len() == outp.len())
    && (forall|i: int|
            0 <= i < inp.len() ==> outp[i] == (if inp[i] == p5_old_char {
                p5_new_char
            } else {
                inp[i]
            }))
}

spec fn step6(inp: Seq<u8>, outp: Seq<u8>) -> bool {
    (inp.len() == outp.len())
    && (forall|k: int|
            0 <= k < outp.len() ==> #[trigger] outp[k] == (if f6_is_space_comma_dot_spec(inp[k]) {
                58  //ASCII -> colon=58

            } else {
                inp[k]
            }))
}

spec fn step7(inp: Seq<u8>, outp: Seq<u8>) -> bool {
    (inp.len() == outp.len())
    && (forall|i: int|
            0 <= i < inp.len() ==> outp[i] == f7_to_toggle_case_spec(#[trigger] inp[i]))
}

spec fn step8(inp: Seq<u8>, outp: Seq<u8>) -> bool {
    (inp.len() == outp.len())
    && (forall|i: int|
            0 <= i < inp.len() ==> (outp[i] == (if f8_is_lower_case(#[trigger] inp[i]) {
                f8_shift_minus_32_spec(inp[i])
            } else {
                inp[i]
            })))
}

spec fn step9(inp: Seq<u8>, p9_old_char: u8, p9_new_char: u8, outp: Seq<u8>) -> bool {
    (inp.len() == outp.len())
    && (forall|i: int|
            0 <= i < inp.len() ==> outp[i] == (if inp[i] == p9_old_char {
                p9_new_char
            } else {
                inp[i]
            }))
}

spec fn step10(inp: Seq<u8>, outp: usize) -> bool {
    (0 <= outp <= inp.len())
    && (f10_count_digits_recursively(inp) == outp)
}

fn chain_driver(str1: &[u8], p3_ch: u8, p5_old_char: u8, p5_new_char: u8, p9_old_char: u8, p9_new_char: u8) -> (r_final: usize)
    ensures
        exists|v1: Seq<u8>, v2: Seq<u8>, v3: Seq<u8>, v4: Seq<u8>, v5: Seq<u8>, v6: Seq<u8>, v7: Seq<u8>, v8: Seq<u8>, v9: Seq<u8>| #[trigger] step1(str1@, v1) && #[trigger] step2(v1, v2) && #[trigger] step3(v2, p3_ch, v3) && #[trigger] step4(v3, v4) && #[trigger] step5(v4, p5_old_char, p5_new_char, v5) && #[trigger] step6(v5, v6) && #[trigger] step7(v6, v7) && #[trigger] step8(v7, v8) && #[trigger] step9(v8, p9_old_char, p9_new_char, v9) && step10(v9, r_final),
{
    let x1 = f1_to_uppercase(str1);
    let x2 = f2_to_toggle_case(x1.as_slice());
    let x3 = f3_replace_blanks_with_chars(x2.as_slice(), p3_ch);
    let x4 = f4_replace_with_colon(x3.as_slice());
    let x5 = f5_replace_chars(x4.as_slice(), p5_old_char, p5_new_char);
    let x6 = f6_replace_with_colon(x5.as_slice());
    let x7 = f7_to_toggle_case(x6.as_slice());
    let x8 = f8_to_uppercase(x7.as_slice());
    let x9 = f9_replace_chars(x8.as_slice(), p9_old_char, p9_new_char);
    let x10 = f10_count_digits(x9.as_slice());
    proof {
        assert(step1(str1@, x1@));
        assert(step2(x1@, x2@));
        assert(step3(x2@, p3_ch, x3@));
        assert(step4(x3@, x4@));
        assert(step5(x4@, p5_old_char, p5_new_char, x5@));
        assert(step6(x5@, x6@));
        assert(step7(x6@, x7@));
        assert(step8(x7@, x8@));
        assert(step9(x8@, p9_old_char, p9_new_char, x9@));
        assert(step10(x9@, x10));
    }
    x10
}

} // verus!