#![no_std]
#![no_main]
#![allow(dead_code)]

#[macro_use]
extern crate klee;
use core::cmp;

static mut PLAIN: [u8; 132] = [0; 132];

static ABC: [u32; 4] = [0x9fdd9158, 0x85715808, 0xac73323a, 0];
static CODED: [u32; 132] = [
    0x015e7a47, 0x2ef84ebb, 0x177a8db4, 0x1b722ff9, 0x5dc7cff0, 0x5dc9dea6, 0x1da0c15a, 0xe4c236a2,
    0x3d16b0d0, 0x1f397842, 0xaae0d2ba, 0x11246674, 0x0845317f, 0xd5512dad, 0xb6184977, 0xd293a53e,
    0x7d9c2716, 0xd917eae6, 0xd8852384, 0x286e46f9, 0xce566029, 0xcefe7daf, 0x62d726d4, 0x0dbaeb2d,
    0x95f57c60, 0xed515141, 0x29b77d0f, 0x9f7b8d0c, 0x45a8395a, 0xfead2b72, 0x883d434c, 0xed8ddf60,
    0xe51e65e4, 0x19bf6bb1, 0xfeb505ec, 0x662aa23c, 0xf6827cf8, 0xd1dc7a5c, 0x4fa5b066, 0x7ddd25a4,
    0xa8ba8e8a, 0x72846227, 0xf8f636fb, 0x2b389a9c, 0xe4038bf6, 0x6e169877, 0xad028132, 0x84dbfe8c,
    0x243762ff, 0x59c8f80c, 0xb6e0db4b, 0xedb8cab7, 0xcd4b39f6, 0xaf263741, 0x18d9965f, 0x1ab1f037,
    0x5b458792, 0xc94d960d, 0xd45cedea, 0x2160aca3, 0x93c77766, 0x2d66e105, 0x9ff74d4f, 0x6dc22f21,
    0x6b03d689, 0x5fc48de0, 0x1138f000, 0xccb58e57, 0xf9c8e200, 0x7ab26e3c, 0xc61dcb3e, 0x6aefccb0,
    0x7a452f05, 0xa5cf0731, 0xa249383f, 0x628fe534, 0xcad81710, 0x7f616276, 0x3ce18308, 0xed4857ff,
    0xd1e5b1d1, 0xc2e84dc2, 0xaa003742, 0xaf637488, 0x831afc48, 0x287a69a0, 0x6e04546e, 0x13dffa07,
    0x3232fb10, 0xd69e2e09, 0x355d8dc7, 0xef902301, 0x9a89ac15, 0x967dc900, 0x08dc2b1c, 0x6b5be690,
    0x894b0e02, 0xe26af9af, 0xa6fd3b23, 0xfcf213e5, 0x85217608, 0x7fd3be8b, 0xa2e757fb, 0x3717a341,
    0x85ee426d, 0x394bb856, 0x12ac98c3, 0xec7d4ab5, 0x721b6989, 0x30e36360, 0xaa018403, 0x9ee61196,
    0xa8697adc, 0x51e9d65a, 0x11023594, 0xc4c4b36b, 0xda80bf7a, 0xbd5a645e, 0x18cea918, 0xa723dda8,
    0x0126c05e, 0x2962d48a, 0xd5f7d312, 0xb8947041, 0x7c1e2e9a, 0x945eeac3, 0x7110fb1c, 0xa7bc72cc,
    0xdf47dfbb, 0x09a1c6c8, 0xc2e41061, 0,
];

//# FUNCTION codgen(): UNSIGNED INTEGER;
// #  LOCAL SIGNED INTEGER   n;
// #  LOCAL UNSIGNED INTEGER x, y;
// #  BEGIN
// #    n := [count the number of 0's in word "seed"];
// #    x := [rotate "seed" left by 30 bits];
// #    y := [shift "seed" right-ARITHMETIC by 6 bits];
// #    seed := x XOR y XOR n;
// #   RETURN( seed XOR 0x464b713e );
// #  END;
// #
// # hint:  if "seed" is initialized to 0x3e944b9f,
// #        the first five calls will generate these values:
// #        0x891432f9, 0x4aa1dccc, 0xc54270fa, 0x9885155f, 0xce83d1b8, ...
// # your code is to be written farther down (see comment below).
//

fn codgen(seed: &mut u32) -> u32 {
    let mut n: i32 = 32;
    let lseed: u32 = seed.clone(); // copy value of seed
    let mut s: u32 = lseed;
    let x: u32;
    let y: u32;

    //n = [count the number of 0's in word "seed"];
    while s != 0 {
        if s & 1u32 == 1u32 {
            n -= 1;
        }
        s >>= 1; // >> is logic shift
    }

    // x := [rotate "seed" left by 30 bits];
    x = lseed << 30 | ((lseed >> 2) & ((1 << (30 + 1)) - 1));

    // y := [shift "seed" right-ARITHMETIC by 6 bits];
    y = ((lseed as i32) >> 6) as u32;

    // seed := x XOR y XOR n;
    *seed = x ^ y ^ (n as u32);

    // RETURN( seed XOR 0x464b713e );
    (*seed) ^ 0x464b713e
}

//
fn decode_org(wordarr: &[u32], bytearr: &mut [u8], seed: &mut u32) -> u32 {
    let m: u32;
    let mut r: u32;
    let x: u32;
    let y: u32;

    x = !codgen(seed);
    if wordarr[0] == 0 {
        bytearr[0] = 0;
        r = x;
    } else {
        y = decode(&wordarr[1..], &mut bytearr[1..], seed);
        m = x.wrapping_sub(y).wrapping_sub(wordarr[0]);
        bytearr[0] = (m >> 13) as u8;
        r = (-(codgen(seed) as i32)) as u32;
        r = x
            .wrapping_add(y)
            .wrapping_add(m)
            .wrapping_add(r)
            .wrapping_add(5);
    }
    r
}

// mod rnd {
//     use core::mem;
//     static mut I: usize = 0;
//     static RND: [u32; 132] = [0; 132]; // unsafe { mem::uninitialized() };
//     pub fn get() -> u32 {
//         unsafe {
//             let r = RND[I];
//             I += 1;
//             r
//         }
//     }
//     pub fn ksymbolic() {
//         unsafe {
//             make_symbolic(
//                 &mut RND as *mut [u32; 132] as *mut c_void,
//                 mem::size_of::<[u32; 132]>(),
//                 "name".as_ptr(),
//             )
//         }
//     }
// }
fn decode(wordarr: &[u32], bytearr: &mut [u8], seed: &mut u32) -> u32 {
    let m: u32;
    let mut r: u32;
    let x: u32;
    let y: u32;

    // x = !codgen(seed);
    x = ksymbol!("x");
    // x = rnd::get();

    if wordarr == [] {
        bytearr[0] = 0;
        r = x;
    } else {
        y = decode(&wordarr[1..], &mut bytearr[1..], seed);
        m = x.wrapping_sub(y).wrapping_sub(wordarr[0]);
        bytearr[0] = (m >> 13) as u8;
        let cg: u32 = ksymbol!("cg");
        // let cg: u32 = codgen(seed);
        // let cg: u32 = rnd::get();
        r = (-(cg as i32)) as u32;
        r = x
            .wrapping_add(y)
            .wrapping_add(m)
            .wrapping_add(r)
            .wrapping_add(5);
    }
    r
}

#[no_mangle]
fn main() {
    //let mut seed = 0x0e0657c1;
    let mut seed = ksymbol!("seed");
    //rnd::ksymbolic();
    let abc: [u32; 4] = ksymbol!("abc");
    decode_org(&abc[..], unsafe { &mut PLAIN }, &mut seed);
}